設 {\displaystyle a,b\in \mathbb {R} \quad a<b} {\displaystyle a,b\in \mathbb {R} \quad a<b}，設 {\displaystyle f,F:[a,b]\longrightarrow \mathbb {R} } {\displaystyle f,F:[a,b]\longrightarrow \mathbb {R} }，滿足
F連續
f是F的導函數，即 {\displaystyle \forall x\in (a,b)\quad F'(x)=f(x)} {\displaystyle \forall x\in (a,b)\quad F'(x)=f(x)}