A polling firm determines that the percent of likely voters who support a certain mayoral candidate can be represented by a function P (t) where t is measured in weeks since the candidate entered the race. Suppose P (7) = 15.
(a) What does P ′(7) = 4 mean?
(b) If P′(7) = 4, what percent of likely voters do we expect to support this candidate 8 weeks
after she entered the race?