here is the the question :
http://upimage.us/server/php/files/mathquestionsnew222.png
http://upimage.us/server/php/files/mathquestionsnew222.png
I tried to come up with the idea of this question but all of my attempts were failed :(
How is this question solved??
$$\dfrac{\tan(A)}{\tan(B)} = \dfrac{\sin(A)}{\cos(A)}\cdot \dfrac{\cos(B)}{\sin(B)} = \dfrac{\cos^2(B)}{\sin^2(B)} = \cot^2(B) = \csc^2(B) - 1$$