Question

How do you simplify: -5(cot^2 theta - csc^2 theta)?

Answer 1

One of the standard identities is

cot^2 Ø = csc^2 Ø - 1

so ...
-5(cot^2Ø - csc^2Ø)
= -5(csc^2Ø - 1 - csc^2Ø)
= -5(-1)
= 5