Cosine of Integer Multiple of Argument/Formulation 7/Examples/Cosine of Quintuple Angle

Example of Use of Cosine of Integer Multiple of Argument/Formulation 7

 * $\map \cos {5 \theta } = \map \cos {\theta} - 2 \sin \theta \paren { \sin 4 \theta + \sin 2 \theta }$

Proof
Follows directly from the Cosine of Integer Multiple of Argument/Formulation 7:

Explicit derivation illustrated below: