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#### The Vibrating String as the sum of travelling waves

## [Mr.] Lynn C. Kurtz, Ph.D.

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Department of Mathematics and Statistics, Retired
Arizona State University
Tempe, AZ 85287

### Introducing complex numbers

#### Confused about complex numbers or how to teach the topic? Click on
*Complex Numbers* to read about
a natural approach to complex numbers. If you want to print that article,
click on *pdf version*
for a pdf document to print.

### Impedance in AC circuits

#### Using same ideas and notation as in the complex numbers article
above, the article *Alternating Current Impedance*
gives a tutorial about why impedance can be modeled with complex numbers.
You will need to have some familiarity with Calculus to get the
full benefit from that article.

### Flying in the wind

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####
Here's a nice extra credit problem or project for a Calculus III student.
The problem is to show that it takes more time to fly an airplane over a closed
course in a steady wind than if there were no wind. If you want to
see if you can show it yourself, do so before looking at the solution
for *Flying in the Wind*.

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Click here to see
how it all ends.

Send e-mail to kurtz@asu.edu.