## Error, (in pdsolve) invalid input: ...

pleae help me for psolve

thanks

pdsolve.mw

 (1)

 (2)

 (3)

## read - Where is the file stored?...

I ran the short program below in trying to understand how the read statement works.  The read statement output the expected values of a, b, c to the screen.  I was curious to find where it had stored the file named 'tempor', so inspected my hard drive in the directory where the program was stored - to find it wasn't there.  I then commented the a, b, c statements and the save command so the program is now as in the second version below:

restart:

a:=2:b:=3:c:=4:

save a, b, c, "tempor";

eval(a);

I ran this program, expecting an error message, but it gave me the same output as before.   I again unsuccessfully searched for the file.   I then turned the computer off after saving the program, rebooted and ran thhe same program below.  It output the same values as before.  I'm thinking that Maple creates a special file, and appends it to the program, something like a table.  I'm not quite sure how this would be used, as opposed to just stating te values of a, b,c in the program.

David

restart:

#a:=2:b:=3:c:=4:

#save a, b, c, "tempor";

eval(a);

## how to sign alable to groups member...

if i have agroup consist of two values for example {0.2,0.5} how to name 0.2 with a certian symple like R and 0.5 with other sympol

## hi . i want to solve this pde. but don't get a sol...

hi . i want to solve this pde. but don't get a solution

restart;
pde := diff(c(x, t), t) = d*(diff(c(x, t), x\$2));
ibs := c(0, t) = (c[1]+c[2])*(1/2), c(-infinity, t) = c[1], c(infinity, t) = c[2];
pdsolve([pde, ibs]);

## Lyapunov Functions in MAPLE...

To determine whether or not equilibrium points of a nonlinear ordinary differential equation is globally stable, a Lyapunov function is often employed. Since there are no general methods for constructing Lyapunov functions, May I know if there are methods in MAPLE that can be used to determine these Lyapunov functions? Thanks

## why warning Warning, incomplete string; use " to ...

I have a function inside a file called proc2.mpl

When I read the file from a worksheet using the command read("proc2.mpl"); I see warning messages

Warning, incomplete string;  use " to end the string
Warning, incomplete string;  use " to end the string

printed on the screen.  Now if I copy the same exact code and past it into the worksheet and invoke the function, I see no warning messages.

Why is that? Here is the content of "proc2.mpl"

process_file := proc()
local str,fileName;

fileName := "output.txt";

str:="
\\begin{align*}
A =& B  \\\\
=& 3
\\end{align*}
";

writebytes(fileName, str);
close(fileName);

end proc:

But now when I call it using process_file(); it works as expected.

Now here is screen shot with same code inside the worksheet itself. No warning messages show up when I call it.

And the above call also works as expected.

So I am now ignoring these warning messages since I also do not know what causes them.

Any ideas why they show up when the code is inside a .mpl file and not in the work sheet?

Maple 2017.3 on windows.

## show/hide content of table .. bug? ...

Just want some input if anyone thinks this is a bug or not

Hiding the contents of equation labels in one table (table -> properties -> uncheck show equation labels) removes all reference to the labels within that table.  Is that supposed to occur?

The table below has show equation labels checked.  If I uncheck the show equation labels in the first table I would expect the reference labels (1) and (2) to disappear and (3) and (4) references in the next table to remain unchanged.

However unchecking show equation labels in the first table relabels the two equations in the second table to (1) and (2) as shown below.  Is this a bug?

However this doesn't disrupt further content in the worksheet if references were made to equation label (1). After unchecking show equation labels in the first table, all original references to label (1) are replaced with the actual value (sin(x))

## Help with polarplot and complexplot ...

Could someone help me with the following.  The syntax produces an unfinished graph with a warning.

> with(plots);
> z := polar(1.05, (1/10)*Pi);

> display(polarplot(1, color = grey, axis[radial] = [color = "Blue"]), complexplot(seq(evalc(z))^n,
n = 1 .. 21));

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

the graphic looks like this

The graphic should look like this

Thanks, any help appreciated.

Les

## How to remove equation labels? in Maple...

Pl. help me remove the equation labels or hide the equation labels in my doc enclosed. What should i do to prevent equation labels from forming in my document. Please refer last two rows in the table below from the document.

Thanks for helping.Ramakrishnan V

Conversion from ppm to % vol is 1ppm = 0.0001 %

Conversion from % vol to ppm is

Avagadro's law between mass and volume is

where T is abs temperature and M is molecular weight;

M/(0.08205T)]*ppm*((A/F)*EA+1) /ρex; Emission is mg/kg fuel

If SFC is x g/kWhr; then Mass flow of exhaust is  (x/1000)*[M/(0.08205T)]*ppm*((A/F)*EA+1) /ρex; Emission is mg/kWhr

If the distance covered per liter is DCL km/liter, then (SFC/1000)*(DCL)/  is distance covered in km/kWhr

1 g/cc = 1 kg/lit; 1kg/m3 = 1 g/lit; Fuel density  is 0.77 kg/lit

Emission in mg/km = 0.77*Emission is mg/kg fuel/(km/liter fuel)

SFC is in g/kWhr

Measured emission is  E in ppm

Excess Air percentage is EA in per unit point

Molecular Weight of pollutant is M g/mol

Molecular weight of air =  =  g/mol

SFC

g/kWh

 (1)

kg/liter

DCL

km/liter fuel

A/F

EA

 (2)

K

 (3)

kg/m3

=

CO

CO2

HC

NO2

O2

N2

Air

M [g/mol]

Emission [% ] or[ppm]

%

%

ppm

ppm

%

%

%

Emission [mg/Nm3]

 (4)

 (5)

 (6)

 (7)

 (8)

 (9)

 (10)

Emission

mg/kWh

=

=

=

=

=

=

=

Emission

mg/kg fuel

=

=

=

 (11)

=

 (12)

=

 (13)

=  =

=

Emission

[mg/km]

Why in the above row, col2 and col3 have no equn nos?

