Proof of Theorem cxpsqrtlem
| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | ax-icn 11214 | . . 3
⊢ i ∈
ℂ | 
| 2 |  | sqrtcl 15400 | . . . 4
⊢ (𝐴 ∈ ℂ →
(√‘𝐴) ∈
ℂ) | 
| 3 | 2 | ad2antrr 726 | . . 3
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (√‘𝐴)
∈ ℂ) | 
| 4 |  | mulcl 11239 | . . 3
⊢ ((i
∈ ℂ ∧ (√‘𝐴) ∈ ℂ) → (i ·
(√‘𝐴)) ∈
ℂ) | 
| 5 | 1, 3, 4 | sylancr 587 | . 2
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (i · (√‘𝐴)) ∈ ℂ) | 
| 6 |  | imval 15146 | . . . 4
⊢ ((i
· (√‘𝐴))
∈ ℂ → (ℑ‘(i · (√‘𝐴))) = (ℜ‘((i ·
(√‘𝐴)) /
i))) | 
| 7 | 5, 6 | syl 17 | . . 3
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℑ‘(i · (√‘𝐴))) = (ℜ‘((i ·
(√‘𝐴)) /
i))) | 
| 8 |  | ine0 11698 | . . . . . 6
⊢ i ≠
0 | 
| 9 |  | divcan3 11948 | . . . . . 6
⊢
(((√‘𝐴)
∈ ℂ ∧ i ∈ ℂ ∧ i ≠ 0) → ((i ·
(√‘𝐴)) / i) =
(√‘𝐴)) | 
| 10 | 1, 8, 9 | mp3an23 1455 | . . . . 5
⊢
((√‘𝐴)
∈ ℂ → ((i · (√‘𝐴)) / i) = (√‘𝐴)) | 
| 11 | 3, 10 | syl 17 | . . . 4
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ ((i · (√‘𝐴)) / i) = (√‘𝐴)) | 
| 12 | 11 | fveq2d 6910 | . . 3
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘((i · (√‘𝐴)) / i)) =
(ℜ‘(√‘𝐴))) | 
| 13 |  | halfre 12480 | . . . . . . . . . . . . 13
⊢ (1 / 2)
∈ ℝ | 
| 14 | 13 | recni 11275 | . . . . . . . . . . . 12
⊢ (1 / 2)
∈ ℂ | 
| 15 |  | logcl 26610 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) ∈
ℂ) | 
| 16 |  | mulcl 11239 | . . . . . . . . . . . 12
⊢ (((1 / 2)
∈ ℂ ∧ (log‘𝐴) ∈ ℂ) → ((1 / 2) ·
(log‘𝐴)) ∈
ℂ) | 
| 17 | 14, 15, 16 | sylancr 587 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((1 / 2)
· (log‘𝐴))
∈ ℂ) | 
| 18 | 17 | recld 15233 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℜ‘((1 / 2) · (log‘𝐴))) ∈ ℝ) | 
| 19 | 18 | reefcld 16124 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) ∈ ℝ) | 
| 20 | 17 | imcld 15234 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘((1 / 2) · (log‘𝐴))) ∈ ℝ) | 
| 21 | 20 | recoscld 16180 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) ∈ ℝ) | 
| 22 | 18 | rpefcld 16141 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) ∈
ℝ+) | 
| 23 | 22 | rpge0d 13081 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 0 ≤
(exp‘(ℜ‘((1 / 2) · (log‘𝐴))))) | 
| 24 |  | immul2 15176 | . . . . . . . . . . . . 13
⊢ (((1 / 2)
∈ ℝ ∧ (log‘𝐴) ∈ ℂ) → (ℑ‘((1
/ 2) · (log‘𝐴))) = ((1 / 2) ·
(ℑ‘(log‘𝐴)))) | 
| 25 | 13, 15, 24 | sylancr 587 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘((1 / 2) · (log‘𝐴))) = ((1 / 2) ·
(ℑ‘(log‘𝐴)))) | 
| 26 | 15 | imcld 15234 | . . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘(log‘𝐴)) ∈ ℝ) | 
| 27 | 26 | recnd 11289 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘(log‘𝐴)) ∈ ℂ) | 
| 28 |  | mulcom 11241 | . . . . . . . . . . . . 13
⊢ (((1 / 2)
