Hey folks I need some help with basic string manipulation.

Say I want to find the sum of the digits of 123

What I've been doing is the loooong way of converting 123 to a string, breaking it up into 3 seperate numbers, converting these back to their decimal value, then adding them up.

How could I make this more efficient? Is there some part of StringTools that would do this for me?

Then...

a. How to write a  proc(a,h,A,B,C) procedure which calculates the area of the projection of the pyramid OKLMS on the plane p:A*x+B*y+C*z+D=0,where O(0,0,0), K(a,0,0), L(a,a,0), M(0,a,0), and S(a/2,a/2,h)?
b.  How to write a  proc(r,h,A,B,C) procedure which calculates the area of the projection of the cone
with the base {(x,y,z): x^2+y^2<=r^2,z=0} and the vertex S(0,0,h) on the plane p:A*x+B*y+C*z+D=0?

I would like to have some help to write the maple code (hopefully compiled) for

An Exact Polynomial Algorithm for the 0/1 Knapsack Problem , Edouard Petrounevitch
http://www.optimset.com/knapsack.pdf

I think such algorithm looks promising but I am no expert when it comes to optimization :-)

Is there a function or procedure within Maple (v13) that will return the highest power of a polynomial?

Related to this, how do I determine the error return value from coeff(a,x,i) ?

TIA

Dears,  I want to generate a following matrix

g:=proc(i,k); if 86<=i<=100    then if i+1<=k<=100  then Y   end if end if end proc:

A:=Matrix(100,100,g);

Is this true (Can i use two if statments)

Could any one help me

Amr

Coon's patch defines a patch from 4 curves forming a chain. 4-examples to Coon's patch are given following worksheet. Boundary curves in the examples are constructed by parametric cubic curves (in Bezier and Hermite form). First example is in 3D and comparable to parametric bicubic surface. Rest of examples are in 2D (abstract surface) which can be described shortly as:

• 2D Example#1: 4 circular-arc like curves are combined by Coon's patch to form a circular-like region

hoping someone can help me, one of my exam prep exercises asks the following

"

Consider the equation x^2+y^2 = 2+cos(x)*sin(y). Transform the equation into polar coordinates
using the ”subs” routine, and plot the resulting equation in polar coordinates (read the helppages
of plot to find the syntax for polar plots). Evaluate an appropriate integral to find the
area enclosed by the curve.  "

I did the conversion and plotting by

I have always preferred the notation  for the derivative of

Hi all,

I have this two equations:

ap[k]=Sum(a[n]*sin(n*theta)*f(n,k),n=1..nn);

a[n]=Sum(ap[k]*g(n,k),k=1..kk);

Where ap[k] and a[n] are the unknowns.

I want to convert the two equations in the Matrix form A*X=b to solve it numerically and where X=[ap[k, k=1..kk] and a[n, n=1..nn]] and A the matrix with a rand (nn+kk,nn+kk) the coef and b the second member and a vector (nn+kk)

Thank you for any help to do this with Maple

Hi everybody,

I've got a 3d maple plot which I would like to export to a 3d cad format. There are a couple of file formats and I do not want to narrow that to one (autocad, catia, solid edge, proEngineer ...)

If this is not possible: is there any file format which I can export to, from which with a third party tool it is possible to export to 3d cad file.

Thank you

Harald

http://www.tiny9.com/u/Math5543

Fun interactive paradox about the MRB constant.

Comes with free Mathematica player.

I want to use the poset package on Maple 14 but am having trouble installing it. Could someone give me a heads up.

Thanks

Dear friends,

Here a toy version of my problem. I would like  to write several equations and to export all of them to latex. It consist

in three steps

FIRST  I would like to generate for

j1=0..2:

j2=0..2;

j3=0..2;

the equations(for all the combinations of j1, j2 and j3):

assume(a>0, b>0, c>0, d >0, Qs >0):

j1*a + j2*b + j3*c + k/d*X1 = Q1

I am unable to solve the following differential equation for u(t). I right-click and select Solve DE but it gives me an incomprehensible solution. Kindly tell me how what to do:

diff(u(t)^2, t, t)+`&x`(`&x`(alpha, u(t)), diff(u(t), t))+`&x`(beta, u(t)^3) = 0

The same equation in "String" notation:

"2*diff(u(t),t)^2+2*u(t)*diff(diff(u(t),t),t)+alpha*u(t)*diff(u(t),t)+beta*u(t)^3 = 0"

The same equation in D notation: