What is -5( cos squared theta -csc squared theta)

Question

My question is what is -5( cos² -csc²) any info on how to do this would be appreciated 

Answer 1

= -5(cos^2(x) - csc^2(x)) cosx = a/h, cscx = h/a

= -5(a^2/h^2 - h^2/a^2)

= -5(a^4 - h^4)/a^2h^2))

= (5h^4 - 5a^4)/a^2h^2

on a unit circle h^2 = a^2 + o^2