Proof of Theorem sqrt2irrlemOLD
| Step | Hyp | Ref
| Expression |
| 1 | | 2cn 11091 |
. . . . . . . . . . . 12
⊢ 2 ∈
ℂ |
| 2 | | sqrtth 14104 |
. . . . . . . . . . . 12
⊢ (2 ∈
ℂ → ((√‘2)↑2) = 2) |
| 3 | 1, 2 | ax-mp 5 |
. . . . . . . . . . 11
⊢
((√‘2)↑2) = 2 |
| 4 | | sqrt2irrlem.3 |
. . . . . . . . . . . 12
⊢ (𝜑 → (√‘2) = (𝐴 / 𝐵)) |
| 5 | 4 | oveq1d 6665 |
. . . . . . . . . . 11
⊢ (𝜑 → ((√‘2)↑2)
= ((𝐴 / 𝐵)↑2)) |
| 6 | 3, 5 | syl5eqr 2670 |
. . . . . . . . . 10
⊢ (𝜑 → 2 = ((𝐴 / 𝐵)↑2)) |
| 7 | | sqrt2irrlem.1 |
. . . . . . . . . . . 12
⊢ (𝜑 → 𝐴 ∈ ℤ) |
| 8 | 7 | zcnd 11483 |
. . . . . . . . . . 11
⊢ (𝜑 → 𝐴 ∈ ℂ) |
| 9 | | sqrt2irrlem.2 |
. . . . . . . . . . . 12
⊢ (𝜑 → 𝐵 ∈ ℕ) |
| 10 | 9 | nncnd 11036 |
. . . . . . . . . . 11
⊢ (𝜑 → 𝐵 ∈ ℂ) |
| 11 | 9 | nnne0d 11065 |
. . . . . . . . . . 11
⊢ (𝜑 → 𝐵 ≠ 0) |
| 12 | 8, 10, 11 | sqdivd 13021 |
. . . . . . . . . 10
⊢ (𝜑 → ((𝐴 / 𝐵)↑2) = ((𝐴↑2) / (𝐵↑2))) |
| 13 | 6, 12 | eqtrd 2656 |
. . . . . . . . 9
⊢ (𝜑 → 2 = ((𝐴↑2) / (𝐵↑2))) |
| 14 | 13 | oveq1d 6665 |
. . . . . . . 8
⊢ (𝜑 → (2 · (𝐵↑2)) = (((𝐴↑2) / (𝐵↑2)) · (𝐵↑2))) |
| 15 | 8 | sqcld 13006 |
. . . . . . . . 9
⊢ (𝜑 → (𝐴↑2) ∈ ℂ) |
| 16 | 9 | nnsqcld 13029 |
. . . . . . . . . 10
⊢ (𝜑 → (𝐵↑2) ∈ ℕ) |
| 17 | 16 | nncnd 11036 |
. . . . . . . . 9
⊢ (𝜑 → (𝐵↑2) ∈ ℂ) |
| 18 | 16 | nnne0d 11065 |
. . . . . . . . 9
⊢ (𝜑 → (𝐵↑2) ≠ 0) |
| 19 | 15, 17, 18 | divcan1d 10802 |
. . . . . . . 8
⊢ (𝜑 → (((𝐴↑2) / (𝐵↑2)) · (𝐵↑2)) = (𝐴↑2)) |
| 20 | 14, 19 | eqtrd 2656 |
. . . . . . 7
⊢ (𝜑 → (2 · (𝐵↑2)) = (𝐴↑2)) |
| 21 | 20 | oveq1d 6665 |
. . . . . 6
⊢ (𝜑 → ((2 · (𝐵↑2)) / 2) = ((𝐴↑2) / 2)) |
| 22 | 1 | a1i 11 |
. . . . . . 7
⊢ (𝜑 → 2 ∈
ℂ) |
| 23 | | 2ne0 11113 |
. . . . . . . 8
⊢ 2 ≠
0 |
| 24 | 23 | a1i 11 |
. . . . . . 7
⊢ (𝜑 → 2 ≠ 0) |
| 25 | 17, 22, 24 | divcan3d 10806 |
. . . . . 6
⊢ (𝜑 → ((2 · (𝐵↑2)) / 2) = (𝐵↑2)) |
