Can someone help me with letter b along with an explanation.

Step-by-step explanation:
Forced vital capacity: the maximum amount of air you can forcibly exhale from your lungs after fully inhaling. It is about 80 percent of total capacity, or 4.8 liters, because some air remains in your lungs after you exhale
9514 1404 393
Answer:
a) 1.70 L
b) 16 breaths per minute
Step-by-step explanation:
a) The maximum value of v(t) occurs when the sine function is at its maximum value of 1. In that case, the volume is ...
1.27 +0.43×1 = 1.70 . . . liters
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b) One full breath cycle takes a period of time that makes the argument of the sine function be 2π. The that time period is ...
1.71t = 2π
t = 2π/1.71 ≈ 3.6744 . . . seconds
Then the number of breaths per minute is ...
(60 seconds/minute)/(3.6744 seconds/breath) ≈ 16.33 breaths/minute
The person takes about 16 breaths per minute while sleeping.