Trig
posted by Don .
Prove the equation is an identity :
csc3theta  csctheta + cottheta/csctheta = cotsqtheta + costheta
wow ... try that one

Here's where parentheses come in handy.
As written, the identity is wrong. What you meant to say was
(csc^3  csc + cot)/csc
= (csc(csc^2  1) + cot)/csc
= (csc cot^2 + cot)/csc
= csc cot^2/csc + cot/csc
= cot^2 + cos/sin * sin
= cot^2 + cos