Hello,

      I've been using frontend in conjuction with pdsolve to handle a very large system of PDEs; namely the system has many irrelevant functions that can be frozen with frontend, allowing pdsolve to solve it much quicker.

     However, I ran into a strange case, which I've included in the attached file. Namely, for this particular system of equations, the system is a PDE with respect to t, so I freeze functions of x. However, doing so produces incorrect results (labelled bad) compared to the unfrozen case (labelled good). The frontend command is working as expected (this can be verified by uncommenting the frontend/print commands); it seems that pdsolve is treating the frozen and unfrozen cases differently.

     Any idea why this behavior is occuring? (The obvious solution is to simply not use frontend here; again, I'm using this same code for much larger PDEs and frontend speeds up exceution by an order of magnitude).

Thanks!

MWE.txt

I have a system of nonlinear ODE and I solved them numerically using rkf45. the solution is in time domain and the variables are x, y and z.

I want to convert this solution from time domain to frequency domain. I know that I should do FFT, but I do not know how to do this. 

I tried to do this, but I found that I have to get the solution of x, y and z in the form of vector with respect to time. I am not sure if I understant this problem corectly.

Thanks in advance.

A sphere, radius one unit with centre at the origin of the x, y and z axes is cut along the planes x=0, y=0 and z=0 yielding 8 total pieces, none of which are cubes.

For a sphere radius 2, cut along the planes x=2,y=2,z=2, x=-2,y=-2,z=-2, you get  64 pieces of which 8 are cubes.

Derive an expression for the number of  pieces you will get with a sphere radius integer R, cut along the planes x,y,z=1, x,y,z=-1, x,y,z=2,…     x,y,z=R-1, x,y,z=1-R  

How many of those pieces will be cubes?

The question arose from slicing onions!

A := <<1|2|3>,<0|4|5>,<0|0|6>>;

V :=<1,2,3>;

c :=MatrixVektormutiply(A,v);

i want to create a vector for example from 0 to 20 by 0.5 step.and use it in my function would you please suggest me a way for do it.

Thanks All!!!!!!!

Dear Users!

Hope you would be fine. I want to construct system of equations by comparing the likes powers of x^i*y^j*t^k1*exp(k2*eta) for an expression H1 present in attached file. Please see the fix my problem. I shall be very thankful for your kind help. 

Help.mw

Hi all,

I use GraphTheory:-DrawGraph (Maple 2018)
Is there a simple way to suppress or modify the ellipses plotted around a vertex ?

(by "simple" I mean: without using plootools:-getdata and doing some ad hoc modifications)

Thanks for your help


BTW: I'm asking you this because DrawGraph returns poor results in some situations:

with(GraphTheory):
g := Graph({{"azertyuiopqsdfghjklmwxcvbn", 1}, {"azertyuiopqsdfghjklmwxcvbn", 2}}):
DrawGraph(g, style=tree, root="azertyuiopqsdfghjklmwxcvbn")

What is incorrect I am getting the error:

Download errr.mw

You know in maple's linear algebra the X_ij is true for i,j>0, X₀₀ is meaningless.

Is it possible in Maple when we call X₀₀ it returns the X₁₁ element of the matrix, instead of

Error, Matrix index out of range

I try to do this by writing a procedure as bellow:

X := proc (i, j)

X[i+1, j+1]

end proc

but it does not work.

restart;
with(LinearAlgebra);
X := proc (i, j)

X[i+1, j+1]:

end proc;

X := Matrix(2, 2, [[m[1, 1], m[1, 2]], [m[2, 1], m[2, 2]]]);
X[0, 0];
Error, Matrix index out of range

Any suggestion?

From  time to tiime Malel emits a sort of "Boiing" noise when I make a keyboard error. I am not sure exaclty when it does this, but it is loud. Is it possible to turn it off? I have looked quite extensively and cannot find out anything.

Hi all you out there.

I have an UNSORTED sequence  L of floats with elements in the range [a, b > a].
Let c some number such that c < b.
I want to find the smallest k such that L[k] > c.

This problem is related to the search of the "First Hitting Point" (or "First Passage Time") of a random process.
The attached file provides a notional example.
It contains a procedure named FirstHittingPassage which doesn't satisfies me for it is based on an unsmart  "confusion" between an Array and a list.

Would you have a smarter way to proceed ?

Thanks in advance

FirstHittingTime.mw

I need help with writing the code, I have this for part a but I dont think it is correct

   with(Student[Calculus1]);
   Tangent(2/(1+exp(-x)), x = 0, output = plot);
 

(a) Find an equation of the tangent line to the curve
                                 2    
                        y = -----------
                            1 + exp(-x)
 at (0,1). 
(b) Graph the curve and the tangent line on the same axes.
(c) Use animate to show how the tangent line to the curve changes as we move along the curve between x=-5 and x=5.
 

Having trouble with starting off the three ways to complete this question.

Give three ways to plot the unit circle?

Hi everybody,

I'm facing that strange and blocking situation:

I was in a Maple 2018 worksheet "W"   (Windows 7, worksheet mode, not document mode) when, probably from some spurious keys combination, the small vertical bar that materializes the position of the mouse disappeared, rendering any further writting impossible.
In the same Maple session I had a few other worksheets  where the this same bar was still present: so it was not a Windows problem (this bar appeared in Word documents too).

I quitted Maple and ran it again. The result is still the same: among all the worksheet I load, only the worksheet  "W"  does not exhibit the location of the mouse.
This problem still persists after rebooting my working station.

Does anyone have any idea to fix this ?

Thanks in advance