Translate each of the following statements into mathematical language, sketch a plot of the appropriate function, and indicate the concavity.
(a) The cost of a car continues to increase and at a faster and faster rate.
(b) During the last 2 years, the United States has continued to cut its consumption of oil, but at a slower and slower rate.
(c) World population continues to grow, but at a slower and slower rate.
(d) The angle that the Leaning Tower of Pisa makes with the vertical is increasing more and more rapidly.
(e) Upper Midwest firm's profit growth slows.
(f) The XYZ Company has been losing money, but will soon turn this situation around.