Today I Learned

[fresh_42]

I just read that there is a program which can calculate the 19th derivative at $x=0$ in under a second of:
$$
x \longmapsto \dfrac{\sin(x^3+2x+1)+\dfrac{3+\cos(\sin(\log|1+x|))}{\exp\left(\tanh\left(\sinh\left(\cosh\left(\dfrac{\sin(\cos(\tan(\exp(x))))}{\cos(\sin(\exp(\tan(x+2))))}\right)\right)\right)\right) }}{2+\sin(\sinh(\cos(\tan^{-1}(\log(\exp(x)+x^2+3)))))}
$$
using a field extension of the real (or complex) numbers I never had heard of.

 

[mfb]

Why can't you just take a Taylor expansion up to ~20th order of all these things and then use some matrix multiplication? Some cancellation I am missing?

 

[fresh_42]

Why can't you just take a Taylor expansion up to ~20th order of all these things and then use some matrix multiplication? Some cancellation I am missing?

Wiki said Mathematica needs 6 minutes.

 

[mfb]

Maybe it tried to calculate the 19th derivative (analytically) first and then plug in x=0.
Where is that article?

 

[fresh_42]

Maybe it tried to calculate the 19th derivative (analytically) first and then plug in x=0.
Where is that article?

https://de.wikipedia.org/wiki/Levi-Civita-Körper

 

[fresh_42]

TIL that the ingredients of coke are dangerous goods to transport: one half is an acid, the other inflammable!

 

[Drakkith]

TIL that the ingredients of coke are dangerous goods to transport: one half is an acid, the other inflammable!

Something similar is true of water!

 

[fresh_42]

Something similar is true of water!

But you do not transport it separated, at least not for the purpose to drink it afterwards. I mainly wondered in which of the two parts the sugar was in, as they have said one part is the acid (the black concentrate) and the other part the aromata (clear inflammatory fluids). Do they - apart from water - also add the sugar separately?

 

[Drakkith]

But you do not transport it separated, at least not for the purpose to drink it afterwards. I mainly wondered in which of the two parts the sugar was in, as they have said one part is the acid (the black concentrate) and the other part the aromata (clear inflammatory fluids). Do they - apart from water - also add the sugar separately?

Probably. I'm almost certain they do if they use high fructose corn syrup, as one of the major reason HFCS is used instead of solid granule sugar is that it is cheaper to transport in bulk.

 

[Klystron]

[...SNIP...] Returns at the discretion of Arthur I. Platt Co. 20% re-stock or $20.00 whichever is larger. Orders under $50.00 must be paid with VISA/MasterCard or a $20.00 service charge added. International orders must be paid with VISA/MasterCard only. $20.00 per 1000 clips charge for certificate of compliance. [snip]

Today I learned the name of the company and family members who make adjustable clips to hold tools; on peg boards in my case. The company name sounded familiar when I read @Tom.G's post concerning explicit, if not concise , return instructions.
https://www.toolclip.com/

 

[Tom.G]

TIL that the ingredients of coke are dangerous goods to transport: one half is an acid, the other inflammable!

I had a neighbor that drove tanker trucks, sometimes delivering 'stuff' to coke. He said he would not drinki it because the concrete loading docks are pitted/dissolved from the occassional leak or spill.

Buyer beware!

 

[Drakkith]

I had a neighbor that drove tanker trucks, sometimes delivering 'stuff' to coke. He said he would not drinki it because the concrete loading docks are pitted/dissolved from the occassional leak or spill.

Buyer beware!

That's why you don't drink concentrated acid.

 

[rbelli1]

That's why you don't drink concentrated acid.

Or pour it directly into your eyes!

BoB

 

[Tom.G]

Or pour it directly into your eyes!
View attachment 240111

BoB

Well, Boric Acid is a pretty good fungicide, it is an old-time home remedy eye wash, gets rid of Athletes Foot and kills fungus in the nooks and crannies in damp places like the bathroom and in gloves that have been perspired in too much.

It seems that label may have a duplicate entry of Sodium Borate and Boric Acid, the latter being Sodium Borate deca-hydrate.

 

[davenn]

I had a neighbor that drove tanker trucks, sometimes delivering 'stuff' to coke. He said he would not drinki it because the concrete loading docks are pitted/dissolved from the occassional leak or spill.

Buyer beware!

bad for the teeth and the sugar puts on the kg's but as far as the acidic effects go, I have had 2 doctors tell me
"your stomach acids are so much stronger"

 

[Tom.G]

bad for the teeth and the sugar puts on the kg's but as far as the acidic effects go, I have had 2 doctors tell me
"your stomach acids are so much stronger"

"Yes but", those stomach acids contact the teeth only on hopefully rare occassions.

 

[Borg]

TIL that congressional hearings began with a Founding Father raising his hand to say, “Investigate me!” - Robert Morris

 

[OmCheeto]

TIL that Facebook has a Twitter account.

 

[Tom.G]

TIL that Facebook has a Twitter account.

Sounds rather incestuous.

 

[DrGreg]

TIL that Facebook has a Twitter account.

Sounds rather incestuous.

So that's why Facebook went down yesterday! Something like matter meeting antimatter?

 

[OmCheeto]

So that's why Facebook went down yesterday! Something like matter meeting antimatter?

After Facebook came back up, I became curious, and learned that Twitter has a Facebook account.
The odd thing was, that Twitter has ≈16,000,000 followers on Facebook.
Since I use both mainly for "news", it seemed like the equivalent of reading the Wall Street Journal to find out what is happening with the New York Times.

Likewise, Facebook has ≈13,500,000 followers on Twitter.

It really makes no sense to me, whatsoever.

