Posted by **clerkbob** on Monday, March 11, 2013 at 3:09pm.

A new college textbook edition typically generates most of its sales in the year of its publication. Sales drop off in subsequent years as a result of competition from the used book market. Suppose that the annual sales of a particular textbook may be modeled by

S(t) = 30,000 te−1.5t, textbooks, where t is the number of years since the edition was published.

Use integration by parts to determine how many textbooks will be sold in the first three years of the edition?