## Why solution set is empty....

Hello. I am trying to solve the following polynomial system. Maple solution is empty but when I add the polynomial X4_4-2^(1/2)/10 to the list then maple gives me a set of solutions. What could I be doing wrong?

with(SolveTools):
F:=[
10*X4_4 + Y1_1,
10*X4_4*Y1_1 + 2,
20*X4_4*Y3_1,
2*Y3_1,
10*X4_4*Y1_2,
20*X4_4*Y3_2 + 2,
10*X4_4 + 2*Y3_2,
4*L2 - 7*L1 + 5*L3 - 6*L4 + 5*L5 + 9*L6 - 6*L7 - 1,
L1 + 10*L2*X4_4,
10*L5*X4_4,
2*L4 + 20*L3*X4_4,
2*L7 + 20*L6*X4_4
]:
V:=[X4_4, Y1_1, Y1_2, Y3_1, Y3_2, L1, L2, L3, L4, L5, L6, L7]:

Sols := PolynomialSystem(F, V);

## Corrupted maple file...

Auto_regne_dokument.mw

My maple froze while it was running. I saved and closed it and now it gives me this message when i try to open it "There was a problem in the loading process, you worksheet may be incomplete.".

There is only one backup file and it is corrupted as well. I tried to see if i could work it out in the text file, but im not very good at doing this.

If anyone knows how to uncorrupt it pls help me

## max value for R3...

I have problem to calculate the max value for 3d  phase potret for each period. Thank You

## Solving a PDE analytically with a boundary conditi...

I wanted to solve a pde of two variables in spherical coordinates with a boundary condition at a specific radius. I am doing something wrong because the pdsolve just evaluates for several minutes and does not actually give anything.

Could someone have a look and let me know what I am doing wrong.

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## how do i make phaseportrait 2d animation curves...

how to make a phaseportrait curves with animation? so i can see how the curve going on. Thank you

caring_phase_pemanenan_predator_dgn_parametersesuai_jurnal.mw

## Horizontal and vertical lines on the graph...

Hi everyone, I am trying to draw horizontal and vertical line on the graph. Command is working but vertical line is not displayed. Looking for help in this regrads.

vertical_and_horizonatl_line_help.mw

## Need help to remove error in my worksheet?...

Hi everyone, I am trying to draw bar graph for my expression, but received error. Could anyone please help me in this regard.

Help_Bar_graph.mw

## Why 'dsolve' of a simple 1st order ODE with Dirac ...

Hi

On the latest Maple 2022 version, using dsolve with 1st order ODE and Dirac function returns an incorrect solution

dsolve({D(y)(t) + y(t)/tau = Dirac(t)/tau, y(0) = 0})

See attached image. The correct impulse response should be :

y(t) = exp(-t/tau)*Heaviside(t)/tau

The returned solution is 0 for t = 0 and scaled by a 1/2 for t > 0. I never had such an issue with older Maple versions. Is this a bug or am I doing something wrong

Here is the expected solution followed by the Maple solution:

## How can I plot time difference versus numeric valu...

acer helped me out last week with converting strings to dates which was very helpful. However now I stumble on 2 other problems:

- I do not succeed to plot DS6 (time difference versus a numeric value) and to not understand why

- in the cvs data sheet the length of the columns is not equal. The empty cells are automatical filled with "". This prevents me to use numelems as it will also take into consideration the cells filled with "". Is there a way to prevent this

As usual I would like to thank you all, power users, for your patience and help

Test.mw

## How to find increase or decrease in percentage?...

Hi Everyone; I have plotted two different expressions separately and then shown them in a single graph. From the final display, we can observe that the peak of one expression, A is larger than that of another expression B. Now, the question is, how do I calculate the decrease or increase in the percentage of both curves? This means the peak of expression A is 20%, 8%, or 7% decreases or increases as of expression A.

Help_percentage_inccrease_or_decrease.mw

more explanation, each curve has its maximum point at some value of x, need to calculate that point for each curve. Then, we combined all curves we observed that the peak of each curve is smaller than others, so I am interested to observing that difference in percentage at the maximum value of x.

for reference, I uploading a file of which idea I want to implement for my problem. This is not my problem, but I want to implement it like this.

For_reference.mw

## Can I convert a date time string into a form I can...

This is most likely a simple question for the power users of this forum, but I do not manage to find a solution. I have date in an Excel file. The first column consists of dates (mm/dd/yyyy) and the second of time (hh:mm). I can easily concatenate both in Maple using cat("9/7/2023", "10:22") but how can I convert the obtained string into a date+time that Maple understands?

Thank you in advance for your help.

## How to solve a linear system with 7 variables and ...

I create a system of equations (with 9 linear equations and 7 variables).
I get 7 equations from the multiplication of a matrix M with a transposed vector of the 7 variables equals the transposed vector of the 7 variables. Other two simple equations are necessary because they are restrictions. Those two equations a re very simple and thave the 7 variable sin it.
To start I have been trying with fsolve but i haven't been able to solve it yet, as I also get the error: "Error, (in fsolve) number of equations, 9, does not match number of variables, 7"
Have you andy idea to solve this problem? Thanks in advance.

## How to find the value of constants?...

Hi all, any one help  me to find the values of constants by using given condition and then how to varify that the goiven condition varify the expression. I have found manually but want to varify through maple.

help.mw

## How do I write Homotopy Perturbation method for a ...

HPM.mw

• How do I write Homotopy Perturbation method for a partial differential equation for this question in Maple?

## Error using SingularValues in a procedure...

Using the SingularValues command with any output type specified causes this error

Error, (in sanity) invalid input: LinearAlgebra:-SingularValues expects value for keyword parameter output to be of type {list(identical(U,S,Vt,list)), identical(U,S,Vt,list)}, but received [U, S, Vt]

Below is a minimal example to trigger the error. Is there something wrong about how I am calling the function?

restart:
with(LinearAlgebra):

sanity := proc()
local A,U,S,Vt;
A :=RandomMatrix(3,10);
U,S,Vt := SingularValues(A, output=['U','S','Vt']);
end proc:

sanity();

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