Proof of Theorem sinhalfpilem
Step | Hyp | Ref
| Expression |
1 | | sq1 10548 |
. . . 4
⊢
(1↑2) = 1 |
2 | | pire 13347 |
. . . . . . . . . . . . . . . . 17
⊢ π
∈ ℝ |
3 | 2 | recni 7911 |
. . . . . . . . . . . . . . . 16
⊢ π
∈ ℂ |
4 | | 2cn 8928 |
. . . . . . . . . . . . . . . 16
⊢ 2 ∈
ℂ |
5 | | 2ap0 8950 |
. . . . . . . . . . . . . . . 16
⊢ 2 #
0 |
6 | 3, 4, 5 | divcanap2i 8651 |
. . . . . . . . . . . . . . 15
⊢ (2
· (π / 2)) = π |
7 | 6 | fveq2i 5489 |
. . . . . . . . . . . . . 14
⊢
(sin‘(2 · (π / 2))) = (sin‘π) |
8 | 2 | rehalfcli 9105 |
. . . . . . . . . . . . . . . 16
⊢ (π /
2) ∈ ℝ |
9 | 8 | recni 7911 |
. . . . . . . . . . . . . . 15
⊢ (π /
2) ∈ ℂ |
10 | | sin2t 11690 |
. . . . . . . . . . . . . . 15
⊢ ((π /
2) ∈ ℂ → (sin‘(2 · (π / 2))) = (2 ·
((sin‘(π / 2)) · (cos‘(π / 2))))) |
11 | 9, 10 | ax-mp 5 |
. . . . . . . . . . . . . 14
⊢
(sin‘(2 · (π / 2))) = (2 · ((sin‘(π /
2)) · (cos‘(π / 2)))) |
12 | 7, 11 | eqtr3i 2188 |
. . . . . . . . . . . . 13
⊢
(sin‘π) = (2 · ((sin‘(π / 2)) ·
(cos‘(π / 2)))) |
13 | | sinpi 13346 |
. . . . . . . . . . . . 13
⊢
(sin‘π) = 0 |
14 | 12, 13 | eqtr3i 2188 |
. . . . . . . . . . . 12
⊢ (2
· ((sin‘(π / 2)) · (cos‘(π / 2)))) =
0 |
15 | | 0cn 7891 |
. . . . . . . . . . . . 13
⊢ 0 ∈
ℂ |
16 | | sincl 11647 |
. . . . . . . . . . . . . . 15
⊢ ((π /
2) ∈ ℂ → (sin‘(π / 2)) ∈
ℂ) |
17 | 9, 16 | ax-mp 5 |
. . . . . . . . . . . . . 14
⊢
(sin‘(π / 2)) ∈ ℂ |
18 | | coscl 11648 |
. . . . . . . . . . . . . . 15
⊢ ((π /
2) ∈ ℂ → (cos‘(π / 2)) ∈
ℂ) |
19 | 9, 18 | ax-mp 5 |
. . . . . . . . . . . . . 14
⊢
(cos‘(π / 2)) ∈ ℂ |
20 | 17, 19 | mulcli 7904 |
. . . . . . . . . . . . 13
⊢
((sin‘(π / 2)) · (cos‘(π / 2))) ∈
ℂ |
21 | 15, 4, 20, 5 | divmulapi 8662 |
. . . . . . . . . . . 12
⊢ ((0 / 2)
= ((sin‘(π / 2)) · (cos‘(π / 2))) ↔ (2 ·
((sin‘(π / 2)) · (cos‘(π / 2)))) = 0) |
22 | 14, 21 | mpbir 145 |
. . . . . . . . . . 11
⊢ (0 / 2) =
((sin‘(π / 2)) · (cos‘(π / 2))) |
23 | 4, 5 | div0api 8642 |
. . . . . . . . . . 11
⊢ (0 / 2) =
0 |
24 | 22, 23 | eqtr3i 2188 |
. . . . . . . . . 10
⊢
((sin‘(π / 2)) · (cos‘(π / 2))) =
0 |
25 | | resincl 11661 |
. . . . . . . . . . . . 13
⊢ ((π /
2) ∈ ℝ → (sin‘(π / 2)) ∈
ℝ) |
26 | 8, 25 | ax-mp 5 |
. . . . . . . . . . . 12
⊢
(sin‘(π / 2)) ∈ ℝ |
27 | | 2re 8927 |
. . . . . . . . . . . . . . 15
⊢ 2 ∈
ℝ |
28 | | pipos 13349 |
. . . . . . . . . . . . . . 15
⊢ 0 <
π |
29 | | 2pos 8948 |
. . . . . . . . . . . . . . 15
⊢ 0 <
2 |
30 | 2, 27, 28, 29 | divgt0ii 8814 |
. . . . . . . . . . . . . 14
⊢ 0 <
(π / 2) |
31 | | 4re 8934 |
. . . . . . . . . . . . . . . 16
⊢ 4 ∈
ℝ |
32 | | pigt2lt4 13345 |
. . . . . . . . . . . . . . . . 17
⊢ (2 <
π ∧ π < 4) |
33 | 32 | simpri 112 |
. . . . . . . . . . . . . . . 16
⊢ π <
4 |
34 | 2, 31, 33 | ltleii 8001 |
. . . . . . . . . . . . . . 15
⊢ π ≤
4 |
35 | 27, 29 | pm3.2i 270 |
. . . . . . . . . . . . . . . . 17
⊢ (2 ∈
ℝ ∧ 0 < 2) |
