## How can I solve the following PDE system...

Hello,

I'm a prime in maple, I have got a problem while trying to solve the following PDE system of equations

declare:=(T(x,y),v(x,y),P(x));
declare := T(x, y), v(x, y), P(x)

> sys1:=[10^6*v(x,y)*diff(T(x,y),x)-0.1*diff(T(x,y),y,y)-10^3*diff(v(x,y),y)^2=0,diff(v(x,y),x)=0,-diff(P(x),x)+10^3*diff(v(x,y),y,y)=0];

>IBC = {v(0, 0.2) = 150, v(0, -0.2) = 150, T(x,0) =400, T(0,0,2) =300,P(0.3)=0.1 };

## Plotting non-numeric data...

I have some 'discrete' data which I wish to analyze with Maple.  For example, I have

## Loop problem...

Hi experts, I want to make a loop. Each time the function f should be changed according to n and m. The values that I obtain with Powell (not important for the undertstanding of the problem) should be put into the matrix A[n,m] > List := Powell(f, Xmin0); [-587.000914326964951, [-0.344030213998255226, 100.344030214880177], 12, 134] > m:=1; n:=1; for n to 3 do for m to 3 do end do end do; m:=m+1; n:=n+1; f := proc (Q1, Q2)->m*Q1+n*Q2 end proc; A[n,m]:=Powell(f); # not important for the understanding of the problem

## Box around plot is far too big...

Hi,

in Maple 12 (worksheet mode), the box Maple draws around a plot to allow the user to resize the plot using the mouse appears in all my plots far too big if I label the axis. Before labelling the axes, the box has the appropriate size, but as soon as I label the axis, the box becomes far too big resulting in my plot being very small while the bos goes from one end of the screen to the other.

Any help on that?

Thank you very much in advance,

Ben

## Tickmarks in plot3d...

Hi,

in Maple 12 (worksheet mode), the tickmark-option does not work: I enter in a plot3d-command (this command works otherwise) axis[3]=[tickmarks=5] in order to get 5 divisions on the z-axis.

The error message is "Error, (in plot3d) incorrect value for option gridlines: 5".

The workaround of tickmarks=[5,5,5] works. Other axis-options work, e. g. axis[3]=[color=green] .

Any help on that will be appreciated.

Ben

## Lable a plot...

Hi, obviously a very simple question, but not for me: I plot 3 graphes into one plot by : plot1 := plot(pts, x = 0 .. 5, y = 0 .. 1000, style = line, color = red); plot2 := plot(pts2, x = 0 .. 5, y = 0 .. 1000, style = line, color = blue); plot3 := plot(pts3, x = 0 .. 5, y = 0 .. 1000, style = line, color = green); G := textplot({[1, 1, "function"], [.5, .75, "derivative"]}); display(plot1, plot2, plot3) I tried to use texplot to lable the achses but it did not work. Is there another way to do it?

## fortuna's wheel

by: Maple

I was considering what sorts of "normally coded" things might get broken by the loading of a Maple Library package and the ensuing rebinding of names.

And so I tried this,

```> with(RealDomain): # rebinds sin

> convert( cos(x), sin );
sin(2 x)
1/2 --------
sin(x)
```

I was actually surprised to see that work OK. I was expecting `convert`...

## speed of mysql database connection...

I loaded a 1600*3 matrix into Maple 12  from my mysql datbase on my computer and it took 3 minutes to load it .

I assume that the speed will be increase significantly if I had a fast internet connection ( both up and down ).

My Internet connection (tcp / ip) is extremly slow !!    Is this correct ?   Are there any other way to speed up the data exchange ?

## Plot a list...

Hi experts, I am producing a List X[n]. After that I just want to plot the values X[n] := [n, P[n]] with n on the x axw and P[n] on the y axe. for i from .1 by .1 to 5 do n := n+1; P[n] := (i*2+3*i^2) X[n] := [n, P[n]] end do; X[1] Unfortunately I get the error message and an empty plot: Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

## solve numerically a pde system...

Hi,

I am a relatively new user of Maple, and I try to solve numerically the following PDE system :

> pde01 := diff(c(z, t), t) = (diff(c(z, t), z, z))-(diff(c(z, t), z))+k*(a-c(z, t));

> pde02 := diff(b(z, t), t) = (diff(b(z, t), z, z))-(diff(b(z, t), z))+k*(a-b(z, t));

> cl1 := c(0, t) = piecewise(t <= 0.3, 100, 0.3 < t and t <=0 .5, 200, 0.5 < t, 100);

> cl2 := c(l, t) = b(l, t);

> cl3 := (D[1](c))(l, t) = (D[1](b))(l, t);

> cl4 := b(L, t) = a;

## How can I prove if the set is empty...

I have a little problem. I have some linear unequalities and I wan't to prove if the following set is empty.
S:={(a,c) | (a-2*b-d+2*c)*delta <= d-c-a+b, a-b >= d-c, a>=0, b>=0}

b:=2;
d:=5;
delta:=2;

I have proved it like this:
solve({(a-2*b-d+2*c)*delta <= d-c-a+b, a-b >= d-c, a>=0, b>=0}, [a,c]);

## approximation with maple...

i have

p(n):= (2310*n^5+5775*n^4+5019*n^3+(3507/2)*n^2+(409/2)*n+5/2)/(27720*n^7+97020*n^6+132300*n^5+88200*n^4+29400*n^3+4410*n^2+210*n)

how can apprximate p(n) with another polynomial (say: a second degree polynomial in n) or a rational function (ration of two second order polynomials) of less degree of n? and how good is that approximation

## Grouping negative and positive terms...

My output consists of a lot of terms (100+) and I need to isolate all the negative (positive) terms. Can anyone help? Thank you in advance.

## set ordering change

by: Maple

The following type of difference in behaviour, due to deterministic ordering of sets as introduced in Maple 12, may affect implementations of some algorithms.

```    |\^/|     Maple 11 (X86 64 LINUX)
._|\|   |/|_. Copyright (c) Maplesoft, a division of Waterloo Maple Inc. 2007
<____ ____>  Waterloo Maple Inc.
|       Type ? for help.

> seq(x, x in {a,b,c,d,e,f,g}) assuming d>0;
...```

## how to manupulate algebraic expression...

I have:

a(n):=(27720*n^(6)+83160*n^(5)+93030*n^(4)+47460*n^(3)+10689*n^(2)+819*n+5)/(27720*n^(7)+97020*n^(6)+132300*n^(5)+88200*n^(4)+29400*n^(3)+4410*n^(2)+210*n):

now i want to multiply by (n+1/2) that is

a(n)*(n+1/2)

now i want to express it in a simples form. may be like this:

c(n) + d(n)/p(n)

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