## how to plot dualaxisplot in dialog?...

try:
p := dualaxisplot(listplot(ma, color = red), listplot(me, color = blue), style = line, gridlines = false);
catch:
p := dualaxisplot(listplot(me, color = red), listplot(me, color = blue), style = line, gridlines = false);
end try:
return p:
end proc:

CheckGraph := proc(text,graphparam1,graphparam2)
local maplet, choice:
maplet := Maplet(
[
[Plotter['PL1'](graphparam1)],
[Plotter['PL2'](graphparam2)],
#[Plotter['PL2'](graphparam2)],
[text, ComboBox['CoB1']("No Refund", sort(["Jackpot"], lexorder))],
[Button("OK", Shutdown(['CoB1'])), Button("Cancel", Shutdown())]
],
):
choice := Maplets[Display](maplet):
end proc:

>graph1
can show graph but after using Plotter['PL1'] , it can not show graph in dialog

CheckGraph("Has Jackpot?",graph1,graph2):

how to plot dualaxisplot in dialog?

## factoring with exponentials...

I would like to factor an algebraic expression that contains exponentials.
Maple spits it back unfactored. Did I enter it wrong?

factor(exp(4*y) + 2*exp(2*y) + 1);

## Problem with DEplot3d...

Good afternoon everybody,

I am a beginer user in maple and I am having problems to plot a system of differential equations. My code is

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

restart; with(VectorCalculus); with(LinearAlgebra); with(DEtools);
> p := 2*u*x*y^2; q := (x-1)/x;
> doth := simplify(-(sqrt(6)*x^3*(y-1)^2+u*((3+sqrt(6))*x^3*(y-1)^2+3*y^2-9*x*y^2+3*x^2*(y^2+2*y-1)))/p); ddotphi := simplify((y-1)*(sqrt(6)*x*y^2*(x-1)+u*(3*y^2-(6+sqrt(6))*x*y^2+x^2*((3+sqrt(6))*y^2+6*y-3)))/p);

>ode1 := diff(x(t), t) = x(t)*(1-x(t))*doth-x(t)^2*ddotphi/sqrt(6); ode2 := diff(y(t), t) = y(t)*(y(t)-1)*doth; ode3 := diff(u(t), t) = sqrt(3/2)*u(t)*(1+u(t))*q;

>DEplot3d([ode1, ode2, ode3], [x(t), y(t), u(t)], t = -2 .. 2, x = 0 .. 1, y = 0 .. 1, u = -1 .. 0, [[x(0) = .9, y(0) = .25, u(0) = -.95], [x(0) = .9, y(0) = .25, u(0) = -.5], [x(0) = .85, y(0) = .2, u(0) = -.15], [x(0) = .25, y(0) = .5, u(0) = -.5], [x(0) = .7, y(0) = .5, u(0) = -.6]], linecolor = [red, green, black, navy, maroon], thickness = 2, axes = boxed, labels = [x(t), y(t), u(t)], arrows = medium, stepsize = 0.1e-1, orientation = [30, 65]);

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

and the next error appears

Error, (in DEtools/DEplot/direction3d) unable to store 'HFloat(HFloat(undefined))+HFloat(HFloat(undefined))*I' when datatype=float[8]

I have no idea what to do, and searching for solutions I have only found things that I dont understand.

Thank you very much in advance

## Why is this happening?...

I want the legend to be produced to look like the third to last example. https://fr.maplesoft.com/support/help/Maple/view.aspx?path=plots/contourplot

However, mine keeps coming out like this.

## solving multivariate functions who migth be a part...

hello how do i solve these equations and what type exactly are they ? so i can find more information

(i dont understand if this is a partial-something)

for the following function

i need to evaluate it at the following point

fy(pi/2,pi)  and  fz(pi/2,pi)

this is the part i dont understand how to do, i keep getting 0 in the equation.

thanks for you! and your time

## Is it possible to execute a section without select...

I would like to "run" or execute parts of my code that I put in a same section. Unfortunately, selecting "Execute" when right-clicking on a section does nothing...

## using indexed name for variable vs. two underscor...

For entering system of linear ode's, from textbook, such as this example

I can either use x[1],x[2]  or x__1 and x__2.

Maple dsolve works with both. The Latex generated is also exactly the same Which is x_{1} and x_{2}.

The only minor difference I see is on the screen in the worksheet (I only use 1D), where the subscript looks a little nicer in the case of x[1] vs. x__1

The subscript in the case of x[1] is upright while the one in x__1 is italic. I like the first one more.

