More derivatives...

Product rule
$ \frac{d}{dx}\bigl[f(x)\,g(x)\bigr] = f'(x)\,g(x) + f(x)\,g'(x) $

Quotient rule
$ \frac{d}{dx}\left[\frac{f(x)}{g(x)}\right] = \frac{f'(x)\,g(x) - f(x)\,g'(x)}{\bigl[g(x)\bigr]^2} $

Chain rule
$ \frac{d}{dx}\bigl[f\bigl(g(x)\bigr)\bigr] = f'\bigl(g(x)\bigr)\cdot g'(x) $