| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2itscp.a |  |-  ( ph -> A e. RR ) | 
						
							| 2 |  | 2itscp.b |  |-  ( ph -> B e. RR ) | 
						
							| 3 |  | 2itscp.x |  |-  ( ph -> X e. RR ) | 
						
							| 4 |  | 2itscp.y |  |-  ( ph -> Y e. RR ) | 
						
							| 5 |  | 2itscp.d |  |-  D = ( X - A ) | 
						
							| 6 |  | 2itscp.e |  |-  E = ( B - Y ) | 
						
							| 7 |  | 2itscp.c |  |-  C = ( ( D x. B ) + ( E x. A ) ) | 
						
							| 8 |  | 2itscp.r |  |-  ( ph -> R e. RR ) | 
						
							| 9 |  | 2itscp.l |  |-  ( ph -> ( ( A ^ 2 ) + ( B ^ 2 ) ) < ( R ^ 2 ) ) | 
						
							| 10 |  | itscnhlinecirc02plem1.n |  |-  ( ph -> B =/= Y ) | 
						
							| 11 |  | 4re |  |-  4 e. RR | 
						
							| 12 | 11 | a1i |  |-  ( ph -> 4 e. RR ) | 
						
							| 13 | 3 1 | resubcld |  |-  ( ph -> ( X - A ) e. RR ) | 
						
							| 14 | 5 13 | eqeltrid |  |-  ( ph -> D e. RR ) | 
						
							| 15 | 14 | resqcld |  |-  ( ph -> ( D ^ 2 ) e. RR ) | 
						
							| 16 | 14 2 | remulcld |  |-  ( ph -> ( D x. B ) e. RR ) | 
						
							| 17 | 2 4 | resubcld |  |-  ( ph -> ( B - Y ) e. RR ) | 
						
							| 18 | 6 17 | eqeltrid |  |-  ( ph -> E e. RR ) | 
						
							| 19 | 18 1 | remulcld |  |-  ( ph -> ( E x. A ) e. RR ) | 
						
							| 20 | 16 19 | readdcld |  |-  ( ph -> ( ( D x. B ) + ( E x. A ) ) e. RR ) | 
						
							| 21 | 7 20 | eqeltrid |  |-  ( ph -> C e. RR ) | 
						
							| 22 | 21 | resqcld |  |-  ( ph -> ( C ^ 2 ) e. RR ) | 
						
							| 23 | 15 22 | remulcld |  |-  ( ph -> ( ( D ^ 2 ) x. ( C ^ 2 ) ) e. RR ) | 
						
							| 24 | 18 | resqcld |  |-  ( ph -> ( E ^ 2 ) e. RR ) | 
						
							| 25 | 24 15 | readdcld |  |-  ( ph -> ( ( E ^ 2 ) + ( D ^ 2 ) ) e. RR ) | 
						
							| 26 | 8 | resqcld |  |-  ( ph -> ( R ^ 2 ) e. RR ) | 
						
							| 27 | 24 26 | remulcld |  |-  ( ph -> ( ( E ^ 2 ) x. ( R ^ 2 ) ) e. RR ) | 
						
							| 28 | 22 27 | resubcld |  |-  ( ph -> ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) e. RR ) | 
						
							| 29 | 25 28 | remulcld |  |-  ( ph -> ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) e. RR ) | 
						
							| 30 | 23 29 | resubcld |  |-  ( ph -> ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) e. RR ) | 
						
							| 31 |  | 4pos |  |-  0 < 4 | 
						
							| 32 | 31 | a1i |  |-  ( ph -> 0 < 4 ) | 
						
							| 33 | 15 26 | remulcld |  |-  ( ph -> ( ( D ^ 2 ) x. ( R ^ 2 ) ) e. RR ) | 
						
							| 34 | 27 33 | readdcld |  |-  ( ph -> ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) e. RR ) | 
						
							| 35 | 34 22 | resubcld |  |-  ( ph -> ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) e. RR ) | 
						
							| 36 | 6 | a1i |  |-  ( ph -> E = ( B - Y ) ) | 
						
							| 37 | 2 | recnd |  |-  ( ph -> B e. CC ) | 
						
							| 38 | 4 | recnd |  |-  ( ph -> Y e. CC ) | 
						
							| 39 | 37 38 10 | subne0d |  |-  ( ph -> ( B - Y ) =/= 0 ) | 
						
							| 40 | 36 39 | eqnetrd |  |-  ( ph -> E =/= 0 ) | 
						
							| 41 | 18 40 | sqgt0d |  |-  ( ph -> 0 < ( E ^ 2 ) ) | 
						
							| 42 | 10 | orcd |  |-  ( ph -> ( B =/= Y \/ A =/= X ) ) | 
						
							| 43 |  | eqid |  |-  ( ( E ^ 2 ) + ( D ^ 2 ) ) = ( ( E ^ 2 ) + ( D ^ 2 ) ) | 
						
							| 44 |  | eqid |  |-  ( ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) - ( C ^ 2 ) ) = ( ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) - ( C ^ 2 ) ) | 
						
