How do i solve this trig equation. ((sin(s)^2 - sin(s) - 2)(1 - sin(s))/(cos(x)^2?

[sin²(s) - sin(s) - 2] [1 - sin(s)] / cos²(x)

= [sin(s) - 2] [sin(s) + 1] [1 - sin(s)] / cos²(x) ...... for x² - x - 2 = (x - 2) (x + 1)

= [sin(s) - 2] {[1 + sin(s)] [1 - sin(s)]} / cos²(x) ...... for sin(s) + 1 = 1 + sin(s)

= [sin(s) - 2] [1 - sin²(s)] / cos²(x) ...... for (1 + x)(1 - x) = 1 - x²

= [sin(s) - 2] [sin²(s) + cos²(s) - sin²(s)] / cos²(x) ...... for sin²(s) + cos²(s) = 1

= [sin(s) - 2] cos²(s) / cos²(x)

= sin(s) - 2

Replace cos^2(x) with 1 - sin^2(x) to get:
(sin^2(x) - sin(x) - 2)(1 - sin(x)) / (1 - sin^2(x))
Let c = sin(x)
(c^2 - c - 2)(1 - c) / (1 - c^2)
= (c - 2)(c + 1)(1 - c) / ((1 - c)(1 + c))
= (c - 2)
= sin(x) - 2