Description: Define the sine function. (Contributed by NM, 14-Mar-2005)
Ref | Expression | ||
---|---|---|---|
Assertion | df-sin | |- sin = ( x e. CC |-> ( ( ( exp ` ( _i x. x ) ) - ( exp ` ( -u _i x. x ) ) ) / ( 2 x. _i ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | csin | |- sin |
|
1 | vx | |- x |
|
2 | cc | |- CC |
|
3 | ce | |- exp |
|
4 | ci | |- _i |
|
5 | cmul | |- x. |
|
6 | 1 | cv | |- x |
7 | 4 6 5 | co | |- ( _i x. x ) |
8 | 7 3 | cfv | |- ( exp ` ( _i x. x ) ) |
9 | cmin | |- - |
|
10 | 4 | cneg | |- -u _i |
11 | 10 6 5 | co | |- ( -u _i x. x ) |
12 | 11 3 | cfv | |- ( exp ` ( -u _i x. x ) ) |
13 | 8 12 9 | co | |- ( ( exp ` ( _i x. x ) ) - ( exp ` ( -u _i x. x ) ) ) |
14 | cdiv | |- / |
|
15 | c2 | |- 2 |
|
16 | 15 4 5 | co | |- ( 2 x. _i ) |
17 | 13 16 14 | co | |- ( ( ( exp ` ( _i x. x ) ) - ( exp ` ( -u _i x. x ) ) ) / ( 2 x. _i ) ) |
18 | 1 2 17 | cmpt | |- ( x e. CC |-> ( ( ( exp ` ( _i x. x ) ) - ( exp ` ( -u _i x. x ) ) ) / ( 2 x. _i ) ) ) |
19 | 0 18 | wceq | |- sin = ( x e. CC |-> ( ( ( exp ` ( _i x. x ) ) - ( exp ` ( -u _i x. x ) ) ) / ( 2 x. _i ) ) ) |