Download wrong_answers.mwwrong_answers.mwwrong_answers.mw

Ramakrishnan V

rukmini_ramki@hotmail.com

Greetings all,

I was wondering if any Maple users out there are using the lastest Microsoft tablet, the Surface Pro 4 with Maple?

I would be interested in any opinions and specifically if the pen is effective when used as an input device with Maple

Thanks

hello everyone

can any one tell me what is this anti reduction method. In the paper of serdal palmuk,the link is given bellow

http://www.hindawi.com/journals/mpe/2009/202307/

in this paper question #4 is first solved by anti reduction method for  exact solution.

but i dont understand this method,

if anybody know this then please also tell me how to solve this,

and in the next  (6 & 7 ) examples "in the pourus media equation" they first find its particular exact solution.i also dont understand this,so please tell me

actually i know how to solve ODE to find its exact solution but  i dont know how we find exact solutions of partial differtial equations,

so please help me to solve this problem

thanks

I wish to define a function with a finite number of inputs, but I do not know that number ahead of time (in other words the user will specify n and my function operates on vectors of size n). How can this be done?

How to find the integral
,

assuming k and n  integer?
It is known (McCrea W. H., Whipple F. J. W.Random paths in two and three dimensions, Proc. Roy. Soc. Edinburgh. 1940. V. 60. P. 281–298) that

G(n,n)=2/Pi*sum(1/(2*k-1),k=1..n).

The general case is reduced to the case k=n.
This is not a creature of pure reason: the one appears in electric circuits
(see M. Skopenkov, A. Paharev, A. Ustinov, Through resistor net, Mat. pros. Issue 18 (2014), 33-65, in Russian, http://www.mccme.ru/free-books/matpros/pdf/mp-18.pdf).
I found G(8,8) = 182144/(45045*Pi) in 657.797 s and G(9,9) = 3186538/(765765*Pi) in 4157.687 s on my comp by

restart; s := time():(1/2)*VectorCalculus:-int((1-cos(9*Pi*x)*cos(9*Pi*y))/(sin((1/2)*Pi*x)^2+sin((1/2)*Pi*y)^2), [x, y] = Rectangle(0 .. 1, 0 .. 1)); time()-s;
Mathematica 10.3.0 does G(9,9) in 250.391 s on my comp.

I have run into a "funny" feature of 2-D input: It seems to convert something like k/2 into this k*`^`(2,-1). While this would often not be an issue (it is correct after all), it becomes a problem when used in an argument list to a procedure. It becomes even more of a problem when, by chance, I have overloaded `^` to act on specific types that I have defined.

Let me try to explain briefly. I have a package called "Lattice" that does whatever it does (not of relevance here). I am writing a little manual for this package, for which I use 2-D input so I can write it in Maple and have the examples right in it and "live".

Here is what happens:

with(Lattice) # load the package

QFh:=Quad(0,kf/2) # Define an element for Lattice

Error, invalid input: Lattice:-`^` expects its 1st argument, element, to be of type Element, but received 2

Copy-pasting kf/2 into a 1-d worksheet, I get

QFh := Quad(0, kf*Lattice[`^`](2, -1));

So it uses Lattice[`^`] which actually appears to bypass the overload I have in the Lattice package. `^` is defined like this in Lattice:

`^`:=proc(element::Element,n::algebraic) option overload; # Element is a defined type in Lattice
...
end proc;

How can I possibly rewrite `^` to fall-back to Maple's ^ operator when called as Lattice[`^`] ?? I know there is a function overload() but have no experience with it. Would it even help?

Or am I missing something completely here? I do not use 2-D input for my usual work, but in this case I want and need to use it. The reason for its bizarre rewrite of "/2" is beyond me. Note that I can replace /2 by *0.5; but that causes problems later on for algebraic work as 1/2 is not 0.5 in Maple. I tried *1/2 but that has the same problem.

Has anyone a clean solution for this? I assume this effect is not limited to my own package but would affect others as well.

M.D.

PS: I ran into this using Maple 15 but I doubt it is specific to this particular version.

Hello,

My code records the values I need, however, I need to implement a modulo of 2*Pi on my result for theta. But this leads to a graph with no plots and I'm not sure how to fix it. Any help is greatly aprreciated! Thank you in advance!

