f(x)= - 1/cos5xf'(x)=((0*cos5x)+(-1*(-sin5x))) *5= 5sin5x f(x)=ctgxf'(x)= -1/sin^2x f(x)=sin5xcos6x-cos5xsin6x=sin(5x-6x)=-sinx f'(x)=-cosx
f(x)= - 1/cos5x
f'(x)=((0*cos5x)+(-1*(-sin5x))) *5= 5sin5x
f(x)=ctgx
f'(x)= -1/sin^2x
f(x)=sin5xcos6x-cos5xsin6x=sin(5x-6x)=-sinx
f'(x)=-cosx