Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Good day sirs,

I am having trouble identifying the error in the system of first-order ODEs. It gives the error code of

" Error, (in dsolve/numeric/process_input) received more than one indication of the dependent vars [theta[1](t), theta[2](t), theta[3](t), theta[4](t), theta[5](t), theta[6](t), theta[7](t), theta[8](t), theta[9](t)].

The document is attached below.

Thank you
"  Systems_error.mw

The attached worksheet contains expressions that cause a warning message to appear in my worksheet.  In another post it was suggested that the variable i should be explicitly declared local in the definition of the arrow expression. However, as shown in the same worksheet, this gives rise to an error message. Subsequently, I found a statement in help that suggested this approach would not work in 2-d math notation.  Are there any other ways of eliminating these warnings in 2-d math notation?

warningmessage.mw

Dear all

I run my code, I think evrything is well coded, but I get the following error 

invalid left hand side in assignment

Please, I need a help to solve this problem,  I haven't any idea about the origin of this error 

IOMMcode.mw

Thank you 

In a Maple session I have several worksheets open. When I click on the close cross of a worksheet tab the following can happen:

Closing the worksheet next to it works as normal

 

This occurs irregularly. For far I could not make it reproducible to report it to Maplesoft support. Anyone has seen something like this or ideas what the cause could be? 

Is this new in Maple 2022.2 or was it there before? I have no way now to verify. Could someone please check? I am not using assuming anywhere, so this must be internal.
 

interface(version);

`Standard Worksheet Interface, Maple 2022.2, Windows 10, October 23 2022 Build ID 1657361`

restart;

ode := diff(f(Z), Z$2) = 3602879701896397*(3860741894751515/1125899906842624 + (5048392920194975*f(Z)^2)/1073741824 - (2484212754397225*f(Z)^4)/1073741824 - (321579057930643*f(Z)^6)/2147483648 - (4936153155163025*f(Z)^8)/2251799813685248)/(4611686018427387904*f(Z)^3*(4178268760908915/1073741824 + 315761000*f(Z)^2));
dsolve([ode,f(0)=1,D(f)(0)=0])

diff(diff(f(Z), Z), Z) = (3602879701896397/4611686018427387904)*(3860741894751515/1125899906842624+(5048392920194975/1073741824)*f(Z)^2-(2484212754397225/1073741824)*f(Z)^4-(321579057930643/2147483648)*f(Z)^6-(4936153155163025/2251799813685248)*f(Z)^8)/(f(Z)^3*(4178268760908915/1073741824+315761000*f(Z)^2))

Error, (in dsolve) when calling 'assume'. Received: 'the assumed property or properties cannot be satisfied'

 


Maple 2022.2 on windows 10

Download dsolve_nov_10_2022.mw

This integral produces very large result and division by zero when simplified. I do not have earlier version of Maple to check if this is a new problem or not

f:=1/(3*u^(2/3)+3*((-4*u^(1/3)+1)*u^(4/3))^(1/2)-12*u);
anti:=int(f,u);
MmaTranslator:-Mma:-LeafCount(anti);
simplify(anti)

For reference, this is Mathematica's results with leaf count only 35 instead of 41,385 and no problem when simplifying.

f=1/(3*u^(2/3)+3*((-4*u^(1/3)+1)*u^(4/3))^(1/2)-12*u)
anti=Integrate[f,u]
LeafCount[anti]
Simplify[anti]

Could someone please check if this fails same way on earlier Maple version?

Hi,

I am fairly new to Maple and trying to figure out how to output text to a file, but nothing seems to be working. I would like to generate code files for Julia using Maple expressions.

I am in worksheet mode, using a 'code edit' region. If I do:

jlfile := fopen("./juliafunc.jl",WRITE,TEXT);

then the file is created, as intended. However, neither of the following commands seem to write any text to the file:

writeline(jlfile,"This is a test.");
fprintf(jlfile,"This is a test.\n");

(these are similar to the examples in the dcumentation)

Is there something I am doing wrong? I am using Maple 2020 on Linux.

Maple help stopped working, when I call the help from the menu or the corresponding button in the toolbar, the help is not displayed. What I can do?

Hi everyone, I have a question regarding the time in a plot.

The idea behind is, that i dont have to adjust the time after every change of parameters.

I have a function that only is valid until a certain time. I evaluete the time until cut off for example like this:

tempLrest := Optimization:-Minimize(tempLrest(t), t = 0 .. 2);
              tempLrest := [2.47883089786094 10^-8  , [t = 0.414486068771508]]

cutoff := tempLrest[2];

Now i want to call "cutoff" in an odeplot like this: 

odeplot(sol1, [t, z(t)], 0 ..cutoff , size = [300, 300])

unfortunately this doesnt work. 

Does everyone know how to solve this problem?

Thank you in advance!

Hello everybody. My lovely Dutch math book is progressing. Last week ive been scanning a copy of Advanced Engineering Mathematics from the library, a grueling task which took me 24 full hours to complete. But ive got a book that should be able to teach it with the right mindset and social contract (this Dutch book is too distracting, i cant even think). I will finish it though.. The sturdy that stands i guess. 

