Metamath Proof Explorer


Theorem efiatan2

Description: Value of the exponential of an artcangent. (Contributed by Mario Carneiro, 3-Apr-2015)

Ref Expression
Assertion efiatan2
|- ( A e. dom arctan -> ( exp ` ( _i x. ( arctan ` A ) ) ) = ( ( 1 + ( _i x. A ) ) / ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 ax-icn
 |-  _i e. CC
2 atancl
 |-  ( A e. dom arctan -> ( arctan ` A ) e. CC )
3 mulcl
 |-  ( ( _i e. CC /\ ( arctan ` A ) e. CC ) -> ( _i x. ( arctan ` A ) ) e. CC )
4 1 2 3 sylancr
 |-  ( A e. dom arctan -> ( _i x. ( arctan ` A ) ) e. CC )
5 efcl
 |-  ( ( _i x. ( arctan ` A ) ) e. CC -> ( exp ` ( _i x. ( arctan ` A ) ) ) e. CC )
6 4 5 syl
 |-  ( A e. dom arctan -> ( exp ` ( _i x. ( arctan ` A ) ) ) e. CC )
7 ax-1cn
 |-  1 e. CC
8 atandm2
 |-  ( A e. dom arctan <-> ( A e. CC /\ ( 1 - ( _i x. A ) ) =/= 0 /\ ( 1 + ( _i x. A ) ) =/= 0 ) )
9 8 simp1bi
 |-  ( A e. dom arctan -> A e. CC )
10 9 sqcld
 |-  ( A e. dom arctan -> ( A ^ 2 ) e. CC )
11 addcl
 |-  ( ( 1 e. CC /\ ( A ^ 2 ) e. CC ) -> ( 1 + ( A ^ 2 ) ) e. CC )
12 7 10 11 sylancr
 |-  ( A e. dom arctan -> ( 1 + ( A ^ 2 ) ) e. CC )
13 12 sqrtcld
 |-  ( A e. dom arctan -> ( sqrt ` ( 1 + ( A ^ 2 ) ) ) e. CC )
14 12 sqsqrtd
 |-  ( A e. dom arctan -> ( ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ^ 2 ) = ( 1 + ( A ^ 2 ) ) )
15 atandm4
 |-  ( A e. dom arctan <-> ( A e. CC /\ ( 1 + ( A ^ 2 ) ) =/= 0 ) )
16 15 simprbi
 |-  ( A e. dom arctan -> ( 1 + ( A ^ 2 ) ) =/= 0 )
17 14 16 eqnetrd
 |-  ( A e. dom arctan -> ( ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ^ 2 ) =/= 0 )
18 sqne0
 |-  ( ( sqrt ` ( 1 + ( A ^ 2 ) ) ) e. CC -> ( ( ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ^ 2 ) =/= 0 <-> ( sqrt ` ( 1 + ( A ^ 2 ) ) ) =/= 0 ) )
19 13 18 syl
 |-  ( A e. dom arctan -> ( ( ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ^ 2 ) =/= 0 <-> ( sqrt ` ( 1 + ( A ^ 2 ) ) ) =/= 0 ) )
20 17 19 mpbid
 |-  ( A e. dom arctan -> ( sqrt ` ( 1 + ( A ^ 2 ) ) ) =/= 0 )
21 6 13 20 divcan4d
 |-  ( A e. dom arctan -> ( ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) / ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) = ( exp ` ( _i x. ( arctan ` A ) ) ) )
22 halfcn
 |-  ( 1 / 2 ) e. CC
23 12 16 logcld
 |-  ( A e. dom arctan -> ( log ` ( 1 + ( A ^ 2 ) ) ) e. CC )
24 mulcl
 |-  ( ( ( 1 / 2 ) e. CC /\ ( log ` ( 1 + ( A ^ 2 ) ) ) e. CC ) -> ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) e. CC )
25 22 23 24 sylancr
 |-  ( A e. dom arctan -> ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) e. CC )
26 efadd
 |-  ( ( ( _i x. ( arctan ` A ) ) e. CC /\ ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) e. CC ) -> ( exp ` ( ( _i x. ( arctan ` A ) ) + ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) = ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) )