Kind regards,

Gam

bia Man

i've got a list of 6 ODEs with 6 initial conditions:

MH,MS,M,a,G,e,afb are just constants

Eqns2 := diff(xH(t), t) = vxH(t),
            diff(vxH(t), t) = -G*M*xH(t)/(xH(t)^2+yH(t)^2)^(3/2),
            diff(yH(t), t) = vyH(t),
            diff(vyH(t), t) = -G*M*yH(t)/(xH(t)^2+yH(t)^2)^(3/2),

            diff(theta(t), t) = omega(t),

            diff(omega(t), t) = -G*MS*afb^2*(xH(t)*sin(theta(t))-yH(t)*cos(theta(t))*            (xH(t)*cos(theta(t))+yH(t)*sin(theta(t)))/(xH(t)^2+yH(t)^2)^(5/2):

ICs2 := xH(0) = a*(1+e), vxH(0) = 0, vyH(0) = sqrt(G*M*(1-e)/(a*(1+e))), yH(0) = 0, 0 < theta(0), theta(0) <= Pi,        omega(0) = 10*Pi/T_H:

soln2 := dsolve({Eqns2, ICs2}, {omega(t), theta(t), vxH(t), vyH(t), xH(t), yH(t)}, numeric)

But it doesn't solve it , but instead displays this error message:

Error, (in dsolve/numeric/process_input) system must be entered as a set/list of expressions/equations

Can someone find a syntax error or a typo that would explain this?

When assigning a color to a given wave length I initially used ColorTools WavelengthToColor. Acer commented that this wasn't the most accurate. I looked into this a little further and it seems there could be a better result. The attached document compares some different ways of assigning colors to wave lengths. 

Warning- The CIEDE2000 computation for deltaE is very slow. I think this is because of the hue angle calculations which use piecewise a lot. The CIE94 delta E method produces nearly the same result and takes minutes instead of hours.

Questions;

 I think I could speed up my calculation if I could find the position of the minimum element of an Array similar to FindMinimalElement of a list. 

I created my own atan2 function (similar to Excel). If there were a built in Maple equivalent perhaps it would be faster? I didn't see any such function.

6bit_Wavelength_Color_CIEDE2000.mw

Hello,

I have a procedure which plots a graph. I need the x-axes, which in this case is theta, to range between -3 and +3. However, I am not sure as to how I can create this restricted range. Any help is greatly appreciated! Thank you in advance!

Kind regards,

Gambia Man

Download Poincare_section_Boyd_plot.mw

Download Poincare_section_Boyd_plot.mw

Hi,

Wondered if anyone could help with the query below.

Consider f(x,y) defined as:
f := proc (x, y) options operator, arrow; x*y/(x+y) end proc

Then f(A, B); becomes:
(A * B )/(A + B)

now consider the polynomial:(poly2)

poly2:=(A*B+A*X+B*X)*(Y+X)/((A+B)*X*(2*Y+X))

This polynomial is just the expansion of the polynomial below (lets call it poly1) which MAPLE does not recognize.

(A*B/(A+B)+X)/(X+Y*X/(Y+X))

Here you can see that A,B on top and X,Y on the bottom are clearly of the form f(x,y).

Is there a way you can get MAPLE to recognize certain algebraic forms such that the polynomial poly2 could be written either as poly1 (already shown above) or as poly3 below:

poly3:=(f(A, B)+X)/(X+f(Y, X))

I have tried using simplify in the following form but not much luck. It doesn't seem to recognize anything other than the obvious.

simplify(poly2, {A*B/(A+B) = F1}, tdeg(A, B))

(I am still a bit new to the MAPLE syntax and procedures so apologies if I have missed something obvious function that can do this.)

Thanks.

In Maple 2015, the DrawNetwork command option "horizontal" does not seem to work. Is this a bug? It doesn't even display horizontally on the online Maple Help webpage. Any help would be appreciated.

Hello,

I have a question about poincare sections. I have this piece of code i need to analyse and I want to use a poincare section in order to so. How could I do it? I am interested in theta and omega. Any help is greatly appreciated! Thank you in advance!

Kind regards,

Gambia Man

Download New_Poincare_section.mw

http://www.maplesoft.com/support/help/Maple/view.aspx?path=Physics/.

i see bra and ket expression are so beautiful,

however,

how do real valued eigenvectors involve in calculation of bra and ket style computation?

assume a,b,c,d,B2,B3 are matrices and y is unknown

eq2 := a*b+c*d+a;
eq3 := a*c+c*d+c;
eq4 := a*b+c*a+b*c;
eq5 := a*b+a*d+b*c;
solve([eq2=B2,eq3=B3,eq4=B2,eq5=y],[a,b,c,d]);

which function can solve this kind of system of matrices?

how to solve a,b,c,d in terms of y?