y=cos^3(X) + 3^cosx + log4 cos7x
с решением...
y'= (cos^3(X) + 3^cosx + log4 cos7x)' = 3cos^2(x)*(-sin(x)) + cosx*3^(cosx-1)*(-sinx) + 1/(cos7x*ln4)*(-sin7x)*7