Evaluate the double angle of sine given a triangle

The video tutorial explains how to determine the quadrant of an angle and the characteristics of a triangle in the third quadrant, focusing on the signs of the sides. It highlights common student mistakes, such as forgetting the signs, and demonstrates how to apply trigonometric formulas to find sine and cosine values.

What is the relationship between sine and cosine in the context of a triangle?

Calculate the sine and cosine values for the triangle described in the third quadrant.