What is the newest installment of 'Random Thoughts' on Physics Forums?

[WWGD]

I like the new world. My MS email account thinks I'm Swedish after years taking me for Spanish, my AOL account thinks I'm a republican living in Iowa, FB thinks I'm an American abroad, and probably has denounced me already at the IRS, and only Google leaves me alone. Isn't that funny? Google? They only try to figure out which music I like most, desperately and in vain. If you can't convince them, confuse them.

I keep getting ED promos, tooth decay repair and offers to help me finish my high school degree.

 

[WWGD]

My confusion is of a different nature: what's an app? You need an app ( a nap), you want an app with your meal ( an appetizer), or the standard , application. If my doctor asks me if I want an app, I will assume he means an appendectomy. I am saying no to that.

 

[fresh_42]

I keep getting ED promos, tooth decay repair and offers to help me finish my high school degree.

I haven't checked what they advertise. Especially the Swedish ads are a bit wild. AOL is easy to explain. It all started with the Obama campaign when I clicked through a few emails (from either side) just to see how they run their campaigns. Senator Ernst is doing her best to keep me republican ever since (Rep. Duckworth (D) has given up on me). I once signed in on a dating site (more than 20 years ago) and I still get "offers" from them and surprisingly some other clearly dubious sites.

 

[WWGD]

I haven't checked what they advertise. Especially the Swedish ads are a bit wild. AOL is easy to explain. It all started with the Obama campaign when I clicked through a few emails (from either side) just to see how they run their campaigns. Senator Ernst is doing her best to keep me republican ever since (Rep. Duckworth (D) has given up on me). I once signed in on a dating site (more than 20 years ago) and I still get "offers" from them and surprisingly some other clearly dubious sites.

I make it a point to have non-gmail accounts because it seems google is good at integrating all your online ( and, worse, otherwise) history.

 

[fresh_42]

I make it a point to have non-gmail accounts because it seems google is good at integrating all your online ( and, worse, otherwise) history.

I think it's a Don Quijote fight against windmills. Most immediate is FB in their responses to my surf habits. My gmail account is practically free from any spam. I regularly delete my google history, so it's merely youtube which tries to guess my taste. Well, they offer Springsteen and Chuck Berry, so nothing wrong with it.

 

[mathwonk]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

 

[WWGD]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

That's why/how laziness can be helpful. Just use x-x=0.

 

[WWGD]

I think it's a Don Quijote fight against windmills. Most immediate is FB in their responses to my surf habits. My gmail account is practically free from any spam. I regularly delete my google history, so it's merely youtube which tries to guess my taste. Well, they offer Springsteen and Chuck Berry, so nothing wrong with it.

You tube has offered me just about every type of music; a few times even things I liked.

 

[fresh_42]

As a student, (at Harvard no less), when asked to show the sum of two irrationals is not nec. irrational, I started from a non - repeating decimal, like .141592653589793..., then created another decimal, also non - repeating, say .858407346410206..., whose decimals added to 9 with each decimal I started with. It finally dawned on me, that starting from an irrational x, I had created the irrational number 1-x. Only afterwards did I think of just using -x. And I was in the "honors" class! So I empathize to some extent with your student on this problem.

I remember an exam when the student was asked about linear functions. She perfectly repeated the definition, but when asked to give an example, she struggled. I remember that I thought: "0." - "Do you know a nontrivial one?" - "1." However, I wasn't asked.

 

[WWGD]

I remember an exam when the student was asked about linear functions. She perfectly repeated the definition, but when asked to give an example, she struggled. I remember that I thought: "0." - "Do you know a nontrivial one?" - "1." However, I wasn't asked.

Good luck with that. I got so confused ; my students too, trying to explain the difference between a linear and an affine function.

 

[mathwonk]

When I took linear algebra it was all abstract, sort of like in Artin's Geometric algebra, and often in infinite dimensions. When I finally taught it, I was amazed that if you use matrices, in finite dimensions you can actually calculate most of that stuff!

 

[WWGD]

When I took linear algebra it was all abstract, sort of like in Artin's Geometric algebra, and often in infinite dimensions. When I finally taught it, I was amazed that if you use matrices, in finite dimensions you can actually calculate most of that stuff!

Infinite dimensions? Isn't that functional analysis?

 

[mathwonk]

I guess so, it was calculus according to Lynn Loomis, on Banach spaces. We learned that the derivative of f at p is a bounded linear map T such that the map f(x+p)-f(p) - T(x) is "little-oh" in the sense that its norm, divided by the norm of x, goes to zero with x. is that right? most of the class members were freshmen, but not me. the unoffical text was Dieudonne's Foundations of modern analysis.

