1. The problem statement, all variables and given/known data e^x*cosy=0 -e^x*siny=0 3. The attempt at a solution Since they both equal to 0 I set them equal to each other: e^x*cosy = -e^x*siny I can cancel the e^x and I get: tany = -1 Thus y = 7π/4 + n where n is an integer. However this is incorrect when I plug it back into the original set of equations. Why is this wrong?