| Step | Hyp | Ref | Expression | 
						
							| 1 |  | areacirc.1 |  |-  S = { <. x , y >. | ( ( x e. RR /\ y e. RR ) /\ ( ( x ^ 2 ) + ( y ^ 2 ) ) <_ ( R ^ 2 ) ) } | 
						
							| 2 |  | opabssxp |  |-  { <. x , y >. | ( ( x e. RR /\ y e. RR ) /\ ( ( x ^ 2 ) + ( y ^ 2 ) ) <_ ( R ^ 2 ) ) } C_ ( RR X. RR ) | 
						
							| 3 | 1 2 | eqsstri |  |-  S C_ ( RR X. RR ) | 
						
							| 4 | 3 | a1i |  |-  ( ( R e. RR /\ 0 <_ R ) -> S C_ ( RR X. RR ) ) | 
						
							| 5 | 1 | areacirclem5 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( S " { t } ) = if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) | 
						
							| 6 |  | resqcl |  |-  ( R e. RR -> ( R ^ 2 ) e. RR ) | 
						
							| 7 | 6 | 3ad2ant1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( R ^ 2 ) e. RR ) | 
						
							| 8 |  | resqcl |  |-  ( t e. RR -> ( t ^ 2 ) e. RR ) | 
						
							| 9 | 8 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( t ^ 2 ) e. RR ) | 
						
							| 10 | 7 9 | resubcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. RR ) | 
						
							| 11 | 10 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. RR ) | 
						
							| 12 |  | absresq |  |-  ( t e. RR -> ( ( abs ` t ) ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 13 | 12 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 14 | 13 | breq1d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( ( abs ` t ) ^ 2 ) <_ ( R ^ 2 ) <-> ( t ^ 2 ) <_ ( R ^ 2 ) ) ) | 
						
							| 15 |  | recn |  |-  ( t e. RR -> t e. CC ) | 
						
							| 16 | 15 | abscld |  |-  ( t e. RR -> ( abs ` t ) e. RR ) | 
						
							| 17 | 16 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( abs ` t ) e. RR ) | 
						
							| 18 |  | simp1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> R e. RR ) | 
						
							| 19 | 15 | absge0d |  |-  ( t e. RR -> 0 <_ ( abs ` t ) ) | 
						
							| 20 | 19 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> 0 <_ ( abs ` t ) ) | 
						
							| 21 |  | simp2 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> 0 <_ R ) | 
						
							| 22 | 17 18 20 21 | le2sqd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R <-> ( ( abs ` t ) ^ 2 ) <_ ( R ^ 2 ) ) ) | 
						
							| 23 | 7 9 | subge0d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) <-> ( t ^ 2 ) <_ ( R ^ 2 ) ) ) | 
						
							| 24 | 14 22 23 | 3bitr4d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R <-> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 25 | 24 | biimpa |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) | 
						
							| 26 | 11 25 | resqrtcld |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 27 | 26 | renegcld |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 28 |  | iccmbl |  |-  ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR /\ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol ) | 
						
							| 29 | 27 26 28 | syl2anc |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol ) | 
						
							| 30 |  | mblvol |  |-  ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 31 | 29 30 | syl |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 32 | 11 25 | sqrtge0d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> 0 <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 33 | 26 26 32 32 | addge0d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 34 |  | recn |  |-  ( R e. RR -> R e. CC ) | 
						
							| 35 | 34 | sqcld |  |-  ( R e. RR -> ( R ^ 2 ) e. CC ) | 
						
							| 36 | 35 | 3ad2ant1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( R ^ 2 ) e. CC ) | 
						
							| 37 | 15 | sqcld |  |-  ( t e. RR -> ( t ^ 2 ) e. CC ) | 
						
							| 38 | 37 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( t ^ 2 ) e. CC ) | 
						
							| 39 | 36 38 | subcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. CC ) | 
						
							| 40 | 39 | sqrtcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. CC ) | 
						
							| 41 | 40 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. CC ) | 
						
							| 42 | 41 41 | subnegd |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 43 | 42 | breq2d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 44 | 26 27 | subge0d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 45 | 43 44 | bitr3d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 46 | 33 45 | mpbid |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 47 |  | ovolicc |  |-  ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR /\ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR /\ -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) -> ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 48 | 27 26 46 47 | syl3anc |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 49 | 31 48 | eqtrd |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 50 | 26 27 | resubcld |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. RR ) | 
						
							| 51 | 49 50 | eqeltrd |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) e. RR ) | 
						
							| 52 |  | volf |  |-  vol : dom vol --> ( 0 [,] +oo ) | 
						
							| 53 |  | ffn |  |-  ( vol : dom vol --> ( 0 [,] +oo ) -> vol Fn dom vol ) | 
						
							| 54 |  | elpreima |  |-  ( vol Fn dom vol -> ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. ( `' vol " RR ) <-> ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol /\ ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) e. RR ) ) ) | 
						
							| 55 | 52 53 54 | mp2b |  |-  ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. ( `' vol " RR ) <-> ( ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol /\ ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) e. RR ) ) | 
						
							| 56 | 29 51 55 | sylanbrc |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) <_ R ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. ( `' vol " RR ) ) | 
						
							| 57 |  | 0mbl |  |-  (/) e. dom vol | 
						
							| 58 |  | mblvol |  |-  ( (/) e. dom vol -> ( vol ` (/) ) = ( vol* ` (/) ) ) | 
						
							| 59 | 57 58 | ax-mp |  |-  ( vol ` (/) ) = ( vol* ` (/) ) | 
						
							| 60 |  | ovol0 |  |-  ( vol* ` (/) ) = 0 | 
						
							| 61 | 59 60 | eqtri |  |-  ( vol ` (/) ) = 0 | 
						
							| 62 |  | 0re |  |-  0 e. RR | 
						
							| 63 | 61 62 | eqeltri |  |-  ( vol ` (/) ) e. RR | 
						
							| 64 |  | elpreima |  |-  ( vol Fn dom vol -> ( (/) e. ( `' vol " RR ) <-> ( (/) e. dom vol /\ ( vol ` (/) ) e. RR ) ) ) | 
						
							| 65 | 52 53 64 | mp2b |  |-  ( (/) e. ( `' vol " RR ) <-> ( (/) e. dom vol /\ ( vol ` (/) ) e. RR ) ) | 
						
							| 66 | 57 63 65 | mpbir2an |  |-  (/) e. ( `' vol " RR ) | 
						
							| 67 | 66 | a1i |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ -. ( abs ` t ) <_ R ) -> (/) e. ( `' vol " RR ) ) | 
						
							| 68 | 56 67 | ifclda |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) e. ( `' vol " RR ) ) | 
						
							| 69 | 5 68 | eqeltrd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( S " { t } ) e. ( `' vol " RR ) ) | 
						
							| 70 | 69 | 3expa |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. RR ) -> ( S " { t } ) e. ( `' vol " RR ) ) | 
						
							| 71 | 70 | ralrimiva |  |-  ( ( R e. RR /\ 0 <_ R ) -> A. t e. RR ( S " { t } ) e. ( `' vol " RR ) ) | 
						
							| 72 | 5 | fveq2d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( vol ` ( S " { t } ) ) = ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) | 
						
							| 73 | 72 | 3expa |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. RR ) -> ( vol ` ( S " { t } ) ) = ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) | 
						
							| 74 | 73 | mpteq2dva |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR |-> ( vol ` ( S " { t } ) ) ) = ( t e. RR |-> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) ) | 
						
