Let \( f(t) = -\frac{1}{3}t^2 + 1 \) (mm/hour) be the rate a…

Let \( f(t) = -\frac{1}{3}t^2 + 1 \) (mm/hour) be the rate at which rain falls on a given day in Provo at time \( t \) (hours). The initial amount of rainfall at time \( t = 0 \) is 0.5 millimeters. What is the total amount of rainfall in Provo after \( t = 3 \) hours of rain? Be sure to include units in your answer.