The operators tag has no wiki summary.
18
votes
11answers
640 views
Generating an ordered list of pairs of elements from ordered lists
I have a pair of ordered lists. I want to generate a new ordered list (using the same ordering) of length n by applying a binary operator to pairs of elements, one from each list, along with the index ...
13
votes
5answers
646 views
Having the derivative be an operator
How do I create an operator which acts like a derivative to everything to the right of it:
for example:
$ \left( \partial_x + \partial_y + z \right ) x \psi $
How do I make that evaluate to:
$x ...
4
votes
2answers
902 views
How to find (numerical) value of a derivative at point?
I have the following function:
f[0, 0] = 0
f[x_, y_] := Exp[-(x^2 + y^2)^(-1)]
How do I find its partial derivatives at any given point, including $(0,0)$? This ...
6
votes
3answers
461 views
Using D to find a symbolic derivative
I need to do the following:
Define a function
Take the derivative of this function and have a look at the symoblic representation
Substitute in some values
With the bonus that I want to use the ...
4
votes
1answer
254 views
How to change coordinates of a differential operator?
I'm doing a basic quantum mechanics problem and am trying to learn how to do it in Mathematica. Any help would be much appreciated.
$\vec{L} = \vec{x} \times \vec{p}$
where $\vec{x}$ has ...
7
votes
1answer
254 views
How do I expand a sum?
I have a problem with Mathematica's symbolic manipulations. As an example, consider the following expression:
$$\sum _{i=1}^n -2 x_i \left(-a x_i-b+y_i\right)=0$$
How do I get Mathematica to expand ...
8
votes
2answers
178 views
Change associativity of the @ operator
The @ operator in Mathematica is right-associative by default, i.e.
f@g@h
evaluates as
f@(g@h)
Is it possible to make the ...
