The derivative of any polynomial function of one variable is easily obtained. If (or a constant function) and are both differentiable on some set , then so are , , , and . If, in addition, is nonzero on , then (and also ) are differentiable on . Also, if is differentiable on , then is differentiable on . For the trivial case of , for some constant (a degree 0 polynomial):
For any real-valued differentiable functions and :
And for any real number r:
Which covers any single variable polynomial function. Derivatives of non-polynomial functions require additional rules.