What should i do to remove the equn numbers 11, 12 and 13?

Temperature of exhaust is in T K

Density of exhaust is say  kg/m3

DCL is distance covered per kWh

 (14)

Emission in g/kWhr is

Emission g/g of fuel = Emission in g/kWhr/SFC in g/kWhrper

Emission in mg/km = 0.77*Emission is mg/kg fuel*(km/liter fuel)

## i want to solve a equation with newton method ...

hi . i want to solve a equation with newton method but i cant,

restart;
f(x):=x^2-3;
df(x):=diff(f(x),x);
x:=1;
for i from 2 to 5 by 1 do
x:=x-(f(x)/df(x));
print(x);
end do

## how to write multiline string to a file?...

I want to save multiline string to a file. I am not sure Maple likes my string. Also when I look at the textfile after writing the string to it, the string does not look like what is expected. I given small example

First, created a "proc.mpl" in the folder. Here is the content of "proc.mpl"

process_file := proc()
local str;

str:="
\\begin{align*}
A =& B \\\\
=& 3
\\end{align*}
";

FileTools[Text][WriteString]("output.txt", str);
FileTools[Text][Close]("output.txt");

end proc:

Then opened Maple, and from a worksheet, called the above proc() like this

restart;
currentdir("C:\\where_the_file_is");
Warning, incomplete string;  use " to end the string
Warning, incomplete string;  use " to end the string
Warning, incomplete string;  use " to end the string
process_file();

You see these warnings there. So how does one make a multiline string in Maple? Please tell me it is possible. Else this whole process will not work.

When I look at the "output.txt", where the string is written, this is what shows


\begin{align*}
A =& B \      =& 3
\end{align*}


Which is wrong, I expected this


\begin{align*}
A =& B \\
=& 3
\end{align*}


I use \ to escape each \, since this is Latex code.

QUestions are:

1) Can one have multiline string in Maple? as in

"
line one
line two
"

With implied carriage return, just as it appears in the input?  I do this all the time in Mathematica.

2) Is something wrong with how I am saving the string to the file?

On a side note: I noticed I had to close the textfile to see the output in it. It looks like FileTools[Text][WriteString] does not flush the string autmatically to a otuput file after each write() which is a little annoying.

Using Maple 2017.3 on windows.

This is how the above is done in Mathematica

And this is "test.txt" which shows the output as expected

   \begin{align*}
A =& B \\
=& 3
\end{align*}

I'd like to do the same in Maple.

## Underline in axis labels...

Hi,

How do I get underlined text -- axis labels and legend -- in plot command? Tried many ways, but could not succeed. I would appreciate any inputs.

Regards,

Omkar

## Error in dsolve numeric....

Hi, There is a problem in solving ODE using dsolve/numeric code.

Ba.mw

## How to solve the problem about VRPTW?...

Hi, I do not understand how to solve errors in MAPLE on my project. My project is to solve Vehicle Routing Problem with Time Windows, and then the error is "Error, (in Optimization: -LPSolve) no feasible integer point found; use feasibilitytolerance option to adjust tolerance". I do not understand about feasibilitytolerance. Can anyone help me? Thankyou.

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## series and csgn...

1. The general case (the first output) is fine, but the second output is wrong. Surprisingly, replacing series(ee, ...) with series(sqrt(1/x)*erf(sqrt(x)), ...) does something different:

ee := sqrt(1/x)*erf(sqrt(x));

series(ee, x = 0, 2);
% assuming x < 0;
-2/sqrt(Pi)+2*x/(3*sqrt(Pi))+O(x^2)

series(ee, x = 0, 2) assuming x < 0; # wrong
2/sqrt(Pi)-2*x/(3*sqrt(Pi))+O(x^2)

series(sqrt(1/x)*erf(sqrt(x)), x = 0, 2) assuming x < 0;
Error, (in assuming) when calling 'series/signum'. Received: 'no series at 0'

2. Should Maple be able to handle nested discontinuities? The constant term here is incorrect, so the remainder is not O(z^2).

series(ln(I*ln(-1+z)), z = 0, 2);
ln(Pi)-(1/2*I)*csgn(ln(-1+z))*(csgn(I*(-1+z))+1)*Pi-I*csgn(I*(-1+z))*z/Pi+O(z^2)

3. This is wrong (it would mean that I^z is unbounded for large positive z):

series(a^z, z = infinity, 2);
exp((1/2*I)*z*(1-signum(a))*Pi)*abs(a)^z

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