Sava D. answered 06/09/20
Math master degree tutor with good understanding of calculus
Well, there are infinitely many functions with the same derivative.
let g(x) = f(x) +1.
Then,
g'(x) = f'(x) +0.
There is no value of x for which g(x)=f(x).
To be specific, let
g(x) = 2x+1
and
f(x) = 2x.
g'(x) = f'(x) = 2.