Proof of Theorem itgmulc2lem2
| Step | Hyp | Ref
| Expression |
| 1 | | itgmulc2.4 |
. . . . . . 7
⊢ (𝜑 → 𝐶 ∈ ℝ) |
| 2 | 1 | adantr 480 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐶 ∈ ℝ) |
| 3 | | max0sub 13238 |
. . . . . 6
⊢ (𝐶 ∈ ℝ → (if(0
≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) = 𝐶) |
| 4 | 2, 3 | syl 17 |
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) = 𝐶) |
| 5 | 4 | oveq1d 7446 |
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → ((if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) · 𝐵) = (𝐶 · 𝐵)) |
| 6 | | 0re 11263 |
. . . . . . . 8
⊢ 0 ∈
ℝ |
| 7 | | ifcl 4571 |
. . . . . . . 8
⊢ ((𝐶 ∈ ℝ ∧ 0 ∈
ℝ) → if(0 ≤ 𝐶, 𝐶, 0) ∈ ℝ) |
| 8 | 1, 6, 7 | sylancl 586 |
. . . . . . 7
⊢ (𝜑 → if(0 ≤ 𝐶, 𝐶, 0) ∈ ℝ) |
| 9 | 8 | recnd 11289 |
. . . . . 6
⊢ (𝜑 → if(0 ≤ 𝐶, 𝐶, 0) ∈ ℂ) |
| 10 | 9 | adantr 480 |
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ 𝐶, 𝐶, 0) ∈ ℂ) |
| 11 | 1 | renegcld 11690 |
. . . . . . . 8
⊢ (𝜑 → -𝐶 ∈ ℝ) |
| 12 | | ifcl 4571 |
. . . . . . . 8
⊢ ((-𝐶 ∈ ℝ ∧ 0 ∈
ℝ) → if(0 ≤ -𝐶, -𝐶, 0) ∈ ℝ) |
| 13 | 11, 6, 12 | sylancl 586 |
. . . . . . 7
⊢ (𝜑 → if(0 ≤ -𝐶, -𝐶, 0) ∈ ℝ) |
| 14 | 13 | recnd 11289 |
. . . . . 6
⊢ (𝜑 → if(0 ≤ -𝐶, -𝐶, 0) ∈ ℂ) |
| 15 | 14 | adantr 480 |
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ -𝐶, -𝐶, 0) ∈ ℂ) |
| 16 | | itgmulc2.5 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ ℝ) |
| 17 | 16 | recnd 11289 |
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ ℂ) |
| 18 | 10, 15, 17 | subdird 11720 |
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → ((if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) · 𝐵) = ((if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) − (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵))) |
| 19 | 5, 18 | eqtr3d 2779 |
. . 3
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝐶 · 𝐵) = ((if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) − (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵))) |
| 20 | 19 | itgeq2dv 25817 |
. 2
⊢ (𝜑 → ∫𝐴(𝐶 · 𝐵) d𝑥 = ∫𝐴((if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) − (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵)) d𝑥) |
| 21 | 8 | adantr 480 |
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ 𝐶, 𝐶, 0) ∈ ℝ) |
| 22 | 21, 16 | remulcld 11291 |
. . 3
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) ∈ ℝ) |
| 23 | | itgmulc2.2 |
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ 𝑉) |
| 24 | | itgmulc2.3 |
. . . 4
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ 𝐵) ∈
𝐿1) |
| 25 | 9, 23, 24 | iblmulc2 25866 |
. . 3
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ 𝐶, 𝐶, 0) · 𝐵)) ∈
𝐿1) |
| 26 | 13 | adantr 480 |
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ -𝐶, -𝐶, 0) ∈ ℝ) |
| 27 | 26, 16 | remulcld 11291 |
. . 3
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) ∈ ℝ) |
| 28 | 14, 23, 24 | iblmulc2 25866 |
. . 3
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵)) ∈
𝐿1) |
| 29 | 22, 25, 27, 28 | itgsub 25861 |
. 2
⊢ (𝜑 → ∫𝐴((if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) − (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵)) d𝑥 = (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) d𝑥)) |
