Using Your Calculator - Try It Out Problem 1

The key: Convert the words into an expression that you can evaluate with your calculator. How you solve the problem at this point depends upon how confident you are in using your calculator. Try solving it both ways as suggested below so you are convinced that your scientific calculator works in a way you really do understand!

Method: Straight-forward entry into Scientific Calculator:

Note first that it does not matter for this problem whether we are in degrees mode or radians, since we will be taking the sine of an angle which will be given by the inverse tangent function. Also, remember that the key TAN^-1 does not mean "one over tangent" but "the angle whose tangent is."
Think of this as a "nested" problem: you want to calculate the sine of an angle, and the angle is the angle whose tangent is the square root of 7. Use the following key strokes:
```
 SIN   TAN^-1  SQRT  7   ENTER 
```
and the answer is 0.93541

Method: Stepwise Calculation of Each Piece:

We need the square root of 7. Intermediate answer: 2.64575
We need to find the angle whose tangent is this number: Intermediate answer: 1.20943 radians
We need to find the sine of this angle: 0.93541

In this latter example, you may have to use your ANS key to get the previous answer entered in the right order. On a TI-82 type calculator, this second way of stepping through the calculations takes many more key strokes than the first, so if you do not need the intermediate answers, the first method is preferred.

Try another problem like this one.

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The Shodor Education Foundation, Inc.
in cooperation with the Department of Chemistry,
Appalachian State University