∈ ℂ ∧ (ℑ‘(log‘𝐴)) ∈ ℂ) → ((1 / 2) ·
(ℑ‘(log‘𝐴))) = ((ℑ‘(log‘𝐴)) · (1 /
2))) | 
| 29 | 14, 27, 28 | sylancr 587 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((1 / 2)
· (ℑ‘(log‘𝐴))) = ((ℑ‘(log‘𝐴)) · (1 /
2))) | 
| 30 | 25, 29 | eqtrd 2777 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘((1 / 2) · (log‘𝐴))) = ((ℑ‘(log‘𝐴)) · (1 /
2))) | 
| 31 |  | logimcl 26611 | . . . . . . . . . . . . . . 15
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-π <
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π)) | 
| 32 | 31 | simpld 494 | . . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -π <
(ℑ‘(log‘𝐴))) | 
| 33 |  | pire 26500 | . . . . . . . . . . . . . . . 16
⊢ π
∈ ℝ | 
| 34 | 33 | renegcli 11570 | . . . . . . . . . . . . . . 15
⊢ -π
∈ ℝ | 
| 35 |  | ltle 11349 | . . . . . . . . . . . . . . 15
⊢ ((-π
∈ ℝ ∧ (ℑ‘(log‘𝐴)) ∈ ℝ) → (-π <
(ℑ‘(log‘𝐴)) → -π ≤
(ℑ‘(log‘𝐴)))) | 
| 36 | 34, 26, 35 | sylancr 587 | . . . . . . . . . . . . . 14
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-π <
(ℑ‘(log‘𝐴)) → -π ≤
(ℑ‘(log‘𝐴)))) | 
| 37 | 32, 36 | mpd 15 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -π ≤
(ℑ‘(log‘𝐴))) | 
| 38 | 31 | simprd 495 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘(log‘𝐴)) ≤ π) | 
| 39 | 34, 33 | elicc2i 13453 | . . . . . . . . . . . . 13
⊢
((ℑ‘(log‘𝐴)) ∈ (-π[,]π) ↔
((ℑ‘(log‘𝐴)) ∈ ℝ ∧ -π ≤
(ℑ‘(log‘𝐴)) ∧ (ℑ‘(log‘𝐴)) ≤ π)) | 
| 40 | 26, 37, 38, 39 | syl3anbrc 1344 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘(log‘𝐴)) ∈ (-π[,]π)) | 
| 41 |  | halfgt0 12482 | . . . . . . . . . . . . . 14
⊢ 0 < (1
/ 2) | 
| 42 | 13, 41 | elrpii 13037 | . . . . . . . . . . . . 13
⊢ (1 / 2)
∈ ℝ+ | 
| 43 | 33 | recni 11275 | . . . . . . . . . . . . . . 15
⊢ π
∈ ℂ | 
| 44 |  | 2cn 12341 | . . . . . . . . . . . . . . 15
⊢ 2 ∈
ℂ | 
| 45 |  | 2ne0 12370 | . . . . . . . . . . . . . . 15
⊢ 2 ≠
0 | 
| 46 |  | divneg 11959 | . . . . . . . . . . . . . . 15
⊢ ((π
∈ ℂ ∧ 2 ∈ ℂ ∧ 2 ≠ 0) → -(π / 2) =
(-π / 2)) | 
| 47 | 43, 44, 45, 46 | mp3an 1463 | . . . . . . . . . . . . . 14
⊢ -(π /
2) = (-π / 2) | 
| 48 | 34 | recni 11275 | . . . . . . . . . . . . . . 15
⊢ -π
∈ ℂ | 
| 49 | 48, 44, 45 | divreci 12012 | . . . . . . . . . . . . . 14
⊢ (-π /
2) = (-π · (1 / 2)) | 
| 50 | 47, 49 | eqtr2i 2766 | . . . . . . . . . . . . 13
⊢ (-π
· (1 / 2)) = -(π / 2) | 
| 51 | 43, 44, 45 | divreci 12012 | . . . . . . . . . . . . . 14
⊢ (π /
2) = (π · (1 / 2)) | 
| 52 | 51 | eqcomi 2746 | . . . . . . . . . . . . 13
⊢ (π
· (1 / 2)) = (π / 2) | 
| 53 | 34, 33, 42, 50, 52 | iccdili 13531 | . . . . . . . . . . . 12
⊢
((ℑ‘(log‘𝐴)) ∈ (-π[,]π) →
((ℑ‘(log‘𝐴)) · (1 / 2)) ∈ (-(π /
2)[,](π / 2))) | 
| 54 | 40, 53 | syl 17 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
((ℑ‘(log‘𝐴)) · (1 / 2)) ∈ (-(π /
