# Transforming cos(x) into sin(x)/tan(x): cos2sintan

### 5.23.16 Transforming cos(x) into sin(x)/tan(x): cos2sintan

The cos2sintan command replaces cos(x) by sin(x)/tan(x) in an expression.

- cos2sintan takes one argument:
  expr, an expression containing trigonometric functions.
- cos2sintan(expr) returns expr with anything of the form cos(x) replaced by sin(x)/tan(x).

#### Example.

Input:

cos2sintan(cos(2*x))

Output:

sin | ⎛ ⎝ | 2 x | ⎞ ⎠

tan | ⎛ ⎝ | 2 x | ⎞ ⎠