Cosine of Integer Multiple of Argument/Formulation 5/Examples/Cosine of Quintuple Angle

Example of Use of Cosine of Integer Multiple of Argument/Formulation 5

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

Proof
Follows directly from the Cosine of Integer Multiple of Argument/Formulation 5:

Explicit derivation illustrated below: