Establish the identity.
[sin^3 (x) + cos^3 (x)]/[1 - 2 cos^2 (x)] =
[sec(x) - sin(x)]/[tan(x) - 1]
skeeter had a valid point as well. the secant is undefined for the specified values of x. so that may cause problems. after graphing the two functions, i saw that the graphs were the same and so i overlooked it. i guess the point here was to do the algebraic manipulation to show you know your trig identities and how to use them