The area under a parabolic curve = (2/3)bh. Sketch the graph of the parabolic arch y = h- (4h/b^2)x^2, (-b/2)=< x =< b/2 , assuming that h & b are positive. Then use calculus to find the area of the region enclosed between the arch and the x-axis.

I have no idea how to go about even starting to graph that, can anyone please explain how this would be achieved? Thanks