Proof of Theorem argrege0
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | logcl 26611 | . . . 4
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) ∈
ℂ) | 
| 2 | 1 | 3adant3 1132 | . . 3
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(log‘𝐴) ∈
ℂ) | 
| 3 | 2 | imcld 15235 | . 2
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℑ‘(log‘𝐴)) ∈ ℝ) | 
| 4 |  | simp3 1138 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
≤ (ℜ‘𝐴)) | 
| 5 |  | simp1 1136 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
𝐴 ∈
ℂ) | 
| 6 | 5 | abscld 15476 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘𝐴) ∈
ℝ) | 
| 7 | 6 | recnd 11290 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘𝐴) ∈
ℂ) | 
| 8 | 7 | mul01d 11461 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘𝐴) · 0)
= 0) | 
| 9 |  | absrpcl 15328 | . . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (abs‘𝐴) ∈
ℝ+) | 
| 10 | 9 | 3adant3 1132 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘𝐴) ∈
ℝ+) | 
| 11 | 10 | rpne0d 13083 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘𝐴) ≠
0) | 
| 12 | 5, 7, 11 | divcld 12044 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(𝐴 / (abs‘𝐴)) ∈
ℂ) | 
| 13 | 6, 12 | remul2d 15267 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℜ‘((abs‘𝐴) · (𝐴 / (abs‘𝐴)))) = ((abs‘𝐴) · (ℜ‘(𝐴 / (abs‘𝐴))))) | 
| 14 | 5, 7, 11 | divcan2d 12046 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘𝐴) ·
(𝐴 / (abs‘𝐴))) = 𝐴) | 
| 15 | 14 | fveq2d 6909 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℜ‘((abs‘𝐴) · (𝐴 / (abs‘𝐴)))) = (ℜ‘𝐴)) | 
| 16 | 13, 15 | eqtr3d 2778 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘𝐴) ·
(ℜ‘(𝐴 /
(abs‘𝐴)))) =
(ℜ‘𝐴)) | 
| 17 | 4, 8, 16 | 3brtr4d 5174 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘𝐴) · 0)
≤ ((abs‘𝐴)
· (ℜ‘(𝐴 /
(abs‘𝐴))))) | 
| 18 |  | 0re 11264 | . . . . . . . . . 10
⊢ 0 ∈
ℝ | 
| 19 | 18 | a1i 11 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
∈ ℝ) | 
| 20 | 12 | recld 15234 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℜ‘(𝐴 /
(abs‘𝐴))) ∈
ℝ) | 
| 21 | 19, 20, 10 | lemul2d 13122 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → (0
≤ (ℜ‘(𝐴 /
(abs‘𝐴))) ↔
((abs‘𝐴) · 0)
≤ ((abs‘𝐴)
· (ℜ‘(𝐴 /
(abs‘𝐴)))))) | 
| 22 | 17, 21 | mpbird 257 | . . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
≤ (ℜ‘(𝐴 /
(abs‘𝐴)))) | 
| 23 |  | efiarg 26650 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(i
· (ℑ‘(log‘𝐴)))) = (𝐴 / (abs‘𝐴))) | 
| 24 | 23 | 3adant3 1132 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(exp‘(i · (ℑ‘(log‘𝐴)))) = (𝐴 / (abs‘𝐴))) | 
| 25 | 24 | fveq2d 6909 | . . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℜ‘(exp‘(i · (ℑ‘(log‘𝐴))))) = (ℜ‘(𝐴 / (abs‘𝐴)))) | 
| 26 | 22, 25 | breqtrrd 5170 | . . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
≤ (ℜ‘(exp‘(i · (ℑ‘(log‘𝐴)))))) | 
| 27 |  | recosval 16173 | . . . . . . 7
⊢
((ℑ‘(log‘𝐴)) ∈ ℝ →
(cos‘(ℑ‘(log‘𝐴))) = (ℜ‘(exp‘(i ·
(ℑ‘(log‘𝐴)))))) | 
| 28 | 3, 27 | syl 17 | . . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(cos‘(ℑ‘(log‘𝐴))) = (ℜ‘(exp‘(i ·
(ℑ‘(log‘𝐴)))))) | 
| 29 | 26, 28 | breqtrrd 5170 | . . . . 5
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
≤ (cos‘(ℑ‘(log‘𝐴)))) | 
| 30 |  | halfpire 26507 | . . . . . . . . . 10
⊢ (π /
2) ∈ ℝ | 
| 31 |  | pirp 26504 | . . . . . . . . . . 11
⊢ π
∈ ℝ+ | 
| 32 |  | rphalfcl 13063 | . . . . . . . . . . 11
