Cuuuuuuuuuuuuuuuuuuu

`= ((sin^2 x + cos^2 x) - 2sin x * cos x - 1)/((sin x)/(cos x) - sin x - cos x)`

`=  (-2sin x * cos x)/(sin x * (1/(cos x) - cos x))`

`=(- 2cos^2 x)/(1 - cos^2 x)`

`=(- 2cos^2 x)/(sin^2 x)`

`= - 2cot^2 x`

`@Sad2006`