### 10.2.9 Transforming arcsin into arccos

The asin2acos command transforms any arc sines in an expression to arc cosines by using the identity

arcsin(x)= |
π
2
| −arccos(x).

- asin2acos takes expr, an expression containing inverse trigonometric functions.
- asin2acos(expr) returns expr with all instances of asin replaced according to the above formula.

#### Example

asin2acos(acos(x)+asin(x))

Output (after simplification):

π
2