							| 45 | 1 2 3 4 5 6 7 8 9 42 43 44 | 2itscp |  |-  ( ph -> 0 < ( ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) - ( C ^ 2 ) ) ) | 
						
							| 46 | 24 | recnd |  |-  ( ph -> ( E ^ 2 ) e. CC ) | 
						
							| 47 | 15 | recnd |  |-  ( ph -> ( D ^ 2 ) e. CC ) | 
						
							| 48 | 26 | recnd |  |-  ( ph -> ( R ^ 2 ) e. CC ) | 
						
							| 49 | 46 47 48 | adddird |  |-  ( ph -> ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( R ^ 2 ) ) = ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) | 
						
							| 50 | 46 47 | addcld |  |-  ( ph -> ( ( E ^ 2 ) + ( D ^ 2 ) ) e. CC ) | 
						
							| 51 | 50 48 | mulcomd |  |-  ( ph -> ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( R ^ 2 ) ) = ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) ) | 
						
							| 52 | 49 51 | eqtr3d |  |-  ( ph -> ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) = ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) ) | 
						
							| 53 | 52 | oveq1d |  |-  ( ph -> ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) = ( ( ( R ^ 2 ) x. ( ( E ^ 2 ) + ( D ^ 2 ) ) ) - ( C ^ 2 ) ) ) | 
						
							| 54 | 45 53 | breqtrrd |  |-  ( ph -> 0 < ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) ) | 
						
							| 55 | 24 35 41 54 | mulgt0d |  |-  ( ph -> 0 < ( ( E ^ 2 ) x. ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) ) ) | 
						
							| 56 | 47 46 48 | mul12d |  |-  ( ph -> ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) = ( ( E ^ 2 ) x. ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) | 
						
							| 57 | 56 | oveq2d |  |-  ( ph -> ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( E ^ 2 ) x. ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 58 | 46 48 | mulcld |  |-  ( ph -> ( ( E ^ 2 ) x. ( R ^ 2 ) ) e. CC ) | 
						
							| 59 | 47 48 | mulcld |  |-  ( ph -> ( ( D ^ 2 ) x. ( R ^ 2 ) ) e. CC ) | 
						
							| 60 | 46 58 59 | adddid |  |-  ( ph -> ( ( E ^ 2 ) x. ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( E ^ 2 ) x. ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 61 | 57 60 | eqtr4d |  |-  ( ph -> ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( E ^ 2 ) x. ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 62 | 61 | oveq1d |  |-  ( ph -> ( ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) = ( ( ( E ^ 2 ) x. ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 63 | 58 59 | addcld |  |-  ( ph -> ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) e. CC ) | 
						
							| 64 | 22 | recnd |  |-  ( ph -> ( C ^ 2 ) e. CC ) | 
						
							| 65 | 46 63 64 | subdid |  |-  ( ph -> ( ( E ^ 2 ) x. ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) ) = ( ( ( E ^ 2 ) x. ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 66 | 62 65 | eqtr4d |  |-  ( ph -> ( ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) = ( ( E ^ 2 ) x. ( ( ( ( E ^ 2 ) x. ( R ^ 2 ) ) + ( ( D ^ 2 ) x. ( R ^ 2 ) ) ) - ( C ^ 2 ) ) ) ) | 
						
							| 67 | 55 66 | breqtrrd |  |-  ( ph -> 0 < ( ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 68 | 18 | recnd |  |-  ( ph -> E e. CC ) | 
						
							| 69 | 68 | sqcld |  |-  ( ph -> ( E ^ 2 ) e. CC ) | 
						
							| 70 | 14 | recnd |  |-  ( ph -> D e. CC ) | 
						
							| 71 | 70 | sqcld |  |-  ( ph -> ( D ^ 2 ) e. CC ) | 
						
							| 72 | 27 | recnd |  |-  ( ph -> ( ( E ^ 2 ) x. ( R ^ 2 ) ) e. CC ) | 
						
							| 73 |  | mulsubaddmulsub |  |-  ( ( ( ( E ^ 2 ) e. CC /\ ( D ^ 2 ) e. CC ) /\ ( ( C ^ 2 ) e. CC /\ ( ( E ^ 2 ) x. ( R ^ 2 ) ) e. CC ) ) -> ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) = ( ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 74 | 69 71 64 72 73 | syl22anc |  |-  ( ph -> ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) = ( ( ( ( E ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) + ( ( D ^ 2 ) x. ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) - ( ( E ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 75 | 67 74 | breqtrrd |  |-  ( ph -> 0 < ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) | 
						