 

[WWGD]

I guess so, it was calculus according to Lynn Loomis, on Banach spaces. We learned that the derivative of f at p is a bounded linear map T such that the map f(x+p)-f(p) - T(x) is "little-oh" in the sense that its norm, divided by the norm of x, goes to zero with x. is that right? most of the class members were freshmen, but not me. the unoffical text was Dieudonne's Foundations of modern analysis.

I remember seeing the example of a discontinuous( unbounded) linear map.

 

[mathwonk]

me too, maybe if e1,e2,... is an infinite sequence of unit length independent vectors, and T(ej) = j, then although ej/j-->0, T(ej/j) = 1, for all j.

(It seems I still know Banach spaces better than I know trig and one vbl calc.)
My conclusion was that since, given how I was taught, I did not understand anything, if one wants to understand, one should be taught the opposite to how I was. Of course that also may not be sufficient. Maybe it was actually my fault that I did not think and work hard enough, ask questions, look for examples? Nahhh...

 

[WWGD]

me too, maybe if e1,e2,... is an infinite sequence of unit length independent vectors, and T(ej) = j, then although ej/j-->0, T(ej/j) = 1, for all j.

(It seems I still know Banach spaces better than I know trig and one vbl calc.)
My conclusion was that since, given how I was taught, I did not understand anything, if one wants to understand, one should be taught the opposite to how I was. Of course that also may not be sufficient. Maybe it was actually my fault that I did not think and work hard enough, ask questions, look for examples? Nahhh...

I understood it a bit differently. The norm of the operator is the sup over the unit ball. We normalize a countable subset of the basis so that ||e_i||=1 . Then we declare T(e_i)=i (Standard norm on the Reals/Image), so that the Sup of the images goes to $\infty$. But I like your way too, to have more than one approach to see it be more understandable.

 

[WWGD]

I hear constant wailing by dogs every time they hear firemen alarms. Wonder if something could be done about it. I am not a crazy Peta person but they seem to go through a bad time.

 

[Jonathan Scott]

I hear constant wailing by dogs every time they hear firemen alarms. Wonder if something could be done about it. I am not a crazy Peta person but they seem to go through a bad time.

I think they probably enjoy the opportunity to sing along. I knew a dog who would start the moment he saw a violin case being opened, even before playing started. He definitely hated being shut out of the room.

 

[WWGD]

More on absurdly accurate (human) population counts:
The population of Mexico is 130,009,263...wait! , I was just notified 2 people just died and 4 were born. Make that 130,009,265. Why don't they just tell you130 million, or at least 130,009,000?

 

[fresh_42]

More on absurdly accurate (human) population counts:
The population of Mexico is 130,009,263...wait! , I was just notified 2 people just died and 4 were born. Make that 130,009,265. Why don't they just tell you130 million, or at least 130,009,000?

https://www.umrechnung.org/weltbevoelkerung-aktuelle-momentane/weltbevoelkerungs-zaehler.htm

 

[WWGD]

https://www.umrechnung.org/weltbevoelkerung-aktuelle-momentane/weltbevoelkerungs-zaehler.htm

I get that, but that is a counter intended to be accurate. I am talking about almanacs and websites like Worldometer Corona who use these ultra-accurate counts.

 

[WWGD]

Sorry if this is trivial: If I have an Excel spreadsheet: Is it possible to alphabetize ( " A to Z") several columns simultaneously? I remember once trying to do that and only one column was alphabetized, screwing up the whole spreadsheet. The process of alfa is clearly not reversible unless you notice right away and do a 'Ctrl+Z".

 

[Ibix]

Not without VBA, as far as I know. You can sort multiple columns in the sense that you could have a surname column and first name column and sort the table by surname then first name (i.e., Smith, Jane comes before Smith, John but after Jones, John), but not both columns independently (i.e. so that Jane comes before both Johns and Jones comes before both Smiths).

 

[Ibix]

If anyone knows a way, please do say. There have been a few times it would be useful and I've had to resort to jiggery-pokery due to not being able to do this kind of sort.

 

[WWGD]

Not without VBA, as far as I know. You can sort multiple columns in the sense that you could have a surname column and first name column and sort the table by surname then first name (i.e., Smith, Jane comes before Smith, John but after Jones, John), but not both columns independently (i.e. so that Jane comes before both Johns and Jones comes before both Smiths).

