# TrigCombine Command

From GeoGebra Manual

This page is about a feature that is supported only in GeoGebra 4.2. |

- TrigCombine[ <Expression> ]
- Transforms a trigonometric expression including products of trigonometric functions into an expression without products involving sums of variables.
**Example:**`TrigCombine[sin(x) cos(3x)]`

gives \frac{sin(4x)-sin(2x)}{2}.

- TrigCombine[ <Expression>, <Target Function> ]
- Transforms a trigonometric expression including products of trigonometric functions into an expression without products involving sums of variables, preferring the given target function.
**Example:**`TrigCombine[(tan(p) + tan(q)) / (1 - tan(p) tan(q)), tan(x)]`

gives*tan(p + q)*.

**Note:**See also TrigExpand Command and TrigSimplify Command.