f(x) = x2+9x-23
f(x) = 5 / x2
f(x)= 3x4
f(x) = x2-9x+23
f(x) = x2-3x
f(x) = 3t
f'(x)= 2x-3
f´(x) = 13x3
f´(x) = 0
f´(x) = 2x-9
f´(x) = 2x+9
f´(x) = -10 / x3
