The volume of air in a person's lungs can be modeled with a periodic function. The graph below represents the volume of air, in mL, in a person's lungs over time t, measured in seconds. (0, 2800), (2, 1200), (4, 2800), (6, 1200)
What is the amplitude?
The amplitude of a periodic function is the maximum displacement from the mean position. In this case, the maximum volume of air in the person's lungs is 2800 mL and the minimum volume is 1200 mL.
So, the amplitude is (2800 mL - 1200 mL) / 2 = 1600 mL.