■ ■ ■ ■ ■ ■where c = e−C.
Find c, using the fact that M = 40° when t = 0:
40 = 68 − ce^0 means c = 28.
Find k, using the fact that M = 43° when t = 3:Since the phone rang at t = 3, you have 30 min to solve the problem.One possible graph of h is shown; it has the following properties:
continuity on [−4,4],
symmetry about the y-axis,
roots at x = −1, 1,
horizontal tangents at x = −2, 0, 2,
points of inflection at x = −3, −2, −1, 1, 2, 3,
corners at x = −3, 3.