## Assumption ignored while solving integral...

Hi folks,

I'm trying to get the fundamental solution of

-diff(A,t)+a(x,t)*laplacian(A,[x,y,z])=0;

I had some troubles entering the code here, so I uploaded the maple commands here: http://pastebin.com/m2765fda0

when I call eval(phi(x,t,xi,tau));  to calculate the fundamental solution, I always get the error 'Error, (in w) numerical exception: division by 0'.

Shouldn't my assumptions avoid this error?

Manuel

## How to fix the ratio of height to width for a figu...

Dear all,

How can I fix the ratio of height to width as 0.618 when plotting figures ? The command scale=constrained seems not appropriate   If  someone  knows how to realize it , please tell me ASAP. Thank you very much !

Kindly regards,

Yours

huang

## Make me run faster `if` you can...

Dear all

Can anyone suggest how the following code could run faster?

## dsolve method...

Hi

I used maple to solve a 4th order ode:

ode:=(h2(x)*diff(eta1IItrans(x),x\$4)+diff(h2(x),x)*diff(eta1IItrans(x),x\$3)+(1/(g1*h1))*((w^2)*(h1+h2(x))*diff(eta1IItrans(x),x\$2)+(w^2)*diff(h2(x),x)*diff(eta1IItrans(x),x)+(w^4/g)*eta1IItrans(x))=0);

avec h2:=x->h2I*exp(d*x):

I have 2 questions:

-I can get a solution only with precise values of parameters (g, h, d etc...) but I would like a literal one.

## Drawing Scale-free networks...

And again, I've got a problem with drawing graphs with DrawGraph. I've generated some scale-free networks with Barabasi's algorithm (not implemented in Maple 12. I did that myself).
Now, I wanted to display these graphs in a nice way, in which you can clearly distinguish the hubs from the other nodes. I thought that the "style=spring" command would do so, but it puts nodes very near to each other, sometimes even overlapping.
Is there another solution to draw such a scale-free network in a nice way?
Thanks for helping.

## JCHelpCallBack...

I would like to investigate the JCHelpCallBack example using OpenMaple. The sample can be found under the directory,

```\$MAPLE/samples/OpenMaple/Java/jcmaple/
```

I've set LD_LIBRARY_PATH. And I can compile and run the jcmaple.java sample. That starts up what appears to be a commandline Maple session. And within that session I can issue the help query ?int OK. I can also issue INTERFACE_HELP(display,topic=int) and that too works, although it dispays as double-lined.

## MathMLEditor, again...

How do I convert a 2D expression constructed with MathMLEditor to a normal 1 D string? I know that example 6 from the maplet builder tutorial does this, but the result is often in a prefix notation. For example, if I enter "x-square + 1" as a 2D expression in the MathMLEditor, the result is `&plus;`(x^2,1). I would like to get more normal x^2+1. I have examined the code generated by the maplet builder and experimented with options in the MathMLEditor and MathML[Import], but to no avail. Is there a way to convert the prefix notation to the more normal infix?

## Bug(?) in webpage...

My login is rejected and I need a new password, again, and again.

I tried it under

Windows Xp- Firefox2.16, Firefox3, IE7, Opera9

Linux(Ubuntu)-Firefox2.14, Opera9

Since it is very uncomfortable I ask help, idea, suggestion.

Many thanks in advance and sorry a little bit off-topic.

Sandor

## Carrying units within a procedure...

To all,

I am trying to plot a procedure phi(beta, x) which uses dimensional units (length).  The code listed below returns an error message regarding "invalid units".  I have redefined the standard units to report length in inches, but I don't see why this should prevent me from plotting the procedure over a range of x (the procedure works when the arguments are specified discretely.  Thank you for your assistance.

Define constant beta:

## assistance...

I need mentorship and material that is going to assist me in how to use maple.

## statistics...

I need help with this problem !!!!!!!!   My brain is turning to mashed patato's  Thank-You

In a study on infants, one of the characteristics measured was head circumfrence. The mean head circumference of 15 infants was 34.6 centimeters (cm).

## Statistics...

The data in the table represents the ages of the winners of an award for the past five years. Use the data to answer questions (D) and  (E)

39     40

-------------

48     48

-------------

42

## Phase PLane for the simple pendulum...

```Hi all,
```
```> deq := diff(theta(t), t, t) = -g*sin(theta(t))/L;

2
```

## Change of variables involving square roots...

I have a particular system of partial differential equations to which I want to apply a change of variables involving square roots using PDEtools[dchange]. The result turns out to be not in a simple form due to the square roots. Why is this so ? Is there a better way solving the problem than the one I am suggesting below ? The system of partial differential equations of interest is the following:

## pdsolve - boundary condition...

Hallo Everybody,

I hope someone can help me.

I want to solve numerically the diffusion equation,

diff(csh(rh, t), t) = Dif*(diff(rh^2*(diff(csh(rh, t), rh)), rh))/(r0*rh^2)

where "Dif" is the diffusivity and "r0" is the initial value of rh (the equations were normalized).

subject to the following boundary and initial conditions:

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