Finding values of cos(x) and sin(x) with the unit circle - In Third Quadrant - Tutorial 3

Using the unit circle we can find values of sin(x) and cos(x) in the third quadrant, angles between 180 and 270°, using the fact that the point on the unit circle is diametrically opposite its corresponding point in the first quadrant. In this tutorial I work through several examples showing exactly how to find the values of sine and cosine in the 3rd quadrant.

[won]

Thank you so much, this helped me a lot.