							| 75 |  | renegcl |  |-  ( R e. RR -> -u R e. RR ) | 
						
							| 76 | 75 | adantr |  |-  ( ( R e. RR /\ 0 <_ R ) -> -u R e. RR ) | 
						
							| 77 |  | simpl |  |-  ( ( R e. RR /\ 0 <_ R ) -> R e. RR ) | 
						
							| 78 |  | iccssre |  |-  ( ( -u R e. RR /\ R e. RR ) -> ( -u R [,] R ) C_ RR ) | 
						
							| 79 | 76 77 78 | syl2anc |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( -u R [,] R ) C_ RR ) | 
						
							| 80 |  | rembl |  |-  RR e. dom vol | 
						
							| 81 | 80 | a1i |  |-  ( ( R e. RR /\ 0 <_ R ) -> RR e. dom vol ) | 
						
							| 82 |  | fvexd |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( -u R [,] R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) e. _V ) | 
						
							| 83 |  | eldif |  |-  ( t e. ( RR \ ( -u R [,] R ) ) <-> ( t e. RR /\ -. t e. ( -u R [,] R ) ) ) | 
						
							| 84 |  | 3anass |  |-  ( ( t e. RR /\ -u R <_ t /\ t <_ R ) <-> ( t e. RR /\ ( -u R <_ t /\ t <_ R ) ) ) | 
						
							| 85 | 84 | a1i |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( t e. RR /\ -u R <_ t /\ t <_ R ) <-> ( t e. RR /\ ( -u R <_ t /\ t <_ R ) ) ) ) | 
						
							| 86 | 75 | 3ad2ant1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> -u R e. RR ) | 
						
							| 87 |  | elicc2 |  |-  ( ( -u R e. RR /\ R e. RR ) -> ( t e. ( -u R [,] R ) <-> ( t e. RR /\ -u R <_ t /\ t <_ R ) ) ) | 
						
							| 88 | 86 18 87 | syl2anc |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( t e. ( -u R [,] R ) <-> ( t e. RR /\ -u R <_ t /\ t <_ R ) ) ) | 
						
							| 89 |  | simp3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> t e. RR ) | 
						
							| 90 | 89 18 | absled |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R <-> ( -u R <_ t /\ t <_ R ) ) ) | 
						
							| 91 | 89 | biantrurd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( -u R <_ t /\ t <_ R ) <-> ( t e. RR /\ ( -u R <_ t /\ t <_ R ) ) ) ) | 
						
							| 92 | 90 91 | bitrd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R <-> ( t e. RR /\ ( -u R <_ t /\ t <_ R ) ) ) ) | 
						
							| 93 | 85 88 92 | 3bitr4rd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R <-> t e. ( -u R [,] R ) ) ) | 
						
							| 94 | 93 | biimpd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) <_ R -> t e. ( -u R [,] R ) ) ) | 
						
							| 95 | 94 | con3d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -. t e. ( -u R [,] R ) -> -. ( abs ` t ) <_ R ) ) | 
						
							| 96 | 95 | 3expia |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR -> ( -. t e. ( -u R [,] R ) -> -. ( abs ` t ) <_ R ) ) ) | 
						
							| 97 | 96 | impd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( ( t e. RR /\ -. t e. ( -u R [,] R ) ) -> -. ( abs ` t ) <_ R ) ) | 
						
							| 98 | 83 97 | biimtrid |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( RR \ ( -u R [,] R ) ) -> -. ( abs ` t ) <_ R ) ) | 
						
							| 99 | 98 | imp |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( RR \ ( -u R [,] R ) ) ) -> -. ( abs ` t ) <_ R ) | 
						
							| 100 |  | iffalse |  |-  ( -. ( abs ` t ) <_ R -> if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) = (/) ) | 
						
							| 101 | 100 | fveq2d |  |-  ( -. ( abs ` t ) <_ R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( vol ` (/) ) ) | 
						
							| 102 | 101 61 | eqtrdi |  |-  ( -. ( abs ` t ) <_ R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) | 
						
							| 103 | 99 102 | syl |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( RR \ ( -u R [,] R ) ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) | 
						
							| 104 | 76 77 87 | syl2anc |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) <-> ( t e. RR /\ -u R <_ t /\ t <_ R ) ) ) | 
						
							| 105 | 90 | biimprd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( -u R <_ t /\ t <_ R ) -> ( abs ` t ) <_ R ) ) | 
						
							| 106 | 105 | expd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -u R <_ t -> ( t <_ R -> ( abs ` t ) <_ R ) ) ) | 
						
							| 107 | 106 | 3expia |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR -> ( -u R <_ t -> ( t <_ R -> ( abs ` t ) <_ R ) ) ) ) | 
						
							| 108 | 107 | 3impd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( ( t e. RR /\ -u R <_ t /\ t <_ R ) -> ( abs ` t ) <_ R ) ) | 
						
							| 109 | 104 108 | sylbid |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) -> ( abs ` t ) <_ R ) ) | 
						
							| 110 | 109 | 3impia |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( abs ` t ) <_ R ) | 
						
							| 111 |  | iftrue |  |-  ( ( abs ` t ) <_ R -> if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) = ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 112 | 111 | fveq2d |  |-  ( ( abs ` t ) <_ R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 113 | 110 112 | syl |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 114 | 6 | 3ad2ant1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( R ^ 2 ) e. RR ) | 
						
							| 115 | 75 78 | mpancom |  |-  ( R e. RR -> ( -u R [,] R ) C_ RR ) | 
						
							| 116 | 115 | sselda |  |-  ( ( R e. RR /\ t e. ( -u R [,] R ) ) -> t e. RR ) | 
						
							| 117 | 116 | 3adant2 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> t e. RR ) | 
						
							| 118 | 117 | resqcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( t ^ 2 ) e. RR ) | 
						
							| 119 | 114 118 | resubcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. RR ) | 
						
							| 120 | 75 87 | mpancom |  |-  ( R e. RR -> ( t e. ( -u R [,] R ) <-> ( t e. RR /\ -u R <_ t /\ t <_ R ) ) ) | 
						
							| 121 | 120 | adantr |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) <-> ( t e. RR /\ -u R <_ t /\ t <_ R ) ) ) | 
						
							| 122 | 22 90 14 | 3bitr3rd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( t ^ 2 ) <_ ( R ^ 2 ) <-> ( -u R <_ t /\ t <_ R ) ) ) | 
						
							| 123 | 23 122 | bitrd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) <-> ( -u R <_ t /\ t <_ R ) ) ) | 
						
							| 124 | 123 | biimprd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( -u R <_ t /\ t <_ R ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 125 | 124 | expd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -u R <_ t -> ( t <_ R -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 126 | 125 | 3expia |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR -> ( -u R <_ t -> ( t <_ R -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 127 | 126 | 3impd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( ( t e. RR /\ -u R <_ t /\ t <_ R ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 128 | 121 127 | sylbid |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 129 | 128 | 3impia |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) | 
						
							| 130 | 119 129 | resqrtcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 131 | 130 | renegcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 132 | 131 130 28 | syl2anc |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol ) | 
						
							| 133 | 132 30 | syl |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 134 | 119 | recnd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. CC ) | 
						
							| 135 | 134 | sqrtcld |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. CC ) | 
						
							| 136 | 135 135 | subnegd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 137 | 119 129 | sqrtge0d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> 0 <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 138 | 130 130 137 137 | addge0d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 139 | 136 | breq2d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 140 | 130 131 | subge0d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 141 | 139 140 | bitr3d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 142 | 138 141 | mpbid |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 143 | 131 130 142 47 | syl3anc |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 144 | 135 | 2timesd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 145 | 136 143 144 | 3eqtr4d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 146 | 113 133 145 | 3eqtrd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. ( -u R [,] R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 147 | 146 | 3expa |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( -u R [,] R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 148 | 147 | mpteq2dva |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) |-> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) = ( t e. ( -u R [,] R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 149 |  | areacirclem3 |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) e. L^1 ) | 
						
