I am somewhat surprised to find that

PDEtools:-difforder(sin(diff(f(x),x)));

say, returns 1. Does that really make mathematical sense with diff(f(x),x) here being the argument of a function?

PS: I bumped into this issue because I was trying to write down some structured type, or some other matching criterium, that will return true for some scalarly quantity consisting of any number of functions and their derivatives if and only if all arguments to all functions have differential order zero. This criterium would exclude the above function, for instance.

Update: Just for the sake of completeness, or as a service to any visitor to this thread, the above was readily resolved as being due to a blunder of mine, see a comment of mine below. The thread, though, developed into a quite interesting one concerning issues with conserved currents, and related, in the case of Grassmann-odd quantities, issues that are at the time of writing still unresolved.

Hi, I am trying to solve two nonlinear simultaneous equations with two unknown variables T & W. The Range of one variable T is from 0 to 0.4

When I use fsolve command to solve it, it gives me a solution in which T value is more than the specified range so it is an invalid solution for me. When I specify the range of T from 0 to 0.4 in fsolve, it doesn't give any solution.

Solve command in maple also doesn't give any solution and just shows evaluating.

My question is how can I get all the roots of unknown variables (T & W), which can solve these two simultaneous equations.

The maple worksheet is attached. 

.maple_simul.equation.mw

So, i have 3 vectors:

A=2i-3j+ak

B=bi+j-4k

C=3i+cj+2k

where a,b,c are constants.

such that A is perpedicular on B and C, and the scalar product B*C=2.I have to estimate this constants using an iterative algorithm on Maple and then solve the problem using predefined function from Maple and compare the results.If you have an idea pls let me know.Thank you.Sry if I wasn't clear.

hello. i want to write this functionT with  "for"loop. but i don't know
 

e.mw

friends , 

i want to solve an equation but maple result is " Root of .. " term , how can i get rid of that 

eqqq.mw

thanks  

Hi, There is a problem in solving ODE using dsolve/numeric code. You people would like to help me in resolving the error, here is in attached file,

Latif_paper.mw

Hi,

In part of my program I defined variable Delta bar(`#mover(mi("Δ"),mo("-"))`), and used it and other parameters in a matrix named K (K=f(Delta_bar, x,y,...) then by using some mathematical operations, I initialled parameters to get my matrix named K.

Now I want to convert datatype of my matrix K with following command

M := Matrix(`~`[convert](K, float[8]), datatype = float[8]):

but receive following error:

Error, (in `convert/float`[8]) cannot handle unevaluated name ``#mover(mi("Δ"),mo("&uminus0;"))`` in evalhf

Do anyone know where the problem is?

Ok, so i have this functions

where f(x) represent urban population and g(x) represent the rural population.

And i have to implement an algortihm in Maple to find out after what period of time x the rural population will be with 20% bigger than urban population.

I'm new in Maple and is a little bit hard for me to implement algorithms in this program.If you can help me with any idea, i will really apreciate.Thank you :). 

The following is the PDE I need to solve.

(x*y+1)*(diff(h(x, y), y, y, y))+(x+h(x, y))*(diff(h(x, y), y, y))-(diff(h(x, y), y))^2+k(x, y) = 0, (10.*(x*y+1))*(diff(k(x, y), y,y))+(10.*x+h(x,y))*(diff(k(x, y), y))-(diff(h(x, y), y))*k(x, y) = 0

This is the original boundary condition:

h(0, y) = f(y), h(x, 0) = 0, k(0, y) = g(y), k(x, 0) = 1, k(x, 25) = 0, (D[2](h))(x, 0) = 0, (D[2](h))(x, 25) = 0

After using pdsolve it come out the error:

pdsolve(eval(pde2, P = .1), pdebc4, numeric, [h(x, y), k(x, y)], spacestep = .1)

Error, (in pdsolve/numeric/par_hyp) Incorrect number of initial conditions, expected 0, got 2

If I remove one of the boundary condition when x=0, maybe h(0,y)=f(y), then the error will be this:

Error, (in pdsolve/numeric/par_hyp) Incorrect number of initial conditions, expected 0, got 1

However if I remove both when x=0, it come out this error:

Error, (in pdsolve/numeric) initial/boundary conditions must be defined at one or two points for each independent variable

May I know what is the problem of this equations?

P/S: I know its only differentiate with respect to y and is consider to be an ODE( I need more explantion on this please) and I'm still new to maple. Thanks!!

int(exp(I*x(2-y)),[x=-infinity..infinity, y=0..2]);

how to calculate this integral? where I is imaginary part?

Hello

I would like to solve the two dimensional heat equation in the square [-1,1]^2  using finite difference.

The following code  does not gives me the right answer.

  I appreciate any help

heat2dequation.mw

Hello

I solved a complex PDE equation in maple but I can not plot the output.

The manner was like bellow:

PDE := [diff(A(z, t), z)+(1/2)*alpha*A(z, t)+(I*beta[2]*(1/2))*(diff(A(z, t), t, t))-(I*beta[3]*(1/6))*(diff(A(z, t), t, t, t))-I*(GAMMA(omega[0]))(abs(A(z, t))^2*A(z, t)) = 0];
IBC := {(D[2](A))(z, 1), A(0, t) = -sin(2*Pi*t), A(z, 0) = sin(2*Pi*z), (D[2](A))(z, 0) = 2*z};
pds := pdsolve(PDE, IBC, type = numeric, time = t, range = 0 .. 1);
pds:-plot3d(A(z, t)*conjugate(A(z, t)), t = 0 .. 1, z = 0 .. 10, shading = zhue, axes = boxed, labels = ["x", "t", "A(z,t)"], labelfont = [TIMES, ROMAN, 20], orientation = [-120, 40]);

It is solved but there is an error like:

Error, (in pdsolve/numeric/plot3d) unable to compute solution for z>INFO["failtime"]:
unable to store 11.2781250000000+4390.00000040000*I when datatype=float[8]

could you please help me?

what is the problem?

Hi everyone, 

I seek for creating a discrete random variable with the following characteristics. Let i be an integer between 1 and 100. The random variable is an integer, among i-x, i-x+1, i-x+2..., i-1, i+1, i+2... i+x. For example, with i=20 and x=5, the random variable is an integer between 15 and 25; with i=23 (and again x=5), the random variable is an integer between 18 and 28; and with i=98, the random variable is an integer among 93, 94... 97 and then 99, 100, 1, 2, 3.

Each possible value has the same probability, that is, 1/2x.

Any tips? Thank you in advance.

I have a differential equation which it seems not be solvable. can anyone help me to solve?

Thank you

difeq.mw

I am trying to evaluate the following double integral where hypergeom([x,1/2],[3/2],C) is gauss hypergeometric function 2f1. maple gives back it unevaluated. I doubt it may be due to slow convergence of hypergeometric function. 
 

Download DOUBLE_INT_2.mw