Hi

I want to write the functional Z of J with in terms of the fourier transform of J: .

Actually I'm in Minkowski space and all the integrals should be over 4 dimensions, x,y,k,p should all be four-vectors, but I wanted to keep things short. (The only way I have found to express a 4D integral is using Physics-Intc with the singleparameters of the four vector. Is there a more convenient way to get ?) But still in 1D I cannot solve it.

To find the solution, an exponential of only one integral, is actually pretty easy, since there are integrals over e. g. deliver a delta distribution, but I cannot reproduce this in Maple since he doesn't perform the integral over x.

I have found that I can/have to use the command inttrans-fourier to gain the delta distribution, but when I try to use it for the problem mentioned above I run into all kinds of problems. Not to mention that I cannot manage to perform a fourier transformation in 4D.

Does anybody know how to solve this problem? Thanks!

Hi,

I am using the solve command to solve an equation of the form "linear over quadratic is equal to a constant" where the constant is assumed to be nonzero. This is easily solved by hand, of course, but I to use the solution in other computations. So I asked maple to solve it for me. But when I check maple's solution (i.e. just plug the two solutions in on the left hand side and simplify) maple does not return the original constant. Can anyone help me understand what is going wrong?

Dear Forum, 

I am a new Maple user, and its symbolic prowess is really amazing. So we are trying to interface it with a C library. I want to generate some C code through Maple, and am trying the CodeGeneration package. 

But the default conversion of C(a, b) is b = C language equivalent of expression a.

Now this should be fine for most purposes, but the C library that we are working with, "ACADOToolkit" in this case, requires the equations to be formatted in a certain way. So, I need the following equation in C:

f << dot(v) == (u-0.2*v*v)/m

Now the LHS part of == is to be hard-coded, but we want to generate the equation on the right using maple. Even if I define an equation as 

eq1:=  and then use C(rhs(eq1)), I get the result in the form of cg = u - 0.2 ...., whereas I want this to be assigned to something else, in this case - "f << dot(v)= ".

How can I achieve this ?

Thanks 

Chintan Pathak 

Research Scholar, 

University of Washington

hello , 

how i can exract value from pdsolve ,i need to use dU(x,R)/dR 

thank you 

Download U(R)_numériqueg2.mw

Dear all

I have a confusion between these symbol

Sum , add and sum

If we consider u(n) is a sequence and n integer

and what is the difference between 

sum( u(n),n=0..infinity)

Sum(u(n),n=0..infinity)

and sum('u(n)', n=0..infinity)

Many thanks

HI all,

I have 

> sol2 := dsolve({odesys, H(0) = 4995, R(0) = 65000, W(0) = 102000, l(0) = 96000}, numeric, method = rosenbrock);
print(`output redirected...`); 
proc(x_rosenbrock) ... end;

I want to have a list of my solutions, t, H(t), R(t), W(t), l(t) that I can put into a spreadsheet (.csv, .txt, etc.), for 600 timesteps. 

There are some answers out there, but I am confused by them, and have not been able to make it work.

Thanks!

How can I simplify $\sqrt{1−r^2\exp(2i\theta)}$ in Maple. I could do it by hand but I need this type of simplification later for far more complicated expressions.  I allready tried to enter this as a complex number using II, but simplify(...,'symbolic') didn't simplify this expression. Any suggestion?

I have a nonlinear function Q(a,b,c,d,x,y) and I'd like to get the optimum (x*,y*) for different values of (a,b,c,d). The usual sintax:

NLPSolve(Q(10, 1, 5, 2, x,y), x= 0 .. 50, y = 0 .. 50, initialpoint = {x = 2,y= .5}, assume = nonnegative) does not work when Q contains numerical integration, that is evalf (Int). I have no problem with the definite integral evalf(int). The problem is that most of the cases required numerical integration so I need the former expression.

I'd appreciate very much if someone could help me.

Hi,

how can I check in maple if my variable P is positive (always or only for some certain conditions)

with assumptions

a>0,b>0,c>0,d>0,e>0,f>0,g>0 and a>c,e,g

I need to prove that P is always positive with that assumptions, how?

While performing integration of some expessions I bumped into a strange problem. My expession consists of quite a lot of terms, but here I present the susbset of only 2. If I integrate it as a whole maple does not want to solve it, and leaves it as there was no closed expression to this integral. But if I split this sum and integrate the parts, it all works fine. What is happening here? What do I miss? I used simplify and allvalues but didn't change a thing...

Is there a way to split my terms into list, integrate one by one and they recreate the solution by summing the parts? Its a bit of a workaround, but surely better that doing it manually (I have around 50 terms). I use Maple 2015

Thanks,

Jeremi

Good morning everybody.

I have tried Explore to draw plots in an interactive way.

The function I want to draw (plot3d) is automatically constructed by a specific code, as well as the names of the parameters it depends on. These are of the form P||1, P||2, ...P||N (N is an integer determined during the construction)

... but I did not succeed !

