| Step | Hyp | Ref
| Expression |
| 1 | | df-sec 50657 |
. . 3
⊢ sec =
(𝑥 ∈ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ (1 / (cos‘𝑥))) |
| 2 | 1 | oveq2i 7427 |
. 2
⊢ (ℂ
D sec) = (ℂ D (𝑥
∈ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0} ↦ (1 / (cos‘𝑥)))) |
| 3 | | cnelprrecn 11220 |
. . . . . 6
⊢ ℂ
∈ {ℝ, ℂ} |
| 4 | 3 | a1i 11 |
. . . . 5
⊢ (⊤
→ ℂ ∈ {ℝ, ℂ}) |
| 5 | | 1cnd 11229 |
. . . . 5
⊢ (⊤
→ 1 ∈ ℂ) |
| 6 | | elrabi 3644 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → 𝑥 ∈
ℂ) |
| 7 | | coscl 16219 |
. . . . . . . . 9
⊢ (𝑥 ∈ ℂ →
(cos‘𝑥) ∈
ℂ) |
| 8 | 6, 7 | syl 18 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(cos‘𝑥) ∈
ℂ) |
| 9 | | fveq2 6882 |
. . . . . . . . . . 11
⊢ (𝑦 = 𝑥 → (cos‘𝑦) = (cos‘𝑥)) |
| 10 | 9 | neeq1d 3016 |
. . . . . . . . . 10
⊢ (𝑦 = 𝑥 → ((cos‘𝑦) ≠ 0 ↔ (cos‘𝑥) ≠ 0)) |
| 11 | 10 | elrab 3648 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↔ (𝑥 ∈ ℂ ∧
(cos‘𝑥) ≠
0)) |
| 12 | 11 | simprbi 503 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(cos‘𝑥) ≠
0) |
| 13 | 8, 12 | jca 521 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((cos‘𝑥) ∈
ℂ ∧ (cos‘𝑥)
≠ 0)) |
| 14 | | eldifsn 4751 |
. . . . . . 7
⊢
((cos‘𝑥)
∈ (ℂ ∖ {0}) ↔ ((cos‘𝑥) ∈ ℂ ∧ (cos‘𝑥) ≠ 0)) |
| 15 | 13, 14 | sylibr 237 |
. . . . . 6
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(cos‘𝑥) ∈
(ℂ ∖ {0})) |
| 16 | 15 | adantl 487 |
. . . . 5
⊢
((⊤ ∧ 𝑥
∈ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0}) → (cos‘𝑥)
∈ (ℂ ∖ {0})) |
| 17 | | sincl 16218 |
. . . . . . . 8
⊢ (𝑥 ∈ ℂ →
(sin‘𝑥) ∈
ℂ) |
| 18 | 6, 17 | syl 18 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(sin‘𝑥) ∈
ℂ) |
| 19 | 18 | adantl 487 |
. . . . . 6
⊢
((⊤ ∧ 𝑥
∈ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0}) → (sin‘𝑥)
∈ ℂ) |
| 20 | 19 | negcld 11583 |
. . . . 5
⊢
((⊤ ∧ 𝑥
∈ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0}) → -(sin‘𝑥)
∈ ℂ) |
| 21 | 7 | adantl 487 |
. . . . . 6
⊢
((⊤ ∧ 𝑥
∈ ℂ) → (cos‘𝑥) ∈ ℂ) |
| 22 | 17 | negcld 11583 |
. . . . . . 7
⊢ (𝑥 ∈ ℂ →
-(sin‘𝑥) ∈
ℂ) |
| 23 | 22 | adantl 487 |
. . . . . 6
⊢
((⊤ ∧ 𝑥
∈ ℂ) → -(sin‘𝑥) ∈ ℂ) |
| 24 | | cosf 16217 |
. . . . . . . . . . . 12
⊢
cos:ℂ⟶ℂ |
| 25 | 24 | a1i 11 |
. . . . . . . . . . 11
⊢ (⊤
→ cos:ℂ⟶ℂ) |
| 26 | 25 | feqmptd 6950 |
. . . . . . . . . 10
⊢ (⊤
→ cos = (𝑥 ∈
ℂ ↦ (cos‘𝑥))) |
| 27 | 26 | mptru 1577 |
. . . . . . . . 9
⊢ cos =
(𝑥 ∈ ℂ ↦
(cos‘𝑥)) |
| 28 | 27 | oveq2i 7427 |
. . . . . . . 8
⊢ (ℂ
D cos) = (ℂ D (𝑥
∈ ℂ ↦ (cos‘𝑥))) |
| 29 | | dvcos 26212 |
. . . . . . . 8
⊢ (ℂ
D cos) = (𝑥 ∈ ℂ
↦ -(sin‘𝑥)) |
| 30 | 28, 29 | eqtr3i 2787 |
. . . . . . 7
⊢ (ℂ
D (𝑥 ∈ ℂ ↦
(cos‘𝑥))) = (𝑥 ∈ ℂ ↦
-(sin‘𝑥)) |
| 31 | 30 | a1i 11 |
. . . . . 6
⊢ (⊤
→ (ℂ D (𝑥 ∈
ℂ ↦ (cos‘𝑥))) = (𝑥 ∈ ℂ ↦ -(sin‘𝑥))) |
| 32 | | ssrab2 4031 |
. . . . . . 7
⊢ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
