Using the half angle formula for cosine to evaluate for an angle cos

The video tutorial explains how to calculate the cosine of 112 degrees and 30 minutes by doubling the angle to 225 degrees and using the half-angle formula. The process involves simplifying the expression to find the final cosine value, considering the angle's position in the second quadrant where cosine is negative.

Explain the process of using the half angle formula for cosine.

What is the final answer when evaluating the cosine of 225 degrees?