A)f'(x)=5x^4+9x^2
b)f'(x)=-6x^(-7) -68x^3
c)f'(x)=cosx-xsinx
d)f'(x)=[1*sinx-x*cosx ] /sin^2 x
e)f'(x)=-3x^(-4)+sinx
f)f'(x)=[2x*(5x-4)-x^2*5]/(5x-4)^2 = [10x^2-8x-5x^2]/(5x-4)^2 =
=[ 5x^2-8x]/(5x-4)^2
g)f'(x)=cos(3-4x)*(-4) = -4cos(3-4x)
h)f'(x)=cos√(4-5x) * 1/2√(4-5x) * (-5)
i)f'(x)=101*(4x-5)^100 * 4 = 404*(4x-5)^100