Lim
h-----> 0. (X+h)^3-x^3/h
So I foiled out the numerator
And I got
X^3 +x^2h +2x^2h +2xh^2+h^2+h^3-x^3
So I canceled out x^3 and -x^3
Then I took out the h from the numerator to cancel out the h in the denominator and then I put in the zeros for h but I got the answer 3x^3 but the answer is 3x^2. I don't where it is wrong
x^3 +x^2h +2x^2h+2xh^2+h^2+h^3-x^3
=x^2h +2x^2h +2xh^2+h^2+h^3
all over h
= x^2+2x^2 +2xh +h +h^3
so as h>>zero, then limit is
= 3x^2