Dear collegues,
my problem is that the routines taken fom the numerical recipies didn't give me the solution, I can not find the error?
if some can help me to show where is the error??
my problem is a two-point values problem with relaxation method;
y1' = y3
y2' = y4
y3' = 2/t**2*y1*(1-y1)*(1-2*y1)-0.25*y2**2*(1-y1)
y4' = -2/t*y4+2/t**2*y2*(1-y1)**2+2.3*y2*(y2**2-1)
With the boundaries t=0:y1=y2=0,t=20:y1=y2=1.
I started from the trial solution:
y1 = 1-exp(-.4*sqrt(t)**3)
y2 = 1-exp(-.7*t)
y3 = 0.6*sqrt(t)*exp(-.4*sqrt(t)**3)
y4 =0.7*exp(-.7*t)
when I run the program the correction become bigger with each itteration !!!! this is the problem, so if some can help me to show me what is wrong.
the program and an explaining document can be found in the link in the end of this message.
Yours,

http://www.geocities.com/amin_ahriche/Problem.zip