Cosine of Integer Multiple of Argument/Formulation 2/Examples/Cosine of Quintuple Angle

Example of Use of Cosine of Integer Multiple of Argument/Formulation 2

 * $\map \cos {5 \theta } = \cos^5 \theta \paren {1 - 10 \tan^2 \theta + 5 \tan^4 \theta}$

Proof
Follows directly from the Cosine of Integer Multiple of Argument/Formulation 2: