# Homework Hints 18-4

### 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/

Ask Dr. Math
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 1-2
Remember the formula for the area of a rectangle: A = lw. See Example 1.
Problems 3-5
Remember, the formula for the area of a triangle is A = (1/2)bh. See Example 2.
Problems 6-8
Remember the formula for the area of a trapezoid: A = (1/2)h(b + B). See Example 4.
Problems 9-12
Remember the formula for the area of a rectangle: A = lw. See Example 1.
Problems 13-22
Remember the formula for the area of a trapezoid: A = (1/2)h(b + B). See Example 4.
Problems 23-26
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. You should spend about five minutes in answering each of these questions.
Problems 27-32
Carry out the five-step process for the given antiderivative. The result must match the given function. See Example 3.
Problems 33-40
Draw the given region. There are two ways for finding the area: the first is to use an antiderivative, and the second is to approximate the actual area using known area formulas. This process is shown in Examples 5 and 6.
Problems 41-42
Use the formula for the antiderivative of ex and the definition of the definite integral to evaluate these integrals.
Problems 43-44
Use the formula for the antiderivative of and the definition of the definite integral to evaluate these integrals. See Example 6 (1).
Problems 45-46
First separate each integral into two parts (using the antiderivative of a sum) and then evaluate each integral separately. Use the formula for the antiderivative of ex as well and the formula for the antiderivative of x and finally use the definition of the definite integral to evaluate these integrals.
Problem 50
To answer this question, you must first work Problems 47-49, and then look for a pattern to guess the area under the curve.
Problem 51-52
Follow the directions to repeat Example 6 for the requested number of rectangles.