this post was submitted on 19 Jun 2024
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Science Memes

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[–] [email protected] 7 points 4 months ago

I use \times and redefine it as \cdot

[–] [email protected] 8 points 4 months ago* (last edited 4 months ago)
  • \cdot for vectors and in some cases, scalar variables, e.g., x \cdot y
  • \times for numbers, e.g., 2 \times 8
  • nothing for combination and scalars, e.g., 2x or xy
[–] [email protected] 15 points 4 months ago

\cdot master race. \times users should just use Microsoft Word (unless it's for a Cartesian product or for cross product, of course)

[–] [email protected] 11 points 4 months ago* (last edited 4 months ago) (3 children)

\cdot for matrix multiplication and the dot product, \times for cross product and nothing (or *, if I want to write it explicitly and have no convolution in the expression) for regular multiplication.

[–] [email protected] 2 points 4 months ago (1 children)
[–] [email protected] 1 points 4 months ago

^ for power. ** is usually in a programming setting (but it‘s usually a method and not an operator there.)

[–] [email protected] 3 points 4 months ago (1 children)

or *, if I want to write it explicitly and have no convolution in the expression

But why

[–] [email protected] 5 points 4 months ago* (last edited 4 months ago)

'*' is commonly used for multiplication in computer programming, so it's probably that. Also in your calculator app

[–] [email protected] 2 points 4 months ago

This is the way

[–] [email protected] 5 points 4 months ago

How about nothing at all

[–] [email protected] 2 points 4 months ago

Aye, why not an asterisk / * ?

It's also good for multiplying, innit?

[–] [email protected] 23 points 4 months ago (1 children)

I need 'em both. Not everything I multiply is a number.

[–] [email protected] 4 points 4 months ago

dot product vs cross product

[–] [email protected] 5 points 4 months ago

People using the cross for scalar multiplication are insane

[–] [email protected] 89 points 4 months ago (1 children)
[–] [email protected] 100 points 4 months ago* (last edited 4 months ago) (1 children)

I just downvoted your comment.

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As this is your first time receiving my downvote, I will provide reasons (listed below) to help you avoid making these mistakes again. Note that this will not be the case with future downvotes.

  • Writing variables next to each other to form words. "Y o u" is not an English word. If you want the English word "You" in LaTeX math mode, write \text{You}.
  • Your "rotation matrix" has determinant of -1, meaning it is not a rotation matrix. Propaganda promoting improper rotations will not be tolerated on mander.xyz.

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[–] [email protected] 61 points 4 months ago (2 children)

I didn't actually downvoted your comment but apprently someone did and now I look like an asshole 😢.

[–] [email protected] 8 points 4 months ago

Downvoted because it didn’t end with /s.

[–] [email protected] 39 points 4 months ago* (last edited 4 months ago) (1 children)

Honestly with a writeup like this I wouldn't be mad about it even if you did, this is excellent. I wish all my downvoted comments got this kind of attention.

[–] [email protected] 26 points 4 months ago

It’s an old copypasta from reddit haha. I modified it to add the Fediverse stuff and my complaints with LaTex and improper rotation.

[–] [email protected] 38 points 4 months ago (1 children)

\cdot all the way (except e.g. cross-product for vectors, I'm not an anarchist)

[–] [email protected] 4 points 4 months ago

Same same, cdot is nice and clear

[–] [email protected] 4 points 4 months ago* (last edited 4 months ago)

cdots is within matrices and times is used for a m \times n matrix

[–] [email protected] 1 points 4 months ago* (last edited 4 months ago) (1 children)

\cdot for vector dot products, \times for multiplying plain numbers, whatever i feel like for anything else

edit: dropped the dot in vector dot product, my bad

[–] [email protected] 3 points 4 months ago (1 children)

Vector dot products go with dot, cross with times.

[–] [email protected] 1 points 4 months ago

yeah i accidentally left that out

[–] [email protected] 20 points 4 months ago* (last edited 4 months ago)

(1)(3)(5)

Fight me. Also, one of these is a function

[–] [email protected] 1 points 4 months ago

Cries in Linear Algebra

[–] [email protected] 16 points 4 months ago* (last edited 4 months ago)

times is for cartesian product, cdot if i feel like it

[–] [email protected] 3 points 4 months ago

Depends on whether I want a scalar or vector, sine or cosine

[–] [email protected] 17 points 4 months ago (1 children)
[–] [email protected] 9 points 4 months ago

In LaTeX? You really are a rebel.

[–] [email protected] 29 points 4 months ago (1 children)

As someone that grades undergraduates, I'm happy that they not use the letter "x" to imply multiplication.

[–] [email protected] 8 points 4 months ago (1 children)

I don’t understand why we teach that to children, just to turn around and tell them not to do it a few years later.

[–] [email protected] 7 points 4 months ago

I suppose kids aren't great at centering a dot. But they could draw a six pointed * as easily as an x, it's one more line.

[–] [email protected] 4 points 4 months ago
[–] [email protected] 1 points 4 months ago