AP Calculus Free-Response Questions

a. Find the radius of the sphere as a function of t. b. At what time t will the volume of the sphere be 27 times its volume at t = 0? 1993 Scientific Calculators required. 157. Let f be the function given by f(x)= x3 -5x2 + 3x + k, where k is a constant. a. On what interval is f increasing? b. On what intervals is the graph of f concave downward? ................
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