## How do I solve a Non-autonomous differential equat...

ODE := 2.56*(diff(x(t), t, t))+.32*(diff(x(t), t))+x(t)+0.5e-1*x(t)^3 = 2.5*sin(t)

a1 := 2.56; a2 := .32; a3 := 0.5e-1; B := sin(t)

dfieldplot([diff(x(t), t) = y(t), diff(y(t), t) = (B-a2*y(t)-x(t)-a3*x(t)^3)/a1], [x(t), y(t)], t = -2 .. 2, x = -1 .. 2, y = -1 .. 2, arrows = SLIM, color = black, dirfield = [10, 10])

Error, (in DEtools/dfieldplot) cannot produce plot, non-autonomous DE(s) require initial conditions.

## How do I add a title to a plot quickly...

I frequently title my plots to identify what is being plotted. Very often that means specifying a parameter. For example, I might want the title to read;  Exponential when the power is c.

In the above I want to replace c with a real number. For example, my command might read

> for c from 1 to 10 do
p||c := plot( x^c, x= -1..1, title= the power is c )
end do:

I can then display the sequence of plots nicely labelled.

That does not work.

I cannot find adequate  info about what follows title =  in the help pages or the manual so I end up creating a worksheet and experimenting for quite a while until I find something that works.
(The Help page says: “The value t can be an arbitrary expression.” That’s it. One can go to the typesetting page to get more info about captions which is probably relevant but it begins to feel like learning about sex by looking up words in the dictionary.

BTW, I have been using Maple for 18+ years so I should have a cheat sheet somewhere to remind me of the correct syntax but I am suggesting that Maple would be much more user friendly if this info was in the help pages.

It would be very nice to have a fuller explanation with more examples.

Here is what works:

c:=3;  # special case

plot(x^c, x=-1..1,title=`power is `|| c);  Why back quotes?

or

cc:=convert(c,string);
plot(x^c,x=-1..1,title=[`power is `||cc]);   why barckets?

or not as nice
plot(x^c,x=-1..1,title=power.is.cc);  why dots?

or if you get rid of the is
plot(x^c,x=-1..1,title=[power = c]);  why noy use is?

not as nice
plot(x^c,x=-1..1,title=[power = cc]);  ugly quote marks

Here is a list of failures in this very simple case:

c:=3;

plot(x^c,x=-1..1,title="power is c");

plot(x^c,x=-1..1,title=power is c);

cc:="c";plot(x^c,x=-1..1,title="power is cc");
or

plot(x^c,x=-1..1,title=power is cc);

plot(x^c,x=-1..1,title=power.is.cc);

cc:=convert(c,string);plot(x^c,x=-1..1,title="power is cc");

cc:=convert(c,string);plot(x^c,x=-1..1,title="power is cc");

plot(x^c,x=-1..1,title='power is cc');

plot(x^c,x=-1..1,title=[power, is, cc]);

plot(x^c,x=-1..1,title='power = cc');

plot(x^c,x=-1..1,title=power = cc); but plot(x^2,x=-1..1,title=[power = cc]);is acceptable

another couple of failures:

plot(x^c,x=-1..1,title=[`power is c`]);

plot(x^c,x=-1..1,title=[`power is cc`]);

## How to define differential forms as function of so...

I want to define the co-ordianates (phi, PI, ....)  as functions of some variable eg:- x,y.

## Long waittime when going between output and execut...

Hi everyone,

When my cursor is on an output, the paragraph style changes to 2D Output, as it most likely should. When I then go to a new executable line, it takes forever for all of my expressions to "light up" (meaning that it takes a while for me to be able to use them), and it takes forever for the paragraph to go from 2D Output to 2D Math.

I sadly don't remember when this happened, or what might have caused it, but if any of have any suggestions or answers, I'd greatly appreciate it.

Thanks for listening,

A confused highschool student.

## Plot Numerical-Integration for function in two var...

,Hello dears

I have the following function

where L=10 and I want to plot this function, so I use

But it does not work.

Is there any help.

