# Transforming arccos into arcsin: acos2asin

### 5.23.7 Transforming arccos into arcsin: acos2asin

The acos2asin command transforms any acoss in an expression to asins, using the identity arccos(x) = π/2 − arcsin(x).

- acos2asin takes one argument:
  expr, an expression containing inverse trigonometric functions.
- acos2asin(expr) returns expr with any acoss replaced by the appropriate asins.

#### Example.

Input:

acos2asin(acos(x)+asin(x))

Output (after simplification):

π
2