							| 150 | 148 149 | eqeltrd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( -u R [,] R ) |-> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) e. L^1 ) | 
						
							| 151 | 79 81 82 103 150 | iblss2 |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR |-> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) e. L^1 ) | 
						
							| 152 | 74 151 | eqeltrd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR |-> ( vol ` ( S " { t } ) ) ) e. L^1 ) | 
						
							| 153 |  | dmarea |  |-  ( S e. dom area <-> ( S C_ ( RR X. RR ) /\ A. t e. RR ( S " { t } ) e. ( `' vol " RR ) /\ ( t e. RR |-> ( vol ` ( S " { t } ) ) ) e. L^1 ) ) | 
						
							| 154 | 4 71 152 153 | syl3anbrc |  |-  ( ( R e. RR /\ 0 <_ R ) -> S e. dom area ) | 
						
							| 155 |  | areaval |  |-  ( S e. dom area -> ( area ` S ) = S. RR ( vol ` ( S " { t } ) ) _d t ) | 
						
							| 156 | 154 155 | syl |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( area ` S ) = S. RR ( vol ` ( S " { t } ) ) _d t ) | 
						
							| 157 |  | elioore |  |-  ( t e. ( -u R (,) R ) -> t e. RR ) | 
						
							| 158 | 5 | 3expa |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. RR ) -> ( S " { t } ) = if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) | 
						
							| 159 | 157 158 | sylan2 |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( -u R (,) R ) ) -> ( S " { t } ) = if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) | 
						
							| 160 | 159 | fveq2d |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( -u R (,) R ) ) -> ( vol ` ( S " { t } ) ) = ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) | 
						
							| 161 | 160 | itgeq2dv |  |-  ( ( R e. RR /\ 0 <_ R ) -> S. ( -u R (,) R ) ( vol ` ( S " { t } ) ) _d t = S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t ) | 
						
							| 162 |  | ioossre |  |-  ( -u R (,) R ) C_ RR | 
						
							| 163 | 162 | a1i |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( -u R (,) R ) C_ RR ) | 
						
							| 164 |  | eldif |  |-  ( t e. ( RR \ ( -u R (,) R ) ) <-> ( t e. RR /\ -. t e. ( -u R (,) R ) ) ) | 
						
							| 165 | 75 | rexrd |  |-  ( R e. RR -> -u R e. RR* ) | 
						
							| 166 |  | rexr |  |-  ( R e. RR -> R e. RR* ) | 
						
							| 167 |  | elioo2 |  |-  ( ( -u R e. RR* /\ R e. RR* ) -> ( t e. ( -u R (,) R ) <-> ( t e. RR /\ -u R < t /\ t < R ) ) ) | 
						
							| 168 | 165 166 167 | syl2anc |  |-  ( R e. RR -> ( t e. ( -u R (,) R ) <-> ( t e. RR /\ -u R < t /\ t < R ) ) ) | 
						
							| 169 | 168 | 3ad2ant1 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( t e. ( -u R (,) R ) <-> ( t e. RR /\ -u R < t /\ t < R ) ) ) | 
						
							| 170 | 89 | biantrurd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( -u R < t /\ t < R ) <-> ( t e. RR /\ ( -u R < t /\ t < R ) ) ) ) | 
						
							| 171 | 89 18 | absltd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) < R <-> ( -u R < t /\ t < R ) ) ) | 
						
							| 172 |  | 3anass |  |-  ( ( t e. RR /\ -u R < t /\ t < R ) <-> ( t e. RR /\ ( -u R < t /\ t < R ) ) ) | 
						
							| 173 | 172 | a1i |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( t e. RR /\ -u R < t /\ t < R ) <-> ( t e. RR /\ ( -u R < t /\ t < R ) ) ) ) | 
						
							| 174 | 170 171 173 | 3bitr4rd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( t e. RR /\ -u R < t /\ t < R ) <-> ( abs ` t ) < R ) ) | 
						
							| 175 | 169 174 | bitrd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( t e. ( -u R (,) R ) <-> ( abs ` t ) < R ) ) | 
						
							| 176 | 175 | notbid |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -. t e. ( -u R (,) R ) <-> -. ( abs ` t ) < R ) ) | 
						
							| 177 | 18 17 | lenltd |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( R <_ ( abs ` t ) <-> -. ( abs ` t ) < R ) ) | 
						
							| 178 | 176 177 | bitr4d |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -. t e. ( -u R (,) R ) <-> R <_ ( abs ` t ) ) ) | 
						
							| 179 | 5 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( S " { t } ) = if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) | 
						
							| 180 | 179 | fveq2d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( vol ` ( S " { t } ) ) = ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) ) | 
						
							| 181 | 17 | anim1i |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( ( abs ` t ) e. RR /\ ( abs ` t ) = R ) ) | 
						
							| 182 |  | eqle |  |-  ( ( ( abs ` t ) e. RR /\ ( abs ` t ) = R ) -> ( abs ` t ) <_ R ) | 
						
							| 183 | 181 182 112 | 3syl |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 184 |  | oveq1 |  |-  ( ( abs ` t ) = R -> ( ( abs ` t ) ^ 2 ) = ( R ^ 2 ) ) | 
						
							| 185 | 184 | adantl |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( ( abs ` t ) ^ 2 ) = ( R ^ 2 ) ) | 
						
							| 186 | 13 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( ( abs ` t ) ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 187 | 185 186 | eqtr3d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( R ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 188 |  | fvoveq1 |  |-  ( ( R ^ 2 ) = ( t ^ 2 ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) = ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 189 | 188 | negeqd |  |-  ( ( R ^ 2 ) = ( t ^ 2 ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) = -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 190 | 189 188 | oveq12d |  |-  ( ( R ^ 2 ) = ( t ^ 2 ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 191 | 8 | recnd |  |-  ( t e. RR -> ( t ^ 2 ) e. CC ) | 
						
							| 192 | 191 | subidd |  |-  ( t e. RR -> ( ( t ^ 2 ) - ( t ^ 2 ) ) = 0 ) | 
						
							| 193 | 192 | fveq2d |  |-  ( t e. RR -> ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) = ( sqrt ` 0 ) ) | 
						
							| 194 | 193 | negeqd |  |-  ( t e. RR -> -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) = -u ( sqrt ` 0 ) ) | 
						
							| 195 |  | sqrt0 |  |-  ( sqrt ` 0 ) = 0 | 
						
							| 196 | 195 | negeqi |  |-  -u ( sqrt ` 0 ) = -u 0 | 
						
							| 197 |  | neg0 |  |-  -u 0 = 0 | 
						
							| 198 | 196 197 | eqtri |  |-  -u ( sqrt ` 0 ) = 0 | 
						
							| 199 | 194 198 | eqtrdi |  |-  ( t e. RR -> -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) = 0 ) | 
						
							| 200 | 193 195 | eqtrdi |  |-  ( t e. RR -> ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) = 0 ) | 
						
							| 201 | 199 200 | oveq12d |  |-  ( t e. RR -> ( -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) ) = ( 0 [,] 0 ) ) | 
						
							| 202 | 201 | 3ad2ant3 |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -u ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( t ^ 2 ) - ( t ^ 2 ) ) ) ) = ( 0 [,] 0 ) ) | 
						
							| 203 | 190 202 | sylan9eqr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( R ^ 2 ) = ( t ^ 2 ) ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( 0 [,] 0 ) ) | 
						
							| 204 | 203 | fveq2d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( R ^ 2 ) = ( t ^ 2 ) ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( vol ` ( 0 [,] 0 ) ) ) | 
						
