MaplePrimes Questions

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")

I would like to use Gröbner's method to study polynomial systems (with equality or (and) inequalities) in the case where the variables are REAL. It is known that in general the problem is much more complicated than in the complex case; in particular it is necessary to use gradient methods.
In Maple, we can use the patch "Raglib" (Lip6 laboratory). However "with (RAG)" does not work very well, even for "simple problems" like this one: the $ 9 $ real unknowns are $ X = [x_ {i, j}] \ in M_3 (\ mathbb {R} $. The  system to satify is $ X ^ TX = I_3, x [1,1] <1 / 2,3 / 10 <x [2,3] $, that is, $6$ polynomial equations and $2$ inequalities; clearly, a particular solution is a permutation of the canonical basis. The "HasRealSolutions" command does not provide any result after 2 hours 15 minutes of calculation. The "PointsPerComponents" command indicates that there are no solutions... 
It seems to me that we can also use "RegularChains" but I am not familiar with this library.

  Have you any ideas on these questions? Thank you in advance.
 

What is incorrect I am getting the error:


 

``

``

restart:

``

y := (diff(tau(t), t))^2

(diff(tau(t), t))^2

(1)

"(&PartialD;)/(&PartialD; (tau)) y"

Error, invalid derivative

"(&PartialD;)/(&PartialD; tau) y"

 

``


 

Download errr.mw

You know in maple's linear algebra the Xij 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

I was trying the solution given in 

https://www.mapleprimes.com/questions/225083-Maple-Command-To-Find-Domain-Of-Function

Which works fine for some functions, but fail for some reason for other functions.

restart;
f:=x*ln(y);
solve(evalc(Im(f)), {x,y});

But fails on 

restart;
f:=sqrt(x)*ln(y);
solve(evalc(Im(f)), {x,y});

Using Maple 2018.1 with Physics 

`2018, July 3, 20:10 hours, version in the MapleCloud: 78, version installed in this computer: 74`

Why this error happen on some functions? Is there a way around it?

One way to workaround it I found, is to use solve for one variable at a time. Now Maple do not give an error

restart;
f:=sqrt(x)*ln(y);
solve(evalc(Im(f)), {x});
solve(evalc(Im(f)), {y});

Strange it failed when using {x,y} at same time on this one, but not on the first one. But the above answer is wrong. For "x", it should be x>=0 and not x=0. If I remove the "y" now it gives correct answer

restart;
f:=sqrt(x)*ln(y);
solve(evalc(Im(f)), {x});

f:=sqrt(x);
solve(evalc(Im(f)), {x});


 

This makes no sense to me.

I am finding too many bugs in Maple making it not useable and having to keep coming with workarounds. 

Maybe it should be tested more thoroughly before release.

How to compute inverse of a square matrix in maple?

Like below matrix:

Matrix(6, 6, [[1/EE__1, -nu__21/EE__2, -nu__31/EE__3, 0, 0, 0.], [-nu__12/EE__1, `#mn("1")`/EE__2, -nu__32/EE__3, 0, 0, 0.], [-nu__13/EE__1, -nu__23/EE__2, `#mn("1")`/EE__3, 0, 0, 0], [0, 0, 0, 1/GG__23, 0., 0], [0, 0, 0, 0., 1/GG__13, 0], [0., 0., 0, 0, 0, 1/GG__12]])

Maple help say there is a mode n number, but what actually is it?

how I can dsolve these equations?

thanks.

Boundary conditions are:

u(0) = 0, u(0.1e-2) = 0, w(0) = 0, w(0.1e-2) = 0, (D(w))(0) = 0, (D(w))(0.1e-2) = 0

error masseage:

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system
 

error.mw
 

dsys3 := {1.857142857*10^11*(diff(u(x), x, x)), 1.547619048*10^10*(diff(w(x), x, x, x))-1.300000000*10^11*(diff(w(x), x)), -1.300000000*10^11*(diff(w(x), x, x))+3.541600000*10^(-13)*(1.082793750-81250.00*w(x))/(1.019000000*10^(-6)-w(x))^2+1.040549102*10^(-32)/(1.019000000*10^(-6)-w(x))^4-2.124960000*10^(-15)*(1.082793750-81250.00*w(x))*(diff(w(x), x))^2/(1.019000000*10^(-6)-w(x))^4+1.151020000*10^(-10)*(diff(w(x), x))^2/(1.019000000*10^(-6)-w(x))^3-7.083200000*10^(-16)*(1.082793750-81250.00*w(x))*(diff(w(x), x, x))/(1.019000000*10^(-6)-w(x))^3+2.877550000*10^(-11)*(diff(w(x), x, x))/(1.019000000*10^(-6)-w(x))^2-2.081098205*10^(-34)*(diff(w(x), x))^2/(1.019000000*10^(-6)-w(x))^6-4.162196410*10^(-35)*(diff(w(x), x, x))/(1.019000000*10^(-6)-w(x))^5, u(0) = 0, u(0.1e-2) = 0, w(0) = 0, w(0.1e-2) = 0, (D(w))(0) = 0, (D(w))(0.1e-2) = 0, ((D@@2)(w))(0) = 0, ((D@@2)(w))(0.1e-2) = 0}; dsol5 := dsolve(dsys3, numeric, abserr = 0.1e-1, output = array([.5]))

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

 

``

 

Download error.mw

 

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