(E) The slope ; at the given point and y = 1. The
equation is therefore
y − 1 = −1(x + 2) or x + y + 1 = 0.
(C).
(E) Because f ′(x) > 0 on the interval 2 < x < 3, the value of f increases.
(B) For x < 5, f ′ > 0, so f is increasing; for x > 5, f is decreasing.
(D) The graph of f being concave downward implies that f ′′ < 0, which
implies that f ′ is decreasing.
(D) Speed is the magnitude of velocity; at t = 3, speed = 10 ft/sec.
(D) Speed increases from 0 at t = 2 to 10 at t = 3; it is constant or
decreasing elsewhere.
(E) Acceleration is positive when the velocity increases.
(D) Acceleration is undefined when velocity is not differentiable. Here
that occurs at t = 1, 2, 3.
