Rectangle with subtle curved bottom

I would like to shape the bottom of a rectangle at 600dpi that equates to 5100px by 900 px (8.5 x 1.5) using 5 or so total anchor points.

It would be 1.5" high on the left and 0.825" high on the right.  The curve would look like the, warp-rise effect, but only on the bottom, and then subtly flatten out to the .825 end or right side.

Thank you in advance for your time and experience.

Ciao

Darrell