1. The problem statement, all variables and given/known data Solve y^2*(1-(dy/dx)^2)=1 2. Relevant equations 3. The attempt at a solution I expressed the ODE in terms of dy/dx and considered two cases. I got (a) y^2 = 1 + (x+C)^2 (b) y^2 = 1 + (-x+C)^2 where C is a constant However, my professor told me that there is another way to do this. He hinted me that this was some well-known ODE. Can someone enlighten me on where to find out more about this ODE? Thank you.