## Precalculus (6th Edition) Blitzer

a. $(1,4)$ and $(8,10)$ minutes. b. $(4,8)$ and $(10,12)$ minutes. c. $3$ d. $4$. e. negative f. $117$ beats per minute, $t=10$ minutes. g. $64$ beats per minute, $t=8$ minutes.
Based on the given graph, we have: a. The woman’s heart rate increases during $(1,4)$ and $(8,10)$ minutes. b. The woman’s heart rate decreases during $(4,8)$ and $(10,12)$ minutes. c. There are $3$ turning points during the first 12 minutes. d. We can determine the degree of the polynomial function of best fit as $4$. e. The leading coefficient of the polynomial function should be negative as the end behavior is $x\to\infty, y\to-\infty$ f. Using the graph, we can estimate the woman’s maximum heart rate during the first 12 minutes to be about $117$ beats per minute, which happened at $t=10$ minutes. g. Using the graph, we can estimate the woman’s minimum heart rate during the first 12 minutes to be about $64$ beats per minute, which happened at $t=8$ minutes.