Other than this cosmetic difference, Are there are subtle sematic differences between the two forms in terms of computation? I know x[1] create table x. OK.  While x__1 is a separate symbol. No table is created.,

Which would be  a safer/better option to use in this case?   Or is it just a matter of choice?

```sys:=[ diff(x[1](t),t)=x[1](t)+x[2](t),diff(x[2](t),t)=x[1](t)+3*x[2](t)];
sys:=[ diff(x__1(t),t)=x__1(t)+x__2(t),diff(x__2(t),t)=x__1(t)+3*x__2(t)];
```

In some way, using x__1(t) might be a little easier to read on the eye than x[1](t) since there is only one type of paranthesis involved.

ps. I tried to search for __ in Maple help to read more about it, but ?__ do not show it. I am sure __ is in the help under some other name.

## Empty or null values in matrices...

How do I insert an empty or null value into a matrix imported from a csv file?  The imported data assumes the value is zero.

## replacing pattern in expression...

For display only purposes, to get the Latex looking better, I replace the constant of integrations Maple using which is _C1, _C2., etc... to c[1],c[2],.....

This is something I do at the very end of computation, just before I get the Latex of the expression.

The way I do this now, is not good. .And I am asking if there is a better way to do this replacement. In Mathematica, I can do this using a patterm where I tell it to replace  C?  by c[?] where ? means anything.

Is it possible to do something like this in Maple? Here is an example

```sol:=dsolve(diff(x(t),t\$3) = x(t));
```

This gives solution as

And just before ask for the Latex of this, I change it to

This is done using a function. Please see worksheet below.

The problem with the current solution is that I do not know how many _C there are, so I assumed 10 as worst case, which works for my case. But I prefer a more general solution, may be using pattern in the subs command?

 > restart;
 > replace_all_C:=proc(expr::anything) local n,N,c; local new_expr; local max_count :=10; #worst case, since do not know how many     new_expr:=expr;     for n from 1 to max_count do         N:=convert(n,string);         new_expr:=subs( :-parse(cat("_C",N))=:-parse(cat("c[",N,"]")),new_expr);     od:     return new_expr; end proc:
 > sol:=dsolve(diff(x(t),t\$3) = x(t)); tmp:=replace_all_C(sol)

 >

And now I get the latex of tmp in the above, instead of sol which looks better.

## Plotting f(x) as a function of x logistic map...

Can anyone help with plotting the logistic map as a function in Maple

Logistic map x_(n+1)=f(x_n); f(x_n)=r*X(1-x) with the following values:

r=2.0; x(1)=0.3 f=r.*x.*(1-x)

## w-plane Maple mapping does not agree with comforma...

I created some simple maple 9 code to do some z->w mappings long time ago, on my web page:

https://ingalidakis.com/math/ComplexMaps.html

Upon revising my webpage, I've stumbled upon a page for comformal mappings, by David Bau:

http://davidbau.com/conformal/#exp(z)

Here's the current version of my code in Maple 18:

rrestart;
NULL;
with(plots);
xMax := 1;
yMax := 1;
N := 10;
step := abs(xMax)/N;
GL := proc (x, y) options operator, arrow; x+I*y end proc;
f := sin;
G := {};
for k from -N+1 to N+1 do

G := `union`(G, {complexplot(f(GL(x, (k-1)*step)), x = -xMax .. xMax, color = brown)});

G := `union`(G, {complexplot(f(GL((k-1)*step, y)), y = -yMax .. yMax, color = brown)})

end do;
display(G, scaling = constrained);

The code is pretty simple: I am simply scanning the 1x1 unit square complex grid and create a complex plot of it on the w-plane, by passing it through whatever function is at: f:=x.

Does anyone have any idea why the grid lines on the w-plane do not agree with Bau's grid lines mapping of the w-plane? To try it for exp for example, input "exp(z)" in Bau's home page.

The difference is quite noticeable, especially on exp and log, where the orientation of the w-grid on the left and right half-planes, seem to be opposite of what my code displays.

The reason may be Mathematical, but from what I see from the description on Bau's page, there's no difference on the identity function, so I am clueless.

## XMLTools / FirstChild...

Any idea why the result of the FirstChild function of the attached file is

_XML_Text("\n  ")

Test.zip

I also miss a more complete example on Maple Help for writing, reading and processing xml files.

## optimization of function...

restart;

W := proc ()

global rf;

rf := add(xx[ii]^2-nn, ii = 1 .. nn);

return rf ;

end proc;

Optimization:-Minimize(W(), nn = 1 .. 5, seq(xx[ii] = 1 .. 10, ii = 1 .. nn));

Error, (in W) unable to execute add