Question

cos6x=cos^2 x-sin^2 2x нужно срочно решить,плиззз

Answer 1

cos6x=cos²x-sin²2x
cos²3x-sin²3x=cos²x-sin²2x

(1+cos6x)-(1-cos6x)=1+cos2x-1+cos2x

2cos6x=2cos4x
cos6x-cos4x=0

2sin5x*sinx=0

sin5x=0
5x=πk, k € Z
x=πk/5, k € Z

sinx=0
x=πk, k € Z