The vertical cross section of an irrigation canal is modeled by (x) = 5x/(x + 4), where

The vertical cross section of an irrigation canal is modeled by ƒ(x) = 5x²/(x² + 4), where x is
measured in feet and x = 0 corresponds to the center of the
canal. Use the integration capabilities of a graphing utility to
approximate the fluid force against a vertical gate used to stop
the flow of water when the water is 3 feet deep.