							| 205 |  | iccmbl |  |-  ( ( 0 e. RR /\ 0 e. RR ) -> ( 0 [,] 0 ) e. dom vol ) | 
						
							| 206 | 62 62 205 | mp2an |  |-  ( 0 [,] 0 ) e. dom vol | 
						
							| 207 |  | mblvol |  |-  ( ( 0 [,] 0 ) e. dom vol -> ( vol ` ( 0 [,] 0 ) ) = ( vol* ` ( 0 [,] 0 ) ) ) | 
						
							| 208 | 206 207 | ax-mp |  |-  ( vol ` ( 0 [,] 0 ) ) = ( vol* ` ( 0 [,] 0 ) ) | 
						
							| 209 |  | 0xr |  |-  0 e. RR* | 
						
							| 210 |  | iccid |  |-  ( 0 e. RR* -> ( 0 [,] 0 ) = { 0 } ) | 
						
							| 211 | 210 | fveq2d |  |-  ( 0 e. RR* -> ( vol* ` ( 0 [,] 0 ) ) = ( vol* ` { 0 } ) ) | 
						
							| 212 | 209 211 | ax-mp |  |-  ( vol* ` ( 0 [,] 0 ) ) = ( vol* ` { 0 } ) | 
						
							| 213 |  | ovolsn |  |-  ( 0 e. RR -> ( vol* ` { 0 } ) = 0 ) | 
						
							| 214 | 62 213 | ax-mp |  |-  ( vol* ` { 0 } ) = 0 | 
						
							| 215 | 212 214 | eqtri |  |-  ( vol* ` ( 0 [,] 0 ) ) = 0 | 
						
							| 216 | 208 215 | eqtri |  |-  ( vol ` ( 0 [,] 0 ) ) = 0 | 
						
							| 217 | 204 216 | eqtrdi |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( R ^ 2 ) = ( t ^ 2 ) ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = 0 ) | 
						
							| 218 | 187 217 | syldan |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = 0 ) | 
						
							| 219 | 183 218 | eqtrd |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ ( abs ` t ) = R ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) | 
						
							| 220 | 219 | ex |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( ( abs ` t ) = R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) ) | 
						
							| 221 | 220 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( ( abs ` t ) = R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) ) | 
						
							| 222 | 18 17 | ltnled |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( R < ( abs ` t ) <-> -. ( abs ` t ) <_ R ) ) | 
						
							| 223 | 222 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( R < ( abs ` t ) <-> -. ( abs ` t ) <_ R ) ) | 
						
							| 224 |  | simpl1 |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> R e. RR ) | 
						
							| 225 | 17 | adantr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( abs ` t ) e. RR ) | 
						
							| 226 |  | simpr |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> R <_ ( abs ` t ) ) | 
						
							| 227 | 224 225 226 | leltned |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( R < ( abs ` t ) <-> ( abs ` t ) =/= R ) ) | 
						
							| 228 | 223 227 | bitr3d |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( -. ( abs ` t ) <_ R <-> ( abs ` t ) =/= R ) ) | 
						
							| 229 | 228 102 | biimtrrdi |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( ( abs ` t ) =/= R -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) ) | 
						
							| 230 | 221 229 | pm2.61dne |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = 0 ) | 
						
							| 231 | 180 230 | eqtrd |  |-  ( ( ( R e. RR /\ 0 <_ R /\ t e. RR ) /\ R <_ ( abs ` t ) ) -> ( vol ` ( S " { t } ) ) = 0 ) | 
						
							| 232 | 231 | ex |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( R <_ ( abs ` t ) -> ( vol ` ( S " { t } ) ) = 0 ) ) | 
						
							| 233 | 178 232 | sylbid |  |-  ( ( R e. RR /\ 0 <_ R /\ t e. RR ) -> ( -. t e. ( -u R (,) R ) -> ( vol ` ( S " { t } ) ) = 0 ) ) | 
						
							| 234 | 233 | 3expia |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. RR -> ( -. t e. ( -u R (,) R ) -> ( vol ` ( S " { t } ) ) = 0 ) ) ) | 
						
							| 235 | 234 | impd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( ( t e. RR /\ -. t e. ( -u R (,) R ) ) -> ( vol ` ( S " { t } ) ) = 0 ) ) | 
						
							| 236 | 164 235 | biimtrid |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( t e. ( RR \ ( -u R (,) R ) ) -> ( vol ` ( S " { t } ) ) = 0 ) ) | 
						
							| 237 | 236 | imp |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ t e. ( RR \ ( -u R (,) R ) ) ) -> ( vol ` ( S " { t } ) ) = 0 ) | 
						
							| 238 | 163 237 | itgss |  |-  ( ( R e. RR /\ 0 <_ R ) -> S. ( -u R (,) R ) ( vol ` ( S " { t } ) ) _d t = S. RR ( vol ` ( S " { t } ) ) _d t ) | 
						
							| 239 |  | negeq |  |-  ( R = 0 -> -u R = -u 0 ) | 
						
							| 240 | 239 197 | eqtrdi |  |-  ( R = 0 -> -u R = 0 ) | 
						
							| 241 |  | id |  |-  ( R = 0 -> R = 0 ) | 
						
							| 242 | 240 241 | oveq12d |  |-  ( R = 0 -> ( -u R (,) R ) = ( 0 (,) 0 ) ) | 
						
							| 243 |  | iooid |  |-  ( 0 (,) 0 ) = (/) | 
						
							| 244 | 242 243 | eqtrdi |  |-  ( R = 0 -> ( -u R (,) R ) = (/) ) | 
						
							| 245 | 244 | adantl |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R = 0 ) -> ( -u R (,) R ) = (/) ) | 
						
							| 246 |  | itgeq1 |  |-  ( ( -u R (,) R ) = (/) -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = S. (/) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t ) | 
						
							| 247 | 245 246 | syl |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R = 0 ) -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = S. (/) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t ) | 
						
							| 248 |  | itg0 |  |-  S. (/) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = 0 | 
						
							| 249 |  | sq0 |  |-  ( 0 ^ 2 ) = 0 | 
						
							| 250 | 249 | oveq2i |  |-  ( _pi x. ( 0 ^ 2 ) ) = ( _pi x. 0 ) | 
						
							| 251 |  | picn |  |-  _pi e. CC | 
						
							| 252 | 251 | mul01i |  |-  ( _pi x. 0 ) = 0 | 
						
							| 253 | 250 252 | eqtr2i |  |-  0 = ( _pi x. ( 0 ^ 2 ) ) | 
						
							| 254 |  | oveq1 |  |-  ( R = 0 -> ( R ^ 2 ) = ( 0 ^ 2 ) ) | 
						
							| 255 | 254 | oveq2d |  |-  ( R = 0 -> ( _pi x. ( R ^ 2 ) ) = ( _pi x. ( 0 ^ 2 ) ) ) | 
						
							| 256 | 253 255 | eqtr4id |  |-  ( R = 0 -> 0 = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 257 | 256 | adantl |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R = 0 ) -> 0 = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 258 | 248 257 | eqtrid |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R = 0 ) -> S. (/) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 259 | 247 258 | eqtrd |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R = 0 ) -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 260 |  | simp1 |  |-  ( ( R e. RR /\ 0 <_ R /\ R =/= 0 ) -> R e. RR ) | 
						
							| 261 |  | 0red |  |-  ( ( R e. RR /\ 0 <_ R ) -> 0 e. RR ) | 
						
							| 262 |  | simpr |  |-  ( ( R e. RR /\ 0 <_ R ) -> 0 <_ R ) | 
						
							| 263 | 261 77 262 | leltned |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( 0 < R <-> R =/= 0 ) ) | 
						
							| 264 | 263 | biimp3ar |  |-  ( ( R e. RR /\ 0 <_ R /\ R =/= 0 ) -> 0 < R ) | 
						
							| 265 | 260 264 | elrpd |  |-  ( ( R e. RR /\ 0 <_ R /\ R =/= 0 ) -> R e. RR+ ) | 
						