⊢ (π
∈ ℝ+ → (π / 2) ∈
ℝ+) | 
| 33 |  | rpge0 13049 | . . . . . . . . . . 11
⊢ ((π /
2) ∈ ℝ+ → 0 ≤ (π / 2)) | 
| 34 | 31, 32, 33 | mp2b 10 | . . . . . . . . . 10
⊢ 0 ≤
(π / 2) | 
| 35 |  | pire 26501 | . . . . . . . . . . 11
⊢ π
∈ ℝ | 
| 36 |  | rphalflt 13065 | . . . . . . . . . . . 12
⊢ (π
∈ ℝ+ → (π / 2) < π) | 
| 37 | 31, 36 | ax-mp 5 | . . . . . . . . . . 11
⊢ (π /
2) < π | 
| 38 | 30, 35, 37 | ltleii 11385 | . . . . . . . . . 10
⊢ (π /
2) ≤ π | 
| 39 | 18, 35 | elicc2i 13454 | . . . . . . . . . 10
⊢ ((π /
2) ∈ (0[,]π) ↔ ((π / 2) ∈ ℝ ∧ 0 ≤ (π / 2)
∧ (π / 2) ≤ π)) | 
| 40 | 30, 34, 38, 39 | mpbir3an 1341 | . . . . . . . . 9
⊢ (π /
2) ∈ (0[,]π) | 
| 41 | 3 | recnd 11290 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℑ‘(log‘𝐴)) ∈ ℂ) | 
| 42 | 41 | abscld 15476 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘(ℑ‘(log‘𝐴))) ∈ ℝ) | 
| 43 | 41 | absge0d 15484 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → 0
≤ (abs‘(ℑ‘(log‘𝐴)))) | 
| 44 |  | logimcl 26612 | . . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-π <
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π)) | 
| 45 | 44 | 3adant3 1132 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(-π < (ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π)) | 
| 46 | 45 | simpld 494 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
-π < (ℑ‘(log‘𝐴))) | 
| 47 | 35 | renegcli 11571 | . . . . . . . . . . . . 13
⊢ -π
∈ ℝ | 
| 48 |  | ltle 11350 | . . . . . . . . . . . . 13
⊢ ((-π
∈ ℝ ∧ (ℑ‘(log‘𝐴)) ∈ ℝ) → (-π <
(ℑ‘(log‘𝐴)) → -π ≤
(ℑ‘(log‘𝐴)))) | 
| 49 | 47, 3, 48 | sylancr 587 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(-π < (ℑ‘(log‘𝐴)) → -π ≤
(ℑ‘(log‘𝐴)))) | 
| 50 | 46, 49 | mpd 15 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
-π ≤ (ℑ‘(log‘𝐴))) | 
| 51 | 45 | simprd 495 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℑ‘(log‘𝐴)) ≤ π) | 
| 52 |  | absle 15355 | . . . . . . . . . . . 12
⊢
(((ℑ‘(log‘𝐴)) ∈ ℝ ∧ π ∈ ℝ)
→ ((abs‘(ℑ‘(log‘𝐴))) ≤ π ↔ (-π ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π))) | 
| 53 | 3, 35, 52 | sylancl 586 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) ≤ π ↔ (-π ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π))) | 
| 54 | 50, 51, 53 | mpbir2and 713 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘(ℑ‘(log‘𝐴))) ≤ π) | 
| 55 | 18, 35 | elicc2i 13454 | . . . . . . . . . 10
⊢
((abs‘(ℑ‘(log‘𝐴))) ∈ (0[,]π) ↔
((abs‘(ℑ‘(log‘𝐴))) ∈ ℝ ∧ 0 ≤
(abs‘(ℑ‘(log‘𝐴))) ∧
(abs‘(ℑ‘(log‘𝐴))) ≤ π)) | 
| 56 | 42, 43, 54, 55 | syl3anbrc 1343 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘(ℑ‘(log‘𝐴))) ∈ (0[,]π)) | 
| 57 |  | cosord 26574 | . . . . . . . . 9
⊢ (((π /
2) ∈ (0[,]π) ∧ (abs‘(ℑ‘(log‘𝐴))) ∈ (0[,]π)) →
((π / 2) < (abs‘(ℑ‘(log‘𝐴))) ↔
(cos‘(abs‘(ℑ‘(log‘𝐴)))) < (cos‘(π /
2)))) | 
| 58 | 40, 56, 57 | sylancr 587 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((π / 2) < (abs‘(ℑ‘(log‘𝐴))) ↔
(cos‘(abs‘(ℑ‘(log‘𝐴)))) < (cos‘(π /
2)))) | 
| 59 |  | fveq2 6905 | . . . . . . . . . . 11
⊢
((abs‘(ℑ‘(log‘𝐴))) = (ℑ‘(log‘𝐴)) →
(cos‘(abs‘(ℑ‘(log‘𝐴)))) =
(cos‘(ℑ‘(log‘𝐴)))) | 
| 60 | 59 | a1i 11 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) = (ℑ‘(log‘𝐴)) →
(cos‘(abs‘(ℑ‘(log‘𝐴)))) =
(cos‘(ℑ‘(log‘𝐴))))) | 
| 61 |  | cosneg 16184 | . . . . . . . . . . . 12
⊢
((ℑ‘(log‘𝐴)) ∈ ℂ →
(cos‘-(ℑ‘(log‘𝐴))) =
(cos‘(ℑ‘(log‘𝐴)))) | 
| 62 | 41, 61 | syl 17 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(cos‘-(ℑ‘(log‘𝐴))) =
