This video will go over examples #24, 28 (and ask you to do #23). Find the derivative yourself first, if possible.
Source: Created by Crystal Kirch using Camtasia for Mac
If the WSQ does not show up use this link: https://docs.google.com/spreadsheet/viewform?formkey=dFc4SGZ5WXhqcEdrZ3VQU005ckhlSUE6MA#gid=0
Source: created by google docs