							| 266 | 265 | 3expa |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R =/= 0 ) -> R e. RR+ ) | 
						
							| 267 | 157 16 | syl |  |-  ( t e. ( -u R (,) R ) -> ( abs ` t ) e. RR ) | 
						
							| 268 | 267 | adantl |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( abs ` t ) e. RR ) | 
						
							| 269 |  | rpre |  |-  ( R e. RR+ -> R e. RR ) | 
						
							| 270 | 269 | adantr |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> R e. RR ) | 
						
							| 271 | 269 | renegcld |  |-  ( R e. RR+ -> -u R e. RR ) | 
						
							| 272 | 271 | rexrd |  |-  ( R e. RR+ -> -u R e. RR* ) | 
						
							| 273 |  | rpxr |  |-  ( R e. RR+ -> R e. RR* ) | 
						
							| 274 | 272 273 167 | syl2anc |  |-  ( R e. RR+ -> ( t e. ( -u R (,) R ) <-> ( t e. RR /\ -u R < t /\ t < R ) ) ) | 
						
							| 275 |  | simpr |  |-  ( ( R e. RR+ /\ t e. RR ) -> t e. RR ) | 
						
							| 276 | 269 | adantr |  |-  ( ( R e. RR+ /\ t e. RR ) -> R e. RR ) | 
						
							| 277 | 275 276 | absltd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( abs ` t ) < R <-> ( -u R < t /\ t < R ) ) ) | 
						
							| 278 | 277 | biimprd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( -u R < t /\ t < R ) -> ( abs ` t ) < R ) ) | 
						
							| 279 | 278 | exp4b |  |-  ( R e. RR+ -> ( t e. RR -> ( -u R < t -> ( t < R -> ( abs ` t ) < R ) ) ) ) | 
						
							| 280 | 279 | 3impd |  |-  ( R e. RR+ -> ( ( t e. RR /\ -u R < t /\ t < R ) -> ( abs ` t ) < R ) ) | 
						
							| 281 | 274 280 | sylbid |  |-  ( R e. RR+ -> ( t e. ( -u R (,) R ) -> ( abs ` t ) < R ) ) | 
						
							| 282 | 281 | imp |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( abs ` t ) < R ) | 
						
							| 283 | 268 270 282 | ltled |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( abs ` t ) <_ R ) | 
						
							| 284 | 283 112 | syl |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 285 | 269 | resqcld |  |-  ( R e. RR+ -> ( R ^ 2 ) e. RR ) | 
						
							| 286 | 285 | recnd |  |-  ( R e. RR+ -> ( R ^ 2 ) e. CC ) | 
						
							| 287 | 286 | adantr |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( R ^ 2 ) e. CC ) | 
						
							| 288 | 191 | adantl |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( t ^ 2 ) e. CC ) | 
						
							| 289 | 287 288 | subcld |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. CC ) | 
						
							| 290 | 289 | sqrtcld |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. CC ) | 
						
							| 291 | 290 290 | subnegd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 292 | 157 291 | sylan2 |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 293 | 285 | adantr |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( R ^ 2 ) e. RR ) | 
						
							| 294 | 8 | adantl |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( t ^ 2 ) e. RR ) | 
						
							| 295 | 293 294 | resubcld |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. RR ) | 
						
							| 296 | 157 295 | sylan2 |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( ( R ^ 2 ) - ( t ^ 2 ) ) e. RR ) | 
						
							| 297 |  | 0red |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> 0 e. RR ) | 
						
							| 298 | 16 | adantl |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( abs ` t ) e. RR ) | 
						
							| 299 | 19 | adantl |  |-  ( ( R e. RR+ /\ t e. RR ) -> 0 <_ ( abs ` t ) ) | 
						
							| 300 |  | rpge0 |  |-  ( R e. RR+ -> 0 <_ R ) | 
						
							| 301 | 300 | adantr |  |-  ( ( R e. RR+ /\ t e. RR ) -> 0 <_ R ) | 
						
							| 302 | 298 276 299 301 | lt2sqd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( abs ` t ) < R <-> ( ( abs ` t ) ^ 2 ) < ( R ^ 2 ) ) ) | 
						
							| 303 | 12 | adantl |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( abs ` t ) ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 304 | 303 | breq1d |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( ( abs ` t ) ^ 2 ) < ( R ^ 2 ) <-> ( t ^ 2 ) < ( R ^ 2 ) ) ) | 
						
							| 305 | 302 277 304 | 3bitr3rd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( t ^ 2 ) < ( R ^ 2 ) <-> ( -u R < t /\ t < R ) ) ) | 
						
							| 306 | 294 293 | posdifd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( t ^ 2 ) < ( R ^ 2 ) <-> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 307 | 305 306 | bitr3d |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( -u R < t /\ t < R ) <-> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 308 | 307 | biimpd |  |-  ( ( R e. RR+ /\ t e. RR ) -> ( ( -u R < t /\ t < R ) -> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 309 | 308 | exp4b |  |-  ( R e. RR+ -> ( t e. RR -> ( -u R < t -> ( t < R -> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 310 | 309 | 3impd |  |-  ( R e. RR+ -> ( ( t e. RR /\ -u R < t /\ t < R ) -> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 311 | 274 310 | sylbid |  |-  ( R e. RR+ -> ( t e. ( -u R (,) R ) -> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 312 | 311 | imp |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> 0 < ( ( R ^ 2 ) - ( t ^ 2 ) ) ) | 
						
							| 313 | 297 296 312 | ltled |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> 0 <_ ( ( R ^ 2 ) - ( t ^ 2 ) ) ) | 
						
							| 314 | 296 313 | resqrtcld |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 315 | 314 | renegcld |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. RR ) | 
						
							| 316 | 315 314 28 | syl2anc |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. dom vol ) | 
						
							| 317 | 316 30 | syl |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 318 | 296 313 | sqrtge0d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> 0 <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 319 | 314 314 318 318 | addge0d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 320 | 292 | breq2d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 321 | 314 315 | subge0d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 322 | 320 321 | bitr3d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( 0 <_ ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) <-> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 323 | 319 322 | mpbid |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) <_ ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 324 | 315 314 323 47 | syl3anc |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( vol* ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 325 | 317 324 | eqtrd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) - -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 326 |  | ax-resscn |  |-  RR C_ CC | 
						
							| 327 | 326 | a1i |  |-  ( R e. RR+ -> RR C_ CC ) | 
						
							| 328 | 271 269 78 | syl2anc |  |-  ( R e. RR+ -> ( -u R [,] R ) C_ RR ) | 
						
							| 329 |  | rpcn |  |-  ( R e. RR+ -> R e. CC ) | 
						
							| 330 | 329 | sqcld |  |-  ( R e. RR+ -> ( R ^ 2 ) e. CC ) | 
						
							| 331 | 330 | adantr |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( R ^ 2 ) e. CC ) | 
						
							| 332 | 328 | sselda |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> u e. RR ) | 
						
							| 333 | 332 | recnd |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> u e. CC ) | 
						
							| 334 | 329 | adantr |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> R e. CC ) | 
						
							| 335 |  | rpne0 |  |-  ( R e. RR+ -> R =/= 0 ) | 
						
							| 336 | 335 | adantr |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> R =/= 0 ) | 
						
							| 337 | 333 334 336 | divcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( u / R ) e. CC ) | 
						
							| 338 |  | asincl |  |-  ( ( u / R ) e. CC -> ( arcsin ` ( u / R ) ) e. CC ) | 
						
							| 339 | 337 338 | syl |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( arcsin ` ( u / R ) ) e. CC ) | 
						
							| 340 |  | 1cnd |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> 1 e. CC ) | 
						
