Septuple Angle Formulas

Theorem

Septuple Angle Formula for Cosine

$\cos 7 \theta = 64 \cos^7 \theta - 112 \cos^5 \theta + 56 \cos^3 \theta - 7 \cos \theta$

where $\sin, \cos, \tan$ denote sine, cosine and tangent respectively.

Also see

• Quintuple Angle Formulas
• Sextuple Angle Formulas