## anonymous 3 years ago PreCalc & Trig, picture below, please show your work..

Firstly, calculate the hypotenuse, then find cos(theta), then find theta. Once you have found theta, use it to calculate cos(theta/2). However, if you are required to use identities (which I doubt), remember that $$cos^2(\theta) = \frac{1+cos(\theta)}{2}$$.