i am trying to simulate the spiralling motion of a coin that is rolled on a table.i am having three equations.... 1. the gyroscopic moment equation. 2. the conservation of energy equation. 3. general kinematic equation. three unknowns....curvature radius,precession velocity and coin inclination. the equations i am getting are non-linear.can someine suggest me any numerical methods to solve these approximately. i want those which can be easily programmed.i tried one which uses the jacobian..bit found that the solution was not converging. anyone please help.