MaplePrimes Questions

Wanting to edit a post of mine, I accidentally clicked the 'More'-button and chose 'Edit' on anothers post. I immediately saw that it was not my post, and did of course not alter it. But it left me somewhat shocked, for it would seem to imply that anyone can edit (and delete, as well, have just investigated that) anyones post(s). That I think is something that really needs to be remedied as soon as possible.

Here is my command and i will use to make the user interface.

Orginal:

for i to l do

for j from x to y do

block[i][j] := 1-block[i][j]

end do;

c_block[i] := block[i];

c_block[i] := parse(cat(c_block[i][]))

end do

Can someone help me to edit my command so that i can write it in Click Edit Action for a button? thank you.

Do(for i from 1 to %l do)
   Do(for j from x to y do)
      Do(block[i][j] = 1-block[i][j]); 
    end do);
   Do(c_block[i] := block[i]);
  Do( c_block[i] := parse(cat(c_block[i][])));
end do);

Hey

I have a very simple function and I need to plot it. The plot is however not smooth and there are annoying cuts and steps which don't go away no matter how I set the options. This problem has been puzzling me for a while and I really appreciate any help.

The followings are all the possible options I could find, none seems to work. You can take a look at this file: ploting_problem.mw

Thanks

I saw yesterday evening (at home) a very elegant answer to my question "Intersection of real intervals" .
Unfortunately I can't retrieve it this morning (I'm in the office)

It was something like  coulitbe('_x' ...) ... but I don't remember it entirely
I think it came from Carl Love or maybe Mac Dude

 Could you please send me it again ?

 

Thanks


Suppose I have a triplet a[5], a[6], a[7]and an expression given as below:

V[5]*a[5]+V[6]*a[6]+V[7]*a[7]+V[2]+V[9]

How I can list all possible forms of above expression for triplet "(a[5], a[6], a[7])->(a[5], a[6], a[7]), (a[5], a[6], 0), (a[5], 0, a[7]), (0, a[6], a[7]), (a[5], 0, 0), (0, a[6], 0 ), (0, 0, a[7]), (0, a[6], 0), (0, 0, 0) "etc


Download triplet.mw

Regards

Dear all

I need a help to compute the integral from -1 to 1 of product of derivative of legendre polynomial

> restart;
> with(orthopoly);

P(n, x); # Designe the legendre polynomial of degree n
I would like to compute

int(diff(P(n,x),x)*diff(P(m,x),x),x=-1..1) ;

 

In this previous formula when I put n=2 and m=3 I can get the result but in general  case i cannot,

Many thanks

 

 

Howdy all,

I am trying to create a solar system model by defining a force equation then using the sequence function to create a differential equation and then solving those differential equations using the initial conditions (in X,Y,Z coordinates). So far I have the code below.


m[1] = 1.989*10^30; m[2] = 3.301*10^23; m[3] = 4.867*10^24; m[4] = 5.972*10^24+7.346*10^22; m[5] = 6.417*10^23; m[6] = 1.899*10^27; m[7] = 5.685*10^26; m[8] = 8.682*10^25; m[9] = 1.024*10^26; m[10] = 1.471*10^22; m[11] = 9.3*10^20; m[12] = 2.6*10^20; m[13] = 2*10^20; m[14] = 8.67*10^19; m[15] = 3.9*10^19; mass := Matrix(15, 1, [1.989*10^30, 3.301*10^23, 4.867*10^24, 5.972*10^24+7.346*10^22, 6.417*10^23, 1.899*10^27, 5.685*10^26, 8.682*10^25, 1.024*10^26, 1.471*10^22, 9.3*10^20, 2.6*10^20, 2*10^20, 8.67*10^19, 3.9*10^19]); G := 6.67408*10^(-11)

mass := Vector(4, {(1) = ` 15 x 1 `*Matrix, (2) = `Data Type: `*anything, (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

 

0.6674080000e-10

(1)

sqrt(sum(x[i](t)^2, i = 1 .. 3));

(x[1](t)^2+x[2](t)^2+x[3](t)^2)^(1/2)

 

proc (i, j) options operator, arrow; sqrt(sum((x[i, k](t)-x[j, k](t))^2, k = 1 .. 3)) end proc

 

((x[1, 1](t)-x[3, 1](t))^2+(x[1, 2](t)-x[3, 2](t))^2+(x[1, 3](t)-x[3, 3](t))^2)^(1/2)

