prove the identity:
sin^2 O/ 1-cos O = 1+cosO
O= theta
sin^2 T (1+cos T)
-----------------
(1-cos T)(1+cos T)
sin^2 T (1+cos T)
-----------------
(1 - cos^2 T) but we know sin^2+cos^2= 1
sin^2 T (1+cos T)
-----------------
sin^2 T
which is (1+ cos T)