2)[,](π / 2))) | 
| 55 | 30, 54 | eqeltrd 2841 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℑ‘((1 / 2) · (log‘𝐴))) ∈ (-(π / 2)[,](π /
2))) | 
| 56 |  | cosq14ge0 26553 | . . . . . . . . . 10
⊢
((ℑ‘((1 / 2) · (log‘𝐴))) ∈ (-(π / 2)[,](π / 2)) →
0 ≤ (cos‘(ℑ‘((1 / 2) · (log‘𝐴))))) | 
| 57 | 55, 56 | syl 17 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 0 ≤
(cos‘(ℑ‘((1 / 2) · (log‘𝐴))))) | 
| 58 | 19, 21, 23, 57 | mulge0d 11840 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 0 ≤
((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) · (cos‘(ℑ‘((1
/ 2) · (log‘𝐴)))))) | 
| 59 |  | cxpef 26707 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0 ∧ (1 / 2) ∈
ℂ) → (𝐴↑𝑐(1 / 2)) =
(exp‘((1 / 2) · (log‘𝐴)))) | 
| 60 | 14, 59 | mp3an3 1452 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (𝐴↑𝑐(1 /
2)) = (exp‘((1 / 2) · (log‘𝐴)))) | 
| 61 |  | efeul 16198 | . . . . . . . . . . . 12
⊢ (((1 / 2)
· (log‘𝐴))
∈ ℂ → (exp‘((1 / 2) · (log‘𝐴))) = ((exp‘(ℜ‘((1 / 2)
· (log‘𝐴))))
· ((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))))) | 
| 62 | 17, 61 | syl 17 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘((1 /
2) · (log‘𝐴)))
= ((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) · ((cos‘(ℑ‘((1
/ 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))))) | 
| 63 | 60, 62 | eqtrd 2777 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (𝐴↑𝑐(1 /
2)) = ((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) · ((cos‘(ℑ‘((1
/ 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))))) | 
| 64 | 63 | fveq2d 6910 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℜ‘(𝐴↑𝑐(1 / 2))) =
(ℜ‘((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) ·
((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴))))))))) | 
| 65 | 21 | recnd 11289 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) ∈ ℂ) | 
| 66 | 20 | resincld 16179 | . . . . . . . . . . . . 13
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))) ∈ ℝ) | 
| 67 | 66 | recnd 11289 | . . . . . . . . . . . 12
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))) ∈ ℂ) | 
| 68 |  | mulcl 11239 | . . . . . . . . . . . 12
⊢ ((i
∈ ℂ ∧ (sin‘(ℑ‘((1 / 2) ·
(log‘𝐴)))) ∈
ℂ) → (i · (sin‘(ℑ‘((1 / 2) ·
(log‘𝐴))))) ∈
ℂ) | 
| 69 | 1, 67, 68 | sylancr 587 | . . . . . . . . . . 11
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴))))) ∈ ℂ) | 
| 70 | 65, 69 | addcld 11280 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))) ∈ ℂ) | 
| 71 | 19, 70 | remul2d 15266 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℜ‘((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) ·
((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))))) = ((exp‘(ℜ‘((1 /
2) · (log‘𝐴)))) ·
