Proof of Theorem cotsqcscsq
Step | Hyp | Ref
| Expression |
1 | | cotval 46337 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (cot‘𝐴) =
((cos‘𝐴) /
(sin‘𝐴))) |
2 | 1 | oveq1d 7270 |
. . 3
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((cot‘𝐴)↑2) = (((cos‘𝐴) / (sin‘𝐴))↑2)) |
3 | 2 | oveq2d 7271 |
. 2
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (1 + ((cot‘𝐴)↑2)) = (1 + (((cos‘𝐴) / (sin‘𝐴))↑2))) |
4 | | sincossq 15813 |
. . . . 5
⊢ (𝐴 ∈ ℂ →
(((sin‘𝐴)↑2) +
((cos‘𝐴)↑2)) =
1) |
5 | 4 | oveq1d 7270 |
. . . 4
⊢ (𝐴 ∈ ℂ →
((((sin‘𝐴)↑2) +
((cos‘𝐴)↑2)) /
((sin‘𝐴)↑2)) =
(1 / ((sin‘𝐴)↑2))) |
6 | 5 | adantr 480 |
. . 3
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) / ((sin‘𝐴)↑2)) = (1 / ((sin‘𝐴)↑2))) |
7 | | sincl 15763 |
. . . . . . . 8
⊢ (𝐴 ∈ ℂ →
(sin‘𝐴) ∈
ℂ) |
8 | 7 | sqcld 13790 |
. . . . . . 7
⊢ (𝐴 ∈ ℂ →
((sin‘𝐴)↑2)
∈ ℂ) |
9 | 8 | adantr 480 |
. . . . . 6
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((sin‘𝐴)↑2) ∈ ℂ) |
10 | | sqne0 13771 |
. . . . . . . 8
⊢
((sin‘𝐴)
∈ ℂ → (((sin‘𝐴)↑2) ≠ 0 ↔ (sin‘𝐴) ≠ 0)) |
11 | 7, 10 | syl 17 |
. . . . . . 7
⊢ (𝐴 ∈ ℂ →
(((sin‘𝐴)↑2)
≠ 0 ↔ (sin‘𝐴)
≠ 0)) |
12 | 11 | biimpar 477 |
. . . . . 6
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((sin‘𝐴)↑2) ≠ 0) |
13 | 9, 12 | dividd 11679 |
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (((sin‘𝐴)↑2) / ((sin‘𝐴)↑2)) = 1) |
14 | 13 | oveq1d 7270 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((((sin‘𝐴)↑2) / ((sin‘𝐴)↑2)) + (((cos‘𝐴)↑2) / ((sin‘𝐴)↑2))) = (1 + (((cos‘𝐴)↑2) / ((sin‘𝐴)↑2)))) |
15 | | coscl 15764 |
. . . . . . 7
⊢ (𝐴 ∈ ℂ →
(cos‘𝐴) ∈
ℂ) |
16 | 15 | sqcld 13790 |
. . . . . 6
⊢ (𝐴 ∈ ℂ →
((cos‘𝐴)↑2)
∈ ℂ) |
17 | 16 | adantr 480 |
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((cos‘𝐴)↑2) ∈ ℂ) |
18 | 9, 17, 9, 12 | divdird 11719 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) / ((sin‘𝐴)↑2)) = ((((sin‘𝐴)↑2) / ((sin‘𝐴)↑2)) + (((cos‘𝐴)↑2) / ((sin‘𝐴)↑2)))) |
19 | 15, 7 | jca 511 |
. . . . . 6
⊢ (𝐴 ∈ ℂ →
((cos‘𝐴) ∈
ℂ ∧ (sin‘𝐴)
∈ ℂ)) |
20 | | 2nn0 12180 |
. . . . . . . 8
⊢ 2 ∈
ℕ0 |
21 | | expdiv 13762 |
. . . . . . . 8
⊢
(((cos‘𝐴)