⊆ ℂ |
| 33 | 32 | a1i 11 |
. . . . . 6
⊢ (⊤
→ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0} ⊆ ℂ) |
| 34 | | eqid 2762 |
. . . . . . . 8
⊢
(TopOpen‘ℂfld) =
(TopOpen‘ℂfld) |
| 35 | 34 | cnfldtopon 25009 |
. . . . . . 7
⊢
(TopOpen‘ℂfld) ∈
(TopOn‘ℂ) |
| 36 | 35 | toponrestid 23147 |
. . . . . 6
⊢
(TopOpen‘ℂfld) =
((TopOpen‘ℂfld) ↾t
ℂ) |
| 37 | | coscn 26678 |
. . . . . . . . . 10
⊢ cos
∈ (ℂ–cn→ℂ) |
| 38 | | ssid 3956 |
. . . . . . . . . . 11
⊢ ℂ
⊆ ℂ |
| 39 | 34, 36, 36 | cncfcn 25139 |
. . . . . . . . . . 11
⊢ ((ℂ
⊆ ℂ ∧ ℂ ⊆ ℂ) → (ℂ–cn→ℂ) =
((TopOpen‘ℂfld) Cn
(TopOpen‘ℂfld))) |
| 40 | 38, 38, 39 | mp2an 705 |
. . . . . . . . . 10
⊢
(ℂ–cn→ℂ) =
((TopOpen‘ℂfld) Cn
(TopOpen‘ℂfld)) |
| 41 | 37, 40 | eleqtri 2860 |
. . . . . . . . 9
⊢ cos
∈ ((TopOpen‘ℂfld) Cn
(TopOpen‘ℂfld)) |
| 42 | | cnn0opn 25014 |
. . . . . . . . 9
⊢ (ℂ
∖ {0}) ∈ (TopOpen‘ℂfld) |
| 43 | | cnima 23491 |
. . . . . . . . 9
⊢ ((cos
∈ ((TopOpen‘ℂfld) Cn
(TopOpen‘ℂfld)) ∧ (ℂ ∖ {0}) ∈
(TopOpen‘ℂfld)) → (◡cos “ (ℂ ∖ {0})) ∈
(TopOpen‘ℂfld)) |
| 44 | 41, 42, 43 | mp2an 705 |
. . . . . . . 8
⊢ (◡cos “ (ℂ ∖ {0})) ∈
(TopOpen‘ℂfld) |
| 45 | | coscl 16219 |
. . . . . . . . . . . . 13
⊢ (𝑦 ∈ ℂ →
(cos‘𝑦) ∈
ℂ) |
| 46 | | eldifsn 4751 |
. . . . . . . . . . . . . 14
⊢
((cos‘𝑦)
∈ (ℂ ∖ {0}) ↔ ((cos‘𝑦) ∈ ℂ ∧ (cos‘𝑦) ≠ 0)) |
| 47 | 46 | baib 545 |
. . . . . . . . . . . . 13
⊢
((cos‘𝑦)
∈ ℂ → ((cos‘𝑦) ∈ (ℂ ∖ {0}) ↔
(cos‘𝑦) ≠
0)) |
| 48 | 45, 47 | syl 18 |
. . . . . . . . . . . 12
⊢ (𝑦 ∈ ℂ →
((cos‘𝑦) ∈
(ℂ ∖ {0}) ↔ (cos‘𝑦) ≠ 0)) |
| 49 | 48 | bicomd 226 |
. . . . . . . . . . 11
⊢ (𝑦 ∈ ℂ →
((cos‘𝑦) ≠ 0
↔ (cos‘𝑦) ∈
(ℂ ∖ {0}))) |
| 50 | 49 | rabbiia 3418 |
. . . . . . . . . 10
⊢ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0} =
{𝑦 ∈ ℂ ∣
(cos‘𝑦) ∈
(ℂ ∖ {0})} |
| 51 | 25 | feqmptd 6950 |
. . . . . . . . . . . 12
⊢ (⊤
→ cos = (𝑦 ∈
ℂ ↦ (cos‘𝑦))) |
| 52 | 51 | mptru 1577 |
. . . . . . . . . . 11
⊢ cos =
(𝑦 ∈ ℂ ↦
(cos‘𝑦)) |
| 53 | 52 | mptpreima 6238 |
. . . . . . . . . 10
⊢ (◡cos “ (ℂ ∖ {0})) = {𝑦 ∈ ℂ ∣
(cos‘𝑦) ∈
(ℂ ∖ {0})} |
| 54 | 50, 53 | eqtr4i 2788 |
. . . . . . . . 9
⊢ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0} =
(◡cos “ (ℂ ∖
{0})) |
| 55 | 54 | eleq1i 2853 |
. . . . . . . 8
⊢ ({𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
∈ (TopOpen‘ℂfld) ↔ (◡cos “ (ℂ ∖ {0})) ∈
(TopOpen‘ℂfld)) |
| 56 | 44, 55 | mpbir 234 |
. . . . . . 7
⊢ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
∈ (TopOpen‘ℂfld) |
| 57 | 56 | a1i 11 |
. . . . . 6
⊢ (⊤
→ {𝑦 ∈ ℂ
∣ (cos‘𝑦) ≠
0} ∈ (TopOpen‘ℂfld)) |
| 58 | 4, 21, 23, 31, 33, 36, 34, 57 | dvmptres 26192 |
. . . . 5
⊢ (⊤
→ (ℂ D (𝑥 ∈
{𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ (cos‘𝑥))) =
(𝑥 ∈ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ -(sin‘𝑥))) |
| 59 | 4, 5, 16, 20, 58 | dvrecg 26202 |
