Hey I'm differentiating $x^3$ from first principles and I know the answer is $3x^2$.
But I'm looking at one of the lines from my notes and something doesn't look right.
I have $2x^2h + 2xh^2 = 3x^2h$, which would indeed be equal to $3x^2$ when you take the limit as $h$ approaches $0$.
But should that not read $4x^2h$??????
I'm very bad at maths please help....