These are extended problems in which students explore either a mathematical concept or an application.
Some investigations extend ideas presented in the section.
Some investigations foreshadow topics that students encounter in later sections. Investigations can be used as part of a regular homework assignment, group homework, a small group in-class activity, or as a class discussion. Four investigations from various parts of the book are given below. The federal income tax laws are quite complicated. There have been various proposals to simplify the system.