Sum, product (fg)′=f′g+fg′\left(fg\right)' = f'g + fg'(fg)′=f′g+fg′, quotient (fg)′=f′g−fg′g2\left(\dfrac{f}{g}\right)' = \dfrac{f'g - fg'}{g^2}(gf)′=g2f′g−fg′.