| 30 | | ifcl 4571 |
. . . . . . . 8
⊢ ((𝐵 ∈ ℝ ∧ 0 ∈
ℝ) → if(0 ≤ 𝐵, 𝐵, 0) ∈ ℝ) |
| 31 | 16, 6, 30 | sylancl 586 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ 𝐵, 𝐵, 0) ∈ ℝ) |
| 32 | 21, 31 | remulcld 11291 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) ∈ ℝ) |
| 33 | 16 | iblre 25829 |
. . . . . . . . 9
⊢ (𝜑 → ((𝑥 ∈ 𝐴 ↦ 𝐵) ∈ 𝐿1 ↔
((𝑥 ∈ 𝐴 ↦ if(0 ≤ 𝐵, 𝐵, 0)) ∈ 𝐿1 ∧
(𝑥 ∈ 𝐴 ↦ if(0 ≤ -𝐵, -𝐵, 0)) ∈
𝐿1))) |
| 34 | 24, 33 | mpbid 232 |
. . . . . . . 8
⊢ (𝜑 → ((𝑥 ∈ 𝐴 ↦ if(0 ≤ 𝐵, 𝐵, 0)) ∈ 𝐿1 ∧
(𝑥 ∈ 𝐴 ↦ if(0 ≤ -𝐵, -𝐵, 0)) ∈
𝐿1)) |
| 35 | 34 | simpld 494 |
. . . . . . 7
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ if(0 ≤ 𝐵, 𝐵, 0)) ∈
𝐿1) |
| 36 | 9, 31, 35 | iblmulc2 25866 |
. . . . . 6
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0))) ∈
𝐿1) |
| 37 | 16 | renegcld 11690 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → -𝐵 ∈ ℝ) |
| 38 | | ifcl 4571 |
. . . . . . . 8
⊢ ((-𝐵 ∈ ℝ ∧ 0 ∈
ℝ) → if(0 ≤ -𝐵, -𝐵, 0) ∈ ℝ) |
| 39 | 37, 6, 38 | sylancl 586 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ -𝐵, -𝐵, 0) ∈ ℝ) |
| 40 | 21, 39 | remulcld 11291 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) ∈ ℝ) |
| 41 | 34 | simprd 495 |
. . . . . . 7
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ if(0 ≤ -𝐵, -𝐵, 0)) ∈
𝐿1) |
| 42 | 9, 39, 41 | iblmulc2 25866 |
. . . . . 6
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) ∈
𝐿1) |
| 43 | 32, 36, 40, 42 | itgsub 25861 |
. . . . 5
⊢ (𝜑 → ∫𝐴((if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) d𝑥 = (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 44 | | max0sub 13238 |
. . . . . . . . 9
⊢ (𝐵 ∈ ℝ → (if(0
≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0)) = 𝐵) |
| 45 | 16, 44 | syl 17 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0)) = 𝐵) |
| 46 | 45 | oveq2d 7447 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · (if(0 ≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0))) = (if(0 ≤ 𝐶, 𝐶, 0) · 𝐵)) |
| 47 | 31 | recnd 11289 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ 𝐵, 𝐵, 0) ∈ ℂ) |
| 48 | 39 | recnd 11289 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → if(0 ≤ -𝐵, -𝐵, 0) ∈ ℂ) |
| 49 | 10, 47, 48 | subdid 11719 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · (if(0 ≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0))) = ((if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)))) |
| 50 | 46, 49 | eqtr3d 2779 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) = ((if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)))) |
| 51 | 50 | itgeq2dv 25817 |
. . . . 5
⊢ (𝜑 → ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) d𝑥 = ∫𝐴((if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) d𝑥) |
| 52 | 16, 24 | itgreval 25832 |
. . . . . . 7
⊢ (𝜑 → ∫𝐴𝐵 d𝑥 = (∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 − ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥)) |
| 53 | 52 | oveq2d 7447 |
. . . . . 6
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴𝐵 d𝑥) = (if(0 ≤ 𝐶, 𝐶, 0) · (∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 − ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥))) |
