Derive the orbit of the Moon around the Earth by doing a Verlet algorith of Molecular Dynamics simulation. Use one hour for your step τ. Place the stationary Earth at the origin of the Cartesian system. For initial conditions, use the position and the speed of the Moon when it is at its apogee (furthest from Earth). Plot the orbit.

Dear friends.

I need a simple approach for reading a specified line of a text file.

FileTools[Text] module allows to count the lines. By sequential reading of lines it's possible to reach any position in the file. But for large file this takes a lot of time.

FileTools[Position] allows to set/get position in the file, but the position is counted in bytes.

Are there any workarounds for the problem or the use of Database Package is more preferable?

Using with(Physics):

On an initial condition setting for using dsolve when I do D(theta)(0) it returns  0=0

I'll have to check tonight if it's a mistake on my part.  But perhaps that is supposed to happen.

Hello,

please help check what's wrong with this code. I need the analytic solution and convert to Bessel but return error. Here is the worksheet ID_1.mw

Best regards.

Hi,

this code not answer:

> whit*evalf; tx := evalf((t1+t2)*(1/2));
> t1 := 326*40; t2 := 327*40;
> y1, y2 := eval([y1, y2], Ns(t1), Ns(t2));
>while (t1 < tx) and (tx < t2) do:
yx := rhs(Ns(tx)[c2]):
if yx > 0 then
y2 := yx: t2 := tx:
else
y1 := yx: t1 := tx:
fi;
od;
>Tx = evalf(tx);
> Hx := floor((1/3600)*tx):
> Mx := floor((tx-3600*Hx)*(1/60)):
> Sx := tx-3600*Hx-60*Mx:
> Hx, Mx, Sx;
> XS := [seq(X[i], i = 0 .. 328)]: YS := [seq(Y[i], i = 0 .. 328)]:
> VxS := [seq(Vx[i], i = 0 .. 328)]: VyS := [seq(Vy[i], i = 0 .. 328)]:
> save(G,Mz,Xs,VxS,VyS, 'orbit.sav'):

 can you help me?

This might seem easy but i am a total beginner in Maple and i really need to know how to do this. If i have an expression like this:

X^2 + 3*y + 3*z + X^7

where (y) and (z) are constants of unknown values. I need to integrate the expression over an interval for example (from 1 to 10) so that the answer would still be in terms of (y) and (z).

Would anyone please help me and give me the right expression for writing this on Maple?

Thanks in advance.

(a) Show that if {an} ∞ n=1 is Cauchy then {a 2 n} ∞ n=1 is also Cauchy. (b) Give an example of a Cauchy sequence {a 2 n} ∞ n=1 such that {an} ∞ n=1 is not Cauchy

Show that 2^3 + x ^2 − 3x + 2 is O(x ^3 ).

guys , i have a metric and i want to define a componenets of a tensor and then obtain its covariant derivative with respect to a metric, what is your idea ?

N_1=-A(r)^1/2 , A_2=A_3=A_4=0 , what is D_[nu] N_1 =?

 in general i want to define N[1]=-A(r)^(1/2) and N[2] = N[3]= N[3] = N[4] = 0 And define F[mu, nu] = 2*(D_[mu] N[nu]-D_[nu] N[mu]) And define Omega[mu, nu] = 2*(D_[mu] N[nu]+D_[nu] N[mu]) and compute expression F_[alpha, beta] F_[~alpha`, ~beta ] And N_[alpha] N_[~beta`] F_[ ~alpha, ~lambda ] Omega_[beta, lambda])

i have problem with this how to difine this tensorial terms and how to compute them.

Covariant.mw

thxxxx

Hi EveryOne!

In the the answer of the question "How to find k^th root of the given matrix over finite field (at URL: http://www.mapleprimes.com/questions/203997-How-To-Find-Kth-Root-Of-The-Given-Matrix#comment215683). Carl Love helped to find k^th root of the given matrix M over GF(2^m)/f(x).

Now, I need to compute direct exponentiation of the given matrix M in finite field. (If M = [m_i,j], we say Direct Exponent (element-wise exponent matrix), M_d^k of M is a matrix whose each element is the result of exponentiation of corresponding elements of M. If k=2, then we say M_d² is a direct square matrix of M )

Please help me!!! Thank you very much.

I've seen a few maple presentations where a block of code is wrapped in a box. Does anyone know how this is done?

Hi, I'm trying to solve a system of equation and I keep getting this error. Could anyone help me figure out what I'm doing wrong?

My problem is:

> alpha := .3; G := 3.5; L := 6; f := 1.1;

for i to 50 do

I0 := x(z)+y[i](z); ICon := x(0) = 1, y[i](0) = 0;

for j to 50 do

i <> j;

d1 := diff(x(z), z) = -G*x(z)*y[i](z)/IC-alpha*x(z);

d2 := diff(y[i](z), z) = G*y[i](z)*y[j](z)/IC-alpha*y[i](z);

dsys := {d1, d2};

F := dsolve({ICon, op(dsys)}, [x(z), y[i](z)], numeric);

end do;

end do;
Error, (in dsolve/numeric/process_input) unknown y[2] present in ODE system is not a specified dependent variable or evaluatable procedure

Hi,

When I calculate the nullspace of a Matrix my solution comes out in a different order than Maple.  So, the question is what steps does Maple use to calculate Nullspace, ColumnSpace, and eigenvalues.  All of these are calculated by Maple in a different order that when I calculate by hand.

What I meant to say is that the answer given by for nullspace is in a different order than if I were do the same calculation by Hand.   

   this is what got calculating the Nullspace by hand ,  when Maple does the calc. It returns the answer in the opposite order

Thanks

Bill

Hello, 

     I an trying to plot a function of a single variable, which is an implicit function of another variable, i.e. I want to plot F(x(t)), given that x and t are related through the implicit constraint equation f(x,t) = 0. Is there any plot stuctures in Maple that would easily let me do this? I tried implicit plot but this seems insufficient. 

     As an example, consider plotting F = x + x^2 subject to f = x + sin(x) + ln (t) = 0. I could also write this as  a function subject o a differential constraint, as is f = diff(x(t), t) + 1/t + (diff(x(t), t))*cos(x(t)) = 0 and try to use some sort of implicit DE plotting routine. 

     Any ideas?

Thanks!

I am running Maple in a windows virtual machine, on a mac computer.

I have a number of worksheets on its disk

Windows advised me to run its error checking utility (chkdsk)

when I try and open them it gives me a number of options:

maple text

plain text 

and maple input

None of these are the same as the original files. What has happened? and how can i fix it?