## MaplePrimes Questions

I have found this free library for Maple. It has got a lot of new or improved commands.

## Help with plotting...

I have a pointplot3d that is running in an infinite loop and I was wondering if there was any way to at the end of my loop show the graph, pause Maple for .1 seconds and delete the graph. Such as in the example:

n:=1;
keepGoing:=1;

while keepGoing=1 do
plot(x^n, x=-5..5);
od;

is there any way I could get Maple to show the graph for .1 seconds then delete the current graph and show the next graph?

pHatfield

## could you help me?...

Dear all: Anybody could tell me how can I obtain this integral with maple? Int(exp^(-a*x^2)*sech(x/2)^2, x=-infinity..infinity); where "a" is positive thank a lot D. Reyes CBPF

## how to draw isocline is ODEs?...

suppose i have an ODE dx/dt=x/t how do i draw isoclines? thanks

## Linux directory change...

I have a Maple code which I wrote on a Windows machine. Now I need to run it on a Linux machine. I set the directory by the command

currentdir("C:/example"):

How should I change this if I want it to be /home/user/example ?

and I use

fopen("C:/mydir/examp/example.dat", WRITE):

How should I change this line in Linux if I want it to be in /usr/local/mydir/examp/example.dat?

## something about isoclines on direction field.....

hello i was asked to draw direction field and some isoclines for some ODEs Now i have some problems: the equation is t*diff(x(t),t)-x(t)=0 and i use contourplot(x(t)/t,t=-10..10,x=-10..10); to draw the isoclines... however, the output is not quite as i expected, it looks like some curve because if i draw it by hand, i put dx/dt=x/t and set x/t=c ( c is some constants) then the graph should be some straight line what am i doing wrong??

## Is it possible to get Maple to only find integer s...

The problem I'm having is that I have a large system of linear equations, the solution to which I know must be integers between 1 and 9. I have tried applying bounds etc., but the problem is that when I use solve, it said 'evaluating' for around half an hour, and still came out with nothing. Does anyone have any ideas as to how to make this faster, because I suspect that it's trying to find all solutions, and then eliminating the ones of the wrong form, rather than only looking for solutions where each variable is an integer between 1 and 9.

## How can I solve a complex semidefinite program (SD...

Hello Maple experts,

I'm currently trying to get more familiar with semidefinite programs (SDP), i.e. I want to minimize/maximize a linear objective matrix function over linear equality/inequality constraints with a positive semidefinite matrix condition.

It seems that there are a number of Matlab packages available but so far I couldn't really see how I could do this with Maple (which I would prefer to Matlab if there is a reasonable solution...)

## How to define a function?...

I am in a mode with a red arrow on the left.

How do I define f to be an algebraic function of x over C, the complex numbers, such as

f(x)=x+7+I

I want to be able to plug in complex numbers for x and have a complex number

returned, say

f(9-5*I)=16-4*I

## Change background color of plot...

Is there a way to change the background color of a plot viewing area different from the white?

Thanks!

## animating a point plot...

Hey,

I am trying to animate this code, I have a loop that makes a matrix of random numbers

with(RandomTools):for i from 1 to 20 do
>   for j from 1 to 2 do
>   p[i, j] := i+Generate(float, 0..1);
>   od;
> od;

and if I try to plot the following this works such as

points:= {seq([p[T,1], p[T, 2], T],T=1..20)};
pointplot3d(points, symbol=box);

This gives me all 20 points on the plot

## Basic plotting in maple...

Hello,

I am trying to do some basic plots with maple, but when I plot them they look strange and do not look like they should, what am I doing wrong?

The plot I tried to do is:

plot(cos(20*Pi*t), t = -5 .. 5)

I am having this problem with most of the plots I try to do, they do not come out symmetrical and have strange anomalies in them.

Thanks,

## New User - Symbolic differentiation to find Statio...

Hi all,

I have the following function:

phiS := (C,q) -> w*(int(a*f*g(x), x=0..a*f) + int(x*g(x), x=a*f..((w+pi2)*q-pi2*C)/w) + int(q*g(x), x=((w+pi2)*q-pi2*C)/w..infinity)) - s*q - pi1*(f-C) - pi2*int((C-q)*g(x), x=((w+pi2)*q-pi2*C)/w..infinity);

when I type the command:

simplify(diff(phiS(C,q),C));

I get the correct output (I've differentiated phiS on paper): pi1- pi2*int(g(x), x=((w+pi2)*q-pi2*C)/w..infinity);

***************

## exporting from maple 11...

Is it possible to write questions of MapleTA just from maple 11?

I mean, I know is possible to write questions and export them to Maple T.A. but every "execution group" will be a diferent query for the maple and setences like

RandomTools[Generate](integer(range=0..4));

will return always the same number, an i cannot use sentence like parse(time) because parse is restricted.

Thanks.