How do I find the Sine and Cosine in a circle?

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2 Answers
May 24, 2018

Please see below.

Explanation:

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Here is a unit circle with the values of sine and cosine of popular angles on it:

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As you can see, the angles are labeled in radians and degrees both. Yo should be able to find the information you need to fill the table you posted.

May 24, 2018

Consider an arc AM, with extremity M that rotates counterclockwise on the trig unit circle, with radius R = 1 unity.
The projection of arc AM on the 4 axis defines the 4 main trig functions:
The projection of arc AM on the axis OA x defines f(x) = cos x
The projection of AM on the axis OBy defines f(x) = sin x
The projection of AM on the AT axis defines f(x) = tan x
The projection of AM on the BU axis defines f(x) = cot x
The trig unit circle is usually used as proof to solve trig equations and inequalities.
For example. Arc AM = x --> #cos x = 1/2# --> #x = +- pi/3#
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