Alright, Denisha, let's do this!
First, we need to find a common denominator. It's simply going to be cosx(sinx-1)
Soooo, we end up with ((sinx-1)2 - cos2x)/(cosx(sinx-1)) = (sin2x - 2sinx +1 - cos2x)/(cosx(sinx-1))
Since 1 - cos2x = sin2x, we then have...
(sin2x - 2sinx + sin2x)/(cosx(sinx-1)) = (2sin2x - 2sinx)/(cosx(sinx-1)) = (2sinx(sinx-1))/(cosx(sinx-1)) = 2sinx/cosx = 2tanx
