Greetings,

I need some help/advice because I think I am going crazy..!

I am trying to solve numerically a system of two PDE's. My initial condition is a gaussian and I apply cyclic boundaries.

With Maple 18 and pdsolve/numeric I am waiting a considerable amount of time and the result is a bell shaped travelling wave that increases its height over time. The clush between two such waves leaves them almost unaffected (the big pass through the small one).

With Mathematica 10 and NDSolve the waiting time is almost zero and the result (after few timesteps) is a shock wave travelling with steady height. Moreover, the clush between two of them is fully plastic (the big "eat" the small one)

I double-triple check the equations and the boundary conditions and I assure you that are the same..Any ideas what is hapening? Is there any way to check that the Maple results are correct?

Hi,

I just started to use Maple and I have a question if there exists in it an equivalent function to Mathematica's FindInstance? In general, I have an inequality and I would like to find few first solutions to it.

Hello,

In a worksheet, I don't know why the brackets like this "[" where normally I put my maple inputs and generally before the symbol ">" are not present (or displayed).

1) Are these brackets important for the computation of calculations in a worksheet ?

2) How can I do to display them again?

Thank you foryour help.

I would like to pay attention to an article " Sums and Integrals: The Swiss analysis knife " by Bill Casselman, where the Euler-Maclaurin formula is discussed.  It should be noted all that matter is implemented in Maple through the commands bernoulli and eulermac. For example,

bernoulli(666);

eulermac(1/x, x);

,

eulermac(sin(x), x, 6);

BTW, as far as I know it, this boring stuff is substantially used in modern physics. The one is considered in

Ronald Graham, Donald E. Knuth, and Oren Patashnik, Concrete mathematics, Addison-Wesley, 1989.

The last chapter is concerned with the Euler-MacLaurin formula.


           

Hi,

a researcher at our department starts multiple Maple programs in parallel on our Linux servers.

Sometimes a high percentage of the resulting mserver processes hang. ps shows their state as

SNl (sleeping, multithreaded). strace to the processes shows that every one is waiting on a

futex without timeout. The problem occurs in versions 16 and 18. This is annoying.

Is there a fix for this?

Matthias Bauer

hi I am tying to create a matrix: 

for i from 1 to 5 do

for j from 1 to 5 do

 A[i][j]:=i+j;

od

od;

But it doesn't create a matrix. As when I tried inverse operation it doesn't work. How can I create a matrix? Also can the index start from 0??

thanks

f := x^2*(y/x+sqrt(-7*y^2/x^2))/(y^2*(x/y+sqrt(-7*x^2/y^2)));
v := parametrization(f, x, y, t);

it can not parametrize.

i do not know which book teach group theory and algebraic curve

can we call this algebraic curve over finite field ?

how to represent a function as an algebraic curve equation for parametrization?

When I do simplify(LegendreP(n, 1, cos(t))), Maple gives me -sqrt(1-cos(t))*sqrt(cos(t)+1). Isn't it the same thing as -sin(t)? How can I have Maple further convert/simplify it to -sin(t)? (I tried simplify(%, trig) but it didn't work). I am new on Maple. Thanks in advance for anyone's help!

Trying to use the Explore() to parametrize a couple of plots simultaneously.

According to the help: "A plotting command to be explored can be a function call to plot, plot3d, a command in the plots package, or any user-defined procedure which returns a two- or three-dimensional plot structure or an Array of such plot structures."

However with the definitions

restart;
with(plots):
with(plottools):
Parab1 := ''plot(a*x^2, x = -1 .. 1, y = -3 .. 3)'';
Parab2 := ''plot(a*x^2+1, x = -1 .. 1, y = -3 .. 3)'';
L:=Array(1..2);
L[1]:=Parab1;L[2]:=Parab2;

I then find the following:

Explore(L[1], parameters = [a = -1.0 .. 1.0]);
gives the expected parabola, and the slider updates the parabola dynamically, as expected, and of course the same with L[2] in place of L[1]. However,

Explore(L, parameters = [a = -1.0 .. 1.0])

does not work, giving "Warning, expecting only range variable x in expression a*x^2 to be plotted but found name a". If I use display(L) in the command above, I receive two adjacent plots, as expected but they do not update as the parameter a is changed via the slider.

I'd guess I need to delay or promote variable evaluation somehow, but I can't seem to make it work. What am I missing?

Hello,

This is the system of equations in term of sin and cos. I have used the command "solve" in Maple but it yielded only 2 solutions. I've tried to use with(RealDomain): It yielded more solutions but most of them were wrong.

f1 := -8100+(-30+70*cos(t1)-40*cos(t2))^2+(-70*sin(t1)+40*sin(t2))^2

f2 := (-20-80*cos(t3))^2+(-15+70*cos(t1)+10*cos(t1+t))^2+(-70*sin(t1)-10*sin(t1+t)+80*sin(t3))^2-5625

f3 := (-20-80*cos(t3))^2+(15+40*cos(t2)+10*cos(t1+t))^2+(-40*sin(t2)-10*sin(t1+t)+80*sin(t3))^2-5625

f4 := 10*cos(t1+t)*(30-70*cos(t1)+40*cos(t2))-10*sin(t1+t)*(70*sin(t1)-40*sin(t2))

Anybody know how to solve this system of equations to get the full set of roots?

Thank you very much in advance.

for i from 0 to 3 do print("rawData[", i, "] = new double[] { ", hello(i+1), ",", data[i+1], "};") end do

wrong format after copy to notepad from the maple 15

do not know why it insert a empty line, and make "};" in another line

and there is unexpected " 

wrong format example:

"rawData[", 0, "] = new double[] { ", 73.25, ",", 0.1510425143,

"};"
"rawData[", 1, "] = new double[] { ", 73.15, ",", 0.3974080269,

"};"
"rawData[", 2, "] = new double[] { ", 72.85, ",", 0.4661517269,

"};"
"rawData[", 3, "] = new double[] { ", 73.25, ",", 0.3974080269,

"};"

expected format:
rawData[0] = new double[] { 25.0, 20.0 };
rawData[1] = new double[] { 27.0, 34.0 };

I have a expression: (x-2)/(x-2) and I want to retrieve all the variables of this expression.

I tried the following commands:

1. indets(expr, name);

2. indets(numer(expr),name);

but all i get is an empty set...it seems that maple will first simplify the expression and then figure out what variables are related to the given expression.

Is there any workaroud to achive what i want?

thanks

Hello,

I am trying to medel a mechanical system using parametric relations. Unfrotunately in some cases, the relations and equations become too lengthy. Maple calculates the relations but when I try to convert them to MATLAB language an error message appears. I have uploaded corresponding file in maple. As can be seen in this file, an error message appeard after trying to convert to MATLAB language. In some cases, for example C22, the relations are too length so that maple cannot show them. Do you have any idea to overcome this problem?

Thanks in advance.

P1.mw

Hello,

i did see that u can calculate minimial polynomials for for example \sqrt(2) or smth.

Suppose now u have a ground field K and an extension L=K(p,q) where p,q are some given rational functions in the indeterminates x,y, now i would like to calculate the minimal polynomial for lets say x+y or x over L which then obviously splits over the field K(x,y).

Thx in advance

(in dsolve/numeric/bvp) initial Newton iteration is not converging.