f(x)=- 2
f(x)=-7/2x - 3
f(x) = x ^ -4
f(x)= - 5x
f(x)= x^4
f ' (x) = 0
f' (x)= -7/2
f ' (x)=4 x^3
f'(x)= -4x^-5 = - 4/ x^5
f' (x) = 5
