In an economic model, the proportion of families whose income is no more than r, and who have a home computer, is given by p(a) = a+ k(1-e-") where a, k and c are positive constants. determine p'(a) and p"(r). Does p(x) have a maximum? Sketch a graph of p(x). [Hint: Locate the values of x at which p(x), p'(x) and p"(x) are 0,positive and negative. Recall, 1. the value of p(x) is the height on your vertical axis 2. the value of p'(x) indicates the slope of the tangent 3. p"(x) indicates the curvature of p(x) (i.e. how the tangent itself wants to change)