Let f:[a,b]Rf:[a,b]\to\mathbb{R} be and let F:[a,b]RF:[a,b]\to\mathbb{R} satisfy F(x)=f(x)F'(x)=f(x) for all x(a,b)x\in(a,b).

Corollary (Newton–Leibniz):

abf(x)dx=F(b)F(a).\int_a^b f(x)\,dx = F(b)-F(a).
Remarks

This is the standard evaluation rule for definite integrals using .

Connection to parent theorem: This is the (Part II).