 

[OmCheeto]

TIL that congressional hearings began with a Founding Father raising his hand to say, “Investigate me!” - Robert Morris

However, nobody has provided an explanation for how such a wonderful word — maladministration — vanished from the political lexicon.​

I agree. That is a wonderful word.

 

[Tom.G]

Today I Learned that the Google home page sends two encrypted packets to Google every time you leave their home page. This occurs even if you enter the new web address in the adress field without invovling Google at all. Tracking where you go? I haven't tried it on their other pages such as News.

 

[pedro the swift]

Today I learned that I don't know as much as I thought I did!

 

[jim hardy]

This occurs even if you enter the new web address in the adress field without invovling Google at all. Tracking where you go?

Somebody is.
I got spam for products related to anything i looked up until i learned to set up email filters.
My default search engine is now duckduckgo. They claim to not tell marketers where you've been

 

[BillTre]

The midge larvae I found that recently invaded one of my paramecia culture (I grow them to feed baby fish) were probably predating upon the paramecia which explains the reduction in the paramecia population.
Midges are extremely very small flies that are commonly found in fish rooms and are commonly found in drains.
Turns out their larvae can be pretty efficient predators as shown in this Science magazine video I recently found.

 

[WWGD]

I found these two social hacks to be useful :

1) don't ask someone about something they don't know. Most will resent you because this will bring up a deficiency and they will connect this discomfort with you. Of course it is not always easy to tell, but better to err by caution. Conversely, to make someone feel good about themselves and about you, ask them about something they are knowledgeable about.

2)Substitute ( or, more accurately, rephrase) the use of "sorry" by expressing gratitude to the party you're expressing your regrets*. Instead of : Sorry I am being slow understanding this, say : Thanks for your patience in waiting for me to get up to speed.

Apologizing too much makes one seem weak.

* Doesn't apply to real apologies, but to the more casual use of sorry, e.g., sorry for being late, slow.

 

[mfb]

don't ask someone about something they don't know

What do you expect to get from such a question anyway?
If you know that the person cannot help you you won't ask for help, obviously. If the person might not know the answer but still provide some help (telling you who to ask, or where to look in more detail, or whatever) then you can focus on that help.
If you don't know that the person doesn't know the answer: Well, bad luck.

 

[WWGD]

What do you expect to get from such a question anyway?
If you know that the person cannot help you you won't ask for help, obviously. If the person might not know the answer but still provide some help (telling you who to ask, or where to look in more detail, or whatever) then you can focus on that help.
If you don't know that the person doesn't know the answer: Well, bad luck.

Well, I meant to say be thoughtful about this. People ( most people) resent displaying their lack of knowledge or lack of competence, which is brought up when they are asked to do something they don't know how to do. I asked a subway /metro employee an engineering-related question even though she was not an engineer. She was surly and upset. I have had similar responses when asking under these conditions.

 

[jim hardy]

TIL how deadly is moisture around a keyboard.
This morning I got a few drops of rain on this old laptop and the keyboard quit recognizing most keystrokes.
So i shut it down with power button and dried it in the oven at maybe 115F.
Now a d and f give no response
s gives s
g gives two characters gt
h gives two characters hy
q gives two characters q.
w gives w , e gives e, r gives r,
t gives two characters gt,
and so on .
some key someplace toggles INSERT function.

So right now I'm using it with a usb keyboard plugged into the side... at least i know it's not software (can't blame this one on Windows)

Will disassemble and try a cleaning the keyboard in a day or two.

Wish me luck ?

old jim.

 

[pinball1970]

TIL how deadly is moisture around a keyboard.
This morning I got a few drops of rain on this old laptop and the keyboard quit recognizing most keystrokes.
So i shut it down with power button and dried it in the oven at maybe 115F.
Now a d and f give no response
s gives s

and so on .
some key someplace toggles INSERT function.

So right now I'm using it with a usb keyboard plugged into the side... at least i know it's not software (can't blame this one on Windows)

Will disassemble and try a cleaning the keyboard in a day or two.

Wish me luck ?

old jim.

Q.uestion

W,hy gthe oven?

I gthyink you may need gto gtegt new keyboard Jim

 

[Rive]

Wish me luck ?

Get some bags of desiccant somewhere and put them in a hermetic bag together with your (switched off) laptop for some days. If you do that fast it spares you a new keyboard.
Since you already used it for some time it is likely that you will have to replace the keyboard (keeping wet electronics powered means a lot of hygroscopic salts building up on the PCB, making any resistive contacts/switches common in small keyboards hectic).

 

[Jonathan Scott]

Will disassemble and try a cleaning the keyboard in a day or two.

If you get to the point where you expect to throw it away, you could try a generous application of WD-40 first, sloshed around inside. It's worked for me at least a couple of times in the past (although by then I'd already obtained a replacement for the water-damaged device).

 

[Klystron]

TIL how deadly is moisture around a keyboard.
This morning I got a few drops of rain on this old laptop and the keyboard quit recognizing most keystrokes.
So i shut it down with power button and dried it in the oven at maybe 115F.
...
Will disassemble and try a cleaning the keyboard in a day or two.

Wish me luck ?

old jim.

Good Luck, O-Jim! May the goddess Fortuna hold you tightly to her bosom!

Seriously, please do not put electronics in an oven. Jets of compressed air should displace moisture with less component damage; or the desicant suggestion posted above.

 

[pinball1970]

Good Luck, O-Jim! May the goddess Fortuna hold you tightly to her bosom!

Seriously, please do not put electronics in an oven. Jets of compressed air should displace moisture with less component damage; or the desicant suggestion posted above.

Hair dryer not oven