Recall that $\displaystyle \cos^2{\theta} = 1-\sin^2{\theta} = (1-\sin{\theta})(1+\sin{\theta})$
with that do i have to foil method this? --> (1 - sin theta)(1 + sin theta)/
1 + sin theta
or cancel the(1 + sin theta).. / 1 + sin theta here --> (1 - sin theta)(1 + sin theta)/ 1 + sin theta