I'm having a trouble with this trivial code in Maple. The output is, well, ... stupid ! I'm askingMaple to do a vectorial sum and substraction of 5 cross products, and what I get is silly : a sum of vectors, but it doesn't give the total vector ! What the hell !?

with(linalg):
with(DEtools):

ly := 9.4607*10^15:
M0 := 1.99*10^30:

M1 := 2.20*M0:
M2 := 2.00*M0:
M3 := 1.50*M0:
M4 := 3.00*M0:

r1 := [-3, 3, 0]*ly:
r2 := [0, -2, 0]*ly:
r3 := [1, 2, 0]*ly:
r4 := [6, 4, 0]*ly:

v1 := [25, 15, 0]*10^3:
v2 := [20, -20, 0]*10^3:
v3 := [-5, -25, 0]*10^3:
v4 := [15, 0, 0]*10^3:

Mtot := M1 + M2 + M3 + M4:

rcm := (M1*r1 + M2*r2 + M3*r3 + M4*r4)/Mtot:
vcm := (M1*v1 + M2*v2 + M3*v3 + M4*v4)/Mtot:

Ltot := crossprod(r1, M1*v1) + crossprod(r2, M2*v2) + crossprod(r3, M3*v3) + crossprod(r4, M4*v4) - crossprod(rcm, Mtot*vcm);

I have done other codes with vectors like these, using the crossprod command, and they are all working great.  So I don't understand what is going on here.  I'm using Maple 13.

I'm not a strong user of Maple, so I may have done a simple mistake somewhere, but I really don't see what and where. So what is wrong with this Maple code ?

Dear sir,

in the program boundary conditions D(f)(0)=0 doesn't showing result but when use d(f)(0)=1 it will execute, why is this can you explain this ?program.mw
 

Hi MaplePrimes,

As an amataeur with this computer tool, I want to know the arrow notation.

For example " l -> 8*l ".

a_quandry_MaplePrimes.mw

I'm sure this easy question is okay.

Regards,

Matt

HI Maple primes.  We try to make sense of 'rsolve' in the Maple world.  What is command for source code?

Regards,

Matt

Hi Mapleprimes,

We know that '' rsolve '' is a recurrence equation solver.  It is more than an expression simplifier.

Congratulations to the Maple computer algebra team for creating such a great computer tool.  simply want to know more.

rsolve_on_May_16_2017.pdf

Surely there are many steps to determine the values to place.

Regards,

Matt

Hi Mapleprimes,,,

We see Maple file.

We are aware of oeis.org/A103435/

sequence data

Where F(m)=2*F(m-1)+4*F(m-2).

Goal - to increase refereed database.

M.mw

Regards,

Matthew Charles Anderson

Legislative Assistant

Oregon USA

Age 42.

Dear please check once it showing an error program.mw as intial value is not conververging

Dear sir,

I tried to solve a fourth order problem. But I got the error message as better to use midpoint method. Can I know what is midpoint method and here I uploading the problem please verify it if I did anything mistake?program.mw

Hi Mapleprimes,

I wrote some quick maple code -

for a from 1 to 10 do
if isprime(a)=false then print(ifactor(a)) else print('1',a) end do;
end do

I want to use the factors command to reproduce oeis.org/A027750/

Can anyone help me with this?

Regards,

Matt

Hi everybody,

The Collatz conjecture can be used to give students a taste of a topic in Number Theory.  See the Wikipedia article for a good explaination.

https://en.wikipedia.org/wiki/Collatz_conjecture

Also, a conjecture is something that is probrably true.  Enjoy my little Maple procedure.  (in .mw and .pdf forms)

Collatz_third_time.mw

Collatz_third_time.pdf

Comments are appreciated.

Matt

HI MaplePrimes,

Is the Goldbach Weak Conjecture proven?

Consider odd primes p, q, and r.  The question is, Is the sum p+q+r sufficient to reach all odd numbers greater than 9?

See - 

https://en.wikipedia.org/wiki/Goldbach's_weak_conjecture

I tried an example.

looping_for_Goldbach_Weak_Conjecture_8.mw

looping_for_Goldbach_Weak_Conjecture_8.pdf

Regards,

Matt

My code :

> restart; with*PDEtools;

> PDE := diff(u(x, t), `$`(t, 2)) = 4*(diff(u(x, t), `$`(x, 2)));

> pdsolve({PDE, u(x, 0) = cos((1/2)*x), (D[1](u))(x, 0) = 0}, u(x, t));
 

And i get Error, (in pdsolve/BC) invalid input: indets expects 1 or 2 arguments, but received 3.Please help me find my Error.Thank you!!!

Hello, Sir 

I tried to execute the program for a set values for more than one parameter but it is not existing, please can you do a favor for me in this case, that is how to write a program to execute set of values for more than one parameter at a time and how to plot the graph?

stretching_cylinder_new.mw

HI MaplePrimes.com and other watchers,

Please enjoy the attaced files about combinatorics.
You may already know what '4 choose 3' is.

an_excercise_in_combinatorics.mw

an_excercise_in_combinatorics.pdf

Hopefully this can be useful to the casual mathematical observer.

Regards,

Matt

I am trying to plot f=[r^2 *cos(theta)+r*sin(theta)],as a DensityPlot[] in polar coordinates.

here r is a function of theta, r=r1(θ)..r2(θ) , for this reason, I have a problem to plot f in density plot

f=[r^2 *cos(theta)+r*sin(theta)];

r1(theta)= 0.3+0.1*cos(theta);
r2(theta)= 0.5+0.1*cos(theta);

display(changecoords(densityplot(f, r =r1(theta)..r2(theta), theta = 0 .. 2*Pi, style = patchnogrid, colorstyle = HUE), polar), axes = box, orientation = [270, 0], labels = [x, y, ``]);

(Error, (in plots/densityplot) bad range arguments r = .3+.1*cos(theta) .. .5+.1*cos(theta), theta = 0 .. 2*Pi )