SOLUTION: prove 2sin(2x)(1-2sin^2x)=sin(4x)

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: prove 2sin(2x)(1-2sin^2x)=sin(4x)      Log On


   

Question 964726: prove 2sin(2x)(1-2sin^2x)=sin(4x)
Answer by t0hierry(194) About Me  (Show Source):
You can put this solution on YOUR website!
sin(4x) = 2 sin(2x) cos(2x)
= 2 sin(2x) (1-2 sin^2 x)
using
cos(2x) = cos(x+x) = cos^2(x) - sin^2(x) = 1-2 sin^2 x