Question

sin 4x = (4sin x cosx)(2cos^2x-1)

Answer 1

is this a proof? if so

start with left hand side
\[\sin(4x)\]
\[2\sin(2x)\cos(2x)\]
\[2(2sinxcox)(2\cos^2(x) - 1)\]
\[(4sinxcox)(2\cos^2x-1)\]