After some investigations I was able to reduced the problem to the following one

N  := 2:
F  := add(P||k * x^k, k=0..N):
G := [seq(P||k=-1.0 .. 1.0, k=0..N)]:
Explore(plot(F, x=0..1), parameters=G)

The result is the classical imbedded window with a plot of -1-x_x^2 and three sliders below.
But as soon as I push anu of them the plot disappears and connot be recoverd.

But the following sequence seems to work as expected

N  := 2:
F  := add(P__k * x^k, k=0..N):
G := [seq(P__k=-1.0 .. 1.0, k=0..N)]:
Explore(plot(F, x=0..1), parameters=G)


Before changing my code, could you please confirm me that parameter names such that P||k are not correctly accounted for by Explore ?


Auxiliary question : more generally, are there points which I have to count carefully when I use the P||k construction ?

Thanks in advance

Hello,

a=number      b=number

=maple("Qm:=x->(diff(KelvinBei(0,x),x)*psi2(x)-(diff(KelvinBer(0,x),x)*psi1(x)))/&1";B11)

=maple("Qv:=x->(&1*psi2(x)-(&2*psi1(x)))/(&3*&4)";B6;B7;B2;B11)

=maple("Fm:=x->(Qv(x)+(&1*Qm(x)))/2";B3)

I need abs(max(Fm(x))) and abs(min(Fm(x))) values of function Fm(x), locals, for a<x<b in excel.

Now I use a vector to do this, but I need an exact values not an approximation of a fuction evaluated with n values of x.

what I do:

=maple("seq(i,i=&1..&2,&3)";N2;N3;N4)

=maple("A:=&1";N5)

=maple("G:=map(g->evalf(eval(Fm(x),x=g)),[A])")

=maple("max(abs~(G))")

Someone can help me??

Hello,

I tried to plot the problem presented below:

restart; with(plots); C := setcolors(); with(LinearAlgebra);

formula1 := 2.6*BodyWeight*abs(sin(4*Pi*t));
2.6 BodyWeight |sin(4 Pi t)|
BodyWeight := 80*9.81;
plot(formula1, t = 0 .. 2);

eq2 := formula1-SpringConstant*y(t)-DampConstant*(diff(y(t), t)) = Mass*(diff(y(t), `$`(t, 2)));
2040.480 |sin(4 Pi t)| - SpringConstant y(t)

/ d \ / d / d \\
- DampConstant |--- y(t)| = Mass |--- |--- y(t)||
\ dt / \ dt \ dt //
DampConstant := 50;
50
Mass := .200;
Springt := 200;
200
SpringConstant := Youngsmodulus*Surface/DeltaLength;
DeltaLength := 0.2e-1-y(t);
Surface := .15;
Youngsmodulus := 6.5*10^6/(t+1)+6.5*10^6;
plot(Youngsmodulus, t = 0 .. 10000);

eq2;
2040.480 |sin(4 Pi t)|

/ 6 \
|6.5000000 10 6|
0.15 |------------- + 6.5000000 10 | y(t)
\ t + 1 / / d \
- ----------------------------------------- - 50 |--- y(t)| =
0.02 - y(t) \ dt /

/ d / d \\
0.200 |--- |--- y(t)||
\ dt \ dt //

incs := y(0) = 0, (D(y))(0) = 0;
eq4 := dsolve({eq2, incs}, y(t), type = numeric, method = lsode[backfull], maxfun = 0);
proc(x_lsode) ... end;

plots:-odeplot(eq4, [t, y(t)], 0 .. 5);

 When I try to plot it beyond t=5, Maple gives the following error:

Warning, could not obtain numerical solution at all points, plot may be incomplete

Does anyone know how to plot it even further?

vz := 2*(-eta^2+1);

D_im := .22;

r0 := 1;

pde := diff(vz*Y(eta, z), z)-D_im*((diff(eta*(diff(Y(eta, z), eta)), eta))/eta+diff(Y(eta, z), `$`(z, 2)))/r0 = 0;

pde := expand(%);

ibc := [Y(1, z) = 0, (D[1](Y))(0, z) = 0, Y(eta, 0) = 1, (D[2](Y))(eta, 0) = 0];

sol := pdsolve(pde, ibc, numeric, time = z, range = 0 .. 1);

pds := sol:-value(z = 0, output = listprocedure);

sol:-plot(z = 0.1e-3, numpoints = 50, color = blue, view = 0 .. 1)

So I was trying to solve this conservation equation for the radial coordinate eta and the z coordinate being treated as time. The flow is in z direction. Now unfortunately it is diverging. Not sure why though. What am I doing wrong?

Hi All,

I seem to have problems with the table formatting in Maple TA 2016, concretely changing the cell padding has no effect. Is this a general issue ? I don't have this problem in Maple TA 10 (I tried both versions using the same browser (Safari)).

Thanks!

Elisabeth