(C) The direction of a is . Since and , the
acceleration is always directed downward. Its magnitude, , is 2
for all t.
(D) Using the notations vx, vy, ax, and ay, we are given that ,
where k is a constant. Then
(E).
(B) The rate of change of the distance from the origin with respect to
time is given by .
(B) In parametric form, x = r cos θ = 6 cos 2θ cos θ; hence:
(B) A local minimum exists where f changes from decreasing (f ′ < 0) to
increasing (f ′ > 0). Note that f has local maxima at both endpoints, x = 0
and x = 5.
(D) See Answer 68.
