Evaluate Trigonometric Expressions With Your Calculator

In the next couple of pages, we are going to use what we have learned about trigonometric ratios to solve real-life problems.  Before we do that, we must practice entering trigonometric expressions into our calculators.

Keep in mind that every calculator is slightly different in how expressions are entered.  You might need to read your owner’s manual to see how your specific calculator works.

The first thing to clarify is the mode.  Your calculator can either be in degree mode or radian mode.  For this course, all angles will be in degrees, so make sure to set your calculator to degree mode.  Once you have done that, we can practice entering some trigonometric expressions.

Example 1:
Find the value of sin 30°.

Solution:
The value your calculator should show is 0.5.

Example 2:
Find the value of cos 68°.

Solution:
cos 68° ≈ 0.37

Example 3:
Find the value of cot 39°.

Solution:
Remember that cotangent is the reciprocal of tangent.

tan 39° ≈ 0.81