A) I have to find the exact value of cos8*cos38* + sin8*sin38*(the *'s are degrees)

Now, I'm 90% sure I have to use cos(A+/-B)=cosAcosB +/- sinAsinB, but I've never understood what to do from that point.

B) I also have to prove that sin^2(x)/1-cos(x)=sec(x)+1/sec(x), yet I've tried several times and reach nothing but deadends.

Mucho Gracias for the help in advance!