734 reputation
412
bio website
location
age
visits member for 2 years, 5 months
seen Jul 18 at 10:19

Aug
12
comment Change variables in differential expressions
I do not think the chain rule is applied correctly. If I use expr[r_]:=D[b[r],r] and then evaluate expr[1/x] I get b'[x] and not -b'[x] x^2...
Aug
12
awarded  Critic
Jul
11
comment How can I get Mathematica to simplify $\Vert\{1,\sin(t),\cos(t)\}\Vert_2$ to $\sqrt{2}$?
@term-rewritica: no, you are right $\cos^2 x + \sin^2 x$ is always 1. However $|\cos x|^2+ | \sin x|^2$ is not always equal to 1.
Jun
12
accepted Incorrect results for elementary integrals when using Integrate
Jun
12
awarded  Nice Answer
Jun
6
comment How can I eliminate a function in a system of PDEs, Maple-style?
An even easier question would be: how can one eliminate a function in a set of ordinary differential equations using Mathematica.
Jun
5
awarded  Commentator
Jun
5
revised Different determinants on 2 different computers
added 1 characters in body
Jun
5
comment Different determinants on 2 different computers
@Öskå: Eigenvalues[{A,B}] solves the problem $\det(A - \lambda B)=0$ for $\lambda$; however in a numerically stable version unlike writing down the polynomial equation for $\lambda$ and then solving it...
Jun
4
answered Different determinants on 2 different computers
May
4
comment Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
Thank you: this is exactly the problem I was suffering. In fact, I did know that Flat affects the pattern matching but I did not know that for a pattern only the attributes at the time when it is set are important and that the attributes are then stored.
May
3
accepted Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
May
3
comment Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
Thanks for your question. I figured out that my example was a bit to minimal. I changed the question such that now it is clear where the infinite recursion appears.
May
3
revised Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
deleted 59 characters in body; edited title
May
3
comment Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
Sorry for the confusion. I tried to find a minimal example and it was too minimal (and I did not see that some old Attributes were still set). I edit the question...
May
3
revised Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
added 205 characters in body
May
3
comment Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
@Rojo: otimes[anything]
May
3
comment Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
@MarkMcClure: it also does not work with NonCommutativeMultiply. NonCommutativeMultiply[a] remains unevaluated.
May
3
asked Constructing a function with Flat and OneIdentity attribute with the property that otimes[a]:>a
Apr
25
revised Incorrect results for elementary integrals when using Integrate
added 23 characters in body