The graphs of $y=f(x)$ and $y=f'(x)$ are closely related. Since
$f'(a)$ represents the slope of the tangent line to $y=f(x)$ at
$\left(a, f(a)\right)$, the slope of $y=f(x)$ at $x$ is the
same as the height of the graph $y=f'(x)$ at that $x$, as
illustrated below.