Question

Решите пример плиз

cos^4x-sin^4x=1/2

Answer 1

$cos^4x-sin^4x=0.5\ (cos^2 x+sin^2x)(cos^2x-sin^2x)=0.5\ cos^2x-sin^2x=0.5\ cos 2x=0.5\ 2x=pm frac{pi}{3} +2pi n,n in Z\ \ boxed{x=pmfrac{pi}{6}+pi n,n in Z }$