Mathematica

how to solve for all integer solutions, linear
vars = {a, b, c, d, e, f}; eqns = Flatten[{ 5 a + 3 b + 2 c + 6 d + 5 e + f == 25, a + b + c <= 4, d + e + f <= 5, Thread[vars >= 0]}]; soln = {Reduce[eqns, vars, Integers] // ToRules}; Length[soln] 80 There are 80 solutions. Looking at only solutions for which all variables are non... 3 May 2010 06:34

Front-end - a strange behaviour of Plot3D
The command Plot3D[1,{x,0,1},{y,1,1}] produce a 3D plot which CONTINOUSLY ROTATE when the output cell is selected. It is like the rotation with mouse, but it is without any mouse action. I pretty sure that it is a bug, this morning Plot3D gives static picture. What it is? TIA slawek ... 4 May 2010 06:47

space between Output cels
I came across a Notebook, from a Mathematica textbook, that I really like...it has a nice background color, etc. which makes it easier to see what I'm doing....however...when you have multiple lines of code in an Input cell , e.g. 2, the first output Cell is contiguous with the Input cell....however, the next ... 5 May 2010 07:07

Evaluating a sum from terms generated by the Array
Array[((-1)^(# + 1) (x)^#)/#! &, 3, 1] // Total x^3/6 - x^2/2 + x Plus @@ Array[((-1)^(# + 1) (x)^#)/#! &, 3, 1] x^3/6 - x^2/2 + x Sum[(-1)^(n + 1) x^n/n!, {n, 3}] x^3/6 - x^2/2 + x Series[1 - E^-x, {x, 0, 3}] // Normal x^3/6 - x^2/2 + x % == %% == %%% == %%%% True Bob Hanlon ---- d... 3 May 2010 06:34

Function construction and also symmetric matrices
How about this? randomSymmetricMatrix[dimension_Integer] := Module[{a= Table[Join[ConstantArray[0, (i - 1)], {1/2}, Table[RandomReal[], {k, dimension - i}]], {i, dimension}]}, a+Transpose[a]] On Wed, 24 Mar 2010 04:40 -0500, "Diamond, Mark" <dot(a)dot.dot> wrote: Brilliant. Thank you, both Raffy and R... 3 May 2010 08:43

Evaluating a sum from terms generated by the Array function
I want to evaluate a sum from a series I created using the Array function. For example; I specify Array[((-1)^(# + 1) (x)^#)/# ! &, 3, 1 ] which gives me the following 3 terms of output: {x, -(x^2/2), x^3/6} Can anyone tell if and how I can turn these 3 terms into a sum to be evaluated? ... 3 May 2010 06:34

how to solve for all integer solutions, linear programming
Howdy, I have a small linear programming problem that I would like to solve for all integer solutions: 5a + 3b + 2c + 6d + 5e + f = 25 a + b + c <= 4 d + e + f <= 5 a,b,c,d,e,f >= 0 How can I pose this problem to Mathematica? I have looked at (and fiddled around with) the LinearProgramming func... 19 May 2010 20:29

Series acting on a symbolic function
I would like to define a custom special function in Mathematica, let me call it F[x]. I want it to behave like Sin[x], BesselJ[0,x], etc. If the argument is symbolic, I do not want Mathematica to do any special simplifications or evaluations. However, when using Series[] in an expression like Series[... F[x] .... 30 Apr 2010 06:11

Can anyone help?
I am currently using the trial version of Mathematica (no save/ export). I want to take the graph on this website: http://www.wolframalpha.com/input/?i=GDP+per+capita,+life+expectancy (you can get the Mathematica notebook file by clicking "DOWNLOAD AS: Live Mathematica") Could someone export this graph as an exc... 3 May 2010 06:34

Odd phenomenon
I did a symbolic calculation in which x,y,z were treated exactly the same. The result was three long, messy expressions, but the result for x was much simpler than those for y and z, even after FullSimplify. I then changed the expression for x into one for y (z->w,y->z,x->y,w->x) and the expression for x int... 30 Apr 2010 06:11