| 54 | 31, 35 | itgcl 25819 |
. . . . . . 7
⊢ (𝜑 → ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 ∈ ℂ) |
| 55 | 39, 41 | itgcl 25819 |
. . . . . . 7
⊢ (𝜑 → ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥 ∈ ℂ) |
| 56 | 9, 54, 55 | subdid 11719 |
. . . . . 6
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) · (∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 − ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥)) = ((if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) − (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥))) |
| 57 | | max1 13227 |
. . . . . . . . 9
⊢ ((0
∈ ℝ ∧ 𝐶
∈ ℝ) → 0 ≤ if(0 ≤ 𝐶, 𝐶, 0)) |
| 58 | 6, 1, 57 | sylancr 587 |
. . . . . . . 8
⊢ (𝜑 → 0 ≤ if(0 ≤ 𝐶, 𝐶, 0)) |
| 59 | | max1 13227 |
. . . . . . . . 9
⊢ ((0
∈ ℝ ∧ 𝐵
∈ ℝ) → 0 ≤ if(0 ≤ 𝐵, 𝐵, 0)) |
| 60 | 6, 16, 59 | sylancr 587 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 0 ≤ if(0 ≤ 𝐵, 𝐵, 0)) |
| 61 | 9, 31, 35, 8, 31, 58, 60 | itgmulc2lem1 25867 |
. . . . . . 7
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) = ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥) |
| 62 | | max1 13227 |
. . . . . . . . 9
⊢ ((0
∈ ℝ ∧ -𝐵
∈ ℝ) → 0 ≤ if(0 ≤ -𝐵, -𝐵, 0)) |
| 63 | 6, 37, 62 | sylancr 587 |
. . . . . . . 8
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 0 ≤ if(0 ≤ -𝐵, -𝐵, 0)) |
| 64 | 9, 39, 41, 8, 39, 58, 63 | itgmulc2lem1 25867 |
. . . . . . 7
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥) = ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥) |
| 65 | 61, 64 | oveq12d 7449 |
. . . . . 6
⊢ (𝜑 → ((if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) − (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥)) = (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 66 | 53, 56, 65 | 3eqtrd 2781 |
. . . . 5
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴𝐵 d𝑥) = (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 67 | 43, 51, 66 | 3eqtr4d 2787 |
. . . 4
⊢ (𝜑 → ∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) d𝑥 = (if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴𝐵 d𝑥)) |
| 68 | 26, 31 | remulcld 11291 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) ∈ ℝ) |
| 69 | 14, 31, 35 | iblmulc2 25866 |
. . . . . 6
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0))) ∈
𝐿1) |
| 70 | 26, 39 | remulcld 11291 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) ∈ ℝ) |
| 71 | 14, 39, 41 | iblmulc2 25866 |
. . . . . 6
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) ∈
𝐿1) |
| 72 | 68, 69, 70, 71 | itgsub 25861 |
. . . . 5
⊢ (𝜑 → ∫𝐴((if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) d𝑥 = (∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 73 | 45 | oveq2d 7447 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · (if(0 ≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0))) = (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵)) |
| 74 | 15, 47, 48 | subdid 11719 |
. . . . . . 7
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · (if(0 ≤ 𝐵, 𝐵, 0) − if(0 ≤ -𝐵, -𝐵, 0))) = ((if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)))) |
