Sextuple Angle Formula for Tangent

Theorem

 * $\tan 6 \theta = \dfrac { 6 \tan \theta - 20 \tan^3 \theta + 6 \tan^5 \theta } { 1 - 15 \tan^2 \theta + 15 \tan^4 \theta - \tan^6 \theta }$

where $\tan$ denotes tangent.