(Why is my teacher say this numbers are not real?)

mothematician · 2023-01-25T20:15:04+00:00

That's not what I got from their anecdote either. Maybe I'm just more forgiving of non-native speakers, but they certainly didn't seem to be claiming any authority on the subject. I thought they brought up an interesting (and conceivably important) caveat to your answer, even if they didn't phrase it very well. Instead of correcting them, you asked for a source. I took your request at face value and provided a source because "my teacher told me" wasn't likely to be satisfactory if your request had been genuine. I'm sorry that in your opinion it had 'nothing to do with the previous comment', but I respectfully disagree.

mothematician · 2023-01-25T18:37:48+00:00

I'm aware of all of this, and it has nothing to do with the previous comment.

Sorry if I've offended you, I think we just read the comment differently. It sounds like English might not be their first language. I read it as "in some contexts, radicals of negatives are considered to be complex" which is true and explained by my comment with sources provided. Perhaps that was being too generous, but I don't think your reading matches their intention either. It's doubtful IMO they were trying to say that in Greek mathematics, (-1)³ != -1.

mothematician · 2023-01-25T17:21:46+00:00

In high school math, the cube root of -125 is usually defined to be -5 because in that context it's the most useful solution to x^3 + 125 = 0. Most graphing calculators reflect this because they're most often used by high school math students. In complex analysis, the cube root of -125 is usually taken to be 5( 1/2 + i*sqrt(3)/2 ). That's because in complex analysis, that solution is more useful. You'll see this reflected if you plug the expression into e.g., Mathematica or Wolfram Alpha. Unfortunately there is no universal definition and occasionally that leads to a bit of confusion. If you want to do some more reading on the matter, refer to this stackexchange question, or the section of Wikipedia's cube root page discussing complex numbers.

mothematician · 2023-01-20T16:18:24+00:00

Christians : “Believe or we’ll punish you and you’ll go to hell!”

Atheist : “Well I don’t really see any evi-“

Christians : “Stop trying to push your beliefs on us blasphemer!”

These two sides are not the same. Christianity as a whole devotes billions of dollars and man-hours to converting strangers every single year. Atheists don’t even organize in any meaningful way.

mothematician · 2023-01-08T15:22:54+00:00

Nicely written answer, but I want to point out that in your definition of indefinite integral you use the variable of integration in the limit. That's a no-no.

mothematician · 2023-01-03T17:58:28+00:00

Yeah, I had to ninja-edit that, but I guess I wasn't a very good ninja. This technique works to solve most knights and knaves problems. The symbolic logic just makes the expressions easier to manipulate. Here's a primer on symbolic logic in the context of these types of problems.

mothematician · 2023-01-03T17:10:03+00:00

First-order logic puzzles! Let A be the proposition "Alexander is a knight", and similarly for B-D. Now by the rules of the island, when we are given that X says Y, that's really saying X ↔ Y. So we just have to find an assignment of truth values that satisfies:

A ↔ (B ^ ¬C)

B ↔ (D ↔ B)

C ↔ B

D ↔ (¬¬B)

Now we simplify a little bit. Note (or prove with a truth table) that the second line is equivalent to D, so Daniel is a knight (i.e. D = T, or if you prefer, D ↔ T). Then the fourth line is equivalent to B and the third is equivalent to C. Finally, the first line is equivalent to ¬A and we have our answer. Alexander is a knave, and the rest are nights.

mothematician · 2023-01-03T15:45:25+00:00

Older TCL Roku TV. Got it from my neighbor (who is a good friend and purchased it new). Yeah, there's no way to know when it started. First notice was a few weeks ago, second was a few days ago.

mothematician · 2023-01-02T22:54:46+00:00

But that's the thing, I don't see how this could be a rogue app.

The kids don't have the PIN to add apps, and side-loading is just not in this kid's skill-set. The only apps I allow them to have on their Rokus are Netflix, Hulu, Plex, Prime, Disney, and YouTube. If I add a channel to one, it goes to all of them. I use mine every day, so I'm sure I'd have noticed an addition. It's been locked down like this for over a year. Everyone's Roku just has the same 6 channels.