36 | | ledivmul 8772 |
. . . . . . . . . . . . . . . . 17
⊢ ((π
∈ ℝ ∧ 2 ∈ ℝ ∧ (2 ∈ ℝ ∧ 0 < 2))
→ ((π / 2) ≤ 2 ↔ π ≤ (2 · 2))) |
37 | 2, 27, 35, 36 | mp3an 1327 |
. . . . . . . . . . . . . . . 16
⊢ ((π /
2) ≤ 2 ↔ π ≤ (2 · 2)) |
38 | | 2t2e4 9011 |
. . . . . . . . . . . . . . . . 17
⊢ (2
· 2) = 4 |
39 | 38 | breq2i 3990 |
. . . . . . . . . . . . . . . 16
⊢ (π
≤ (2 · 2) ↔ π ≤ 4) |
40 | 37, 39 | bitr2i 184 |
. . . . . . . . . . . . . . 15
⊢ (π
≤ 4 ↔ (π / 2) ≤ 2) |
41 | 34, 40 | mpbi 144 |
. . . . . . . . . . . . . 14
⊢ (π /
2) ≤ 2 |
42 | | 0xr 7945 |
. . . . . . . . . . . . . . 15
⊢ 0 ∈
ℝ* |
43 | | elioc2 9872 |
. . . . . . . . . . . . . . 15
⊢ ((0
∈ ℝ* ∧ 2 ∈ ℝ) → ((π / 2) ∈
(0(,]2) ↔ ((π / 2) ∈ ℝ ∧ 0 < (π / 2) ∧ (π /
2) ≤ 2))) |
44 | 42, 27, 43 | mp2an 423 |
. . . . . . . . . . . . . 14
⊢ ((π /
2) ∈ (0(,]2) ↔ ((π / 2) ∈ ℝ ∧ 0 < (π / 2)
∧ (π / 2) ≤ 2)) |
45 | 8, 30, 41, 44 | mpbir3an 1169 |
. . . . . . . . . . . . 13
⊢ (π /
2) ∈ (0(,]2) |
46 | | sin02gt0 11704 |
. . . . . . . . . . . . 13
⊢ ((π /
2) ∈ (0(,]2) → 0 < (sin‘(π / 2))) |
47 | 45, 46 | ax-mp 5 |
. . . . . . . . . . . 12
⊢ 0 <
(sin‘(π / 2)) |
48 | 26, 47 | gt0ap0ii 8526 |
. . . . . . . . . . 11
⊢
(sin‘(π / 2)) # 0 |
49 | 15, 17, 19, 48 | divmulapi 8662 |
. . . . . . . . . 10
⊢ ((0 /
(sin‘(π / 2))) = (cos‘(π / 2)) ↔ ((sin‘(π / 2))
· (cos‘(π / 2))) = 0) |
50 | 24, 49 | mpbir 145 |
. . . . . . . . 9
⊢ (0 /
(sin‘(π / 2))) = (cos‘(π / 2)) |
51 | 17, 48 | div0api 8642 |
. . . . . . . . 9
⊢ (0 /
(sin‘(π / 2))) = 0 |
52 | 50, 51 | eqtr3i 2188 |
. . . . . . . 8
⊢
(cos‘(π / 2)) = 0 |
53 | 52 | oveq1i 5852 |
. . . . . . 7
⊢
((cos‘(π / 2))↑2) = (0↑2) |
54 | | sq0 10545 |
. . . . . . 7
⊢
(0↑2) = 0 |
55 | 53, 54 | eqtri 2186 |
. . . . . 6
⊢
((cos‘(π / 2))↑2) = 0 |
56 | 55 | oveq2i 5853 |
. . . . 5
⊢
(((sin‘(π / 2))↑2) + ((cos‘(π / 2))↑2)) =
(((sin‘(π / 2))↑2) + 0) |
57 | | sincossq 11689 |
. . . . . 6
⊢ ((π /
2) ∈ ℂ → (((sin‘(π / 2))↑2) + ((cos‘(π /
2))↑2)) = 1) |
58 | 9, 57 | ax-mp 5 |
. . . . 5
⊢
(((sin‘(π / 2))↑2) + ((cos‘(π / 2))↑2)) =
1 |
59 | 56, 58 | eqtr3i 2188 |
. . . 4
⊢
(((sin‘(π / 2))↑2) + 0) = 1 |
60 | 17 | sqcli 10535 |
. . . . 5
⊢
((sin‘(π / 2))↑2) ∈ ℂ |
61 | 60 | addid1i 8040 |
. . . 4
⊢
(((sin‘(π / 2))↑2) + 0) = ((sin‘(π /
2))↑2) |
62 | 1, 59, 61 | 3eqtr2ri 2193 |
. . 3
⊢
((sin‘(π / 2))↑2) = (1↑2) |
63 | | 0re 7899 |
. . . . 5
⊢ 0 ∈
ℝ |
64 | 63, 26, 47 | ltleii 8001 |
. . . 4
⊢ 0 ≤
(sin‘(π / 2)) |
65 | | 1re 7898 |
. . . 4
⊢ 1 ∈
ℝ |
66 | | 0le1 8379 |
. . . 4
⊢ 0 ≤
1 |
67 | | sq11 10527 |
. . . 4
⊢
((((sin‘(π / 2)) ∈ ℝ ∧ 0 ≤ (sin‘(π /
2))) ∧ (1 ∈ ℝ ∧ 0 ≤ 1)) → (((sin‘(π /
2))↑2) = (1↑2) ↔ (sin‘(π / 2)) = 1)) |
68 | 26, 64, 65, 66, 67 | mp4an 424 |
. . 3
⊢
(((sin‘(π / 2))↑2) = (1↑2) ↔ (sin‘(π /
2)) = 1) |
69 | 62, 68 | mpbi 144 |
. 2
⊢
(sin‘(π / 2)) = 1 |
70 | 69, 52 | pm3.2i 270 |
1
⊢
((sin‘(π / 2)) = 1 ∧ (cos‘(π / 2)) =
0) |