Given that cosz=BL find the value of
cotz-cosecz/secz+tanz
I'll just use x=BL to make things easier to read
cosz = x
sinz = √(1-x^2)
(cotz-cscz)/(tanz+secz) = [(cosz-1)/sinz]/[(sinz+1)/cosz]
= [cosz(cosz-1)]/[sinz(sinz+1)]
= [x(x-1)]/[√(1-x^2)(√(1-x^2)+1)]
= (x^2-x)/(1-x^2+√(1-x^2))
Massage that as you will