Hi

I guess I should know this but what is the difference between a Matrix and an Array in Maple?

thanks

I've been given the relationship:

R*sqrt(sigma)-1-(1)/(4)*(l-(2*kappa*R^2)/(R*sqrt(sigma)))/(1+coth(R*sqrt(sigma)))-kappa*R^2/6+m/(2*R), for the particular case where m=l=0, and where

R=exp[(kappa*(R^2))/6]. On a sketch of R vs kappa, apparently sigma >0 on the lower branch, but there should be some sigma < 0 on the upper branch.

To attempt to solve this whole problem, I use the following commands:

restart;with(plots):

Please help plot solution of ODE in polar coords or tell how can i define a piecewise function that will make me able to plot the right and left side of singularities.

>sys1:=diff(r(t),t$2)=2*cos(teta(t))/r(t)^3,diff(teta(t),t$2)=sin(teta(t))/r(t)^3;funcs:=[r(t),teta(t)]:InC:=r(0)=1,teta(0)=15,D(r)(0)=0,D(teta)(0)=-2;

>FNUM:=dsolve({sys1,InC},numeric,funcs);

>odeplot(FNUM,funcs,t=0..230,numpoints=2000,coords=polar,view=[-20..20,-20..20]);

Thanks

Hello

I have the following nonlinear differential equation:

deq := (diff(y(x), x, x))*y(x)-1+x*y(x)^2 = cos(x);

I solved it numerically:

sol := dsolve({deq, y(0) = 1, (D(y))(0) = 1}, numeric);

ysol := proc (x) options operator, arrow; rhs(sol(x)[2]) end proc;

plot('ysol(x)', x = 0 .. 5);

but I would like to substitute it to the left side of deq and plot it, to be sure that it's plot is the same as cos(x).

My question is in regards to the events feature in dsolve numeric.

At a particular event time, I was wondering if it is possible to call a previous moment, that is something like

eq:={ diff(y(t),t) = y(t) };

ic:={ y(0) = 2 };

de:=dsolve( eq union ic, numeric, events=[[ t =5, [ y(t) = y( t - 2 ) ]]],range=0..10);


If it is possible to "globaly" declare previous steps of the dsolve, I believe that the above de would work. However,...

Hi everyone, here we are again with more serius issues this time.

I have a system of DE to solve. My system is made of coupled 3 PDE`s with 1 ODE. My problem is that the computation is aborted due failure at memory allocation, here is the message:

"Error, (in factor/nexteval) Cannot Allocate Memory (size=151060480)"

I`ve checked the kernelopts about datalimit and its already infinity. My computer is a Turion x2 with 4Gb of Ram (system...

Hello,

I want to evaluate an integral over the Dirac function with basically the following assignments. (I had some troubles parsing here...) Then I want to plot function rho(epsilon). What I get is just an empty graph with nothing displayed although test has only values in the range -3...3. I am pretty new to maple and don't know how to compute this in another way.

> test(x,y,z) := .2686733768*x^2+.2686733768*z^2-.2178281566+.2686733768*y^2+(-1)*1.000000000*sqrt...

Hello,

I have this relatively simple 4 equations which I am trying to solve simultaneously. But for some reason Maple just returns a pair of empty square brackets as solutions. "[ ]" like this.

I have uploaded the Maple Worksheet for your convenience. It would be very helpful if anyone can take a look at it and point out out the problem. Thank you.

Simultaneous_Eq.mw

I tried to find out whether the expression

g1:=2*mu*(phi+ln(mu/(exp(phi)*sigma2-sigma2+mu)))/((-sigma2+mu)*phi)+mu*(1/(exp(phi)*sigma2-sigma2+mu)-mu/(exp(phi)*sigma2-sigma2+mu)^2)*(exp(phi)*sigma2-sigma2+mu)/((-sigma2+mu)*phi)-mu^2*(phi+ln(mu/(exp(phi)*sigma2-sigma2+mu)))/((-sigma2+mu)^2*phi);

is positive under the given assumptions:

         
is(signum(g1)=1) assuming mu>0, sigma2>0, phi>0, sigma2<>mu;

I need to use the flexible beam in my model. I want to know if the component's correctness can be guaranteed, but I can't find any correlative documents or thesis, only find an article titled "Dymola – Flexible Bodies library". Is the flexible beam in maplesim similar to this? based on the modelica library? applied the finite element method? Some detailed information is very helpful.

Hi

I have a little problem, I tried to find out the Temperature of the Electrons in a Plasma,

the cross section name is sigma and I'm working with noble gases and there Threshold energies.

In the end I wand to find out  T_e but there comes only "Warning, solutions may have been lost"

Can anyone help me please?

Thank you very much

greetings from munich

Hi

I want to solve this

2010.pdf 

Hi,

I'm dealing with a complicated expression:

exp((1/6)*kappa*R^2-0.5000000000e-1/R)*sqrt(x)-1+(1/2)*kappa*exp((1/6)*kappa*R^2-0.5000000000e-1/R)/(sqrt(x)*(1+coth(exp((1/6)*kappa*R^2-0.5000000000e-1/R)*sqrt(x))))-(1/6)*kappa*(exp((1/6)*kappa*R^2-0.5000000000e-1/R))^2+0.5000000000e-1/exp((1/6)*kappa*R^2-0.5000000000e-1/R) = 0.

I want to plot various graphs of kappa vs x for different values of R on one axis. How is this possible in Maple?...

Is there a possiblity to create custom multibody components with the custom component template? Is there another template available for this purpose, or do you propose another solution?

Thanks a lot,

Bernd

Can anyone help me convert this outdated maple code into something current? Particularity I need help finding the equivalent command to "stats:-empirical" as I can't even find documentation for it.

with(stats): with(linalg): with(StringTools):

P1:=matrix([[.6,.3,.1],[.4,.5,.1],[.3,.4,.3]]);

j:=1:  res:="S":

for i to 50 do  

    j:=random[empirical[op(convert(row(P1,j),list))]]():