', Consider the cost function C(x) = 5x2 + 18x + 21 (thousand dollars). a) What is the marginal cost at production level x - 4? b) Use the marginal cost at X: 4 to estimate the cost of producing 4. 25 units. cl) Let R(x) x2 + 31x + 36 denote the revenue in thousands of dollars generated from the production of x units. What' Is the break-even point? (Recall that the break-even point" Is when the revenue is equal to the cost.) d) Compute and compare the marginal revenue and marginal cost at the break-even point. Should the ' company increase production beyond the break-even point? IE b) To estimate the cost of producing 4.25 units using the marginal cost at x = 4, use the fact that ' l C(a + h) - C(a) m C'(a) - h. Let C(a) = 6(4). Then a = 4 . . Find the value of C(4). C(x)= 5x2 +18x+21 C(4) = 173' Since a = 4, C'(a) = C'(4). Let C(a + h) be the cost of producing 4.25 units, C(4.25). Then h = 0.25 . Subsitute the known information into the equation and solve for C(4.25). C(a + h) C(a) e C'(a) - h C(4.25) (3(4) e 014) - h C(4.25) .~.. 187.5' Print ( Clear all )