How to solve with numeric pdsolve?

first domain: from 0 to x1 (for example: from 0 to 0.2), thermal diffusivity, a1=1*10^(-6), lambda1=3
second domain: from x1 to x2 (for example: from 0.2 to 0.3), thermal diffusivity, a2=5*10^(-7),lambda2=1
IC:=T(x,0)=298 for both domain,
BC1:=T(0,t)=1200;
BC2:=T(x1+x2,t)=D[1](T)(x1+x2,t)=-10*(T(x1+x2), t)-298)/lambda2),

Regards
wzel

Hi, everyone.

I have got a question. There are n variables q[1],q[2],...q[n]. Each variable can take the value of 1,2, or 3, and I want get all the possible values of sum of these n variables,i.e. sum(q[i]...i=1..n). 
When n=2, I  write the procedure as follows:
    for q[1] from 1 to 3 do
      for q[2] from 1 to  3   do

Hi,

I have this procedure:

f := proc(x) if x < 0 then x^2+1; else cos(x); end if; end proc:

When I calculate NLPSolve(f,-Pi..2*Pi); the result is good. In NLPSolve, f(Pi) or f(-Pi) are also calculated.

When I want to determine f(Pi), I have this error code:

Error, (in f) cannot determine if this expression is true or false: Pi < 0

Why ? 

I must change my procedure with adding "evalf" to get a result for f(Pi):...

Hi all,

I'm having a problem with CodeGeneration[C].

In my simple example that reproduces the problem, there's a procedure containing just a single rtable statement. The contents of the rtable are 6 formulae depending on a single variable, p.

When I stuff the procedure xpr_3 into CodeGeneration[C], strange things will happen. It appears to me that CodeGeneration[C] is omitting anything with the variable p in it. However xpr_3 can be evaluated the usual way.

Suppose I have, say three arrays. I want to perform division on all the same positional elements of the array one and two, and raise the result to a power of designated by the same positional element of the third array.  In other words, the function applies to each of the elements of the array separately.  How do I do that without getting into programming?  Ratch

Hello,

I ran into problems while trying to write the input to NLPSolve in the Matrix Form because the problem dimensions depend on the input data. Take the following example:

max f(x)           <- f a nonlinear function of x

st: x₁+x₂+x₃+x₄                     ≤ b

I've written a procedure which currently outputs, for example, 3/8*2^(1/3)*k^(4/3). However when I plot this it doesn't give me the correct graph that I'm looking for. I've found that rewriting the equation as  3/8*2^(1/3)*(k^2)^2/3 will give me the proper function in Maple, however I don't know how to get my procedure to output the equation in terms of k^2. I'm sure there's a fairly straightforward solution- does anyone know what I'm missing?

Cheers.

I'm taking a calculus of variations class and checking some answers with Maples VariationalCalculus package and the EulerLagrange command in particular.

I've done an exercise by hand for which I don't get the same results from Maple and I'm trying to see why.

Can anyone help me construct the EL equation "manually", in partcular how do I get the partial derivartive of an expression containing x, y(x) and diff(y(x),x) with respect to diff(y(x),x) ? That...

Has anyone successfully integrated a 3D plot from Maple (X3D?) into PowerPoint that can be manipulated within a presentation?  I have read an article on Tecplot's (another graphics software package) web site that explains how to export a Tecplot file as an X3D file and then embedding the X3D file into PowerPoint using a X3D plug-in.  See below:

http://www.tecplot.com/Training/PlotTips/AddingPizzazztoPresentations.aspx

The X3D plot can...

Hi,

I'm using Maple versions 9.5 and 14.

I have a quite complicated functtion defined by means of a piecewise statement. Translation of that function into C code is required, so I tried to use CodeGeneration[C] and codegen[prep2trans]. The help of Maple version 9.5 tells me that the prep2trans command isneccessary to get the job done. It's about converting the MAPLE piecewise instruction into a  if ... then ... else if ......

Hi, I am new to using maple. For one of my classes we have been asked to find the root of a function using the bisection method. The function I am trying to find the root for is x-2^(-x) for 0<=x<=1. This is the sequence of commands that I am using

 f:= x-> x-2^(-x);

a:=0; b:=1;

 while b-a> 0.00001 do

      m:= (a+b)/2:

      if f(a...

Hi,

I would like to build a piecewise function automatically.

I would like something like this but with 33 pieces:

> piecewise(0<=t and t<1, f[1](t)[i][j], 1<=t and t<2, f[2](t-1)[i][j], 2<=t and t<3, f[3](t-2)[i][j], ...,0);

I tried to use the seq command, and it worked with the condition argument of piecewise.:

> seq(1-q<=t and t<q,q=1..3);
          -t <=...

I get the following error message when trying to use LinearSolve(with inplace option) to solve a linear system of size 2000x2000 with 416 digits.

maple: fatal error, lost connection to kernel

Any suggestion to the cause of this error or how to avoid it?