. . . 4
⊢ (⊤
→ (ℂ D (𝑥 ∈
{𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ (1 / (cos‘𝑥)))) = (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↦ -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)))) |
| 60 | 59 | mptru 1577 |
. . 3
⊢ (ℂ
D (𝑥 ∈ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ (1 / (cos‘𝑥)))) = (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↦ -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2))) |
| 61 | 18 | negcld 11583 |
. . . . . . . . . . 11
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
-(sin‘𝑥) ∈
ℂ) |
| 62 | 61 | mullidd 11254 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → (1 ·
-(sin‘𝑥)) =
-(sin‘𝑥)) |
| 63 | | sqval 14180 |
. . . . . . . . . . 11
⊢
((cos‘𝑥)
∈ ℂ → ((cos‘𝑥)↑2) = ((cos‘𝑥) · (cos‘𝑥))) |
| 64 | 8, 63 | syl 18 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((cos‘𝑥)↑2) =
((cos‘𝑥) ·
(cos‘𝑥))) |
| 65 | 62, 64 | oveq12d 7434 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → ((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)) =
(-(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 66 | 65 | negeqd 11478 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)) =
-(-(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 67 | 8, 8 | mulcld 11256 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((cos‘𝑥) ·
(cos‘𝑥)) ∈
ℂ) |
| 68 | 8, 8, 12, 12 | mulne0d 11893 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((cos‘𝑥) ·
(cos‘𝑥)) ≠
0) |
| 69 | 61, 67, 68 | divnegd 12031 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
-(-(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥))) =
(--(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 70 | 18 | negnegd 11587 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
--(sin‘𝑥) =
(sin‘𝑥)) |
| 71 | 70 | oveq1d 7431 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(--(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥))) =
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 72 | 69, 71 | eqtrd 2797 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
-(-(sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥))) =
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 73 | 66, 72 | eqtrd 2797 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)) =
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 74 | | ax-1cn 11185 |
. . . . . . . . . . 11
⊢ 1 ∈
ℂ |
| 75 | 74 | a1i 11 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → 1 ∈
ℂ) |
| 76 | 75, 8, 18, 8, 12, 12 | divmuldivd 12059 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → ((1 /
(cos‘𝑥)) ·
((sin‘𝑥) /
(cos‘𝑥))) = ((1
· (sin‘𝑥)) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 77 | 18 | mullidd 11254 |
. . . . . . . . . 10
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → (1 ·
(sin‘𝑥)) =