| 26 | 21, 25 | eqtr3d 2658 |
. . . . 5
⊢ (𝜑 → ((𝐴↑2) / 2) = (𝐵↑2)) |
| 27 | 26, 16 | eqeltrd 2701 |
. . . 4
⊢ (𝜑 → ((𝐴↑2) / 2) ∈
ℕ) |
| 28 | 27 | nnzd 11481 |
. . 3
⊢ (𝜑 → ((𝐴↑2) / 2) ∈
ℤ) |
| 29 | | zesq 12987 |
. . . 4
⊢ (𝐴 ∈ ℤ → ((𝐴 / 2) ∈ ℤ ↔
((𝐴↑2) / 2) ∈
ℤ)) |
| 30 | 7, 29 | syl 17 |
. . 3
⊢ (𝜑 → ((𝐴 / 2) ∈ ℤ ↔ ((𝐴↑2) / 2) ∈
ℤ)) |
| 31 | 28, 30 | mpbird 247 |
. 2
⊢ (𝜑 → (𝐴 / 2) ∈ ℤ) |
| 32 | 1 | sqvali 12943 |
. . . . . . . 8
⊢
(2↑2) = (2 · 2) |
| 33 | 32 | oveq2i 6661 |
. . . . . . 7
⊢ ((𝐴↑2) / (2↑2)) = ((𝐴↑2) / (2 ·
2)) |
| 34 | 8, 22, 24 | sqdivd 13021 |
. . . . . . 7
⊢ (𝜑 → ((𝐴 / 2)↑2) = ((𝐴↑2) / (2↑2))) |
| 35 | 15, 22, 22, 24, 24 | divdiv1d 10832 |
. . . . . . 7
⊢ (𝜑 → (((𝐴↑2) / 2) / 2) = ((𝐴↑2) / (2 · 2))) |
| 36 | 33, 34, 35 | 3eqtr4a 2682 |
. . . . . 6
⊢ (𝜑 → ((𝐴 / 2)↑2) = (((𝐴↑2) / 2) / 2)) |
| 37 | 26 | oveq1d 6665 |
. . . . . 6
⊢ (𝜑 → (((𝐴↑2) / 2) / 2) = ((𝐵↑2) / 2)) |
| 38 | 36, 37 | eqtrd 2656 |
. . . . 5
⊢ (𝜑 → ((𝐴 / 2)↑2) = ((𝐵↑2) / 2)) |
| 39 | | zsqcl 12934 |
. . . . . 6
⊢ ((𝐴 / 2) ∈ ℤ →
((𝐴 / 2)↑2) ∈
ℤ) |
| 40 | 31, 39 | syl 17 |
. . . . 5
⊢ (𝜑 → ((𝐴 / 2)↑2) ∈
ℤ) |
| 41 | 38, 40 | eqeltrrd 2702 |
. . . 4
⊢ (𝜑 → ((𝐵↑2) / 2) ∈
ℤ) |
| 42 | 16 | nnrpd 11870 |
. . . . . 6
⊢ (𝜑 → (𝐵↑2) ∈
ℝ+) |
| 43 | 42 | rphalfcld 11884 |
. . . . 5
⊢ (𝜑 → ((𝐵↑2) / 2) ∈
ℝ+) |
| 44 | 43 | rpgt0d 11875 |
. . . 4
⊢ (𝜑 → 0 < ((𝐵↑2) / 2)) |
| 45 | | elnnz 11387 |
. . . 4
⊢ (((𝐵↑2) / 2) ∈ ℕ
↔ (((𝐵↑2) / 2)
∈ ℤ ∧ 0 < ((𝐵↑2) / 2))) |
| 46 | 41, 44, 45 | sylanbrc 698 |
. . 3
⊢ (𝜑 → ((𝐵↑2) / 2) ∈
ℕ) |
| 47 | | nnesq 12988 |
. . . 4
⊢ (𝐵 ∈ ℕ → ((𝐵 / 2) ∈ ℕ ↔
((𝐵↑2) / 2) ∈
ℕ)) |
| 48 | 9, 47 | syl 17 |
. . 3
⊢ (𝜑 → ((𝐵 / 2) ∈ ℕ ↔ ((𝐵↑2) / 2) ∈
ℕ)) |
| 49 | 46, 48 | mpbird 247 |
. 2
⊢ (𝜑 → (𝐵 / 2) ∈ ℕ) |
| 50 | 31, 49 | jca 554 |
1
⊢ (𝜑 → ((𝐴 / 2) ∈ ℤ ∧ (𝐵 / 2) ∈
ℕ)) |