							| 341 | 337 | sqcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( ( u / R ) ^ 2 ) e. CC ) | 
						
							| 342 | 340 341 | subcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( 1 - ( ( u / R ) ^ 2 ) ) e. CC ) | 
						
							| 343 | 342 | sqrtcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) e. CC ) | 
						
							| 344 | 337 343 | mulcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) e. CC ) | 
						
							| 345 | 339 344 | addcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) e. CC ) | 
						
							| 346 | 331 345 | mulcld |  |-  ( ( R e. RR+ /\ u e. ( -u R [,] R ) ) -> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) e. CC ) | 
						
							| 347 |  | tgioo4 |  |-  ( topGen ` ran (,) ) = ( ( TopOpen ` CCfld ) |`t RR ) | 
						
							| 348 |  | eqid |  |-  ( TopOpen ` CCfld ) = ( TopOpen ` CCfld ) | 
						
							| 349 |  | iccntr |  |-  ( ( -u R e. RR /\ R e. RR ) -> ( ( int ` ( topGen ` ran (,) ) ) ` ( -u R [,] R ) ) = ( -u R (,) R ) ) | 
						
							| 350 | 271 269 349 | syl2anc |  |-  ( R e. RR+ -> ( ( int ` ( topGen ` ran (,) ) ) ` ( -u R [,] R ) ) = ( -u R (,) R ) ) | 
						
							| 351 | 327 328 346 347 348 350 | dvmptntr |  |-  ( R e. RR+ -> ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) = ( RR _D ( u e. ( -u R (,) R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ) | 
						
							| 352 |  | areacirclem1 |  |-  ( R e. RR+ -> ( RR _D ( u e. ( -u R (,) R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) = ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) ) | 
						
							| 353 | 351 352 | eqtrd |  |-  ( R e. RR+ -> ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) = ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) ) | 
						
							| 354 | 353 | adantr |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) = ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) ) | 
						
							| 355 |  | oveq1 |  |-  ( u = t -> ( u ^ 2 ) = ( t ^ 2 ) ) | 
						
							| 356 | 355 | oveq2d |  |-  ( u = t -> ( ( R ^ 2 ) - ( u ^ 2 ) ) = ( ( R ^ 2 ) - ( t ^ 2 ) ) ) | 
						
							| 357 | 356 | fveq2d |  |-  ( u = t -> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) = ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) | 
						
							| 358 | 357 | oveq2d |  |-  ( u = t -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 359 | 358 | adantl |  |-  ( ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) /\ u = t ) -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 360 |  | simpr |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> t e. ( -u R (,) R ) ) | 
						
							| 361 |  | ovexd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) e. _V ) | 
						
							| 362 | 354 359 360 361 | fvmptd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) = ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 363 | 157 290 | sylan2 |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) e. CC ) | 
						
							| 364 | 363 | 2timesd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 365 | 362 364 | eqtrd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) = ( ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) + ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) | 
						
							| 366 | 292 325 365 | 3eqtr4rd |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) = ( vol ` ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) ) ) | 
						
							| 367 | 284 366 | eqtr4d |  |-  ( ( R e. RR+ /\ t e. ( -u R (,) R ) ) -> ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) = ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) ) | 
						
							| 368 | 367 | itgeq2dv |  |-  ( R e. RR+ -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = S. ( -u R (,) R ) ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) _d t ) | 
						
							| 369 | 269 269 300 300 | addge0d |  |-  ( R e. RR+ -> 0 <_ ( R + R ) ) | 
						
							| 370 | 329 329 | subnegd |  |-  ( R e. RR+ -> ( R - -u R ) = ( R + R ) ) | 
						
							| 371 | 370 | breq2d |  |-  ( R e. RR+ -> ( 0 <_ ( R - -u R ) <-> 0 <_ ( R + R ) ) ) | 
						
							| 372 | 269 271 | subge0d |  |-  ( R e. RR+ -> ( 0 <_ ( R - -u R ) <-> -u R <_ R ) ) | 
						
							| 373 | 371 372 | bitr3d |  |-  ( R e. RR+ -> ( 0 <_ ( R + R ) <-> -u R <_ R ) ) | 
						
							| 374 | 369 373 | mpbid |  |-  ( R e. RR+ -> -u R <_ R ) | 
						
							| 375 |  | 2cn |  |-  2 e. CC | 
						
							| 376 | 162 326 | sstri |  |-  ( -u R (,) R ) C_ CC | 
						
							| 377 |  | ssid |  |-  CC C_ CC | 
						
							| 378 | 375 376 377 | 3pm3.2i |  |-  ( 2 e. CC /\ ( -u R (,) R ) C_ CC /\ CC C_ CC ) | 
						
							| 379 |  | cncfmptc |  |-  ( ( 2 e. CC /\ ( -u R (,) R ) C_ CC /\ CC C_ CC ) -> ( u e. ( -u R (,) R ) |-> 2 ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 380 | 378 379 | mp1i |  |-  ( R e. RR+ -> ( u e. ( -u R (,) R ) |-> 2 ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 381 |  | ioossicc |  |-  ( -u R (,) R ) C_ ( -u R [,] R ) | 
						
							| 382 |  | resmpt |  |-  ( ( -u R (,) R ) C_ ( -u R [,] R ) -> ( ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) |` ( -u R (,) R ) ) = ( u e. ( -u R (,) R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) | 
						
							| 383 | 381 382 | ax-mp |  |-  ( ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) |` ( -u R (,) R ) ) = ( u e. ( -u R (,) R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) | 
						
							| 384 |  | areacirclem2 |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) e. ( ( -u R [,] R ) -cn-> CC ) ) | 
						
							| 385 | 269 300 384 | syl2anc |  |-  ( R e. RR+ -> ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) e. ( ( -u R [,] R ) -cn-> CC ) ) | 
						
							| 386 |  | rescncf |  |-  ( ( -u R (,) R ) C_ ( -u R [,] R ) -> ( ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) e. ( ( -u R [,] R ) -cn-> CC ) -> ( ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) |` ( -u R (,) R ) ) e. ( ( -u R (,) R ) -cn-> CC ) ) ) | 
						
							| 387 | 381 385 386 | mpsyl |  |-  ( R e. RR+ -> ( ( u e. ( -u R [,] R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) |` ( -u R (,) R ) ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 388 | 383 387 | eqeltrrid |  |-  ( R e. RR+ -> ( u e. ( -u R (,) R ) |-> ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 389 | 380 388 | mulcncf |  |-  ( R e. RR+ -> ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 390 | 353 389 | eqeltrd |  |-  ( R e. RR+ -> ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) e. ( ( -u R (,) R ) -cn-> CC ) ) | 
						
							| 391 | 381 | a1i |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( -u R (,) R ) C_ ( -u R [,] R ) ) | 
						
							| 392 |  | ioombl |  |-  ( -u R (,) R ) e. dom vol | 
						
							| 393 | 392 | a1i |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( -u R (,) R ) e. dom vol ) | 
						
							| 394 |  | ovexd |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ u e. ( -u R [,] R ) ) -> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) e. _V ) | 
						
							| 395 |  | areacirclem3 |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( u e. ( -u R [,] R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) e. L^1 ) | 
						
							| 396 | 391 393 394 395 | iblss |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) e. L^1 ) | 
						
							| 397 | 269 300 396 | syl2anc |  |-  ( R e. RR+ -> ( u e. ( -u R (,) R ) |-> ( 2 x. ( sqrt ` ( ( R ^ 2 ) - ( u ^ 2 ) ) ) ) ) e. L^1 ) | 
						
							| 398 | 353 397 | eqeltrd |  |-  ( R e. RR+ -> ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) e. L^1 ) | 
						
							| 399 |  | areacirclem4 |  |-  ( R e. RR+ -> ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) e. ( ( -u R [,] R ) -cn-> CC ) ) | 
						
