# Homework Hints 2-4

### Note: Homework Hints are given only for the Level 1 and Level 2 problems.

However, as you go through the book be sure you look at all the examples in the text. If you need hints for the Level 3 problems, check some sources for help on the internet (see the LINKS for that particular section). As a last resort, you can call the author at (707) 829-0606.

On the other hand, the problems designated “Problem Solving” generally require techniques that do not have textbook examples.

There are many sources for homework help on the internet.

Algebra.help
Here is a site where technology meets mathematics. You can search a particular topic or choose lessons, calculators, worksheets for extra practice or other resources.
http://www.algebrahelp.com/

Dr. Math is a registered trademark. This is an excellent site at which you can search to see if your question has been previously asked, or you can send your question directly to Dr. Math to receive an answer.
http://mathforum.org/dr.math/

Quick Math
This site provides online graphing calculators. This is especially useful if you do not have your own calculator.
http://www.quickmath.com/

The Math Forum @ Drexel
This site provides an internet mathematics library that can help if you need extra help. For additional homework help at this site, click one of the links in the right-hand column.
http://mathforum.org/

Problems 1-4
There are many problems throughout the text labeled IN YOUR OWN WORDS. Just relax; do not be afraid to give your opinion. For the most part, these questions do not have “right” or “wrong” answers. Several of these problems ask for examples. Do your best to find examples that are your own. You should spend about five minutes in answering each of these questions.
Problems 5-10
See Example 5. Your answer will be a set of ordered pairs.
Problems 11-24
Remember that the cardinality of a set is the number of elements in that set.
Pay close attention to Problems 16-18, and note that the empty set, { }, and the set containing the empty set are not the same. Finally, if the set can be put into a 1-1 correspondence with the set of counting numbers.
Problems 21-23
Be sure to distinguish between the empty set and the set containing empty set.
Problem 24
Distinguish between the set A and the set containing the set A, {A}.
Problems 25-28
See Example 5.
Problems 29-32
See Example 1.
Problems 33-34
See Example 6.