Question

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

Answer 1

Please see below.

Explanation:

.

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

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.

Answer 2

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`