Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs

Dashboard
Notifications
Mark all as read

Activity for whybecause‭

Type On... Excerpt Status Date
Comment Post #285015 @#36356 I think the point you're making, which I would agree with, is that not all things *can* be made intuitive. That's right, and it's right to point that out to a student, in such cases.
(more)
7 days ago
Edit Post #285525 Post edited:
10 days ago
Edit Post #285525 Post edited:
10 days ago
Edit Post #285525 Initial revision 10 days ago
Answer A: How's it possible to arrange 0 objects? How can 0! = 1?
This explanation may work for some but not for others--it is perhaps a matter of taste or intuition whether you feel that it is sensible. Is doing nothing a "way of arranging" zero objects? Eh, you can get very philosophical about this and probably not in a productive way. I find the following...
(more)
10 days ago
Comment Post #285447 I suspect this question isn't stated fully enough, and also should probably be stated as a pure math problem rather than relying on any domain knowledge about ETF's. If you're minimizing overlap and want to buy as few as possible, and those are literally the only constraints ... then choose zero of ...
(more)
18 days ago
Edit Post #285436 Post edited:
and the universe
19 days ago
Edit Post #285436 Post edited:
countable -> finite
19 days ago
Comment Post #285436 Right, wasn't being careful, I'll edit.
(more)
19 days ago
Edit Post #285436 Post edited:
writing style
19 days ago
Edit Post #285436 Initial revision 19 days ago
Question Are we in a "history-valley" for Topology?
Here is my current rough timeline of Topology: Newton invents the calculus People like Riemann and Cauchy make it rigorous, and by this time, we have the $\varepsilon,\delta$ definition of continuity of a real valued function of a real variable. We realize that we want a definition of the con...
(more)
19 days ago
Edit Post #285435 Post edited:
19 days ago
Edit Post #285435 Initial revision 19 days ago
Answer A: Intuitively, why does $p$ vary inversely with $P(C_3 \mid D_2)$? But directly with $P(C_2 \mid D_3)$?
$P(C3|D2)$ is the probability of the car being behind door 3 given that Monty opened door 2. $p$ is the probability that Monty opens door 2, under the assumption that he has a choice between it and door 3. That is to say $p$ is the probability that Monty opens door 2 under the conditions that: (i) ...
(more)
19 days ago
Edit Post #285428 Initial revision 20 days ago
Answer A: Book suggestion category proposal
As long as we only answer it once per field, and are good about closing duplicate questions and redirecting them. Because this kind of question gets asked about once per second, somewhere on a math-related discussion forum.
(more)
20 days ago
Edit Post #285427 Initial revision 20 days ago
Answer A: Solely reputable textbooks ought be cited.
I agree that canonical textbooks are superior--often because they are in the canon for a reason! But if for no other reason, it's super helpful to have everyone literally on the same page. If you say you learned Calculus and then you mention a bunch of stuff I never heard of, or don't know a bunch o...
(more)
20 days ago
Edit Post #285419 Post edited:
20 days ago
Comment Post #285425 From glancing around, it looks to me like actually this is already a success in getting questions answered. Although my survey of the posted questions is brief, it looks to me like the success rate is pretty comparable to SE. I do think that it seems to take longer for a question to get answered, a...
(more)
20 days ago
Comment Post #285426 I agree with you "when I see this what should I think?" is a good math question. But my experience with SE and my brief experience here at Codidact, tells me that these sorts of questions get heavily downvoted and closed. So it made me wonder if it would make sense to give them their own home, so t...
(more)
20 days ago
Edit Post #285425 Initial revision 20 days ago
Answer A: How can we grow this community?
I think you can moderate the negative impression of not having recent questions, by displaying the number of views that a question gets when you post it. That way when someone posts a questions and sees the views update, they at least know that the post is generating some amount of activity. Th...
(more)
20 days ago
Edit Post #285424 Initial revision 20 days ago
Question $\int_{E_n} |g|^q = \left| \int_E \chi_{E_n}\cdot \text{sgn}(g)\cdot g \cdot |g|^{q-1}\cdot |g| \right|$
