Lesson 19 - Numerical Integration, Applications, and Average Value
          Numerical Integration overview
          Example 1
          Example 2
          Example 3
          Example 4
          Example 5
          Example 6
          Applications overview
          Example 7
          Example 8
          Example 9
          Example 10
          Example 11
          Example 12
          Example 13
          Average Value overview
          Example 14
          Example 15
          Example 16
          Example 17