# impulse in inelastic collision in two dimensions

I'm trying to find the impulse in an inelastic collision of two particles.At the end of this page there is formula for that.But I cant reach it bu my own.Here is what I think is the way to find the impulse:

1. If we denote J to the impulse the we can write the final velocities using J
2. No we define a normalized vector n which is the same direction of J
3. so not instead of using x-y coordinated we are using another coordinates system
4. using the constant of restitution we rewrite the equation of conversation of energy eKi = Kf
5. combining conservation of energy and momentum we can find a quadratic equation for J.then we can find the final velocities.

I think this is the way but I have problems finding the final result. If somebody could write down the process it would be great. Thanks for your attention