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 ) ) )  |