10. An ice sculpture in the form of a sphere melts in such a way that it maintains its spherical shape. The volume of the sphere is decreasing at a constant rate of 21 cubic meters per hour. At what rate, in square meters per hour, is the surface area of the sphere decreasing at the moment when the radius is 5 meters? (Hint: Sphere SA = 4rtrand Sphere Var? 477 (B) 40 (C) 80x2 (D) 100 (E) 15 11. lim cosx + sin^2x) + 1 is x2-2 (1) (B) (0)1 (D)0 (E) DNE 12. A particle moves along the x-axis with its position at time I given by x(t) = (t - a)(t-b). where a and b are constants and a #b. For which of the following values of t is the particle at rest? (A) 1 = ab a + b 2 (C) 1 = a + b (B) 13 (D) 1 = 2(a + b) (E) 1 = a and I = b