Command-Click the mouse inside the plot window. You will see that the horizontal and
vertical coordinates of the mouse point are displayed in a field at the top or bottom of the notebook window (exactly where depends on which version of Mathematica you have).
This is useful, for example, if you want a rough idea of where two curves
intersect. Where do the two curves that you've just plotted intersect?

Click here for the answer

They intersect at approximately x=0.5087 and y=0.4870. Try using Solve[]
to obtain the answer symbolically. You'll discover that Mathematica isn't able to
come up with the solution.