Any way the problem here is that the side from which a line interfaces with a shape in the 3D plane only has an x component and is lacking a y and z component. So the calculations are impossilbe, because you cant devide through 0. I suspect its something simple, but like said the repertoire is so terrible it feels like im scrambled eggs if i even remotely think about solving the problem. The facade makes the man right? Feels more like one of these spagetti westerns with only a frontage without anything behind it. 

The Question is as follows (translated from Dutch): "Given is the half ball with the equation z=sqrt(4-x^2-y^2). Check that the given point lays on the half ball and determin the eqation of the interface with the half ball in the given point."

So basically have a vector from that given point that will hit the surface of the half ball.   
 

#Opdracht 2

#a.

restart

z := sqrt(-x^2-y^2+4)

(-x^2-y^2+4)^(1/2)

(1)

"f(x,y):=sqrt(4-x^2-y^2)"

proc (x, y) options operator, arrow, function_assign; sqrt(-x^2-y^2+4) end proc

(2)

a := f(1, 1, sqrt(2))

2^(1/2)

(3)

partafgx := D[1](f)

proc (x, y) options operator, arrow, function_assign; -x/(-x^2-y^2+4)^(1/2) end proc

(4)

b := partafgx(1, 1, sqrt(2))

-(1/2)*2^(1/2)

(5)

c := (D[2](f))(1, 1, sqrt(2))

-(1/2)*2^(1/2)

(6)

raakvlak := z-a = b*(x-1)+c*(y-1)

z-2^(1/2) = -(1/2)*2^(1/2)*(x-1)-(1/2)*2^(1/2)*(y-1)

(7)

evalc(%)

z-2^(1/2) = -(1/2)*2^(1/2)*x+2^(1/2)-(1/2)*2^(1/2)*y

(8)

z = solve(raakvlak, z)

z = -(1/2)*2^(1/2)*x+2*2^(1/2)-(1/2)*2^(1/2)*y

(9)

#b.

restart

"f(x,y):=sqrt(4-x^2-y^2)"

proc (x, y) options operator, arrow, function_assign; sqrt(4-x^2-y^2) end proc

(10)

a := f(2, 0, 0)

0

(11)

partafgx := D[1](f)

proc (x, y) options operator, arrow, function_assign; -x/(4-x^2-y^2)^(1/2) end proc

(12)

b := partafgx(2, 0, 0)

Error, (in partafgx) numeric exception: division by zero

 

c := (D[2](f))(2, 0, 0)

Error, (in unknown) numeric exception: division by zero

 

raakvlak := z-a = b*(x-2)+c*y

z = b*(x-2)+c*y

(13)

z = solve(raakvlak, z)

z = b*x+c*y-2*b

(14)

#ik krijg er niets uit wat ergens op lijkt

#c.

restart

"f(x,y):=sqrt(4-x^2-y^2)"

proc (x, y) options operator, arrow, function_assign; sqrt(4-x^2-y^2) end proc

(15)

a := f(sqrt(2), sqrt(2), 0)

0

(16)

partafgx := D[1](f)

proc (x, y) options operator, arrow, function_assign; -x/(4-x^2-y^2)^(1/2) end proc

(17)

b := partafgx(sqrt(2), sqrt(2), 0)

Error, (in partafgx) numeric exception: division by zero

 

c := (D[2](f))(sqrt(2), sqrt(2), 0)

Error, (in unknown) numeric exception: division by zero

 

raakvlak := z-a = b*(x-sqrt(2))+c*sqrt(2)

z = b*(x-2^(1/2))+c*2^(1/2)

(18)

z = solve(raakvlak, z)

z = -b*2^(1/2)+c*2^(1/2)+b*x

(19)

``

Thank you very much. The first answer "a" was right, but for the other ones, this method they gave does not work. 

Greetings,

The Function 

Download Mapleprimes_Question_Book_2_Paragraph_5.5_Question_2b_2c.mw

After this code:

g1 := PermutationGroup({[[1, 2]], [[1, 2, 3], [4, 5]]})

g1:=<(1, 2), (1, 2, 3)(4, 5)>

I can get a string "<(1, 2), (1, 2, 3)(4, 5)>". Could I use the string to restore the PermutationGroup with an elegant method?

Here is a worksheet with a system of differential equations

Maple_DE_Example.mw

The system is

y'(x)=z(x)*g(x)

z'(x)=y(x)*g(x)

where g(x) is a random number generator seeded by x. That is, for the same x, g gives the same result. 

Using the classical method as an option to dsolve, a solution is plotted. Using rkf45, however, there is pretty much always an error that says

Warning, cannot evaluate the solution further right of ...

Why does it work with classical but not rkf45?

Is there a command that will count the number of digits in a binary number or any number for that matter? For example: 10110  has 5  digits in binary representation.

restart

I choose to define a number in base 10.

number := 22

22

(1)

Then I choose to convert that number into base 2.

number_binary := convert(number, binary)

10110

(2)

On visual inspection it is determined that number_binary has 5 digits in binary representation.

Is there a common command that can count the number of digits in a binary number? Such as, 10110 has 5 digits.

Download Count_digits_in_a_binary_number.mw

Count_digits_in_a_binary_number.mw

I am trying to reproduce this visualization of RGB:

Does any one have anything like this for Maple?

As you can see in the figure below, 

it shows a very strange "font",

you can obviously see very weird spacing even inside one word...

Who knows what's wrong???

Thanks a lot.

B/R

Jankel

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