Exercise. Consider a 4 meter by 3 meter metal plate of varying density given by the function /(r, y) grams per square meter at 3 ..... .... the point (r, y), where r and y are measured in meters. A contour diagram for the function f is given to the right. Using Ar = 2 100 and Ay = 1, estimate and interpret J, f(x, y) dA, where R is the rectangle given by 0