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Given a set of coupled nonlinear equations I want to extract the boundary points that appears in the interpolation function obtained as an output to NDSolve function and then to define them directly as $r_{min}$ and $r_{max}$ respectively.

More specifically my code is given by:

A = Exp[-EulerGamma/2] + 3.66*10^(-10)
sol = NDSolve[{h'[r] ==  h[r]f[r]+1,f[r] == -h[r]x[r]^2,x'[r]== -h[r]x[r],h[5]== 5,f[5]==0,x[5]== A*Exp[-12.5]},{h,f,x},{r,-10^(50),10^(50)},MaxSteps-> 1000,PrecisionGoal->70,WorkingPrecision->70,AccuracyGoal->70]

The output is given by:

enter image description here

which means that the boundary points are: $$ r_{min} = -63.42767159534372314743575944962536112508774436140873584436462308694243 $$ $$ r_{max} = 59.59887472641839166667576516071824661172770432996431126358438280519370 $$

How to extract directly the boundary points without mechanically to copy the boundry points from InterpolatingFunction using ctrl+C and then ctrl+V?

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1 Answer 1

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We can use "Domain" to extract the values.

{rmin, rmax} = (h /. sol[[1]])["Domain"][[1]];
rmin
rmax
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