(cos‘(ℑ‘(log‘𝐴)))) | 
| 63 |  | fveqeq2 6914 | . . . . . . . . . . 11
⊢
((abs‘(ℑ‘(log‘𝐴))) = -(ℑ‘(log‘𝐴)) →
((cos‘(abs‘(ℑ‘(log‘𝐴)))) =
(cos‘(ℑ‘(log‘𝐴))) ↔
(cos‘-(ℑ‘(log‘𝐴))) =
(cos‘(ℑ‘(log‘𝐴))))) | 
| 64 | 62, 63 | syl5ibrcom 247 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) = -(ℑ‘(log‘𝐴)) →
(cos‘(abs‘(ℑ‘(log‘𝐴)))) =
(cos‘(ℑ‘(log‘𝐴))))) | 
| 65 | 3 | absord 15455 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) = (ℑ‘(log‘𝐴)) ∨
(abs‘(ℑ‘(log‘𝐴))) = -(ℑ‘(log‘𝐴)))) | 
| 66 | 60, 64, 65 | mpjaod 860 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(cos‘(abs‘(ℑ‘(log‘𝐴)))) =
(cos‘(ℑ‘(log‘𝐴)))) | 
| 67 |  | coshalfpi 26512 | . . . . . . . . . 10
⊢
(cos‘(π / 2)) = 0 | 
| 68 | 67 | a1i 11 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(cos‘(π / 2)) = 0) | 
| 69 | 66, 68 | breq12d 5155 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((cos‘(abs‘(ℑ‘(log‘𝐴)))) < (cos‘(π / 2)) ↔
(cos‘(ℑ‘(log‘𝐴))) < 0)) | 
| 70 | 58, 69 | bitrd 279 | . . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((π / 2) < (abs‘(ℑ‘(log‘𝐴))) ↔
(cos‘(ℑ‘(log‘𝐴))) < 0)) | 
| 71 | 70 | notbid 318 | . . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(¬ (π / 2) < (abs‘(ℑ‘(log‘𝐴))) ↔ ¬
(cos‘(ℑ‘(log‘𝐴))) < 0)) | 
| 72 |  | lenlt 11340 | . . . . . . 7
⊢
(((abs‘(ℑ‘(log‘𝐴))) ∈ ℝ ∧ (π / 2) ∈
ℝ) → ((abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2) ↔ ¬ (π / 2)
< (abs‘(ℑ‘(log‘𝐴))))) | 
| 73 | 42, 30, 72 | sylancl 586 | . . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2) ↔ ¬ (π / 2)
< (abs‘(ℑ‘(log‘𝐴))))) | 
| 74 | 3 | recoscld 16181 | . . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(cos‘(ℑ‘(log‘𝐴))) ∈ ℝ) | 
| 75 |  | lenlt 11340 | . . . . . . 7
⊢ ((0
∈ ℝ ∧ (cos‘(ℑ‘(log‘𝐴))) ∈ ℝ) → (0 ≤
(cos‘(ℑ‘(log‘𝐴))) ↔ ¬
(cos‘(ℑ‘(log‘𝐴))) < 0)) | 
| 76 | 18, 74, 75 | sylancr 587 | . . . . . 6
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) → (0
≤ (cos‘(ℑ‘(log‘𝐴))) ↔ ¬
(cos‘(ℑ‘(log‘𝐴))) < 0)) | 
| 77 | 71, 73, 76 | 3bitr4d 311 | . . . . 5
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2) ↔ 0 ≤
(cos‘(ℑ‘(log‘𝐴))))) | 
| 78 | 29, 77 | mpbird 257 | . . . 4
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2)) | 
| 79 |  | absle 15355 | . . . . 5
⊢
(((ℑ‘(log‘𝐴)) ∈ ℝ ∧ (π / 2) ∈
ℝ) → ((abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2) ↔ (-(π / 2) ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ (π /
2)))) | 
| 80 | 3, 30, 79 | sylancl 586 | . . . 4
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
((abs‘(ℑ‘(log‘𝐴))) ≤ (π / 2) ↔ (-(π / 2) ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ (π /
2)))) | 
| 81 | 78, 80 | mpbid 232 | . . 3
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(-(π / 2) ≤ (ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ (π /
2))) | 
| 82 | 81 | simpld 494 | . 2
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
-(π / 2) ≤ (ℑ‘(log‘𝐴))) | 
| 83 | 81 | simprd 495 | . 2
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℑ‘(log‘𝐴)) ≤ (π / 2)) | 
| 84 | 30 | renegcli 11571 | . . 3
⊢ -(π /
2) ∈ ℝ | 
| 85 | 84, 30 | elicc2i 13454 | . 2
⊢
((ℑ‘(log‘𝐴)) ∈ (-(π / 2)[,](π / 2)) ↔
((ℑ‘(log‘𝐴)) ∈ ℝ ∧ -(π / 2) ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ (π /
2))) | 
| 86 | 3, 82, 83, 85 | syl3anbrc 1343 | 1
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ 0 ≤
(ℜ‘𝐴)) →
(ℑ‘(log‘𝐴)) ∈ (-(π / 2)[,](π /
2))) |