How to observe this portion of the graph

When I plot the fourier transform of I obtained the following graph:

As you can note, on the horizontal part of the signal, the value of the output is essentially negligible for the eye but is actually non-zero now I was wondering if its possible to zoom in on the graph or scale it in a way to see this non-zero output. But I am unaware of any method. I hope someone can assist me.

Answer 1

[DGM]

There are view control tools in the figure toolbar/menu.

In newer versions, there's also contextual axes toolbars.

You could also try setting ylim([0 1E-5]) or something to change the view extents.