The fundamental theorem of calculus comes in two parts.
One part relates definite integrals to anti-derivatives:
(Second) Fundamental Theorem of Calculus:
If F′(x)=f(x), then ∫baf(x)dx=F(b)−F(a).
In other words, the (definite) integral of the derivative (of F(x))
is the change in the original function. This also gives us an incredibly
powerful way to compute definite integrals:
Find an anti-derivative.
Evaluate at the endpoints.
In practice, 99% of all integrals are computed this way.
Or as Shakespeare put it: Tomorrow, and tomorrow, and tomorrow,
Creeps in this petty pace from day to day,
To the last syllable of recorded time
(Macbeth Act 5, Scene 5)