| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ang.1 |  |-  F = ( x e. ( CC \ { 0 } ) , y e. ( CC \ { 0 } ) |-> ( Im ` ( log ` ( y / x ) ) ) ) | 
						
							| 2 |  | 1cnd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> 1 e. CC ) | 
						
							| 3 |  | simp1 |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> A e. CC ) | 
						
							| 4 | 2 3 | subcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 - A ) e. CC ) | 
						
							| 5 |  | simp3 |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> A =/= 1 ) | 
						
							| 6 | 5 | necomd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> 1 =/= A ) | 
						
							| 7 | 2 3 6 | subne0d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 - A ) =/= 0 ) | 
						
							| 8 |  | ax-1ne0 |  |-  1 =/= 0 | 
						
							| 9 | 8 | a1i |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> 1 =/= 0 ) | 
						
							| 10 | 1 4 7 2 9 | angvald |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( 1 - A ) F 1 ) = ( Im ` ( log ` ( 1 / ( 1 - A ) ) ) ) ) | 
						
							| 11 |  | simp2 |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> A =/= 0 ) | 
						
							| 12 | 3 2 | subcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( A - 1 ) e. CC ) | 
						
							| 13 | 3 2 5 | subne0d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( A - 1 ) =/= 0 ) | 
						
							| 14 | 1 3 11 12 13 | angvald |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( A F ( A - 1 ) ) = ( Im ` ( log ` ( ( A - 1 ) / A ) ) ) ) | 
						
							| 15 | 10 14 | oveq12d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( 1 - A ) F 1 ) + ( A F ( A - 1 ) ) ) = ( ( Im ` ( log ` ( 1 / ( 1 - A ) ) ) ) + ( Im ` ( log ` ( ( A - 1 ) / A ) ) ) ) ) | 
						
							| 16 | 2 4 7 | divcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 / ( 1 - A ) ) e. CC ) | 
						
							| 17 | 4 7 | recne0d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 / ( 1 - A ) ) =/= 0 ) | 
						
							| 18 | 16 17 | logcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( log ` ( 1 / ( 1 - A ) ) ) e. CC ) | 
						
							| 19 | 12 3 11 | divcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( A - 1 ) / A ) e. CC ) | 
						
							| 20 | 12 3 13 11 | divne0d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( A - 1 ) / A ) =/= 0 ) | 
						
							| 21 | 19 20 | logcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( log ` ( ( A - 1 ) / A ) ) e. CC ) | 
						
							| 22 | 18 21 | imaddd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( Im ` ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) ) = ( ( Im ` ( log ` ( 1 / ( 1 - A ) ) ) ) + ( Im ` ( log ` ( ( A - 1 ) / A ) ) ) ) ) | 
						
							| 23 | 15 22 | eqtr4d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( 1 - A ) F 1 ) + ( A F ( A - 1 ) ) ) = ( Im ` ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) ) ) | 
						
							| 24 | 1 2 9 3 11 | angvald |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 F A ) = ( Im ` ( log ` ( A / 1 ) ) ) ) | 
						
							| 25 | 3 | div1d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( A / 1 ) = A ) | 
						
							| 26 | 25 | fveq2d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( log ` ( A / 1 ) ) = ( log ` A ) ) | 
						
							| 27 | 26 | fveq2d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( Im ` ( log ` ( A / 1 ) ) ) = ( Im ` ( log ` A ) ) ) | 
						
							| 28 | 24 27 | eqtrd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( 1 F A ) = ( Im ` ( log ` A ) ) ) | 
						
							| 29 | 23 28 | oveq12d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( ( 1 - A ) F 1 ) + ( A F ( A - 1 ) ) ) + ( 1 F A ) ) = ( ( Im ` ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) ) + ( Im ` ( log ` A ) ) ) ) | 
						
							| 30 | 18 21 | addcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) e. CC ) | 
						
							| 31 | 3 11 | logcld |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( log ` A ) e. CC ) | 
						
							| 32 | 30 31 | imaddd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = ( ( Im ` ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) ) + ( Im ` ( log ` A ) ) ) ) | 
						
