## "eval" results in "vector index out of range"...

Hey Everybody,

I have only been using Maple for a few weeks but have been very much enjoying the functionality of the with(VectorCalculus) tools. That said, I have been having some trouble evaluating vectors at specific values.

> with(VectorCalculus);
> P[0] := PositionVector([t, ln(t)]);
> N[0] := PrincipalNormal(P[0], t);
> P := eval(P[0], t = 1);

## Contour plot pf ode (couple equations)...

Is it possible the contour plot of these coupled equations

restart:with(plots): Nb := .2; Nt := .2; h1 := 1+a*sin(x);h2:= -b-d*sin(x); a := 1;b:=0.1;d:=0.1;F:=1-Q-d;Q:=-1;beta:=0.1;alpha:=0.1;G:=0.5;B:=0.5; eq1 := diff(alpha*f(y),y,y,y,y)+G*(diff(theta(y),y,y))+ B*(diff(phi(y),y,y))+6* beta*(diff(f(y),y,y))*(diff(f(y),y,y,y))^(2)+3* beta*(diff(f(y),y,y,y,y))*(diff(f(y),y,y))^(2)=0; eq2 := diff(theta(y), y, y)+Nb*(diff(theta(y), y))*(diff(phi(y...

## contourplot of an ode...

Is it possible to have a contour plot of an ode,

restart:with(plots);alpha:=1:

de1:=alpha*diff(f(y),y\$4)+(diff(f(y),y\$2)*diff(f(y),y\$3)^2+diff(f(y),y\$4)*diff(f(y),y\$2)^2);

with  such type of bcs?

bc1:= f(1+sin(x)) = .95, f(-.1-.1*sin(x)) = -.95, (D(f))(1+sin(x)) = -1, (D(f))(-.1-.1*sin(x)) = -1;

contourplot({de1,bc1}, [x,y, f(y)],x=1..10, y=1..10);

Thanks

## ordered product of creation and annihilation opera...

Hello,

I am trying to find the product of three groups of creation and annihilation operators. After completing the input of the groups, Maple fails to give me the product of the operators (value of sigma^3) as shown below. What I need is for Maple to give me the ordered product of the three groups, but the "expand" command (lowercase 'e') fails to produce any output. Appreciate any help.

> with(Physics);
> Setup(mathematicalnotation = true);
print(`output redirected...`...

## Getvar() to get a structure from Matlab...

In matlab, a function is returned a structure H, say H.a, H.b, ...

In maple, I want to call this matlab function, but what returned to maple is a Record:

Hs:= getvar("H");

Hs:= Record(a=..., b=..., ...);

So how can I convert this record to a normal maple array? so I can access to each element by Hs[1].

Thank you

Kyle

## Convert D operator to "diff" form...

> f := a+D(x);

> convert(f(t), diff);

Is there a way to tell Maple that "a" is a constant, so (t) won't attach to a? thanks, kyle

## Access Matlab workspace in Maple...

Hi there, I'm trying to pass some calculation to Matlab then retrive the result by getvar(), but seems something is getting wrong.

my matlab function is very simple:

function out =maple_fun(a, b)

out = a + b;

return

this function is saved as maple_fun.m.

in Maple,

restart:
with(Matlab):
DirectoryLocation := " cd  '/Users/Kyle/Documents/MATLAB/'  ":

## Writing code to generate a table with content...

Dear Maple Users

I am pretty new to programming in Maple, so maybe this is not a very difficult question to answer. I want to write some code, which generates a table to be displayed. In every cell I want some content, which is generated by some code as well. How can it be done, and if there are several ways, which one is the best?

Regards

Erik

## What is Wrong with Pasting an Image from Preview t...

System: Mac OS X 10.8.1 + Maple 16

I am trying to copy + paste a selected region from an image shown in Preview to Maple. The image is blank when it is pasted. Why is this not working as expected?

--
Chemistry / Chemical & Materials Engineering
UAHuntsville

## Problem fitting data using Statistics[Fit]...

Hi

I am trying to fit some data to a model.

The model is given by this equation.
y=a*(1-exp(b*x^c))

When I enter the command

`Statistics[Fit](a*(1-exp(b*x^c)),X,Y,x);`
`this error message appears:`
`Error, (in Statistics:-Fit) SVD of estimated Jacobian could not be computed`
` `

Does anyone know, why it appears? and why Maple cannot compute the SVD of the estimated Jabobian Matrix?

## How can I find all of the solutions of the equatio...

How can I find all of the solutions of the equation sinx = (1/8).x ?

## 3D plotting in Maple16 on Ubuntu 12.04, 64bit...

Maple16 on Ubuntu 12.04, 64-bit.  Radeon 4550 video.  plot3d images are kind of split down the middle with left half of the image on the right and right-half on the left, lots of flicker when trying to manipulate with the mouse, surface is monochrome and poorly rendered, crashes maple application if you try to manipulate it too much.

This behavior occurs using the default xorg video driver (not proprietary) and default xorg configuration.  I have not...

## Maple 16 mathematical orb / knot...

Someone asked how to create this in Maple.

## Full Screen Mode in Mac OS X 10.8...

Here is a quick question - Is there anyway to enable full screen mode for Maple on a Mac OS X? I'm currently running Mountain Lion with Maple 16 and will be doing some screencasts and would prefer not to have the menu bar in the videos.

## do loop over 1000+ statements...

`> for i from 1 to 10 do>   exp1 >   exp2 `
`....>   exp1000+> od:`
`Does anyone know how this can be done? `