just take x=eiθ and y=eiφ
substitute and get the answer.
If 2cosθ=x + 1/x,2cosφ=y + 1/y,find values of
1)xmyn + 1/xmyn
2)xm/yn + yn/xm
yes, decoder has decoded correctly, another method by cis...
i hope u cn proceed further, as i cud not capture more than this in 1 pic...:)