Preclass assignment due with problem set # 16

Reading : Stewart: Parts of 8.3 : specifically: the top of p. 583 and all of 586 (Testing by comparing) plus example 4 on 587 - so two pages in all.
Key areas of focus :
What is the main idea behind testing by comparison?
Reading Question :
8.3 #3, 4

There is a question on the ILT.