# TrigCombine Command ##### Command Categories (All commands)

TrigCombine( <Expression> )
Transforms a trigonometric expression including products of trigonometric functions into an expression without products involving sums of variables.
Examples:
• TrigCombine(sin(x) cos(3x)) gives {\frac{1}{2} sin \left( 4 x \right) - \frac{1}{2} sin \left( 2 x \right)}
• TrigCombine(sin(x) + cos(x)) gives {\sqrt{2} cos \left( x - \frac{1}{4} \pi \right)} .
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(sin(x) + cos(x), sin(x)) gives {\sqrt{2} sin \left( x + \frac{1}{4} \pi \right)} .

Notes:
• In the CAS View undefined variables can be used as well.
• Example: TrigCombine(sin(p) cos(3p)) gives {\frac{1}{2} sin \left( 4 p \right) - \frac{1}{2} sin \left( 2 p \right)}.
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