=+a.** The first of these was given as an example in the text and took the general form f 1,2 5 a11 2 cos 1b,2 2 for all , # p/b < 3.1416/b and f 1,2 5 2a for all

, . p/b < 3.1416/b2, with a and b assumed to be greater than 0. Determine the labor input level at which the marginal product of labor begins to decline. (Hint: Recall that the cosine of p/2 < 1.5708 is equal to zero.)