I often have large matrices and have to grab only every nth column or row (for plotting

for example). So far I've been doing it this way:

nthColumns:=proc(v_m, v_n)  

v_m[..,[seq(i, i=1..rtable_size(v_m)[2], v_n)]]

end;

nthRows:=proc(v_m, v_n) 

 v_m[[seq(i, i=1..rtable_size(v_m)[1], v_n)],..]

end;

A := LinearAlgebra:-RandomMatrix(20, 20, outputoptions = [datatype = float[8]]);

I only want to display 'position' in animation while tend <= 12:
This is the trial:

restart:with(plots):
for tend from 0 to 50
while (tend <= 12) do
pos:=animate(textplot3d,[[-1.8,0,alpha*tend, 'position']], tend=0..50,frames=150);
od;
display(pos);

I receive error messages:
error, (in plots/animate) 0=0..50 is an invalid animation range

Then I try:

restart:with(plots):
while (tend <= 12) do

Helo every one,

I'm trying to find the positive real root from:

and substitute it in:

my prog is:

eq5:=u->-3*b*k*u^2-3*b*k^2*u^4-k^3*u^6*b+k*u+5*k^2*u^3-b:  

                   (solve(eq5(u),u)): S:=array([...

I am using Maple 15 and every time I try to plot this equation it doesnt seem to want to plot. This is the code I keep trying to input:

plot(3*e^(-x)*x-e^(-x)-1.5*e^(-x)*(x^2)+e^(-x)*(x^2)*log(x),x=0..9,y=-1..0.6);

Every time I get "Plotting Error, empty plot"

The equation came from the original differential equation .5(d^2y/dx^2)+(dy/dx)+.5y(x)=ln(x)e^(-x)

 Also When i try to plot this equation:

-.5*e^(-10*x)*sin(10*x)-.5*e^(-10*x)*cos(10*x)+(3/2)=300

Solve for x in the following expression.

log x=-4

I use the following commands to export a graph to a file:

plotsetup(gif, plotoutput=cat(filefolder,examplenr,".gif")):
print(display([pol],color=grey,scaling=constrained,axes=none,view=[0..100,0..100])):

filefolder is defined as a complete path: filefolder:="D:/TopUp/models/vergelijking/":
And pol is a pol:=plottools[polygon](polygonlist,color=grey): 

This works fine when I use it directly in a Maple worksheet.

However, if I save...

We want to fit

f(x) = a_0 + a_1 *x + a_2 * x^2 + ... + a_n * x^n

to the data (x_i,f(x_i)) for i = 0 ... n.

It will give rise to the following system

[ a_i ] = [A]^{-1} * [ f(x_i)].

Here [a_i] = [ a_1 a_2 a_3 ... a_n], 

[A] = [ 1 x_0 x_0^2 ... x_0^n ; 1 x_1 x_1^2 ... x_1^n ; 1 x_2 x_2^2 ... x_2^n ; ... ; 1 x_n x_n^2 ... x_n^n]

and 

[f(x_i)] = [f(x_0) f(x_1) f(x_2) ... f(x_n)].

I want to know how to take the fourier transform of a solution to an IVP obtained using dsolve/numeric and consequently plot the transform. any ideas?

I have an animated spacecurve with arrow:

restart:with(plots):

p4:=animate(arrow,[<cos(tend),sin(tend),0.9 tend>,<-cos(tend),-sin(tend),0>,color=red],tend=0..50,axes=boxed,frames=150);

I succeed in putting text at basis of arrow:

l3:=animate(textplot3d,[[cos(tend),sin(tend), 0.9 tend, 'basis'],color=black,align={BELOW},font=[TIMES,ROMAN,14]],tend=0..50,frames=150);

I like tot put text at the end of the arrow. This is my 'progress':

Hello evrybody,

my first question here.

i'm a engineer studend in electronic and i'm working on the inverted pendulum problem at my university.

so i need to use the lagrange way to get my equations in the good form.

i have this equations :

Hello,

I have a plot of a cylinder with points singled out.

Firstly, the points are currently given by (x,y,z) but I would like them in terms of (r,θ,z), how can I do this?

Secondly, I was wondering how to assign to each point an [i,j] value? So you could have r[i,j], θ[i,j] and z[i,j] as matrices of the points?

Points_on_the_initia.mw

Maple is saying 'Error, Vector index out of range'. Can you see how maple executes all steps, so I can see where exactly the problem is?

http://www.maplesoft.com/applications/view.aspx?SID=33040&view=html

it can calculate from numeric data, is it the end?

where do multiset coming from?

if given a multiset, and calculate its power sums, then i express this power sums in terms of symmetirc polynomials, what is the purpose of this?

I often have to create density plots with many (thousands of) points. Hence the first thing I do when I install a new version of maple on linux, is edit dir_of_maple/bin/maple so that

JAVAHEAP=512

is instead

JAVAHEAP=4096

I have done this for years and never have any memory problems. But recently I have sent my code to someone who runs Windows and they seem to have "out of memory" issues when trying to do density plots of large datasets.