Chapter 14.1, Problem 73E

15. A spring-mass system is governed by the differential equation 2x′′ + 72x = 100 sin(3ωt) .For what value of ω will resonance occur?A. 3 B. 6√2 C. 2 D. 10 E. No value

Question 3. A manufacturer has modeled its yearly production function P (the value of its entire production, in millions of dollars) as a Cobb-Douglas function P(L, K) = 1.47L0.65 0.35 where L is the number of labor hours (in thousands) and K is the invested capital (in millions of dollars). ӘР Ət (a) Express the rate of change of production 07-2 in time, in terms of the rate of change of the labor force and the rate of change of the capital in time. (b) Suppose that when L = 30 and K = 8, the labor force is decreasing at a rate of 2000 labor hours per year and capital is increasing at a rate of 500,000 per year. What is the rate of change of production per year?

17. Consider a mass-spring system that satisfies 2y′′(t) + by′(t) + 50y(t) = 0.Which of the following is/are true?(i) If b = 0, the motion is critically damped with period π/5 .(ii) If b = 12, the motion is underdamped.(iii) If b = 40, the motion is overdamped.A. (ii) and (iii) only B. (ii) only C. (i) and (ii) only D. (i) and (iii) only E. All