							| 76 | 12 30 32 75 | mulgt0d |  |-  ( ph -> 0 < ( 4 x. ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) ) | 
						
							| 77 |  | 4cn |  |-  4 e. CC | 
						
							| 78 | 77 | a1i |  |-  ( ph -> 4 e. CC ) | 
						
							| 79 | 21 | recnd |  |-  ( ph -> C e. CC ) | 
						
							| 80 | 79 | sqcld |  |-  ( ph -> ( C ^ 2 ) e. CC ) | 
						
							| 81 | 71 80 | mulcld |  |-  ( ph -> ( ( D ^ 2 ) x. ( C ^ 2 ) ) e. CC ) | 
						
							| 82 | 69 71 | addcld |  |-  ( ph -> ( ( E ^ 2 ) + ( D ^ 2 ) ) e. CC ) | 
						
							| 83 | 8 | recnd |  |-  ( ph -> R e. CC ) | 
						
							| 84 | 83 | sqcld |  |-  ( ph -> ( R ^ 2 ) e. CC ) | 
						
							| 85 | 69 84 | mulcld |  |-  ( ph -> ( ( E ^ 2 ) x. ( R ^ 2 ) ) e. CC ) | 
						
							| 86 | 80 85 | subcld |  |-  ( ph -> ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) e. CC ) | 
						
							| 87 | 82 86 | mulcld |  |-  ( ph -> ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) e. CC ) | 
						
							| 88 | 78 81 87 | subdid |  |-  ( ph -> ( 4 x. ( ( ( D ^ 2 ) x. ( C ^ 2 ) ) - ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) = ( ( 4 x. ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) - ( 4 x. ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) ) | 
						
							| 89 | 76 88 | breqtrd |  |-  ( ph -> 0 < ( ( 4 x. ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) - ( 4 x. ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) ) | 
						
							| 90 |  | 2cnd |  |-  ( ph -> 2 e. CC ) | 
						
							| 91 | 70 79 | mulcld |  |-  ( ph -> ( D x. C ) e. CC ) | 
						
							| 92 | 90 91 | mulcld |  |-  ( ph -> ( 2 x. ( D x. C ) ) e. CC ) | 
						
							| 93 |  | sqneg |  |-  ( ( 2 x. ( D x. C ) ) e. CC -> ( -u ( 2 x. ( D x. C ) ) ^ 2 ) = ( ( 2 x. ( D x. C ) ) ^ 2 ) ) | 
						
							| 94 | 92 93 | syl |  |-  ( ph -> ( -u ( 2 x. ( D x. C ) ) ^ 2 ) = ( ( 2 x. ( D x. C ) ) ^ 2 ) ) | 
						
							| 95 | 90 91 | sqmuld |  |-  ( ph -> ( ( 2 x. ( D x. C ) ) ^ 2 ) = ( ( 2 ^ 2 ) x. ( ( D x. C ) ^ 2 ) ) ) | 
						
							| 96 |  | sq2 |  |-  ( 2 ^ 2 ) = 4 | 
						
							| 97 | 96 | a1i |  |-  ( ph -> ( 2 ^ 2 ) = 4 ) | 
						
							| 98 | 70 79 | sqmuld |  |-  ( ph -> ( ( D x. C ) ^ 2 ) = ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) | 
						
							| 99 | 97 98 | oveq12d |  |-  ( ph -> ( ( 2 ^ 2 ) x. ( ( D x. C ) ^ 2 ) ) = ( 4 x. ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 100 | 94 95 99 | 3eqtrd |  |-  ( ph -> ( -u ( 2 x. ( D x. C ) ) ^ 2 ) = ( 4 x. ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) ) | 
						
							| 101 | 100 | oveq1d |  |-  ( ph -> ( ( -u ( 2 x. ( D x. C ) ) ^ 2 ) - ( 4 x. ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) = ( ( 4 x. ( ( D ^ 2 ) x. ( C ^ 2 ) ) ) - ( 4 x. ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) ) | 
						
							| 102 | 89 101 | breqtrrd |  |-  ( ph -> 0 < ( ( -u ( 2 x. ( D x. C ) ) ^ 2 ) - ( 4 x. ( ( ( E ^ 2 ) + ( D ^ 2 ) ) x. ( ( C ^ 2 ) - ( ( E ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) ) |