trig--verifying identities?

Question

(sinxcosy+cosxsiny) / (cosxcosy-sinxsiny) = (tanx+tany) / (1-tanxtany)

i know you can only work on one side of the problem....but i really dont know how to do this one. i know its alot of work, so if you decide to give it a try thanks so much.

Answer 1

sinxcosy + cosxsiny = sin (x + y)

cosxcosy-sinxsiny = cos(x+y)

sin (x +y)/ cos (x + y) = tan( x + y), which is the equation you have on the right there.

TADA