							| 33 | 29 32 | eqtr4d |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( ( 1 - A ) F 1 ) + ( A F ( A - 1 ) ) ) + ( 1 F A ) ) = ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) ) | 
						
							| 34 |  | eqid |  |-  ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) | 
						
							| 35 |  | eqid |  |-  ( ( ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) / _i ) / ( 2 x. _pi ) ) - ( 1 / 2 ) ) = ( ( ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) / _i ) / ( 2 x. _pi ) ) - ( 1 / 2 ) ) | 
						
							| 36 | 1 34 35 | ang180lem3 |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) e. { -u ( _i x. _pi ) , ( _i x. _pi ) } ) | 
						
							| 37 |  | fveq2 |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = -u ( _i x. _pi ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = ( Im ` -u ( _i x. _pi ) ) ) | 
						
							| 38 |  | ax-icn |  |-  _i e. CC | 
						
							| 39 |  | picn |  |-  _pi e. CC | 
						
							| 40 | 38 39 | mulcli |  |-  ( _i x. _pi ) e. CC | 
						
							| 41 | 40 | imnegi |  |-  ( Im ` -u ( _i x. _pi ) ) = -u ( Im ` ( _i x. _pi ) ) | 
						
							| 42 | 40 | addlidi |  |-  ( 0 + ( _i x. _pi ) ) = ( _i x. _pi ) | 
						
							| 43 | 42 | fveq2i |  |-  ( Im ` ( 0 + ( _i x. _pi ) ) ) = ( Im ` ( _i x. _pi ) ) | 
						
							| 44 |  | 0re |  |-  0 e. RR | 
						
							| 45 |  | pire |  |-  _pi e. RR | 
						
							| 46 | 44 45 | crimi |  |-  ( Im ` ( 0 + ( _i x. _pi ) ) ) = _pi | 
						
							| 47 | 43 46 | eqtr3i |  |-  ( Im ` ( _i x. _pi ) ) = _pi | 
						
							| 48 | 47 | negeqi |  |-  -u ( Im ` ( _i x. _pi ) ) = -u _pi | 
						
							| 49 | 41 48 | eqtri |  |-  ( Im ` -u ( _i x. _pi ) ) = -u _pi | 
						
							| 50 | 37 49 | eqtrdi |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = -u ( _i x. _pi ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = -u _pi ) | 
						
							| 51 |  | fveq2 |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = ( _i x. _pi ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = ( Im ` ( _i x. _pi ) ) ) | 
						
							| 52 | 51 47 | eqtrdi |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = ( _i x. _pi ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = _pi ) | 
						
							| 53 | 50 52 | orim12i |  |-  ( ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = -u ( _i x. _pi ) \/ ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = ( _i x. _pi ) ) -> ( ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = -u _pi \/ ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = _pi ) ) | 
						
							| 54 |  | ovex |  |-  ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) e. _V | 
						
							| 55 | 54 | elpr |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) e. { -u ( _i x. _pi ) , ( _i x. _pi ) } <-> ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = -u ( _i x. _pi ) \/ ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) = ( _i x. _pi ) ) ) | 
						
							| 56 |  | fvex |  |-  ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) e. _V | 
						
							| 57 | 56 | elpr |  |-  ( ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) e. { -u _pi , _pi } <-> ( ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = -u _pi \/ ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) = _pi ) ) | 
						
							| 58 | 53 55 57 | 3imtr4i |  |-  ( ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) e. { -u ( _i x. _pi ) , ( _i x. _pi ) } -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) e. { -u _pi , _pi } ) | 
						
							| 59 | 36 58 | syl |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( Im ` ( ( ( log ` ( 1 / ( 1 - A ) ) ) + ( log ` ( ( A - 1 ) / A ) ) ) + ( log ` A ) ) ) e. { -u _pi , _pi } ) | 
						
							| 60 | 33 59 | eqeltrd |  |-  ( ( A e. CC /\ A =/= 0 /\ A =/= 1 ) -> ( ( ( ( 1 - A ) F 1 ) + ( A F ( A - 1 ) ) ) + ( 1 F A ) ) e. { -u _pi , _pi } ) |