Hi,

I need to solve following problem, but i m facing memory allocation problem in code. I dont know where memory is consuming.

Download nonlinearx.mw

Thanx in advance.

Regards

Sunit

Hi,

I'm trying to stop integration if the numeric procedure takes more than ~2 seconds and set the value to zero. As an example consider

restart;
st:=time():
answer:= evalf( Int(SphericalY(161,5,x,5)*SphericalY(262,5,x,x), x=0..10));
t:= time()-st;

This takes 0.63 seconds on my computer, but I wish to stop it after 0.1 seconds as an example. Is there anyway to access the inside of evalf(Int...)) and kill it after 0.1 seconds?

thanks,

The question is to solve

x^2*(diff(y(x), x, x))+x^3*(diff(y(x), x))+(x^2-2)*y(x) = 0

and evaluate it where y(1) = 1 and y(2) = 2 to find y(3).

When I do the equation,

ODE := x^2*(diff(y(x), x, x))+x^3*(diff(y(x), x))+(x^2-2)*y(x) = 0

dsolve(ODE) y(x) = _C1/x+_C2*(-sqrt(Pi)*sqrt(2)*erf((1/2)*sqrt(2)*x)+2*x*exp(-(1/2)*x^2))/x

I have gotten an erf. Is this correct?

Hi everyone,

I need to write a program to save some files in both Windows or Unix System.

The structure of the path files is different from windows to Unix, so i want to something like this

if (WindowsOS) then

        pathFILE := "\\MyDirectory\\blabla.txt";

elif (UnixOS) then

       pathFILE := "\/MyDirectory\/blabla.txt";

end if;

Thanks for help.

Hello, 

I am trying to plot an equation with mape,

I give the foloowing comand but I receive a warning which I do not know how to deal with it, I wil be thankful if you can help me.

these are the command and wanring:

plot(eval ((6), {n=10, m=1},k=0.1..0.2)

warning, expecting only range variable k in expression.....

I am trying to use Maple17 to create practice integration problems in which the integrands contain square roots.  I want the students to practice converting square roots, perhaps with fractions, to fractional and/or negative powers.  Hopefully Maple can typeset the integrals if I use the inert form "Int", and also do the integrals for me so I can find the answers quicker than doing it by hand, and not have to worry about making a careless mistake.  The trouble is, Maple is converting the square roots to fractional exponents:

Download DisplaySquareRoot.

Download DisplaySquareRoot.mw

I hope at least one of these works.  To make a long story short, when I display an integral using "Int", how do I prevent Maple from converting square roots to fractional exponents?

GS

how do you find the surface area of an ellipsoid (for instance 'x^2/20+y^2/13+z^2/20=1'?) which is formed by rotating completely about the y axis? 

May I know how to use maple to solve

d^3y/dx^3+(1/x)(dy/dx)-(1/x^2)y=0, where y(1)=1, dy/dx=0 at x=1, d^2y/dx^2 =1 at x=1. find y(3).

Thx!

Hi everyone,

I am a new user of maple and i want to know the procedures to follow when solving 4 differential equations simultaneously.

e.g

ds/dt=Λ₀-βcSI/N-μS

dL/dt=Λ1+βcSI/N-μ₁L+ΑcIT/N

dI/dt=kL-μ₂I

dT/dt=r1L+r2I-ΑcIT/N-μT

Any help will be highly appreciated. Regards

> restart; with(plots); with(LinearAlgebra); with(IntegrationTools); pde := rho(x)*(Diff(u(t, x), t, t))+lambda(x)*(Diff(u(t, x), t))-(Diff(P(x)*(Diff(u(t, x), x)), x))-Q(x)*u(t, x)+R(x);

> eq1 := int(pde*phi[i](x), x = -1 .. 1);

eq2 := expand(eq1);

> eq3 := applyop(u -> Parts(u, phi[i](x)) end proc, 3, eq2);

i get an error

Error, (in applyop) improper op or subscript selector

how to correct it??

Good morning sir.

I request your kind support to the above cited question.

With thanks & Regards

M.Anand

Assistant Professor in Mathematics

SR International Institute of Technology,

Hyderabad, Andhra Pradesh, INDIA.

Just came across this

Press esc twice then enter.  Maple becomes unresponsive. 

Hi -

I'm trying to use Maple to integrate an ODE numerically, but to output the integration steps as I go (in an array, or similar). None of the dsolve/numeric output parameters appear to offer this (ie

x=0.00 f = whatever,

x = 0.05 f = whatever2,

x = 0.10 f = whatever3)

Is there a standard feature in Maple that I'm missing, or would I have to force the output from the dsolve procedure in some way, please?

i have a piecewise like " g "

g := piecewise(0 <= t and t <= 0.2e-1, 122.63, 0.2e-1 < t and t < .287, 0, .287 <= t and t <= .307, 122.63, .307 < t and t < .335, 0); plot(g, t = 0 .. .335)

this function is semi periodic just for 10 times consecutive . i want to define it

example     k=[g g g g g g g g g g  g ] or somthing like that.

1.mw 

i want to plot fft form of final piecewise function

and then filter it . and plot them.

Hi there..

I have a question on how to do a pointplot.

before plotting, I need to know the value of lambda[j] and  all the values of lambda already have.

so now I need to plot a graph with the values of lambda with different range and different colour,

Let say I have

> for j from 17 to 32 do k[j] := j+1;

x[j] := add(P[j, 1], j = j-1 .. j+2);

X[j] := add(P[j, 1]^2, j = j-1 .. j+2);

y[j] := add(P[j, 2], j = j-1 .. j+2);

Y[j] := add(P[j, 2]^2, j = j-1 .. j+2);

xy[j] := add(P[j, 1]*P[j, 2], j = j-1 .. j+2);

cx[j] := evalf(x[j]/k[j]);

cy[j] := evalf(y[j]/k[j]);

c11[j] := evalf(X[j]/k[j]-cx[j]^2);

c22[j] := evalf(Y[j]/k[j]-cy[j]^2);

c12[j] := evalf(xy[j]/k[j]-cx[j]*cy[j]);

C[j] := evalf(Matrix(2, 2, [[c11[j], c12[j]], [c12[j], c22[j]]]));

E[j] := simplify(fnormal(LinearAlgebra[Eigenvalues](C[j])));

if E[j][1] > E[j][2] then lambda[j] := E[j][2]/(E[j][1]+E[j][2]) else lambda[j] := E[j][1]/(E[j][1]+E[j][2])  end if;

lambda[j];

 end do;

the range of lambda [j] are as follows:

 0.02< lambda [j]<0.06

 0.06< lambda [j]<0.12

 0.12< lambda [j]<0.18

for i from 17 to 32, do if   0.02< lambda [j]<0.06 then green[i]:=P[i,j]; j:=i+1 elif

 0.06< lambda [j]<0.12 then red[i]:=P[i,j];j:=i+1 ; elif 0.12< lambda [j]<0.18 then blue[i]:=P[i,j];j:=i+1 end if;end do

how to do a point plot with the above situation so that in my plotting all the information are on the same graph.

All help is greatly appreciated.

Thanks