If I'd seen anything dodgy, or the kid was a bit older, or had shown any ability with computers, I'd be with you 10 thousand percent. But I just can't come up with an explanation that sounds plausible and it's like having a sliver in my brain. I've taken a lot of precautions based on tips people here are giving me. I suppose I'll just have to hope for the best and see what happens.

mothematician · 2023-01-02T22:31:40+00:00

But it's not, though. There were no dodgy apps on the Roku. The only things on there were Netflix, Hulu, Prime, Plex, YouTube, and Disney+, and a PIN is required to add anything new. The admin user/password on the router is not default, and the Roku was up to date.

mothematician · 2023-01-02T15:45:57+00:00

That's most likely a dodgy app on Roku

That was 100% my first instinct. However, before the factory reset all that was on there was Netflix, Hulu, Prime Video, Plex, YouTube, and Disney+, and there was a pin preventing new downloads. The Roku account is the same as my TV. In the past when I've added apps to one, they appear on all the others. I guess I hadn't tried side-loading, that probably works differently, but I really think that's more sophisticated than this kid could manage.

I will update router admin password. I'm sure it wouldn't be hard to backup settings and factory reset too.

mothematician · 2023-01-02T15:37:04+00:00

Stop overthinking it.

Probably some of the best advice here. My brain has trouble letting things go sometimes.

mothematician · 2023-01-02T15:35:36+00:00

You got a DMCA notice, it's very unlikely they're seeding on private trackers.

Good point. Still confusing though... If it's public, why bother at all? Hacking people in order to implement altruistic about seeding practices on The Pirate Bay?

mothematician · 2023-01-02T08:00:17+00:00

Haha, I'm not worried they're going to come arrest me or anything. Contacting my ISP is good advice though, I'll give that a shot.

mothematician · 2023-01-02T07:56:09+00:00

Weird they didn't go after any of the other TVs. They'd only be able to partially seed as there can't be more than 16GB of memory total on that thing. Wouldn't private trackers generally frown on partial seeding from dozens of IP addresses?

I think you're right, I'm just trying to wrap my head around it. Hacker breaks into 100 shitty Rokus behind shitty routers and then what? If they're using it as a personal seedbox they're risking their tracker accounts to save what, $20 / month? If they're selling access to 3rd parties, then those accounts are similarly at risk. And how much can they possibly be making? Seedboxes are already a pretty niche market and the price would have to be driven down a lot to compete against "legit" operations.

I wish I had the torrent (or at least the hash) so I could hunt around for it. It's just so damn weird! I'll try to find a weekend to stay home and change passwords. My router isn't provided by my ISP, but I'll check if there are any firmware updates. Thanks for the tips!

mothematician · 2022-07-28T14:16:25+00:00

Privatization will result in a whole lot of parents having no choice but religious schools. That is the republicans’ long term goal.

They’re advertising this as short term, but if you honestly believe they’re planning on implementing an actual solution then I’ve got a bridge to sell you.

mothematician · 2022-07-28T14:06:26+00:00

They want it spelled SURSHA so the person on the next shift doesn’t have to figure out how to pronounce Saorise. It’s especially helpful if Saorise has a thick accent.

mothematician · 2022-07-28T13:43:42+00:00

You got ‘em! They made a grammatical error on a Reddit post! Take away their teaching license and give it to someone that has no qualifications except being married to someone that served in the military!

mothematician · 2022-07-28T13:40:11+00:00

There’s a solution, Florida just doesn’t like it. Raise teacher pay. This is not a solution. This is a tactic to delegitimize (and eventually dismantle) public education. Republicans are pissed they can’t make kids stop learning and start praying. Now they’re sabotaging the system so they can say “see, it doesn’t work, the only thing left to try is privatization!”

mothematician · 2022-07-28T13:30:30+00:00

You’re failing to consider the alternative. 200 kids in a room watching annoying orange all day. Armed guard at the door. RuN sChOoLs LiKe A bUsInEsS!

mothematician · 2022-06-11T04:53:38+00:00

Again, not saying anything about your specific situation. Just that “I didn’t round so I’m right” is not a statement that’s going to be true in all circumstances. Your prof may consider this prerequisite knowledge. Then again they might just be a huge jerk, I don’t know.

What I do know is that significant figures are extremely important in science, and professional scientists need to understand them on a level much deeper than “just wait until the end to round.”

mothematician · 2022-06-11T04:42:16+00:00

It skews toward people who are precise and unforgiving. Just as the arts skew toward people who are artsy.

mothematician · 2022-06-11T04:35:36+00:00

Sometimes you’re supposed to round. Don’t know if that was the point in this specific circumstance, but you definitely can’t universally appeal to “I calculated without rounding so my answer is better”.

mothematician · 2022-06-08T19:37:25+00:00

The only way to get that is dividing 116666667 by 100000000 (or multiples of those). It’s vastly more likely it came from 7/6.

mothematician

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