∈ ℂ ∧ ((sin‘𝐴) ∈ ℂ ∧ (sin‘𝐴) ≠ 0) ∧ 2 ∈
ℕ0) → (((cos‘𝐴) / (sin‘𝐴))↑2) = (((cos‘𝐴)↑2) / ((sin‘𝐴)↑2))) |
22 | 20, 21 | mp3an3 1448 |
. . . . . . 7
⊢
(((cos‘𝐴)
∈ ℂ ∧ ((sin‘𝐴) ∈ ℂ ∧ (sin‘𝐴) ≠ 0)) →
(((cos‘𝐴) /
(sin‘𝐴))↑2) =
(((cos‘𝐴)↑2) /
((sin‘𝐴)↑2))) |
23 | 22 | anassrs 467 |
. . . . . 6
⊢
((((cos‘𝐴)
∈ ℂ ∧ (sin‘𝐴) ∈ ℂ) ∧ (sin‘𝐴) ≠ 0) →
(((cos‘𝐴) /
(sin‘𝐴))↑2) =
(((cos‘𝐴)↑2) /
((sin‘𝐴)↑2))) |
24 | 19, 23 | sylan 579 |
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (((cos‘𝐴) /
(sin‘𝐴))↑2) =
(((cos‘𝐴)↑2) /
((sin‘𝐴)↑2))) |
25 | 24 | oveq2d 7271 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (1 + (((cos‘𝐴)
/ (sin‘𝐴))↑2)) =
(1 + (((cos‘𝐴)↑2) / ((sin‘𝐴)↑2)))) |
26 | 14, 18, 25 | 3eqtr4rd 2789 |
. . 3
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (1 + (((cos‘𝐴)
/ (sin‘𝐴))↑2)) =
((((sin‘𝐴)↑2) +
((cos‘𝐴)↑2)) /
((sin‘𝐴)↑2))) |
27 | | cscval 46336 |
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (csc‘𝐴) = (1 /
(sin‘𝐴))) |
28 | 27 | oveq1d 7270 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((csc‘𝐴)↑2) = ((1 / (sin‘𝐴))↑2)) |
29 | | ax-1cn 10860 |
. . . . . . 7
⊢ 1 ∈
ℂ |
30 | | expdiv 13762 |
. . . . . . 7
⊢ ((1
∈ ℂ ∧ ((sin‘𝐴) ∈ ℂ ∧ (sin‘𝐴) ≠ 0) ∧ 2 ∈
ℕ0) → ((1 / (sin‘𝐴))↑2) = ((1↑2) / ((sin‘𝐴)↑2))) |
31 | 29, 20, 30 | mp3an13 1450 |
. . . . . 6
⊢
(((sin‘𝐴)
∈ ℂ ∧ (sin‘𝐴) ≠ 0) → ((1 / (sin‘𝐴))↑2) = ((1↑2) /
((sin‘𝐴)↑2))) |
32 | 7, 31 | sylan 579 |
. . . . 5
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((1 / (sin‘𝐴))↑2) = ((1↑2) / ((sin‘𝐴)↑2))) |
33 | | sq1 13840 |
. . . . . 6
⊢
(1↑2) = 1 |
34 | 33 | oveq1i 7265 |
. . . . 5
⊢
((1↑2) / ((sin‘𝐴)↑2)) = (1 / ((sin‘𝐴)↑2)) |
35 | 32, 34 | eqtrdi 2795 |
. . . 4
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((1 / (sin‘𝐴))↑2) = (1 / ((sin‘𝐴)↑2))) |
36 | 28, 35 | eqtrd 2778 |
. . 3
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((csc‘𝐴)↑2) = (1 / ((sin‘𝐴)↑2))) |
37 | 6, 26, 36 | 3eqtr4rd 2789 |
. 2
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ ((csc‘𝐴)↑2) = (1 + (((cos‘𝐴) / (sin‘𝐴))↑2))) |
38 | 3, 37 | eqtr4d 2781 |
1
⊢ ((𝐴 ∈ ℂ ∧
(sin‘𝐴) ≠ 0)
→ (1 + ((cot‘𝐴)↑2)) = ((csc‘𝐴)↑2)) |