27 4 25 26 syl2anc
 |-  ( A e. dom arctan -> ( exp ` ( ( _i x. ( arctan ` A ) ) + ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) = ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) )
28 2cn
 |-  2 e. CC
29 28 a1i
 |-  ( A e. dom arctan -> 2 e. CC )
30 mulcl
 |-  ( ( _i e. CC /\ A e. CC ) -> ( _i x. A ) e. CC )
31 1 9 30 sylancr
 |-  ( A e. dom arctan -> ( _i x. A ) e. CC )
32 addcl
 |-  ( ( 1 e. CC /\ ( _i x. A ) e. CC ) -> ( 1 + ( _i x. A ) ) e. CC )
33 7 31 32 sylancr
 |-  ( A e. dom arctan -> ( 1 + ( _i x. A ) ) e. CC )
34 8 simp3bi
 |-  ( A e. dom arctan -> ( 1 + ( _i x. A ) ) =/= 0 )
35 33 34 logcld
 |-  ( A e. dom arctan -> ( log ` ( 1 + ( _i x. A ) ) ) e. CC )
36 29 35 4 subdid
 |-  ( A e. dom arctan -> ( 2 x. ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) ) = ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( 2 x. ( _i x. ( arctan ` A ) ) ) ) )
37 atanval
 |-  ( A e. dom arctan -> ( arctan ` A ) = ( ( _i / 2 ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) )
38 37 oveq2d
 |-  ( A e. dom arctan -> ( ( 2 x. _i ) x. ( arctan ` A ) ) = ( ( 2 x. _i ) x. ( ( _i / 2 ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) ) )
39 1 a1i
 |-  ( A e. dom arctan -> _i e. CC )
40 29 39 2 mulassd
 |-  ( A e. dom arctan -> ( ( 2 x. _i ) x. ( arctan ` A ) ) = ( 2 x. ( _i x. ( arctan ` A ) ) ) )
41 halfcl
 |-  ( _i e. CC -> ( _i / 2 ) e. CC )
42 1 41 ax-mp
 |-  ( _i / 2 ) e. CC
43 28 1 42 mulassi
 |-  ( ( 2 x. _i ) x. ( _i / 2 ) ) = ( 2 x. ( _i x. ( _i / 2 ) ) )
44 28 1 42 mul12i
 |-  ( 2 x. ( _i x. ( _i / 2 ) ) ) = ( _i x. ( 2 x. ( _i / 2 ) ) )
45 2ne0
 |-  2 =/= 0
46 1 28 45 divcan2i
 |-  ( 2 x. ( _i / 2 ) ) = _i
47 46 oveq2i
 |-  ( _i x. ( 2 x. ( _i / 2 ) ) ) = ( _i x. _i )
48 ixi
 |-  ( _i x. _i ) = -u 1
49 47 48 eqtri
 |-  ( _i x. ( 2 x. ( _i / 2 ) ) ) = -u 1
50 43 44 49 3eqtri
 |-  ( ( 2 x. _i ) x. ( _i / 2 ) ) = -u 1
51 50 oveq1i
 |-  ( ( ( 2 x. _i ) x. ( _i / 2 ) ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) = ( -u 1 x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) )
52 subcl
 |-  ( ( 1 e. CC /\ ( _i x. A ) e. CC ) -> ( 1 - ( _i x. A ) ) e. CC )
53 7 31 52 sylancr
 |-  ( A e. dom arctan -> ( 1 - ( _i x. A ) ) e. CC )
54 8 simp2bi
 |-  ( A e. dom arctan -> ( 1 - ( _i x. A ) ) =/= 0 )
55 53 54 logcld
 |-  ( A e. dom arctan -> ( log ` ( 1 - ( _i x. A ) ) ) e. CC )
56 55 35 subcld
 |-  ( A e. dom arctan -> ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) e. CC )
57 56 mulm1d
 |-  ( A e. dom arctan -> ( -u 1 x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) = -u ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) )
58 51 57 syl5eq
