Question 1072923
tan(x/2)
= sin(x/2)/cos(x/2)
=(sqrt((1-cos x)/2))/(sqrt((1+cos x)/2)
=sqrt((1-cos x)/(1+cos x))
=sqrt((1-cos x)^2/(1-cos^2 x))
=sqrt((1-cos x)^2/(sin^2 x))
=(1-cos x)/(sin x)
=1/sin x - cos x/sin x
= csc x - cot x