Csc α - sin α =cos α cot α
show how this is an identity?

Csc a - sin a = cos a cot a
1/sin a - sin a = cos a (cos a / sin a)
(1 - sin^2 a)/sin a = cos^2 a/sin a
cos^2 a/sin a = cos^2 a/sin a

Therefore, the given equation is an identity.

The answer is

21, i'm pretty sure it's right lol