Timeline for What does the {-y,x} in this equation mean? [closed]
Current License: CC BY-SA 4.0
12 events
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| Sep 27, 2020 at 7:38 | comment | added | chyanog |
Normalize[Cross[{x,y}]]/2
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| Sep 27, 2020 at 1:22 | history | closed |
Artes bbgodfrey flinty Rohit Namjoshi Michael E2 |
Not suitable for this site | |
| Sep 27, 2020 at 0:35 | answer | added | cvgmt | timeline score: 1 | |
| Sep 26, 2020 at 21:47 | comment | added | Michael E2 | It probably represents a vector field in the plane. It is the velocity field of a uniformly rotating plate with an angular velocity of one radian per second. The whole expression is an irrotational (curl = 0) rotatory flow in which inner circles rotate faster than outer circles. | |
| Sep 26, 2020 at 20:40 | history | edited | Karsten7 | CC BY-SA 4.0 |
deleted 2 characters in body; edited tags
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| Sep 26, 2020 at 20:05 | review | Close votes | |||
| S Sep 27, 2020 at 1:26 | |||||
| Sep 26, 2020 at 19:30 | comment | added | Bob Hanlon |
{-y, x} is a List. Many operations such as Times, Plus, Divide, etc. have the attribute Listable and exploiting this attribute can simplify code. Without this attribute, the expression would have to be written as 0.5 #/(x^2+y^2)& /@ {-y, x} or Table[0.5 t/(x^2+y^2), {t, {-y, x}}]or some other equivalent.
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| Sep 26, 2020 at 19:18 | review | Low quality posts | |||
| Sep 26, 2020 at 20:40 | |||||
| Sep 26, 2020 at 19:12 | history | edited | Bob | CC BY-SA 4.0 |
deleted 82 characters in body
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| Sep 26, 2020 at 18:57 | comment | added | John Doty |
Evaluate your expressions and see what you get. Maybe try {x,y}+5 to get a hint. Note that () and {} have utterly different meanings.
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| Sep 26, 2020 at 18:47 | review | First posts | |||
| S Sep 27, 2020 at 1:26 | |||||
| Sep 26, 2020 at 18:41 | history | asked | Bob | CC BY-SA 4.0 |