Amr

## How can I solve the following differential equatio...

Hello,
Im beginner in Maple so i need a help with the following differential equation:
y'' - y = 0 where y(0) = 0 and y(1) = 1

I solved this but im confused how can i solve it in Maple.

## How do I fix the possibility calculation error in ...

Hello Users,

I have a question on my work.

I constructed two different equations that looks different.

Two constants the front of each equations (kappa_T and kappa_S)  have difference too much. (without an error)

In my own calculations, I found that two expressions should be same.

Is there a possibility of operation error(or calculation error)?

I want to know which process cause this problem and how can i avoid.

Question_Kappa_T_and_S.mw

## Histogram with the bars adjacent to each other?...

How can I draw a "regular looking" histogram where all the bars adjacent to each other?

I tried looking into the options for histograms with no luck. I included a picture of what kind of output I am looking for.

## system of ordinary equation ...

Dear all

I have a first-order complex ODE, I would like to use the polar coordinates to find the associated system of the ordinary differential equation then I determine the equilibrium point of the system and deduce that there is at least one limit cycle.

syestem_polar_cordinates.mw

## How can I define (and sample) a mixture of two ra...

Hi,

I can't find a unique way to define a mixture of two random variables that enables at the same time to compute its PDF and generate a sample.
In the attached file you will find two methods :

1. the first one is the most formal and only CAS are supposed to be able to allow its implementation:
it enables computing the PDF and the CDF (trivial) but fails to generate a sample.
(PS : in a first attempt I had defined only the PDF, which should have been enough for method=envelope does work... ... at my opinion)

2. the second method is the one one would use in non CAS languages (for instance Matlab, R, ...). It enables generating a sample (of course) but fails to compute the PDF (which is not very surprising).

So my question: does anyone here would have some suggestions to make one these two methods capable to compute both the PDF (eventually the CDF) and generate samples ?

PS: still have this kind of problems (tomleslie suggested months ago that using interface(rtablesize=10) could help but it's not the case here)
Maple Worksheet - Error
Failed to load the worksheet /maplenet/convert/Mixture_of_random_variables.mw .

## Quartile function not working ...

the quartile function gives the wrong answers.

list := [1,2,3,4,5,6,7,8]

Q1 does NOT come back as 2.5 as it should, nor does Q3. I get these weird decimals.

I looked at the help for it but wasn't helpful. All the examples in the help are super complicated. No simple examples like the one I mentioned here.

thanks

## Expression of the matrices...

Hi everyone:

I have two matrices T(t) and Y[i] :N is natural.how can I do it? tnx.

## ImageTools Permission Denied Error...

I am just confused to be getting this error seeings FileTools does not encounter this error when I use it's ListDirectory command:

 >
 >
 (1)
 >
 >

## how to define a sum of integrals of an arbitrary n...

sigma(integral(F(w,cn1,ct1))+integral(F(w,cn2,ct2))+...+integral(F(w,cn80,ct80)))

integral.mw

## lastexception cleared by the creation of an rtable...

In a do loop with a try... catch statement I had placed an assignment to a vector element after catch: but before the line printing the lastexception. That the loop didn't perform as expected, but resulted in an error about ListTools:-FormatMessage wanting its first argument to be a string surprised me. Putting the assigment to the vector after the exception printing worked fine.
It seems that rtables are the exception (no pun intended) to the order being irrelevant.

```restart;
V:=Vector():
for j from 1 to 5 do
try
V(j):=j/(j-1)
catch:
V(j):=17; # clears lastexception apparently
printf(cat(StringTools:-FormatMessage(lastexception[ 2 .. -1 ] ),"\n"));
end try
end do:
#####
restart;
V:=Vector():
for j from 1 to 5 do
try
V(j):=j/(j-1)
catch:
printf(cat(StringTools:-FormatMessage(lastexception[ 2 .. -1 ] ),"\n"));
V(j):=17;
end try
end do:
```

These simple lines confirm my observation:

```restart;
lastexception;
5/0;
lastexception;
5/5;
lastexception;
x:=47;
lastexception;
table();
lastexception;
[1,2,3];
lastexception;
rtable();
lastexception; # Now cleared!
```

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