• To: mathgroup at yoda.physics.unc.edu
• Subject: New User Question About NDSolve
• From: Jay Maddux <jrm5c at poe.acc.virginia.edu>
• Date: Wed, 1 Sep 1993 05:27:34 GMT

```  I am trying to solve a simple heat-flow problem using the NDSolve routine.
The problem is for a one-dimensional, uniformly heated rod, so the equation
I am using is:  t''[x] == C1 (constant)

The boundary conditions are: t[0] == C2
t'[1] == C3*t[1]

This equation can easily be solved by hand (t[x] = Ax^2 + Bx + C), but
I would like to add additional terms if I can get the simplified version
to work with the NDSolve routine.

The error message I get is:
"NDSolve::ndinn: Initial condition t'[0.] is not a number."

The routine works if I do give a value for t'[0], but this is not a number
that I can really determine a priori.

The second boundary condition would seem to require an iterative method to
solve for t[x], so maybe this is the problem ?

I apologize if I have overlooked something obvious here, but I'd appreciate
any help I can get.

Jay
jrm5c at virginia.edu

```

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