## Change the format of x-axis ...

Dear users!

Hope everyone fine with everything. I want to chage the format of x-axis in the attached file. I need the x-axis in degree like (-180^o, -120^o, -60^o, 0 , 60^o, 120^o, 180^o). Also I want the lable on y-axis as:

I am waiting your positive respons.

Help_new.mw

## plotting a line linking points with plot3d...

I wanted to make a 3d plot with lines linking points, but I am struggling with it
(I couldn't find anything in the plot3d documentation, so it might not be supported, which would be odd as its such a normal thing to want to do)

I have tried with no success:

plot3d([1, 2, 3], [4, 5, 6]);
plot3d(Matrix(2, 3, {(1, 1) = 1, (1, 2) = 2, (1, 3) = 3, (2, 1) = 4, (2, 2) = 5, (2, 3) = 6}))

Any thoughts?

## trouble with coeff...

hi, i am trying to get a list of equations using the coeff function. I have the following equation:

restart;
Lambda:=-(1/8)*(D[4](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x))-(1/8)*(D[6](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), y, x))-(1/8)*(D[7](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x, t))-(1/8)*(D[5](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x, x))-(1/8)*(D[12](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x, t, t))-(1/8)*(D[10](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x, x, t))-(1/8)*(D[11](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), y, x, t))-(1/8)*(D[9](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), y, x, x))+(1/8*(-3*(D[8](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))-4))*(diff(u(x, y, t), x, x, x))-(1/8)*(D[1](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))+(1/4)*(D[8](a))(x, y, t, u(x, y, t), diff(u(x, y, t), x), diff(u(x, y, t), y), diff(u(x, y, t), t), diff(u(x, y, t), x, x), diff(u(x, y, t), y, x), diff(u(x, y, t), x, t), diff(u(x, y, t), y, t), diff(u(x, y, t), t, t))*(diff(u(x, y, t), x, x, x));

Now I am trying to get the coefficients of the derivatives of u(x,y,t). So by hand I have done the calculation of taking the coeffient of diff(u(x,y,t),x,x,x) and setting this equal to zero, and then the coefficient of diff(u(x,y,t),x,x,t) and so on. However when I use the coeff function, it will only allow me to compute the coeff of diff(u(x,y,t),x,x,x) and others of third order. However it will not let me use the deriviateves of u of second and first order.

coeff(Lambda,diff(u(x,y,t),x));

this will not work but

coeff(Lambda,diff(u(x,y,t),x,x,x));

will work.

Any help would be great thanks.

## Debuging bizare behaviour in odeplot...

I have a relatively complicated ODE that i am plotting. One of the variables in particular (B[2211], purple line in the graph) should under go an exponential-like decay to zero, but instead flies off into negative territory  (see graph below) despite having a very simple equation:

problem variable rate of change= -problem variable*constant +linear combination of variables that  are always posotive.

My intuition is that this is because i have somehow used the odeplot tool wrong - possibly due to a problem with stepsizes.

Here is a MWE i've made:

aa_problem_MWE.mw

## How to display the legend of a plot when using Doc...

Hi everybody,

Please take the example given in the help pages of DocumentTools[Tabulate] (the one where a cardinal sine is plotted)
Change plot(sin(x)/x) by plot(sin(x),/x, legend=sinc(x))

The legend doesn't appear if the list (named "A" in the help page) is displayed through DocumentTools:-tabulate.

Is it possible to circumvent this problem ?

TIA

## What is wrong with this file?...

Hi all,

I don't know why this file doesn't work anymore! It was ok last week. I even reinstall the Maple on my laptop, but it went wrong again...

Plot_Diff_Temperature.mw

Pls fix this problem for me. I tried various things. The text in the worksheet is in Danish and contains danish letters (æøå) which may have caused the problem.

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/1._Opgaver.mw .

## How to "unwith" a user package ,...

Hi everybody,

I have written a module (let's say MyModule) that  I use as a package in a worksheet (with(MyModule)).

At some point in my worksheet I call the procedure MyProc which is part of MyModule.
I find it not to work as expected. So I modify it within MyModule and generate again the archive which contains this module.

Because my worksheet does a lot of things before the call to MyProc, I would like to test quickly the above modifications.
The idea is to do :
unwith(MyModule):  # packages() no longer exhibits its name
with(MyModule);      # to load the corrected one

Unfortunately, contrary to what happens with a "native" package,  the command unwith(MyModule) is ineffective:

• once done showstat(MyProc) still displays the content of the procedure, and running  the command MyProc(...) proves that it still "exists" in the worksheet

• forcing a reload of MyModule ( with(MyModule) ) and acanning again MyProc ( showstat(MyProc) ) reveals the code MyProc had when MyModule has been loaded for the first time.

Is it possible to "free" a user package through the "unwith" command ?

Hope to read you soon, TIA

PS : to be clearer

A worksheet contains  the definition of N procedures, plus the one of MyModule, and ends with the commands to generate an archive file named MyModule.mla.
MyModule is defined that way

MyModule := module()
option package

export Proc1 := eval(:-Proc1),
......
MyProc := eval(:-MyProc),
......
ProcN := eval(:-ProcN):
end module

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## how to remove duplicates from a set or list?...

The set and list produced by map (see below) contain duplicates.  How to remove duplicates?

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## How to plot multiple curves with arrows pointed at...

Hi, I would like to plot multiple curves with arrows pointed at each curve. I don't know how to plot the arrows with values. A similar figure is attached. Thanks for helping . . .

## Adding arrows to a phase portrait...

Hi there,

I have a function X that I am trying to plot a phase portrait for against it's derivative dX/dt. I currently have the code:

plot([X,diff(X,t),t=0..10],numpoints=1000)

which sketches a graph but does not give any arrows to indicate direction.

Could anybody help?

Many thanks

## How do I plot this function?`...

Hi there,

I have a function defined as:

U:=-[0.25*exp(1/2*epsilon*t)*(1/v^2-1+exp(epsilon*t))^(-0.5)]*sin(4*t)

which I am trying to plot on a 2D graph of axes (t,u(t)).

In the specific case I have epsilon=1/10 and v=2

When I try plot(U), maple returns the error message:

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

Could anybody help me out please?

Many thanks

## Adding a legend to DEplot...

Hi there,

I have an ode that I want to plot, I am trying to plot 2 different graphs on one graph and have tried using display but cannot seem to add a legend to it. Someone suggested adding a legend to each individual graph before combining them but I cannot find out how to add a legend to a DEplot. My code is as follows:

ode:=diff(u(t),t\$2)-0.1*(1-64*u(t)^2)*diff(u(t),t\$1)+16*u(t)=0

Q1:=v/4*sin(4*t)+epsilon*(1/8*(v-v^3)*t*sin(4*t)+v^3/128*(cos(4*t)-cos(12*t)))

A:=DEplot(ode,u(t),t=0..10, [[u(0)=0, D(u)(0)=v]], u=-0.5..0.5, linecolor=black, linestyle=dash, title="Numerical Solution"):

B:=plot(Q1, t=0..10, u=-0.5..0.5,color=blue, legend="Regular Perturbation Expansion"):

display([A,B],title="Comparing the regular perturbation expansion to the numerical solution")

Many thanks

## MAPLE DOES NOT CALCULATE DOUBLE INTEGRAL...

Good day everyone,

I'm relatively new to Maple, and I study engineering (not maths), so maybe my problem is related to a bad approach of the equations.

The problem is that I'm asking Maple to do a double integral of a "complex" expression and it only solve the first integral, but not the second.

Here is the code:

https://www.dropbox.com/home/C%C3%81LCULO%20FUERZAS

Thanks.

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