Prove the following identity.
[sin(x+y)+sin(x-y)]/[cos(x+y)+cos(x-y)] = tan(x)

Question

anonymous · Answer

2 sin((x + y + x - y)/2)*cos((x + y -x +y)/2)
-------------------------------------------------
2cos((x + y + x- y)/2) *cos(x + y -x + y)



sinx
-------
cosx 




tanx

anonymous · Answer

sin(x+y)+sin(x-y)=2sinx cosy
cos  (x+y)+cos (x-y)= 2 cos x cos y
when the first equation will be divided by the second one, 2 and cos y will be cancelled out..
u will get sinx/cosx=tanx

anonymous · Answer

Hey arnab

anonymous · Answer

hello

anonymous · Answer

how are you, long time no see

anonymous · Answer

i am fine. cleared kvpy first level. taking preparation for the interview.. :)

anonymous · Answer

Cool KVPY I wish I had the opportunity 

Good Luck! (Y)