UNIT CIRCLE Circular Functions (Page 6 of 10)

The unit circle can be used to find values for all six circular functions. Let's approximate these functions for an angle measuring 5π/6 radians. To specify a particular value of T (the angle), use the CALC value command. Just be sure the value you use is within the range specified in the window (0 to 2π).

 2nd CALC key. 1: menu selection.

 5 2nd Pi key. Divide key. 6 ENTER key.

 Calculator screen image.

The x-coordinate displayed at the bottom of the screen is the cosine of this angle, and the y-coordinate is the sine. Therefore, cos(5π/6 ) is approximately -0.8660254 and sin(5π/6 ) is approximately 0.5. With these two results, we can find the values of the other four circular functions on the Home screen.
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