1. The problem statement, all variables and given/known data Here is the problem: http://dl.dropbox.com/u/64325990/MATH%20253/help.PNG [Broken] 3. The attempt at a solution http://dl.dropbox.com/u/64325990/Photobook/Photo%202012-05-24%209%2037%2028%20PM.jpg [Broken] This seems to be wrong... Since I have fx and fy which I cannot cancel out. Why is this wrong? I guess it can only cancel is fx = fy but how do I prove that? We don't even know what f is.