Question

решите неравенство f'(x)>0, если f(x)=cos4x+2x.

Answer 1

$f(x)=cos4x+2x\f'(x)=-4sin4x+2 textgreater 0\sin4x textless frac{1}{2}\4xin(frac{pi}{6}+2pi n; frac{5pi}{6}+2pi n)\xin(frac{pi}{24}+frac{pi n}{2};frac{5pi }{24} +frac{pi n}{2})$