f(x)=3X + 5
f(x)=X^2
f(x)=2X^3 - 3X +5
f(x)=9
f(x)=5X
f´(x)=2X
f´(x)=5
f´(x)=0
f´(x)=6X^2 - 3
f´(x)=3
