# Help in second order ode numeric solution

1. Jan 25, 2009

Dear all,

Im trying to solve the following ode:

y'' = -0.12*y + 0.4/sqrt(y^2 + 5.76) , y=y(t) , t: [-50,50]
y(-50)=2.3 , y'(-50)=0

i changed it to a set of two first order ode using z=y'
and solve it with finite differences.

note that the right side doesnt depend on t.

the solution start good and raise till a pick point and than decay till zero, the problem it that when it decay to zero, infact i received again that y=y'=z=0 meaning im reaching my initial point and than the solution raise again to a pick point and decay again to zero etc etc...

the real solution should raise , reach the pick when t=0 and decay again to zero till t=50.

how can i solve that issue and stop the periodic behaviour when it decay to zero ?

thanks a lot