 |-  ( A e. dom arctan -> ( ( ( 2 x. _i ) x. ( _i / 2 ) ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) = -u ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) )
59 2mulicn
 |-  ( 2 x. _i ) e. CC
60 59 a1i
 |-  ( A e. dom arctan -> ( 2 x. _i ) e. CC )
61 42 a1i
 |-  ( A e. dom arctan -> ( _i / 2 ) e. CC )
62 60 61 56 mulassd
 |-  ( A e. dom arctan -> ( ( ( 2 x. _i ) x. ( _i / 2 ) ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) = ( ( 2 x. _i ) x. ( ( _i / 2 ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) ) )
63 55 35 negsubdi2d
 |-  ( A e. dom arctan -> -u ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) )
64 58 62 63 3eqtr3d
 |-  ( A e. dom arctan -> ( ( 2 x. _i ) x. ( ( _i / 2 ) x. ( ( log ` ( 1 - ( _i x. A ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) )
65 38 40 64 3eqtr3d
 |-  ( A e. dom arctan -> ( 2 x. ( _i x. ( arctan ` A ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) )
66 65 oveq2d
 |-  ( A e. dom arctan -> ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( 2 x. ( _i x. ( arctan ` A ) ) ) ) = ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) ) )
67 mulcl
 |-  ( ( 2 e. CC /\ ( log ` ( 1 + ( _i x. A ) ) ) e. CC ) -> ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) e. CC )
68 28 35 67 sylancr
 |-  ( A e. dom arctan -> ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) e. CC )
69 68 35 55 subsubd
 |-  ( A e. dom arctan -> ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) )
70 35 2timesd
 |-  ( A e. dom arctan -> ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 + ( _i x. A ) ) ) ) )
71 35 35 70 mvrladdd
 |-  ( A e. dom arctan -> ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) = ( log ` ( 1 + ( _i x. A ) ) ) )
72 71 oveq1d
 |-  ( A e. dom arctan -> ( ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( log ` ( 1 + ( _i x. A ) ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) )
73 atanlogadd
 |-  ( A e. dom arctan -> ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) e. ran log )
74 logef
 |-  ( ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) e. ran log -> ( log ` ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) )
75 73 74 syl
 |-  ( A e. dom arctan -> ( log ` ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) ) = ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) )
76 efadd
 |-  ( ( ( log ` ( 1 + ( _i x. A ) ) ) e. CC /\ ( log ` ( 1 - ( _i x. A ) ) ) e. CC ) -> ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) x. ( exp ` ( log ` ( 1 - ( _i x. A ) ) ) ) ) )
77 35 55 76 syl2anc
 |-  ( A e. dom arctan -> ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) x. ( exp ` ( log ` ( 1 - ( _i x. A ) ) ) ) ) )
78 eflog
 |-  ( ( ( 1 + ( _i x. A ) ) e. CC /\ ( 1 + ( _i x. A ) ) =/= 0 ) -> ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) = ( 1 + ( _i x. A ) ) )
