posted by lauren .
given sin u=3/4 and cos v= -5/13 with U and V in quadrant 2
Use the identity
tan (u-v) = (tanu tanv)/[1-tanu tanv)
Get the values of tanu and tanv from the sines and cosines that you are given. For example, if cos v = -5/13, sin v = 12/13 and tan v = -12/5 (in the second quadrant).