Pre-Calculus - How to Evaluate Using The Double Angle of Sine

The video tutorial explains how to solve a trigonometry problem involving the sine of a double angle. It begins by setting up the problem and identifying constraints, which help in selecting the correct triangle in the third quadrant. The tutorial then uses the double angle formula for sine and applies the Pythagorean theorem to find the missing side of the triangle. Finally, it calculates the sine of the double angle, resulting in a positive value.

What is the double angle formula for sine, and how is it applied in this context?

How do you calculate the sine of an angle given its opposite and hypotenuse?