Hi,

I was wondering, suppose I have an ordinary differential equation, y''(x)  + y(x) - y(x)^3, and that the RHS is equal to zero (Duffing type equation).. Is there any way to declare this as in Maple, such as,

y''(x):=y(x)^3-y(x);

so that any time Maple sees y''(x) + y(x)-y(x)^3 in an expression, it will replace it with zero? I have tried the above, but it receive an error which says, "error, illegal use of an object as a name." 

Hi!

I am a mechanical engineer.

I want to differentiate a potential energy functional (a multivariable functional combination of integrals) in the variational calculus to get the Euler-Lagrange equations and boundary conditions and then to solve ODE's and PDE's to get a closed form solution.

The form of PE:=F(x1,x2,x3,w1(x1,x2,x3),w2(x1,x2,x3),w3(x1,x2,x3),diff(w1,x1),etc...)

Interested in getting diff(F,w1)  and diff(F,diff(w1,x1)).

Consider two sets in the Euclidean plane, each consisting of 4 points.

First set:  A(0, 0),  B(3, 4),  C(12, 4),  E(4, -1)

Second set:  F(0, -8),  G(12, -4),  H(9, -8),  K(4, -9)

It is easy to check that the set of all pairwise distances between the points of each of the given sets (6 numbers for each set ) are the same. At the same time it is obvious that there is no any...

Dear all,

I have to optimize polynomials with 10Mio data.

for i from 1 to ... do v[i]:=Optimization[NLPSolve](g(A[i,1],A[i,2],0.01273,x),x=0..3,method=branchandbound,maximize)[2]od;

This gives the result I wish, but formated like [x=0.] .

I would like to write only the x-values (floats) to a .txt file.

writedata("c:test.txt",v);

gives an error.

I must have the results on Friday, so would be very grateful for a fast answer.

Fridays Killer Questions 7city Learning:

Question) There are eight balls, one of which is slightly heavier than the others. You have a two-armed scale, which you are allowed to use only twice. Find the ball that’s heavier.

Answer) Put three balls on each side of the scale. If the arms are equal, you know the heavy ball is one of the two remaining. If the arms are unequal, take the three balls on the heavier side, pick two and weigh them against each other.

 I want to evaluate the values of x and y and the data should bo saved in .xls format  from contour plot 

for g=0.1 the data x and y values  should be stored in xls sheet 1  atleast 50 values 

similarly  in separate xls sheet 

for g=0.0 the data x and y values  should be stored in xls sheet 1  atleast 50 values 

with(plots):
g:=y*(1-1/(x^2+y^2)):
colors:=table([0.1=blue,0.0=green,0.2=red]):
display(seq(contourplot(g,x=-1..1,y=0..2,
contours=[i],color=colors[i],axes=boxed,legend=(i)),i=[0.1,0.0,0.2]));

thanks in advance

Dear Experts,

I am novice to Maple 14, to do some numerical work I am using its 2D math input. I am having problem while using an itegral equation with a limit from 0 to infinity, when I use this limit; in answer I got un-solved equatoin instead a numerical value and this un-solved equation have FLOAT value, when I tried with some other input that time maple give answer again 

I have a huge PDE system included reaction-diffusion system with 4 independent and 12 independent variables. I read on the maple help for pdsolve/numeric/method. I found it is only for single partial differential equations in two independent variables. Is there anyone knows the ability of Maple for such a system?

I am trying to solve a square polynomial system (16 x 16, I was able to solve an 8 x 8 fine) using the package RegularChains (with Groebner bases the problem is the same) but I have a memory constraint of 4G in the Linux cluster and my batch job gets terminated after Maple grabs too much memory:

TERM_MEMLIMIT; (job*killed*after*reaching*LSF*memory*usage*limit.Exited, with, true)*(File*size*limit*exceeded.Resource, usage, true)*summary; CPU*time;(4509.00*sec.Max, Memory, true...

How do I install Maple 15 in Windows 8.  I get a requester that says that the GUI version is not supported.

Hi all,

I have the following functions.

restart:
with(IntegrationTools):
N:=4:

i:='i':
for i from 1 to N do
    assume(x[i-1]::constant):
    assume(x[i+1]::constant):
    assume(x[i-1]::constant):
    assume(h::constant):

 phi[i](t):=piecewise(t>=x[i-1] and x[i]>t, (t-x[i])/(h), x[i]

(x[i+1]-t)/(h), 0);

end do;

## my goal is solve the integrals involving phi[i]'s as integrand and x[i]'s as its limits.

i am implementing q-Laplace

http://perso.uclouvain.be/alphonse.magnus/gbang/qbook712.pdf

when there are quite many differentiation rules

how to do a function for a new kind differentiation like a maple do?

1.

qRacah := qhyperterm([q^(-x), alpha*q^(-x)/(gamma*delta)], [alpha*q], q, gamma*delta*q^(x+1)*t, k)*qhyperterm([beta*delta*q^(x+1), gamma*q^(x+1)], [beta*q], q, q^(-x)*t, k);

i use inverse laplace to transform ordinary generating function into exponential generating function

can not further evaluated

2.

i do not know whether x is main variable or q is main variable or both are.

ff := eval(subs(x=0, exponential_genfun));

How to give the different colors in implicit plot  and add legends my codes are 

with(plots):

g:=y*(1-1/(x^2+y^2)):

aa:=[g=0.1,g=0,g=0.5]:

implicitplot({seq(aa[i],i=1..3)},x=-5..5,y=0..2,legend="g=0.1,g=0,g=0.5",color=[red,blue,green],scaling=constrained);

i want to draw  a countour plot and i want the graph in the given below patter  and my codes are 

for Q=1, and Q=2 ,Q=3.2

F:= x^2+2*y^3+Q:
p1:=contourplot( F, x=0..1, Q=1,color=red):
p2:=contourplot( F, x=0..10, Q=2,color=blue):
display(p1,p2):

thanks in advance