de := diff(theta(t), `$`(t, 2))+c*(diff(theta(t), t))+9.8*sin(theta(t))/L = 0; c := 2; L := 2;

init := theta(0) = 0, (D(theta))(0) = 4;

sol := dsolve({de, init}, theta(t), numeric, output=listprocedure);

Theta := subs(sol, theta(t));

plots[animate](plots[arrow],[[0,0],[L*sin(Theta(t)),-L*cos(Theta(t))],colour=red],t=0..5, axes=none,scaling=constrained);

these lines of codes were posted by robert Israel in one of his posts.

As I understand to plot a surface in spherical coordinates we most establish the function relationship of the radius in terms of theta and phi. Then using plot3d and specifying coords=spherical gives you surface. How does one do this for a cone:

Hi, people say that for-next loops are the worst way to apply repeated operations (why?). Assume i have the list

L:=[1,3,5,6];

and the command line that does some stuff in it :

for i from 1 to nops(L)-1 do

sqrt(5*L[i]-L[i+1]);

end do;

Whats a better way to do this? I guess map is useful here, but i cant get it to work.

How do i solve differential equations using Maple.

For example:

dx/dt+(1-cos(t))*x = exp(sin(t))

I have a nice function whose graph is approximately quadratic; the plot shows the area under it should be around 1.6

However, it seems Maple thinks the area is 0.1465

Presumably there is something simple I am doing wrong, but I can't see it.

What follows may seem strange -- it is certainly strange to me -- but I need to be able to make integration work with my functions as apposed to the built-in functions one sees in examples...

with(Student[Calculus1]);

Digits:= 64;

Hi everybody,

I am trying to convert a String from a Maplet Texttfield into a polynom to use it.

Unfortunately it is not as easy as predicted. Can anybody help me with my problem?

I allready tried this, but it did not work:

polyString := "alpha";

poly := convert(polyString, poly);

Thanks a lot.

Rainer

I'm trying to orthonormalize the set of basis vectors of the form form p(x)*exp(-x^2/2), where p(x) is a polynomial of degree less than N.

The basis I'm using for this function space is |e1> = exp(-x^2/2), |e2> = x*exp(-x^2/2), |e3> = x^2 * exp(-x^2/2), and so on.

However the GramSchmidt procedure in the LinearAlgebra package only accepts vectors.

Can someone help me to get around this, and use some procedure to orthonormalize the first four bases for this function space?

Hallo dear proffesionals of Maple

I use Debian 4.0 r3 version with gcc compiler v 4.xx

I have installed properly in my computer the Maple 11 version.

the problem is :

I'm using an old maple worksheet (Maple V) and some of the commands are now not valid (well actually most probably aren't).

Specifically numbers(string) and Digitize. Numbers() has gone to something like length() but I'm not sure about Digitize.

Would be nice if you could look these up in a command update page that lists all the commands that are valid for what versions and what they translate to in the newer versions. Be much easier than trying to trudge through and track down the history changes.

Dear all,
I'm trying to solve a difficult metric in maple. I did the following:
restart;
with(tensor):
coords:=[t, r, theta,phi]:
g:=array(symmetric,sparse,1..4,1..4):
g[1,1]:=1+mu*a(r);
g[2,2]:=-(1+mu*b(r)):
g[3,3]:=-r^2*(1+mu*b(r)):
g[4,4]:=-r^2*(sin(theta))^2*(1+mu*b(r)):
g[4,1]:=mu*omega*f(r)*r^2*sin(theta)^2*(1+mu*b(r))/c:
metric:=create([-1,-1], eval(g));
tensorsGR(coords,metric,contra_metric,det_met, C1, C2, Rm, Rc, R, G, C):
display_allGR (coords,metric,contra_metric, det_met, C1, C2, Rm, Rc, R, G, C);

June 20 2008
nj 4
Hello. I am trying to do a question on inverses of matrices, and I have chosen the fill in the blacks method. I want to produce a matrix for students to enter their answers in. I can get it to produce a matrix with the answers in but when I try and make the answers into blanks it does not work. Does anyone know how to do this? Thanks, nj.

Hi, assume i have a list

m:=[1,5,3];

My (to the core reduced) problem is:

I want to write a procedure that generates the sequence containing the listname together with its elements:

m1,m5,m3

my try:

p:=proc(L::list)

`L`||(op(L));

end proc;

This doesn't work (illegal use of a formal parameter).

What to do ?

Hi,

want to solve this equation for t but getting 'Solutions may be lost' error.

eq3 := exp(-1/k*t)*k/(1+k^2)+(-cos(t)*k+sin(t))/(1+k^2);

solve(eq3=0, t);

Solutions maybe lost.

Is this too much for the symbolic engine? Does anyone know of a technique to solve this type of equation?

Appreciated.

Does anyone here know of any Maple code (public, or in the Maple Library, or on www.mapleapps.com, etc) that implements alpha-beta pruning?

I would like to see some examples of how this can be implemented and used in Maple, and possibly learn from it.