cscx-cotx*cosx=sinx
A few transformations we can make based on trig identities:
csc(x) = 1/sin(x)
cot(x) = cos(x)/sin(x)
So we have:
1/sin(x) - cos(x)/sin(x) * cos(x) = sin(x)
(1 - cos^2(x))/sin(x) = sin(x)
1 - cos^2(x) = sin^2(x)
This is true from the identity:
sin^2(x) - cos^2(x) = 1