Editing Power rule (section)

== Statement of the power rule==
Let <math>f</math> be a function satisfying <math>f(x)=x^r</math> for all <math>x</math>, where <math>r \in \mathbb{R}</math>.{{efn|If <math>r</math> is a rational number whose [[Irreducible fraction|lowest terms representation]] has an odd denominator, then the domain of <math>f</math> is understood to be <math>\mathbb R</math>. Otherwise, the domain is <math>(0,\infty)</math>.}} Then, 
:<math>f'(x) = rx^{r-1} \, .</math>
The power rule for integration states that 
:<math>\int\! x^r \, dx=\frac{x^{r+1}}{r+1}+C</math>
for any real number <math>r \neq -1</math>. It can be derived by inverting the power rule for differentiation. In this equation C is [[Constant of integration|any constant]].