9colai

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8 years, 237 days

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These are questions asked by 9colai

Hi

I'm trying to use the command: DocumentTools[Retrieve](path,label), but i recieve the message "unable to retrieve label reference" no mather what i do. When i use the GUI: Insert - reference and get the value it works fine, but in that way I can't assign the value to a variable in the document.

here is an example:

The document i want to retrieve a value from:

restart;

a := 5;

#a gets the label (1)

 

The document i want to retrieve the value to:

restart;
with(DocumentTools);

path := FileTools:-JoinPath(["test.mw"], base = worksheetdir); = "C:\Users\Nicolai\CloudStation\Nicolai\Skole stof\Sem 7\test.mw"

 

Retrieve(path, "());
Retrieve(path, "(1)");
Retrieve(path, "a");

#None of the above works

 

Is it even possible to do such thing?

with best regards

Nicolai

Hi!

Is there any way to remove the empty space that comes under images when printing the project, while using document mode?

Regards

Nicolai

Hi

I'm trying make Maple write the actual result, when i differenting an expression: x[s] := x(t)+sin(theta(t))*a.
when i differentiate with respect to t, i get:

> diff(x[s], t);
=
print(`output redirected...`); # input placeholder
/ d \ / d \
|--- ()(t)| + cos(theta(t)) |--- theta(t)| a
\ dt / \ dt /

Maple, writes the expression as a table, but i need to see the normal function? Why does it do that? And how can i make it show the expression as a normal function?


When i derive the two parts serperately i get the normal result, but as soon as i add them together, i get the table rasult again?

Is there an easy trick for this one?

-Nicolai

 

 

Hi all

I'm having a hard time, making Maple plot a pretty huge expression in my project.

I have solved a differential equation with initial conditions with method=laplace. The differential equation contains a fourier serie equation, so the more accurate i want the equation to be, the larger the differential equation will be.

Maple solves the equation just fine, and i can plot the solution with 2-4 fourier parts, but when i go higher as i need, the graph ends up empty?

with 20 parts i get the following equation: 

0.*sin(52.88*t)+0.*cos(74.03*t)-0.*sin(74.03*t)-0.*cos(52.88*t)+0.*cos(200.95*t)-0.*sin(200.95*t)+0.*cos(158.65*t)-5.55*10^(-8)*sin(105.76*t)-0.*sin(116.34*t)+0.*cos(31.73*t)-.45*sin(10.58*t)+1.02*cos(10.58*t)+0.*sin(95.19*t)+0.*cos(116.34*t)+0.*sin(179.80*t)-0.*cos(179.80*t)+0.*sin(137.49*t)-0.*sin(31.73*t)-0.*cos(95.19*t)+5.53*10^(-993)*(-1.13*10^992*cos(10.61*t)+8.14*10^991*sin(10.61*t))*exp(-0.7e-1*t)+4.23*10^(-7)*cos(211.53*t)-6.69*10^(-7)*cos(63.46*t)-6.11*10^(-7)*cos(105.76*t)+5.79*10^(-7)*cos(126.92*t)+6.67*10^(-8)*sin(42.31*t)-5.88*10^(-8)*sin(148.07*t)+5.88*10^(-8)*sin(211.53*t)+7.09*10^(-7)*cos(42.31*t)+5.45*10^(-8)*sin(84.61*t)+6.40*10^(-7)*cos(84.61*t)+5.72*10^(-8)*sin(126.92*t)-9.01*10^(-7)*cos(21.15*t)+5.97*10^(-8)*sin(169.22*t)+5.06*10^(-7)*cos(169.22*t)-5.98*10^(-8)*sin(190.38*t)-4.65*10^(-7)*cos(190.38*t)-5.44*10^(-7)*cos(148.07*t)-1.33*10^(-7)*sin(21.15*t)-5.61*10^(-8)*sin(63.46*t)-0.*cos(137.49*t)-0.*sin(158.65*t)

if i plot that expression, the graph ends up empty?

I did also try to solve the equation numerical to plot it with odeplot, but when i try to solve it without the laplace method i get this error message:
"Error, (in dsolve) found the following equations not depending on the unknows of the input system:"

The differential equation is:

ode:=diff(Theta(t), t, t)+2*Zeta*omega[balanceue]*(diff(Theta(t), t))+omega[balanceue]^2*Theta(t) = M[p]/m[balanceue]

and the initial conditions:

ICS := Theta(0) = (1/8)*Pi, (D(Theta))(0) = 0;

when i do:

dsolve({ICS, ode}, Theta(t), method = laplace) it solves just fine.

 

but when i try with:

dsolve({ICS, ode}, Theta(t))

or

dsolve({ICS, ode}, Theta(t),numeric)

I get the message: 

Error, (in dsolve) found the following equations not depending on the unknowns of the input system: {Theta(0) = (1/8)*Pi, (D(Theta))(0) = 0}

It doesnt seem logical at all, is it a bug? Or can anybody help me with this problem?


Regards

Nicolai

Hi!

I just got a simple expression after a longer equation where the last number in the expression is very small, and should be se seen as zero.

E[A]+40,0*10^-9, and it should only say E[A]

Is there a simple command to "round away" 40*10^-9?

It has to be simple because it is written in a report.

Best Regards

 Nicolai

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