# Homework Hints 15-4

### 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 1-8
These problems are basically definitions that you need to know for this section. It would be a good idea not only to look them up to answer these questions, but also to study.
Problems 9-13
See the box labeled GENERAL FORM. These problems are also dealing with information that you should study for this chapter.
Problems 14-15
Follow the directions; a compass will help. See Example 1.
Problems 16-19
Use parabola graph paper; see Example 2.
Problems 20-21
Use ellipse graph paper; see Example 3.
Problems 22-23
Use hyperbola graph paper; see Example 4.
Problems 24-27
Look at the box labeled “GENERAL FORM” to help you identify these conic section. Also, see Example 5.
Problems 28-31
These are circles with center located at the origin. Identify the radius by comparing the given equation with the equation x2 + y2 = r2. It will help if you use a compass to draw these circles.
Problems 32-34
Graph these ellipses by first putting the equations in standard form, as illustrated by Example 6.
Problems 35-37
Graph these ellipses by first putting the equations in standard form, as illustrated by Example 7.
Problems 38-43
Graph these hyperbolas by drawing the central rectangle and the slant asymptotes as shown by
Example 9. Bonus: Problem 41 is the same as Example 9.
Problems 44-47
See Example 9; you will need to change to standard form before graphing. Example 7 shows how to do this for ellipses here you do the same thing for hyperbolas.