Hello tutors, can I get help with the following Riemann sum problem? Thank you.

You are studying the proliferation of norovirus in the Colorado River in the Grand Canyon. The river is measured in miles, with mile 0 at the start of the canyon, and mile 225 near the downstream end of the canyon. You have determined that the population density of norovirus, in billions of viruses per mile, can be modeled by D(x) =15e0.03x2

(a) Write down a mathematical expression that represents the total number of viruses between mile 2 and mile 7. You do not have to actually compute it, just write it down. (In fact, you can't compute it analytically.)

(b) Now approximate the same quantity as in part (a) using a Riemann sum. Specifically, use the following partition of the interval [2,7] 2 < 2.3 < 2.9 < 3.7 < 4.7 < 5.9 < 7, and use the following list of sample points: 2, 2.5, 3, 4, 5, 6.5.