Question

cos²x-cos2x=0,75 ( -2p : - P/2 )

Answer 1

cos^2 x-2cos^2 x+1-0,75=0

-cos^2 x=-0,25

cosx=+-1/2

x=+-p/3+2pk     x=+-2p/3+apk

продолжение во вложении