The Fundamental Theorem of Calculus 
... when f is continuous. Roughly speaking, 2.3 says that if we ﬁrst integrate f and then diﬀerentiate
the result, we get back to the original function f . This shows that an antiderivative can be reversed by
a diﬀerentiation, and it also guarantees the existence, continuity, diﬀerentiability of antider ...