Step |
Hyp |
Ref |
Expression |
1 |
|
picn |
|
2 |
|
sinsub |
|
3 |
1 2
|
mpan2 |
|
4 |
|
cospi |
|
5 |
4
|
oveq2i |
|
6 |
|
sincl |
|
7 |
|
neg1cn |
|
8 |
|
mulcom |
|
9 |
7 8
|
mpan2 |
|
10 |
|
mulm1 |
|
11 |
9 10
|
eqtrd |
|
12 |
6 11
|
syl |
|
13 |
5 12
|
syl5eq |
|
14 |
|
sinpi |
|
15 |
14
|
oveq2i |
|
16 |
|
coscl |
|
17 |
16
|
mul01d |
|
18 |
15 17
|
syl5eq |
|
19 |
13 18
|
oveq12d |
|
20 |
6
|
negcld |
|
21 |
20
|
subid1d |
|
22 |
19 21
|
eqtrd |
|
23 |
3 22
|
eqtrd |
|