| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ipcl.1 |  |-  X = ( BaseSet ` U ) | 
						
							| 2 |  | ipcl.7 |  |-  P = ( .iOLD ` U ) | 
						
							| 3 |  | eqid |  |-  ( +v ` U ) = ( +v ` U ) | 
						
							| 4 |  | eqid |  |-  ( .sOLD ` U ) = ( .sOLD ` U ) | 
						
							| 5 |  | eqid |  |-  ( normCV ` U ) = ( normCV ` U ) | 
						
							| 6 | 1 3 4 5 2 | ipval2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( A P B ) = ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 7 | 6 | fveq2d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( A P B ) ) = ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) ) | 
						
							| 8 | 1 3 4 5 2 | ipval2 |  |-  ( ( U e. NrmCVec /\ B e. X /\ A e. X ) -> ( B P A ) = ( ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 9 | 8 | 3com23 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( B P A ) = ( ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 10 | 1 3 4 5 2 | ipval2lem3 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) e. RR ) | 
						
							| 11 | 10 | recnd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) e. CC ) | 
						
							| 12 |  | neg1cn |  |-  -u 1 e. CC | 
						
							| 13 | 1 3 4 5 2 | ipval2lem4 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ -u 1 e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 14 | 12 13 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 15 | 11 14 | subcld |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC ) | 
						
							| 16 |  | ax-icn |  |-  _i e. CC | 
						
							| 17 | 1 3 4 5 2 | ipval2lem4 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ _i e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 18 | 16 17 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 19 |  | negicn |  |-  -u _i e. CC | 
						
							| 20 | 1 3 4 5 2 | ipval2lem4 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ -u _i e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 21 | 19 20 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. CC ) | 
						
							| 22 | 18 21 | subcld |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC ) | 
						
							| 23 |  | mulcl |  |-  ( ( _i e. CC /\ ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC ) -> ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) e. CC ) | 
						
							| 24 | 16 22 23 | sylancr |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) e. CC ) | 
						
							| 25 | 15 24 | addcld |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) e. CC ) | 
						
							| 26 |  | 4cn |  |-  4 e. CC | 
						
							| 27 |  | 4ne0 |  |-  4 =/= 0 | 
						
							| 28 |  | cjdiv |  |-  ( ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) e. CC /\ 4 e. CC /\ 4 =/= 0 ) -> ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) = ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / ( * ` 4 ) ) ) | 
						
							| 29 | 26 27 28 | mp3an23 |  |-  ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) e. CC -> ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) = ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / ( * ` 4 ) ) ) | 
						
							| 30 | 25 29 | syl |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) = ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / ( * ` 4 ) ) ) | 
						
							| 31 |  | 4re |  |-  4 e. RR | 
						
							| 32 |  | cjre |  |-  ( 4 e. RR -> ( * ` 4 ) = 4 ) | 
						
							| 33 | 31 32 | ax-mp |  |-  ( * ` 4 ) = 4 | 
						
							| 34 | 33 | oveq2i |  |-  ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / ( * ` 4 ) ) = ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / 4 ) | 
						
							| 35 | 1 3 4 5 2 | ipval2lem2 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ -u 1 e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 36 | 12 35 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 37 | 10 36 | resubcld |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. RR ) | 
						
							| 38 | 1 3 4 5 2 | ipval2lem2 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ _i e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 39 | 16 38 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 40 | 1 3 4 5 2 | ipval2lem2 |  |-  ( ( ( U e. NrmCVec /\ A e. X /\ B e. X ) /\ -u _i e. CC ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 41 | 19 40 | mpan2 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) e. RR ) | 
						
							| 42 | 39 41 | resubcld |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. RR ) | 
						
							| 43 |  | cjreim |  |-  ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. RR /\ ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. RR ) -> ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) - ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 44 | 37 42 43 | syl2anc |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) - ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 45 |  | submul2 |  |-  ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC /\ _i e. CC /\ ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC ) -> ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) - ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 46 | 16 45 | mp3an2 |  |-  ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC /\ ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) e. CC ) -> ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) - ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 47 | 15 22 46 | syl2anc |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) - ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 48 | 1 3 | nvcom |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( A ( +v ` U ) B ) = ( B ( +v ` U ) A ) ) | 
						
							| 49 | 48 | fveq2d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) = ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ) | 
						
							| 50 | 49 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) = ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) ) | 
						
							| 51 | 1 3 4 5 | nvdif |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) = ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ) | 
						
							| 52 | 51 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) = ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) | 
						
							| 53 | 50 52 | oveq12d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) = ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) | 
						
							| 54 | 18 21 | negsubdi2d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) = ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) | 
						
							| 55 | 1 3 4 5 | nvpi |  |-  ( ( U e. NrmCVec /\ B e. X /\ A e. X ) -> ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) = ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ) | 
						
							| 56 | 55 | 3com23 |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) = ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ) | 
						
							| 57 | 56 | eqcomd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) = ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ) | 
						
							| 58 | 57 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) = ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) | 
						
							| 59 | 1 3 4 5 | nvpi |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) = ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ) | 
						
							| 60 | 59 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) = ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) | 
						
							| 61 | 58 60 | oveq12d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) = ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) | 
						
							| 62 | 54 61 | eqtrd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) = ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) | 
						
							| 63 | 62 | oveq2d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( _i x. -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) = ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) | 
						
							| 64 | 53 63 | oveq12d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. -u ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 65 | 44 47 64 | 3eqtrd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) = ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) ) | 
						
							| 66 | 65 | oveq1d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / 4 ) = ( ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 67 | 34 66 | eqtrid |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( ( * ` ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) ) / ( * ` 4 ) ) = ( ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 68 | 30 67 | eqtrd |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) = ( ( ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) A ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u 1 ( .sOLD ` U ) A ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( _i ( .sOLD ` U ) A ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( B ( +v ` U ) ( -u _i ( .sOLD ` U ) A ) ) ) ^ 2 ) ) ) ) / 4 ) ) | 
						
							| 69 | 9 68 | eqtr4d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( B P A ) = ( * ` ( ( ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) B ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u 1 ( .sOLD ` U ) B ) ) ) ^ 2 ) ) + ( _i x. ( ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( _i ( .sOLD ` U ) B ) ) ) ^ 2 ) - ( ( ( normCV ` U ) ` ( A ( +v ` U ) ( -u _i ( .sOLD ` U ) B ) ) ) ^ 2 ) ) ) ) / 4 ) ) ) | 
						
							| 70 | 7 69 | eqtr4d |  |-  ( ( U e. NrmCVec /\ A e. X /\ B e. X ) -> ( * ` ( A P B ) ) = ( B P A ) ) |