Найдите производную f(x)=1/(1+cos4x)^5

f'(x)=(1/(1+cos4x)^5)'=(-5)×(1/(1+cos4x)^4)×(1+cos4x)'=

(-5)×(-(sin4x)×4):(1+cos4x)^4)=

20×sin4x:(1+cos4x)^4)