| 75 | 73, 74 | eqtr3d 2779 |
. . . . . 6
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) = ((if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)))) |
| 76 | 75 | itgeq2dv 25817 |
. . . . 5
⊢ (𝜑 → ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) d𝑥 = ∫𝐴((if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) − (if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0))) d𝑥) |
| 77 | 52 | oveq2d 7447 |
. . . . . 6
⊢ (𝜑 → (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴𝐵 d𝑥) = (if(0 ≤ -𝐶, -𝐶, 0) · (∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 − ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥))) |
| 78 | 14, 54, 55 | subdid 11719 |
. . . . . 6
⊢ (𝜑 → (if(0 ≤ -𝐶, -𝐶, 0) · (∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥 − ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥)) = ((if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) − (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥))) |
| 79 | | max1 13227 |
. . . . . . . . 9
⊢ ((0
∈ ℝ ∧ -𝐶
∈ ℝ) → 0 ≤ if(0 ≤ -𝐶, -𝐶, 0)) |
| 80 | 6, 11, 79 | sylancr 587 |
. . . . . . . 8
⊢ (𝜑 → 0 ≤ if(0 ≤ -𝐶, -𝐶, 0)) |
| 81 | 14, 31, 35, 13, 31, 80, 60 | itgmulc2lem1 25867 |
. . . . . . 7
⊢ (𝜑 → (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) = ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥) |
| 82 | 14, 39, 41, 13, 39, 80, 63 | itgmulc2lem1 25867 |
. . . . . . 7
⊢ (𝜑 → (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥) = ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥) |
| 83 | 81, 82 | oveq12d 7449 |
. . . . . 6
⊢ (𝜑 → ((if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ 𝐵, 𝐵, 0) d𝑥) − (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴if(0 ≤ -𝐵, -𝐵, 0) d𝑥)) = (∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 84 | 77, 78, 83 | 3eqtrd 2781 |
. . . . 5
⊢ (𝜑 → (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴𝐵 d𝑥) = (∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ 𝐵, 𝐵, 0)) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · if(0 ≤ -𝐵, -𝐵, 0)) d𝑥)) |
| 85 | 72, 76, 84 | 3eqtr4d 2787 |
. . . 4
⊢ (𝜑 → ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) d𝑥 = (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴𝐵 d𝑥)) |
| 86 | 67, 85 | oveq12d 7449 |
. . 3
⊢ (𝜑 → (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) d𝑥) = ((if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴𝐵 d𝑥) − (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴𝐵 d𝑥))) |
| 87 | 23, 24 | itgcl 25819 |
. . . 4
⊢ (𝜑 → ∫𝐴𝐵 d𝑥 ∈ ℂ) |
| 88 | 9, 14, 87 | subdird 11720 |
. . 3
⊢ (𝜑 → ((if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) · ∫𝐴𝐵 d𝑥) = ((if(0 ≤ 𝐶, 𝐶, 0) · ∫𝐴𝐵 d𝑥) − (if(0 ≤ -𝐶, -𝐶, 0) · ∫𝐴𝐵 d𝑥))) |
| 89 | 1, 3 | syl 17 |
. . . 4
⊢ (𝜑 → (if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) = 𝐶) |
| 90 | 89 | oveq1d 7446 |
. . 3
⊢ (𝜑 → ((if(0 ≤ 𝐶, 𝐶, 0) − if(0 ≤ -𝐶, -𝐶, 0)) · ∫𝐴𝐵 d𝑥) = (𝐶 · ∫𝐴𝐵 d𝑥)) |
| 91 | 86, 88, 90 | 3eqtr2d 2783 |
. 2
⊢ (𝜑 → (∫𝐴(if(0 ≤ 𝐶, 𝐶, 0) · 𝐵) d𝑥 − ∫𝐴(if(0 ≤ -𝐶, -𝐶, 0) · 𝐵) d𝑥) = (𝐶 · ∫𝐴𝐵 d𝑥)) |
| 92 | 20, 29, 91 | 3eqtrrd 2782 |
1
⊢ (𝜑 → (𝐶 · ∫𝐴𝐵 d𝑥) = ∫𝐴(𝐶 · 𝐵) d𝑥) |