Thank you. I am not sure I understood your reply well. Say I have names in the order A,C,B and their corresponding last names in the order D , F,E. (Meaning full names are A+D, C+F, B+E) Can I sort , while keeping the match between names and last names, so that we end up with names column in the order A,B,C and last names in the order D,F,E ? ,i.e., the match between names and last names is preserved? Sorry if I misunderstood you.

 

[Ibix]

Thank you. I am not sure I understood your reply well. Say I have names in the order A,C,B and their corresponding last names in the order D , F,E. (Meaning full names are A+D, C+F, B+E) Can I sort , while keeping the match between names and last names, so that we end up with names column in the order A,B,C and last names in the order D,F,E ? ,i.e., the match between names and last names is preserved? Sorry if I misunderstood you.

Yes. So:

Smith	John
Jones	John
Smith	Jane

can be sorted to get

Jones	John
Smith	Jane
Smith	John

So we've sorted on surname, and used first name to break any ties, if that makes sense. What you can't do in one go is sort the columns independently (breaking the links between first name and surname). So you can't get this:

Jones	Jane
Smith	John
Smith	John

Or, at least, I don't know a way to do it except the obvious select each column one at a time and sort it on its own.

 

[WWGD]

Yes. So:

Smith	John
Jones	John
Smith	Jane

can be sorted to get

Jones	John
Smith	Jane
Smith	John

So we've sorted on surname, and used first name to break and ties, if that makes sense. What you can't do in one go is sort the columns independently (breaking the links between first name and surname). So you can't get this:

Jones	Jane
Smith	John
Smith	John

Or, at least, I don't know a way to do it except the obvious select each column one at a time and sort it on its own.

Excellent, Thank you. After a major screw up in which I shifted down a cell containing cell phones and the last digit of the phone number was shifted by 1 , as part of a pattern, I thought it would be a good idea to ask:

I had a phone number , say 407963225 in cell E41 , but was actual part of row 42, so needed to be moved down to E42. So I selected the cell , moved it down by one row and ended up with phone number 407963226=407963225+1 ; Excel somehow thought in shifting the cell down I was extending a pattern. Happened a few times. Took me a few hours to repair. Point is recent carelssness cost me a good amount of time, so I thought I'd be extra careful. Thanks again, Ibix.

 

[WWGD]

Excellent, Thank you. After a major screw up in which I shifted down a cell containing cell phones and the last digit of the phone number was shifted by 1 , as part of a pattern, I thought it would be a good idea to ask:

I had a phone number , say 407963225 in cell E41 , but was actual part of row 42, so needed to be moved down to E42. So I selected the cell , moved it down by one row and ended up with phone number 407963226=407963225+1 ; Excel somehow thought in shifting the cell down I was extending a pattern. Happened a few times. Took me a few hours to repair. Point is recent carelssness cost me a good amount of time, so I thought I'd be extra careful. Thanks again, Ibix.

I remember once meeting someone interning in a company on Excel. As in 'So and So, the Excel Intern'. Seemed strange, but now I can see how/why that can be.

 

[Ibix]

After a major screw up in which I shifted down a cell containing cell phones and the last digit of the phone number was shifted by 1 , as part of a pattern, I thought it would be a good idea to ask

Ugh. I really hate Excel for doing exactly this kind of smart-but-not-smart-enough kind of thing. But I still have to use it for far too much stuff because I've no better general purpose tool available...

 

[etotheipi]

 

[WWGD]

I finally realized this guy meant Coup D'etat and not Crudite. Conversation started making sense.

 

[WWGD]

View attachment 281766​

Wonder how my former history prof ended up in your museum.

 

[WWGD]

Keep hearing everyone saying older music was better. I suspect it has to see with the fact that bad songs from long ago did not survive, so those who did make it seem better. Survivorship bias. Edit: Just like those who say : Look at how well-adapted all animals are. No, you're seeing those who are well-adapted , so that they made it. Same for songs.

I mean, I am nowhere near being a hip guy, going to the latest clubs, but I don't remember hearing any music from 90s and on, being piped in in any public place. All 60s-90s.

 

[WWGD]

Ok, a special on pickles, so I bought them and will try them on my sandwich. And at the German place, they're advertising The Best of the Wurst. Getting the specials is a way of randomizing the food I eat, which is supposedly a good, healthy thing to do; to rotate nutrients.

 

[WWGD]

Ok, a special on pickles, so I bought them and will try them on my sandwich. And at the German place, they're advertising The Best of the Wurst. Getting the specials is a way of randomizing the food I eat, which is supposedly a good, healthy thing to do; to rotate nutrients.

What part are you skeptical about, Keith? You know I take some license with my entries here ;).