79 33 34 78 syl2anc
 |-  ( A e. dom arctan -> ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) = ( 1 + ( _i x. A ) ) )
80 eflog
 |-  ( ( ( 1 - ( _i x. A ) ) e. CC /\ ( 1 - ( _i x. A ) ) =/= 0 ) -> ( exp ` ( log ` ( 1 - ( _i x. A ) ) ) ) = ( 1 - ( _i x. A ) ) )
81 53 54 80 syl2anc
 |-  ( A e. dom arctan -> ( exp ` ( log ` ( 1 - ( _i x. A ) ) ) ) = ( 1 - ( _i x. A ) ) )
82 79 81 oveq12d
 |-  ( A e. dom arctan -> ( ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) x. ( exp ` ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( ( 1 + ( _i x. A ) ) x. ( 1 - ( _i x. A ) ) ) )
83 sq1
 |-  ( 1 ^ 2 ) = 1
84 83 a1i
 |-  ( A e. dom arctan -> ( 1 ^ 2 ) = 1 )
85 sqmul
 |-  ( ( _i e. CC /\ A e. CC ) -> ( ( _i x. A ) ^ 2 ) = ( ( _i ^ 2 ) x. ( A ^ 2 ) ) )
86 1 9 85 sylancr
 |-  ( A e. dom arctan -> ( ( _i x. A ) ^ 2 ) = ( ( _i ^ 2 ) x. ( A ^ 2 ) ) )
87 i2
 |-  ( _i ^ 2 ) = -u 1
88 87 oveq1i
 |-  ( ( _i ^ 2 ) x. ( A ^ 2 ) ) = ( -u 1 x. ( A ^ 2 ) )
89 10 mulm1d
 |-  ( A e. dom arctan -> ( -u 1 x. ( A ^ 2 ) ) = -u ( A ^ 2 ) )
90 88 89 syl5eq
 |-  ( A e. dom arctan -> ( ( _i ^ 2 ) x. ( A ^ 2 ) ) = -u ( A ^ 2 ) )
91 86 90 eqtrd
 |-  ( A e. dom arctan -> ( ( _i x. A ) ^ 2 ) = -u ( A ^ 2 ) )
92 84 91 oveq12d
 |-  ( A e. dom arctan -> ( ( 1 ^ 2 ) - ( ( _i x. A ) ^ 2 ) ) = ( 1 - -u ( A ^ 2 ) ) )
93 subsq
 |-  ( ( 1 e. CC /\ ( _i x. A ) e. CC ) -> ( ( 1 ^ 2 ) - ( ( _i x. A ) ^ 2 ) ) = ( ( 1 + ( _i x. A ) ) x. ( 1 - ( _i x. A ) ) ) )
94 7 31 93 sylancr
 |-  ( A e. dom arctan -> ( ( 1 ^ 2 ) - ( ( _i x. A ) ^ 2 ) ) = ( ( 1 + ( _i x. A ) ) x. ( 1 - ( _i x. A ) ) ) )
95 subneg
 |-  ( ( 1 e. CC /\ ( A ^ 2 ) e. CC ) -> ( 1 - -u ( A ^ 2 ) ) = ( 1 + ( A ^ 2 ) ) )
96 7 10 95 sylancr
 |-  ( A e. dom arctan -> ( 1 - -u ( A ^ 2 ) ) = ( 1 + ( A ^ 2 ) ) )
97 92 94 96 3eqtr3d
 |-  ( A e. dom arctan -> ( ( 1 + ( _i x. A ) ) x. ( 1 - ( _i x. A ) ) ) = ( 1 + ( A ^ 2 ) ) )
98 77 82 97 3eqtrd
 |-  ( A e. dom arctan -> ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( 1 + ( A ^ 2 ) ) )
99 98 fveq2d
 |-  ( A e. dom arctan -> ( log ` ( exp ` ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) ) ) = ( log ` ( 1 + ( A ^ 2 ) ) ) )
100 75 99 eqtr3d
 |-  ( A e. dom arctan -> ( ( log ` ( 1 + ( _i x. A ) ) ) + ( log ` ( 1 - ( _i x. A ) ) ) ) = ( log ` ( 1 + ( A ^ 2 ) ) ) )
101 69 72 100 3eqtrd
 |-  ( A e. dom arctan -> ( ( 2 x. ( log ` ( 1 + ( _i x. A ) ) ) ) - ( ( log ` ( 1 + ( _i x. A ) ) ) - ( log ` ( 1 - ( _i x. A ) ) ) ) ) = ( log ` ( 1 + ( A ^ 2 ) ) ) )
102 36 66 101 3eqtrd
 |-  ( A e. dom arctan -> ( 2 x. ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) ) = ( log ` ( 1 + ( A ^ 2 ) ) ) )
103 102 oveq1d
 |-  ( A e. dom arctan -> ( ( 2 x. ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) ) / 2 ) = ( ( log ` ( 1 + ( A ^ 2 ) ) ) / 2 ) )