 

proc (i, j) options operator, arrow; [x[j, 1](t)-x[i, 1](t), x[j, 2](t)-x[i, 2](t), x[j, 3](t)-x[i, 3](t)] end proc

 

[x[3, 1](t)-x[1, 1](t), x[3, 2](t)-x[1, 2](t), x[3, 3](t)-x[1, 3](t)]

 

x[3, 1](t)-x[1, 1](t)

 

x[j, 1](t)-x[i, 1](t), x[j, 2](t)-x[i, 2](t), x[j, 3](t)-x[i, 3](t)

 

proc (i, j) options operator, arrow; [seq(x[j, k](t)-x[i, k](t), k = 1 .. 3)] end proc

 

[x[3, 1](t)-x[1, 1](t), x[3, 2](t)-x[1, 2](t), x[3, 3](t)-x[1, 3](t)]

 

x[3, 1](t)-x[1, 1](t)

(2)

diff(x[0, 1](t), t, t) = force(0)[1]:

initialPositions := Matrix([[0, 0, 0], [-0.210e8, 0.426e8, 0.541e7], [0.106e9, -0.244e8, -0.644e7], [-0.139e9, -0.569e8, 0.316e4], [-0.177e9, -0.155e9, 0.111e7], [-0.802e9, 0.131e9, 0.174e8], [-0.480e9, -0.142e10, 0.438e8], [0.280e10, 0.103e10, -0.324e8], [0.420e10, -0.157e10, -0.645e8], [0.132e10, -0.477e10, 0.127e9], [0.431e9, -0.690e8, -0.816e8], [0.228e9, 0.305e9, -0.368e8], [0.300e9, -0.351e9, 0.217e9], [-0.434e9, -0.841e7, -0.284e8], [-0.115e9, -0.466e9, -0.612e8]])

initialPositions := Vector(4, {(1) = ` 15 x 3 `*Matrix, (2) = `Data Type: `*anything, (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

(3)

initialVelocities := Matrix([[0, 0, 0], [-0.462e7, -0.170e7, 0.285e6], [0.666e6, 0.293e7, 0.183e4], [0.936e6, -0.239e7, 83.3], [0.145e7, -0.140e7, -0.650e5], [-0.196e6, -0.106e7, 0.879e4], [0.745e6, -0.271e6, -0.250e5], [-0.208e6, 0.524e6, 0.467e4], [0.161e6, 0.442e6, -0.129e5], [0.463e6, 0.294e5, -0.137e6], [0.193e6, 0.143e7, 0.923e4], [-0.119e7, 0.974e6, 0.116e6], [0.978e6, 0.562e6, -0.470e6], [0.166e6, -0.156e7, -0.131e5], [0.132e7, -0.170e6, 0.395e6]])

initialVelocities := Vector(4, {(1) = ` 15 x 3 `*Matrix, (2) = `Data Type: `*anything, (3) = `Storage: `*rectangular, (4) = `Order: `*Fortran_order})

(4)

ic1 := seq(seq(x[i, k](0) = initialPositions[i+1, k], k = 1 .. 3), i = 0 .. N-1); ic2 := seq(seq((D(x[i, k]))(0) = initialVelocities[i+1, k], k = 1 .. 3), i = 0 .. N-1); equations := {ic1, ic2, ode}; sol := dsolve(equations, numeric)

Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got {x[0, 1](0) = 0, x[0, 2](0) = 0, x[0, 3](0) = 0, x[1, 1](0) = -0.210e8, x[1, 2](0) = 0.426e8, x[1, 3](0) = 0.541e7, x[2, 1](0) = 0.106e9, x[2, 2](0) = -0.244e8, x[2, 3](0) = -0.644e7, x[3, 1](0) = -0.139e9, x[3, 2](0) = -0.569e8, x[3, 3](0) = 0.316e4, x[4, 1](0) = -0.177e9, x[4, 2](0) = -0.155e9, x[4, 3](0) = 0.111e7, x[5, 1](0) = -0.802e9, x[5, 2](0) = 0.131e9, x[5, 3](0) = 0.174e8, x[6, 1](0) = -0.480e9, x[6, 2](0) = -0.142e10, x[6, 3](0) = 0.438e8, x[7, 1](0) = 0.280e10, x[7, 2](0) = 0.103e10, x[7, 3](0) = -0.324e8, x[8, 1](0) = 0.420e10, x[8, 2](0) ...

