I've got this problem that I'm trying to solve, I've been twisting my brain for several hours now.

An area 'A' is limited by the curve y=x^2, the x-axel and the line x=2

In this area is a rectangle with the area R, as seen in the figure.

Calculate the maximum relation between R and A in exact form.

If someone could take a look at this and help me, I would appreciate it very very much!

(sorry for my bad english)