# Evaluating Trigonometry using a Calculator

In these lessons, we will learn how to use a calculator to find the trigonometric value of an angle.
Related Topics: More Lessons on Trigonometry

We could make use of a scientific calculator to obtain the trigonometric value of an angle.

Example:

Find the value of cos 6.35˚.

Solution:

Press

cos 6.35˚ = 0.9939 (correct to 4 decimal places)

Example:

Find the value of sin 40˚ 32 ’ .

Solution:

Press

sin 40˚32 ’ = 0.6499 (correct to 4 decimal places)

Example:

Find the value of x for the following triangle. (Give your answer correct to 4 decimal places)

Solution:

x = 6.21 × sin 31.3˚ = 3.2262

Determining Trigonometric Function Values on the Calculator
Using the TI 84 to find function values for sine, cosine, tangent, cosecant, secant, and cotangent.
Calculators are able to determine trigonometric function values in degrees and radians. However, most calculators can not return the values in radical form. Most will return decimal approximations unless the values are rational. The video will only use angle measure in degrees.
First, make sure that the calculator is in degree mode.
Example:
Determine the following trigonometric values:
1. sin 30°
2. cos 45°
3. tan (-264°)
4. sec(102.5°)
5. csc (432°)
6. cot(-23.45°) Soh Cah Toa - How to Use Your Calculator
This video goes over how to use your calculator to solve trigonometry. Making sure you are in the right mode and entering things in the right order depend on which of the 2 types of calculators you have (Casio or Canon). This video goes over how to solve with both.
Step 2: Find the mode switcher.
Step 3: Solve for sides (multiply and divide) or solve for angles (inverse)

Finding trig ratios and angles using your calculator.
Examples:
1. Use a calculator to find the function value. Use the correct number of significant digits.
a) cos 369.18°
b) tan 426.62°
c) sin 46.6°
d) cot 17.9°
2. Determine θ in degrees. Use the correct number of significant digits.
a) sin θ = 0.42
b) cos θ = 0.29
c) tan θ = 0.91
3. Determine θ in decimal degrees, 0° ≤ θ ≤ 90°. Use the correct number of significant digits.
a) csc θ = 3.6
b) cot θ = 2.1
c) csc θ = 1.63
d) sec θ = 7.25 How to use a calculator to obtain the trigonometric value of an angle? This trigonometric calculator will help you to calculate the trigonometric functions like sine, cosine, tangent, cotangent, secant, cosecant. The angles are to given in degrees and not radians.

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