							| 400 | 271 269 374 390 398 399 | ftc2nc |  |-  ( R e. RR+ -> S. ( -u R (,) R ) ( ( RR _D ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) ` t ) _d t = ( ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` R ) - ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` -u R ) ) ) | 
						
							| 401 |  | eqidd |  |-  ( R e. RR+ -> ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) = ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ) | 
						
							| 402 |  | fvoveq1 |  |-  ( u = R -> ( arcsin ` ( u / R ) ) = ( arcsin ` ( R / R ) ) ) | 
						
							| 403 |  | oveq1 |  |-  ( u = R -> ( u / R ) = ( R / R ) ) | 
						
							| 404 | 403 | oveq1d |  |-  ( u = R -> ( ( u / R ) ^ 2 ) = ( ( R / R ) ^ 2 ) ) | 
						
							| 405 | 404 | oveq2d |  |-  ( u = R -> ( 1 - ( ( u / R ) ^ 2 ) ) = ( 1 - ( ( R / R ) ^ 2 ) ) ) | 
						
							| 406 | 405 | fveq2d |  |-  ( u = R -> ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) = ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) | 
						
							| 407 | 403 406 | oveq12d |  |-  ( u = R -> ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) = ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) | 
						
							| 408 | 402 407 | oveq12d |  |-  ( u = R -> ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) = ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) | 
						
							| 409 | 408 | oveq2d |  |-  ( u = R -> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) = ( ( R ^ 2 ) x. ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 410 | 409 | adantl |  |-  ( ( R e. RR+ /\ u = R ) -> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) = ( ( R ^ 2 ) x. ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 411 |  | ubicc2 |  |-  ( ( -u R e. RR* /\ R e. RR* /\ -u R <_ R ) -> R e. ( -u R [,] R ) ) | 
						
							| 412 | 272 273 374 411 | syl3anc |  |-  ( R e. RR+ -> R e. ( -u R [,] R ) ) | 
						
							| 413 |  | ovexd |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) e. _V ) | 
						
							| 414 | 401 410 412 413 | fvmptd |  |-  ( R e. RR+ -> ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` R ) = ( ( R ^ 2 ) x. ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 415 | 329 335 | dividd |  |-  ( R e. RR+ -> ( R / R ) = 1 ) | 
						
							| 416 | 415 | fveq2d |  |-  ( R e. RR+ -> ( arcsin ` ( R / R ) ) = ( arcsin ` 1 ) ) | 
						
							| 417 |  | asin1 |  |-  ( arcsin ` 1 ) = ( _pi / 2 ) | 
						
							| 418 | 416 417 | eqtrdi |  |-  ( R e. RR+ -> ( arcsin ` ( R / R ) ) = ( _pi / 2 ) ) | 
						
							| 419 | 415 | oveq1d |  |-  ( R e. RR+ -> ( ( R / R ) ^ 2 ) = ( 1 ^ 2 ) ) | 
						
							| 420 |  | sq1 |  |-  ( 1 ^ 2 ) = 1 | 
						
							| 421 | 419 420 | eqtrdi |  |-  ( R e. RR+ -> ( ( R / R ) ^ 2 ) = 1 ) | 
						
							| 422 | 421 | oveq2d |  |-  ( R e. RR+ -> ( 1 - ( ( R / R ) ^ 2 ) ) = ( 1 - 1 ) ) | 
						
							| 423 |  | 1cnd |  |-  ( R e. RR+ -> 1 e. CC ) | 
						
							| 424 | 423 | subidd |  |-  ( R e. RR+ -> ( 1 - 1 ) = 0 ) | 
						
							| 425 | 422 424 | eqtrd |  |-  ( R e. RR+ -> ( 1 - ( ( R / R ) ^ 2 ) ) = 0 ) | 
						
							| 426 | 425 | fveq2d |  |-  ( R e. RR+ -> ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) = ( sqrt ` 0 ) ) | 
						
							| 427 | 426 195 | eqtrdi |  |-  ( R e. RR+ -> ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) = 0 ) | 
						
							| 428 | 427 | oveq2d |  |-  ( R e. RR+ -> ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) = ( ( R / R ) x. 0 ) ) | 
						
							| 429 | 329 329 335 | divcld |  |-  ( R e. RR+ -> ( R / R ) e. CC ) | 
						
							| 430 | 429 | mul01d |  |-  ( R e. RR+ -> ( ( R / R ) x. 0 ) = 0 ) | 
						
							| 431 | 428 430 | eqtrd |  |-  ( R e. RR+ -> ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) = 0 ) | 
						
							| 432 | 418 431 | oveq12d |  |-  ( R e. RR+ -> ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) = ( ( _pi / 2 ) + 0 ) ) | 
						
							| 433 |  | 2ne0 |  |-  2 =/= 0 | 
						
							| 434 | 251 375 433 | divcli |  |-  ( _pi / 2 ) e. CC | 
						
							| 435 | 434 | a1i |  |-  ( R e. RR+ -> ( _pi / 2 ) e. CC ) | 
						
							| 436 | 435 | addridd |  |-  ( R e. RR+ -> ( ( _pi / 2 ) + 0 ) = ( _pi / 2 ) ) | 
						
							| 437 | 432 436 | eqtrd |  |-  ( R e. RR+ -> ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) = ( _pi / 2 ) ) | 
						
							| 438 | 437 | oveq2d |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( arcsin ` ( R / R ) ) + ( ( R / R ) x. ( sqrt ` ( 1 - ( ( R / R ) ^ 2 ) ) ) ) ) ) = ( ( R ^ 2 ) x. ( _pi / 2 ) ) ) | 
						
							| 439 | 414 438 | eqtrd |  |-  ( R e. RR+ -> ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` R ) = ( ( R ^ 2 ) x. ( _pi / 2 ) ) ) | 
						
							| 440 |  | fvoveq1 |  |-  ( u = -u R -> ( arcsin ` ( u / R ) ) = ( arcsin ` ( -u R / R ) ) ) | 
						
							| 441 |  | oveq1 |  |-  ( u = -u R -> ( u / R ) = ( -u R / R ) ) | 
						
							| 442 | 441 | oveq1d |  |-  ( u = -u R -> ( ( u / R ) ^ 2 ) = ( ( -u R / R ) ^ 2 ) ) | 
						
							| 443 | 442 | oveq2d |  |-  ( u = -u R -> ( 1 - ( ( u / R ) ^ 2 ) ) = ( 1 - ( ( -u R / R ) ^ 2 ) ) ) | 
						
							| 444 | 443 | fveq2d |  |-  ( u = -u R -> ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) = ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) | 
						
							| 445 | 441 444 | oveq12d |  |-  ( u = -u R -> ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) = ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) | 
						
							| 446 | 440 445 | oveq12d |  |-  ( u = -u R -> ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) = ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) | 
						
							| 447 | 446 | adantl |  |-  ( ( R e. RR+ /\ u = -u R ) -> ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) = ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) | 
						
							| 448 | 447 | oveq2d |  |-  ( ( R e. RR+ /\ u = -u R ) -> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) = ( ( R ^ 2 ) x. ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 449 |  | lbicc2 |  |-  ( ( -u R e. RR* /\ R e. RR* /\ -u R <_ R ) -> -u R e. ( -u R [,] R ) ) | 
						
							| 450 | 272 273 374 449 | syl3anc |  |-  ( R e. RR+ -> -u R e. ( -u R [,] R ) ) | 
						
							| 451 |  | ovexd |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) e. _V ) | 
						
							| 452 | 401 448 450 451 | fvmptd |  |-  ( R e. RR+ -> ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` -u R ) = ( ( R ^ 2 ) x. ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) ) | 
						
