/sci/ - Science & Math » Thread #12253434

224KiB, 1080x1350, 1602854813499.jpg

View Same Google iqdb SauceNAO

Directional derivative vs divergence

Anonymous Tue 20 Oct 18:11:00 2020 No.12253434 View Reply Original Report

Quoted By: >>12253561 >>12253596 >>12253683 >>12253710 >>12253999 >>12255326 >>12255898 >>12255950 >>12255991

Why does the order of dot product matter when dealing with the del operator? Does this mean that order matters for multiplication for d/dx? If order does matter for multiplication with d/dx, why?

Anonymous

Anonymous Tue 20 Oct 2020 18:29:40 No.12253529 Report

Quoted By:

Idk, more plox

Anonymous

Anonymous Tue 20 Oct 2020 18:30:46 No.12253536 Report

Quoted By: >>12253561

Doesn't order not matter for dot products?

Anonymous

Anonymous Tue 20 Oct 2020 18:35:15 No.12253561 Report

Quoted By: >>12253599

>>12253434
del dot del is just a notational convention.
It's not an inner product. Inner products return scalars.

>>12253536
Almost.
<y, x> is the complex conjugate of <x,y>

Anonymous

View Same Google iqdb SauceNAO BOOBAS.jpg, 26KiB, 598x574

Anonymous Tue 20 Oct 2020 18:42:18 No.12253596 Report

Quoted By: >>12253677

>>12253434

Anonymous

Anonymous Tue 20 Oct 2020 18:42:52 No.12253599 Report

Quoted By: >>12255938

>>12253561
Does this convention apply outside of this situation thought? For example having u multiplied by partial derivative d/dx results in u(d/dx) but vice versa it is du/dx? Or is it specifically in the case of the del operator?

Anonymous

Anonymous Tue 20 Oct 2020 18:58:13 No.12253677 Report

Quoted By:

>>12253596
based booba poster

Anonymous

Anonymous Tue 20 Oct 2020 19:00:02 No.12253683 Report

Quoted By:

>>12253434
scientifically speaking, hummina hummina AWOOGA

Anonymous

Anonymous Tue 20 Oct 2020 19:06:43 No.12253710 Report

Quoted By:

>>12253434
are boobs just frontal ass?

Anonymous

Anonymous Tue 20 Oct 2020 20:24:36 No.12253999 Report

Quoted By: >>12255965

>>12253434
Don't think of the dels as the same.
Don't think of the dot as an operation.
Gradient is just del. It turns scalar fields into vector fields. S->V
Divergence is (del dot). It turns vector fields into scalar fields. V->S

grad div has type V->S->V
div grad has type S->V->S

Anonymous

Anonymous Wed 21 Oct 2020 02:36:28 No.12255326 Report

Quoted By: >>12255901 >>12255957

>>12253434
imagine the smell

Anonymous

Anonymous Wed 21 Oct 2020 07:11:54 No.12255898 Report

Quoted By: >>12255962

>>12253434
It's just notation, using the horrendous "intuition" that \nabla is a "vector of derivative operators". Clearly, it's very bad notation, because this question is constantly asked (not necessarily on /sci/, but in general).

But then again, we can't be assed to teach engineers proper operator theory just so they can learn some basic fluid mechanics, so I guess the confusion will live on...

Anonymous

Anonymous Wed 21 Oct 2020 07:13:26 No.12255901 Report

Quoted By:

>>12255326
piss lavender

Anonymous

Anonymous Wed 21 Oct 2020 07:30:30 No.12255938 Report

Quoted By:

>>12253599
d/dx and del operate the same way.
The order matters if x-dependent functions are involved.

Anonymous

Anonymous Wed 21 Oct 2020 07:36:27 No.12255950 Report

Quoted By:

>>12253434
I can't even imagine what those tiddies would look like

Anonymous

Anonymous Wed 21 Oct 2020 07:38:48 No.12255957 Report

Quoted By:

>>12255326
conceptualize the aroma.

Anonymous

Anonymous Wed 21 Oct 2020 07:40:04 No.12255962 Report

Quoted By:

>>12255898
it works as it’s supposed to, and does no harm besides inducing some autistic screeching due to incorrect terminology.

Anonymous

View Same Google iqdb SauceNAO ..2.jpg, 39KiB, 600x600

Anonymous Wed 21 Oct 2020 07:41:07 No.12255965 Report

Quoted By:

>>12253999

Anonymous

Anonymous Wed 21 Oct 2020 07:50:06 No.12255991 Report

Quoted By:

>>12253434
x * df/dx is different from d/dx (x*f)

Capcode	All Only User Posts Only Moderator Posts Only Admin Posts Only Developer Posts
Show Posts	All Only With Images Only Without Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

Your latest searches