104 35 4 subcld
 |-  ( A e. dom arctan -> ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) e. CC )
105 45 a1i
 |-  ( A e. dom arctan -> 2 =/= 0 )
106 104 29 105 divcan3d
 |-  ( A e. dom arctan -> ( ( 2 x. ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) ) / 2 ) = ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) )
107 23 29 105 divrec2d
 |-  ( A e. dom arctan -> ( ( log ` ( 1 + ( A ^ 2 ) ) ) / 2 ) = ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) )
108 103 106 107 3eqtr3d
 |-  ( A e. dom arctan -> ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) = ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) )
109 35 4 25 subaddd
 |-  ( A e. dom arctan -> ( ( ( log ` ( 1 + ( _i x. A ) ) ) - ( _i x. ( arctan ` A ) ) ) = ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) <-> ( ( _i x. ( arctan ` A ) ) + ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) = ( log ` ( 1 + ( _i x. A ) ) ) ) )
110 108 109 mpbid
 |-  ( A e. dom arctan -> ( ( _i x. ( arctan ` A ) ) + ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) = ( log ` ( 1 + ( _i x. A ) ) ) )
111 110 fveq2d
 |-  ( A e. dom arctan -> ( exp ` ( ( _i x. ( arctan ` A ) ) + ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) = ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) )
112 27 111 eqtr3d
 |-  ( A e. dom arctan -> ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) = ( exp ` ( log ` ( 1 + ( _i x. A ) ) ) ) )
113 22 a1i
 |-  ( A e. dom arctan -> ( 1 / 2 ) e. CC )
114 12 16 113 cxpefd
 |-  ( A e. dom arctan -> ( ( 1 + ( A ^ 2 ) ) ^c ( 1 / 2 ) ) = ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) )
115 cxpsqrt
 |-  ( ( 1 + ( A ^ 2 ) ) e. CC -> ( ( 1 + ( A ^ 2 ) ) ^c ( 1 / 2 ) ) = ( sqrt ` ( 1 + ( A ^ 2 ) ) ) )
116 12 115 syl
 |-  ( A e. dom arctan -> ( ( 1 + ( A ^ 2 ) ) ^c ( 1 / 2 ) ) = ( sqrt ` ( 1 + ( A ^ 2 ) ) ) )
117 114 116 eqtr3d
 |-  ( A e. dom arctan -> ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) = ( sqrt ` ( 1 + ( A ^ 2 ) ) ) )
118 117 oveq2d
 |-  ( A e. dom arctan -> ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( exp ` ( ( 1 / 2 ) x. ( log ` ( 1 + ( A ^ 2 ) ) ) ) ) ) = ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) )
119 112 118 79 3eqtr3d
 |-  ( A e. dom arctan -> ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) = ( 1 + ( _i x. A ) ) )
120 119 oveq1d
 |-  ( A e. dom arctan -> ( ( ( exp ` ( _i x. ( arctan ` A ) ) ) x. ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) / ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) = ( ( 1 + ( _i x. A ) ) / ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) )
121 21 120 eqtr3d
 |-  ( A e. dom arctan -> ( exp ` ( _i x. ( arctan ` A ) ) ) = ( ( 1 + ( _i x. A ) ) / ( sqrt ` ( 1 + ( A ^ 2 ) ) ) ) )