 
 
 
10.2.12  Transforming arctan into arccos
The atan2acos command
transforms any arc tangents in an expression to arc cosines by using the identity
| arctan(x)= |  | −arcsin | ⎛ ⎜
 ⎜
 ⎜
 ⎜
 ⎝
 |  | ⎞ ⎟
 ⎟
 ⎟
 ⎟
 ⎠
 | . | 
- 
atan2acos takes
expr, an expression containing inverse trigonometric functions.
- atan2acos(expr) returns
expr with all instances of atan replaced according to the above formula.
Example
|  | | |  |  | −arccos | ⎛ ⎜
 ⎜
 ⎜
 ⎜
 ⎝
 |  | ⎞ ⎟
 ⎟
 ⎟
 ⎟
 ⎠
 | 
 |  |  |  |  |  |  |  |  |  |  | 
 | 
 
 