I am trying to understand why the following equation is true. Here $E$ is a measurable set and all functions are defined and measurable on it. $1<p,q,<\infty$ such that $\frac 1 p+\frac 1 q=1$ and $g\in L^q(E)$. $En= \\{ x \in E:|g|\le n \\}$. And there exists a number $M$ such that for every $f\...
(more)
20 days ago
Edit Post #285423 Post edited:
20 days ago
Edit Post #285423 Initial revision 20 days ago
Question Should there be more than one sort of math community?
There are, to my mind, two very different but important kinds of mathematical question. There is the kind that the Codidact and SE communities both like: Straight-forward "give the proof/calculation" questions. This can be "How do I solve this?" or "Why is this wrong?" or a few other variations. ...
(more)
20 days ago
Edit Post #285422 Post edited:
20 days ago
Edit Post #285422 Initial revision 20 days ago
Answer A: Without calculations, how can you visualize "that half the squares are white and half are black"?
I could argue: Clearly for every white square there is a corresponding black square. This is true row-by-row because the row-length is even and the colors alternate. Therefore it is also true taking all rows together. But I'm not sure why you can't imagine rotating the board. The upper-left w...
(more)
20 days ago
Comment Post #285342 Mathematical induction is not scientific induction. So in that sense mathematical induction is misnamed. But ... maybe scientific induction is the one that's misnamed. I don't know the history of these terms, but in any case, someone somewhere should change at least one of these names. What c...
(more)
20 days ago
Edit Post #285421 Initial revision 20 days ago
Answer A: Questions with a quote/screenshot and a request to explain
I'm pretty averse to using the downvote, so for me this would depend on context. If it's literally just a screenshot with "how?" written after it, yeah, downvote. But in general I think downvoting has more power to harm a community than to help, so I use it with caution. If there's at least a li...
(more)
20 days ago
Comment Post #283900 If when you ask "How would you know to do the next step?" you have emphasis on the word "the", then I agree with your argument. There is not a unique next step, and not even a unique best next step. But if the question is mean to ask, "What am I supposed to be learning here? How am I supposed ...
(more)
20 days ago
Comment Post #284788 An opinionated answer: I love topology and hate how it's taught in just about every course and textbook I've ever encountered. For this reason, I think you appreciate topology the most after you've learned a lot of other stuff first and then can appreciate what it's talking about because you can fi...
(more)
20 days ago
Edit Post #285419 Post edited:
20 days ago
Edit Post #285419 Initial revision 20 days ago
Answer A: Intuitively, why can $a, b$ cycle in ${\color{red}{b}} = \frac c{\color{red}{a}} \iff {\color{red}{a}} = \frac c{\color{red}{b}}$?
A possibly helpful further note beyond the answers given elsewhere here: Do you intuitively understand why $ab=c$ is equivalent to $a=c/b$ for all $b\ne 0$? If so, and if you intuitively understand the commutativity of multiplication, then these two intuitions put together give you everything that ...
(more)
20 days ago
Comment Post #285015 I would be weary of this sort of explanation. If you have a property which you do not find intuitive, but also not counter-intuitive, then you are ... just stuck. So I do think, if the job is to give intuition, you really need to give the intuition, and not just turn it around on the student.
(more)
20 days ago
Comment Post #285365 As a direct answer to the question, I can't say what we mean by "natural". But I can tell you that it is not well-defined or even a common "abuse of notation" (as you sometimes see even when a notation doesn't make perfect literal sense) to use two pipes inside a single probability function. Someti...
(more)
20 days ago
Edit Post #285418 Post edited:
20 days ago
Edit Post #285418 Initial revision 20 days ago
Answer A: In general, does $\color{forestgreen}{P(A|M)} + \color{red}{P(B|M)} = 1$?
This is a special instance of the more general fact that $P(A)+P(B)=1$ if $A$ and $B$ "partition" the probability space. I'll explain what I mean. A partition of a set is any way of carving up the set into (1) disjoint and (2) exhaustive subsets. For instance if the set is {1,2,3,4} then a par...
(more)
20 days ago