(sin‘𝑥)) |
| 78 | 77 | oveq1d 7431 |
. . . . . . . . 9
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → ((1 ·
(sin‘𝑥)) /
((cos‘𝑥) ·
(cos‘𝑥))) =
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 79 | 76, 78 | eqtrd 2797 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → ((1 /
(cos‘𝑥)) ·
((sin‘𝑥) /
(cos‘𝑥))) =
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥)))) |
| 80 | 79 | eqcomd 2768 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((sin‘𝑥) /
((cos‘𝑥) ·
(cos‘𝑥))) = ((1 /
(cos‘𝑥)) ·
((sin‘𝑥) /
(cos‘𝑥)))) |
| 81 | 73, 80 | eqtrd 2797 |
. . . . . 6
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)) =
((1 / (cos‘𝑥))
· ((sin‘𝑥) /
(cos‘𝑥)))) |
| 82 | | secval 50660 |
. . . . . . . . 9
⊢ ((𝑥 ∈ ℂ ∧
(cos‘𝑥) ≠ 0)
→ (sec‘𝑥) = (1 /
(cos‘𝑥))) |
| 83 | 11, 82 | sylbi 220 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(sec‘𝑥) = (1 /
(cos‘𝑥))) |
| 84 | 83 | eqcomd 2768 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → (1 /
(cos‘𝑥)) =
(sec‘𝑥)) |
| 85 | | tanval 16220 |
. . . . . . . . 9
⊢ ((𝑥 ∈ ℂ ∧
(cos‘𝑥) ≠ 0)
→ (tan‘𝑥) =
((sin‘𝑥) /
(cos‘𝑥))) |
| 86 | 11, 85 | sylbi 220 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
(tan‘𝑥) =
((sin‘𝑥) /
(cos‘𝑥))) |
| 87 | 86 | eqcomd 2768 |
. . . . . . 7
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} →
((sin‘𝑥) /
(cos‘𝑥)) =
(tan‘𝑥)) |
| 88 | 84, 87 | oveq12d 7434 |
. . . . . 6
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → ((1 /
(cos‘𝑥)) ·
((sin‘𝑥) /
(cos‘𝑥))) =
((sec‘𝑥) ·
(tan‘𝑥))) |
| 89 | 81, 88 | eqtrd 2797 |
. . . . 5
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2)) =
((sec‘𝑥) ·
(tan‘𝑥))) |
| 90 | 89 | mpteq2ia 5204 |
. . . 4
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↦ -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2))) =
(𝑥 ∈ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ ((sec‘𝑥)
· (tan‘𝑥))) |
| 91 | 75, 8, 12 | divcld 12018 |
. . . . . . . 8
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} → (1 /
(cos‘𝑥)) ∈
ℂ) |
| 92 | 1, 91 | fmpti 7108 |
. . . . . . 7
⊢
sec:{𝑦 ∈
ℂ ∣ (cos‘𝑦) ≠ 0}⟶ℂ |
| 93 | 92 | fdmi 6718 |
. . . . . 6
⊢ dom sec =
{𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠
0} |
| 94 | 93 | eqcomi 2771 |
. . . . 5
⊢ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0} = dom
sec |
| 95 | 94 | mpteq1i 5200 |
. . . 4
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↦
((sec‘𝑥) ·
(tan‘𝑥))) = (𝑥 ∈ dom sec ↦
((sec‘𝑥) ·
(tan‘𝑥))) |
| 96 | 90, 95 | eqtri 2785 |
. . 3
⊢ (𝑥 ∈ {𝑦 ∈ ℂ ∣ (cos‘𝑦) ≠ 0} ↦ -((1 ·
-(sin‘𝑥)) /
((cos‘𝑥)↑2))) =
(𝑥 ∈ dom sec ↦
((sec‘𝑥) ·
(tan‘𝑥))) |
| 97 | 60, 96 | eqtri 2785 |
. 2
⊢ (ℂ
D (𝑥 ∈ {𝑦 ∈ ℂ ∣
(cos‘𝑦) ≠ 0}
↦ (1 / (cos‘𝑥)))) = (𝑥 ∈ dom sec ↦ ((sec‘𝑥) · (tan‘𝑥))) |
| 98 | 2, 97 | eqtri 2785 |
1
⊢ (ℂ
D sec) = (𝑥 ∈ dom sec
↦ ((sec‘𝑥)
· (tan‘𝑥))) |