(ℜ‘((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴))))))))) | 
| 72 | 21, 66 | crred 15270 | . . . . . . . . . 10
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℜ‘((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴))))))) = (cos‘(ℑ‘((1 / 2)
· (log‘𝐴))))) | 
| 73 | 72 | oveq2d 7447 | . . . . . . . . 9
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) ·
(ℜ‘((cos‘(ℑ‘((1 / 2) · (log‘𝐴)))) + (i ·
(sin‘(ℑ‘((1 / 2) · (log‘𝐴)))))))) = ((exp‘(ℜ‘((1 /
2) · (log‘𝐴)))) · (cos‘(ℑ‘((1
/ 2) · (log‘𝐴)))))) | 
| 74 | 64, 71, 73 | 3eqtrd 2781 | . . . . . . . 8
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) →
(ℜ‘(𝐴↑𝑐(1 / 2))) =
((exp‘(ℜ‘((1 / 2) · (log‘𝐴)))) · (cos‘(ℑ‘((1
/ 2) · (log‘𝐴)))))) | 
| 75 | 58, 74 | breqtrrd 5171 | . . . . . . 7
⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 0 ≤
(ℜ‘(𝐴↑𝑐(1 /
2)))) | 
| 76 | 75 | adantr 480 | . . . . . 6
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ 0 ≤ (ℜ‘(𝐴↑𝑐(1 /
2)))) | 
| 77 |  | simpr 484 | . . . . . . . 8
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (𝐴↑𝑐(1 / 2)) =
-(√‘𝐴)) | 
| 78 | 77 | fveq2d 6910 | . . . . . . 7
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘(𝐴↑𝑐(1 / 2))) =
(ℜ‘-(√‘𝐴))) | 
| 79 | 3 | renegd 15248 | . . . . . . 7
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘-(√‘𝐴)) = -(ℜ‘(√‘𝐴))) | 
| 80 | 78, 79 | eqtrd 2777 | . . . . . 6
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘(𝐴↑𝑐(1 / 2))) =
-(ℜ‘(√‘𝐴))) | 
| 81 | 76, 80 | breqtrd 5169 | . . . . 5
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ 0 ≤ -(ℜ‘(√‘𝐴))) | 
| 82 | 3 | recld 15233 | . . . . . 6
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘(√‘𝐴)) ∈ ℝ) | 
| 83 | 82 | le0neg1d 11834 | . . . . 5
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ ((ℜ‘(√‘𝐴)) ≤ 0 ↔ 0 ≤
-(ℜ‘(√‘𝐴)))) | 
| 84 | 81, 83 | mpbird 257 | . . . 4
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘(√‘𝐴)) ≤ 0) | 
| 85 |  | sqrtrege0 15404 | . . . . 5
⊢ (𝐴 ∈ ℂ → 0 ≤
(ℜ‘(√‘𝐴))) | 
| 86 | 85 | ad2antrr 726 | . . . 4
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ 0 ≤ (ℜ‘(√‘𝐴))) | 
| 87 |  | 0re 11263 | . . . . 5
⊢ 0 ∈
ℝ | 
| 88 |  | letri3 11346 | . . . . 5
⊢
(((ℜ‘(√‘𝐴)) ∈ ℝ ∧ 0 ∈ ℝ)
→ ((ℜ‘(√‘𝐴)) = 0 ↔
((ℜ‘(√‘𝐴)) ≤ 0 ∧ 0 ≤
(ℜ‘(√‘𝐴))))) | 
| 89 | 82, 87, 88 | sylancl 586 | . . . 4
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ ((ℜ‘(√‘𝐴)) = 0 ↔
((ℜ‘(√‘𝐴)) ≤ 0 ∧ 0 ≤
(ℜ‘(√‘𝐴))))) | 
| 90 | 84, 86, 89 | mpbir2and 713 | . . 3
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℜ‘(√‘𝐴)) = 0) | 
| 91 | 7, 12, 90 | 3eqtrd 2781 | . 2
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (ℑ‘(i · (√‘𝐴))) = 0) | 
| 92 | 5, 91 | reim0bd 15239 | 1
⊢ (((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) ∧ (𝐴↑𝑐(1 /
2)) = -(√‘𝐴))
→ (i · (√‘𝐴)) ∈ ℝ) |