 

plots[odeplot](sol, [x[1, 1](t), x[1, 2](t), x[1, 3](t)], t = 0 .. 20, numpoints = 1000, axes = normal)

Error, (in plots/odeplot) input is not a valid dsolve/numeric solution

 

plots[odeplot](sol, [seq(x[1, k](t), k = 1 .. 3)], t = 0 .. 20, numpoints = 1000, axes = normal)

Error, (in plots/odeplot) input is not a valid dsolve/numeric solution

 

plots[odeplot](sol, [seq([seq(x[i, k](t), k = 1 .. 3)], i = 0 .. N-1)], t = 0 .. 20, numpoints = 1000, axes = normal)

Error, (in plots/odeplot) input is not a valid dsolve/numeric solution

 

``


Download ass4.mw

Everything works fine until I try to execute the last line. When I do that I get an error that says "Error, in dsolve/numeric/process_input. invalid specifications of initial conditions.

At this point I am not sure if the problem lies in how I have defined my initial conditions or the way i've defined the force equation but I am open to any suggestions or ideas on where I should go from here.

Thanks in advance!

 

Nick

i use the pdsolve to find the solutions of a system of partial differential equations,

but the result contains some indefinite integrals, how to simplify it further?

thank you

code:

eq1 := {6*(diff(_xi[t](x, t, u), u))-3*(diff(_xi[x](x, t, u), u)), 12*(diff(_xi[t](x, t, u), u, u))-6*(diff(_xi[x](x, t, u), u, u)), 2*(diff(_xi[t](x, t, u), u, u, u))-(diff(_xi[x](x, t, u), u, u, u)), diff(_eta[u](x, t, u), t)+diff(_eta[u](x, t, u), x, x, x)+(diff(_eta[u](x, t, u), x))*u, 18*(diff(_xi[t](x, t, u), x, u))+3*(diff(_eta[u](x, t, u), u, u))-9*(diff(_xi[x](x, t, u), x, u)), 6*(diff(_xi[t](x, t, u), x, x))+3*(diff(_eta[u](x, t, u), x, u))-3*(diff(_xi[x](x, t, u), x, x)), 6*(diff(_xi[t](x, t, u), x, u, u))+diff(_eta[u](x, t, u), u, u, u)-3*(diff(_xi[x](x, t, u), x, u, u)), 12*(diff(_xi[t](x, t, u), u))-6*(diff(_xi[x](x, t, u), u))+6*(diff(_xi[t](x, t, u), x, x, u))-6*(diff(_xi[t](x, t, u), u))*u+3*u*(diff(_xi[x](x, t, u), u))-3*(diff(_xi[x](x, t, u), x, x, u))+3*(diff(_eta[u](x, t, u), x, u, u)), 12*(diff(_xi[t](x, t, u), x))-6*(diff(_xi[x](x, t, u), x))+2*(diff(_xi[t](x, t, u), t))+2*(diff(_xi[t](x, t, u), x, x, x))-4*(diff(_xi[t](x, t, u), x))*u+2*(diff(_xi[x](x, t, u), x))*u+_eta[u](x, t, u)-(diff(_xi[x](x, t, u), t))+3*(diff(_eta[u](x, t, u), x, x, u))-(diff(_xi[x](x, t, u), x, x, x))};

simplify(pdsolve(eq1))

 

I read in the net that the method used in pdsolve numeric is the theta method, my question: is it the most efficient with regard to rate of convergence of the numerical solution of the PDE?

If not then why is it used as the default method?

 

Thanks.

 

nullspace or reducedform or Eigenvectors still can not find eigenvector in terms of  mmm , how to find this?

 

mmm is a variable

 in eigenvector using nullspace and eigenvector using maple function  Eigenvectors ? 

I'm reading a string from a textbox, and I need to know where the line breaks are. Hint:They are not found by searching for \n.

Dear All, 

I am using the comand " export as" form the file menu to obatain a latex version of my worksheet. The generated latex file use a package called amplestd2e.sty that should be loaded for latex compiler to function proper. Do somebody know where to find it. Thank you. N. Jand 

Hi everybody!

I am trying to find explicitely the relations between the columns of a matrix

of non-maximal rank. For example, if I have the matrix

M := Matrix([<1,2,3>, <2,4,6>, <5,6,7>]);

I would like that Maple finds that the second column is twice the first one: v_2 = 2*v_1.

How can I do?

How to reverse the order in a list?

example:

i have m := [1, 1, 0, 0, 1, 1, 1, 0]

I want to get the output like newm:=[0,1,1,1,0,0,1,1].

How to solve? Any command can help?

First 1128 1129 1130 1131 1132 1133 1134 Last Page 1130 of 2428