							| 453 | 329 329 335 | divnegd |  |-  ( R e. RR+ -> -u ( R / R ) = ( -u R / R ) ) | 
						
							| 454 | 415 | negeqd |  |-  ( R e. RR+ -> -u ( R / R ) = -u 1 ) | 
						
							| 455 | 453 454 | eqtr3d |  |-  ( R e. RR+ -> ( -u R / R ) = -u 1 ) | 
						
							| 456 | 455 | fveq2d |  |-  ( R e. RR+ -> ( arcsin ` ( -u R / R ) ) = ( arcsin ` -u 1 ) ) | 
						
							| 457 |  | ax-1cn |  |-  1 e. CC | 
						
							| 458 |  | asinneg |  |-  ( 1 e. CC -> ( arcsin ` -u 1 ) = -u ( arcsin ` 1 ) ) | 
						
							| 459 | 457 458 | ax-mp |  |-  ( arcsin ` -u 1 ) = -u ( arcsin ` 1 ) | 
						
							| 460 | 417 | negeqi |  |-  -u ( arcsin ` 1 ) = -u ( _pi / 2 ) | 
						
							| 461 | 459 460 | eqtri |  |-  ( arcsin ` -u 1 ) = -u ( _pi / 2 ) | 
						
							| 462 | 456 461 | eqtrdi |  |-  ( R e. RR+ -> ( arcsin ` ( -u R / R ) ) = -u ( _pi / 2 ) ) | 
						
							| 463 | 455 | oveq1d |  |-  ( R e. RR+ -> ( ( -u R / R ) ^ 2 ) = ( -u 1 ^ 2 ) ) | 
						
							| 464 |  | neg1sqe1 |  |-  ( -u 1 ^ 2 ) = 1 | 
						
							| 465 | 463 464 | eqtrdi |  |-  ( R e. RR+ -> ( ( -u R / R ) ^ 2 ) = 1 ) | 
						
							| 466 | 465 | oveq2d |  |-  ( R e. RR+ -> ( 1 - ( ( -u R / R ) ^ 2 ) ) = ( 1 - 1 ) ) | 
						
							| 467 | 466 424 | eqtrd |  |-  ( R e. RR+ -> ( 1 - ( ( -u R / R ) ^ 2 ) ) = 0 ) | 
						
							| 468 | 467 | fveq2d |  |-  ( R e. RR+ -> ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) = ( sqrt ` 0 ) ) | 
						
							| 469 | 468 195 | eqtrdi |  |-  ( R e. RR+ -> ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) = 0 ) | 
						
							| 470 | 469 | oveq2d |  |-  ( R e. RR+ -> ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) = ( ( -u R / R ) x. 0 ) ) | 
						
							| 471 | 271 | recnd |  |-  ( R e. RR+ -> -u R e. CC ) | 
						
							| 472 | 471 329 335 | divcld |  |-  ( R e. RR+ -> ( -u R / R ) e. CC ) | 
						
							| 473 | 472 | mul01d |  |-  ( R e. RR+ -> ( ( -u R / R ) x. 0 ) = 0 ) | 
						
							| 474 | 470 473 | eqtrd |  |-  ( R e. RR+ -> ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) = 0 ) | 
						
							| 475 | 462 474 | oveq12d |  |-  ( R e. RR+ -> ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) = ( -u ( _pi / 2 ) + 0 ) ) | 
						
							| 476 | 434 | negcli |  |-  -u ( _pi / 2 ) e. CC | 
						
							| 477 | 476 | a1i |  |-  ( R e. RR+ -> -u ( _pi / 2 ) e. CC ) | 
						
							| 478 | 477 | addridd |  |-  ( R e. RR+ -> ( -u ( _pi / 2 ) + 0 ) = -u ( _pi / 2 ) ) | 
						
							| 479 | 475 478 | eqtrd |  |-  ( R e. RR+ -> ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) = -u ( _pi / 2 ) ) | 
						
							| 480 | 479 | oveq2d |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( arcsin ` ( -u R / R ) ) + ( ( -u R / R ) x. ( sqrt ` ( 1 - ( ( -u R / R ) ^ 2 ) ) ) ) ) ) = ( ( R ^ 2 ) x. -u ( _pi / 2 ) ) ) | 
						
							| 481 | 452 480 | eqtrd |  |-  ( R e. RR+ -> ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` -u R ) = ( ( R ^ 2 ) x. -u ( _pi / 2 ) ) ) | 
						
							| 482 | 439 481 | oveq12d |  |-  ( R e. RR+ -> ( ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` R ) - ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` -u R ) ) = ( ( ( R ^ 2 ) x. ( _pi / 2 ) ) - ( ( R ^ 2 ) x. -u ( _pi / 2 ) ) ) ) | 
						
							| 483 | 434 434 | subnegi |  |-  ( ( _pi / 2 ) - -u ( _pi / 2 ) ) = ( ( _pi / 2 ) + ( _pi / 2 ) ) | 
						
							| 484 |  | pidiv2halves |  |-  ( ( _pi / 2 ) + ( _pi / 2 ) ) = _pi | 
						
							| 485 | 483 484 | eqtri |  |-  ( ( _pi / 2 ) - -u ( _pi / 2 ) ) = _pi | 
						
							| 486 | 485 | a1i |  |-  ( R e. RR+ -> ( ( _pi / 2 ) - -u ( _pi / 2 ) ) = _pi ) | 
						
							| 487 | 486 | oveq2d |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( _pi / 2 ) - -u ( _pi / 2 ) ) ) = ( ( R ^ 2 ) x. _pi ) ) | 
						
							| 488 | 330 435 477 | subdid |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. ( ( _pi / 2 ) - -u ( _pi / 2 ) ) ) = ( ( ( R ^ 2 ) x. ( _pi / 2 ) ) - ( ( R ^ 2 ) x. -u ( _pi / 2 ) ) ) ) | 
						
							| 489 | 251 | a1i |  |-  ( R e. RR+ -> _pi e. CC ) | 
						
							| 490 | 330 489 | mulcomd |  |-  ( R e. RR+ -> ( ( R ^ 2 ) x. _pi ) = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 491 | 487 488 490 | 3eqtr3d |  |-  ( R e. RR+ -> ( ( ( R ^ 2 ) x. ( _pi / 2 ) ) - ( ( R ^ 2 ) x. -u ( _pi / 2 ) ) ) = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 492 | 482 491 | eqtrd |  |-  ( R e. RR+ -> ( ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` R ) - ( ( u e. ( -u R [,] R ) |-> ( ( R ^ 2 ) x. ( ( arcsin ` ( u / R ) ) + ( ( u / R ) x. ( sqrt ` ( 1 - ( ( u / R ) ^ 2 ) ) ) ) ) ) ) ` -u R ) ) = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 493 | 368 400 492 | 3eqtrd |  |-  ( R e. RR+ -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 494 | 266 493 | syl |  |-  ( ( ( R e. RR /\ 0 <_ R ) /\ R =/= 0 ) -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 495 | 259 494 | pm2.61dane |  |-  ( ( R e. RR /\ 0 <_ R ) -> S. ( -u R (,) R ) ( vol ` if ( ( abs ` t ) <_ R , ( -u ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) [,] ( sqrt ` ( ( R ^ 2 ) - ( t ^ 2 ) ) ) ) , (/) ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 496 | 161 238 495 | 3eqtr3d |  |-  ( ( R e. RR /\ 0 <_ R ) -> S. RR ( vol ` ( S " { t } ) ) _d t = ( _pi x. ( R ^ 2 ) ) ) | 
						
							| 497 | 156 496 | eqtrd |  |-  ( ( R e. RR /\ 0 <_ R ) -> ( area ` S ) = ( _pi x. ( R ^ 2 ) ) ) |