Trig
posted by VD on .
(csc(B)+cot (B))(csc(B)cot(B))

You have the pattern of "difference of squares"
(csc(B)+cot (B))(csc(B)cot(B))
= csc^2 B  cot^2 B
But csc^ B = 1 + cot^2B , one of the identies from
sin^2 B + cos^2 B= 1
so csc^2 B  cot^2 B
= 1 + cot^2 B  cot^2 B = 1