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Mar
28
comment How can I simplify a triple integral with exponentials?
@smtux Why do you have to change your code to handle these assumptions? Just use the code I posted. Does it have to be all in one line? To make it easier, I updated the answer and pasted all the code in one cell. So just use this cell instead of yours, that is all.
Mar
28
comment 4th-order Runge-Kutta method to solve a system of coupled ODEs
This post has code for Runge-Kutta solving-a-system-of-odes-with-the-runge-kutta-method
Mar
28
comment 4th-order Runge-Kutta method to solve a system of coupled ODEs
Can you show the equations themselves you are trying to solve with the initial/boundary conditions? If you do not know latex, you can scan them from the book and paste the image.
Mar
28
comment How can I simplify a triple integral with exponentials?
@smtux breaking the multiple integration to sequences of integration just help show where Mathematica needs help. The above just breaks the process to see what was needed (what assumptions). Sometimes if a definite integral hangs, finding the indefinite integral then using limits with assumptions helps as in this case.
Mar
27
comment How can I simplify a triple integral with exponentials?
That can't be what you typed. You have syntax error. No closing ")" error.
Mar
27
comment Is there a way to create a two column page layout in a notebook?
Use Mathematica for computation and graphics, which is what it is best at, and use Latex for typesetting which is what it is best at.
Mar
25
comment Solving differential equations with Wolfram Mathematica
There is an extra i comparing to the textbook it is normal to rename the whole thing to a constant. i.e. $(c_1-c_2)i$ is renamed to new constant, say $C[1]$. So the $i$ goes with the constant and is not left out. This is standard way of reformulating solutions to ode's so the solution is written in terms of trig functions.
Mar
25
comment Solving differential equations with Wolfram Mathematica
Just because two mathematical expressions appear different, this does not mean they do not represent the same thing.
Mar
24
comment Clicking phase plane with mouse
@David this is strange. On my system (windows 7, V 10.02) I do not see any blinking.
Mar
24
comment Clicking phase plane with mouse
@David I do not see any blinking cell problem? If you mean the cell side become black when you click on the Manipulate, then that is expected ofcourse as Manipulate is updating (busy). If you mean when you readjust the notebook size, then added PlotTheme->None fixes this. I updated.
Mar
24
comment selection based on values of other list
In the old days, we used to code like this: list1 = {{1, 2, 3, 4}, {1, 2, 5, 6}, {2, 3, 4, 5}, {5, 6, 7, 8}}; list2 = {1, 2, 3, 4}; N0 = Length[list1]; M0 = Length[list2]; lst = {}; For[i = 1, i <= N0, i++, { candidate = list1[[i, 1]]; found = False; For[j = 1, j <= M0, j++, { If[list2[[j]] == candidate, found = True; Break[] ] } ]; If[found, AppendTo[lst, list1[[i]]]] } ]; lst which gives {{1, 2, 3, 4}, {1, 2, 5, 6}, {2, 3, 4, 5}} nowadays functional programming took all the fun away ;)
Mar
24
comment Dynamic updating of Slot number
Why not simply Manipulate[ sel = {0, Pi/2}; Sin[sel[[n]]], {n, Range[2]} ]
Mar
24
comment Dynamic updating of Slot number
@GordonCoale I thought that is what op wanted. May be I did not read the question carefully.
Mar
24
comment Dynamic updating of Slot number
Try Manipulate[ Sin[# n] & /@ {0, Pi/2}, {n, Range[2]} ]
Mar
24
comment Nullclines and equilibrium point labels
@David added tooltip
Mar
23
comment Strange result of an infinite sum
As for the second case, Mathematica result is not the same as Maple. Maple also gave zero. Screen shot: !Mathematica graphics so there is possibility Mathematica result is wrong for the second case.
Mar
23
comment Strange result of an infinite sum
I tried it on Maple, and it also gave zero. Screen shot: !Mathematica graphics so this means it is highly unlikely the result by Mathematica is wrong.
Mar
23
comment Strange result of an infinite sum
I think o[1]=0 is correct (nice choice of function name btw ;). You have a product that starts at i=0 and when i=0 and a=1 you get Product[1^2-1] for the first element, which is zero. Hence the whole product becomes zero, since zero times anything is zero. Then the sum of zeros is zero.
Mar
23
comment NdSolve problem :NDSolve::ndode: Input is not an ordinary differential equation
what does [Mu]0 = 4 [Pi] *hbar^2*a/m *10^(6) mean? [Mu] times zero? If you are used 2D math notations, you need to copy the code as input form from your cell and paste here. Otherwise, no one can read the above as is. These are the steps: Put all the code in one cell. Make a copy of the cell. Then select the cell and convert to inputForm. Then copy the result as text, then paste it here.
Mar
23
comment (NDSolve) Non-linear 2nd order ODE, regular singular point (looking for good methods for this problem)
at r=0 is a regular singular point. I though the classification of ordinary, regular, and not regular singular points applies to linear ODE's. But what you have is non-linear ODE's. I could be wrong, but I remember something like this from a class.