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1d
comment BEDMAS where the order of Addition before Subtraction matters?
@Drakes it's correct because mathematicians chose that convention. This is not something you can prove mathematically, but perhaps empirically by pointing to books/websites that clarify the "same priority, left to right" aspect of the standard order of operations.
2d
answered Does the graph $y=\sin(x)\times\sin(x^{-2 })$ cross the $x$ axis an infinite amount of times in a finite interval?
Apr
25
revised Does there exist a complex function which is differentiable at one point and nowhere else continuous?
added tag
Apr
25
revised Can a complex function be complex-differentiable at a point and not in a neighborhood?
added tag
Apr
25
comment Why Are Some Sets Not Measurable?
As I mentioned, there are translation-invariant measures other than the zero measure that cause no problem here: for example, the counting measure. If by non-trivial you mean something equivalent to "assigns a finite positive measure to the unit cube", then if your $\sigma$-algebra contains all the Borel sets then a translation-invariant measure is forced to be a multiple of the Lebesgue measure. Thus, I would say that this really is about the Lebesgue measure, both because that's the most likely context in the textbook, and because the Lebesgue measure is the only interesting case.
Apr
25
answered Index set of dyadic partition
Apr
24
revised Show that $d(z,z_1)$ is a metric.
This problem doesn't seem to have to do with functional analysis
Apr
24
comment Why Are Some Sets Not Measurable?
Yes, they're implicitly talking about the Lebesgue measure: assuming the axiom of choice, not every set can be Lebesgue measurable. Some less useful measures can be defined on the $\sigma$-algebra of all sets, like the one that's $0$ for every set, or the one that's $\infty$ for every nonempty set, or the "counting measure" that gives the size of finite sets and $\infty$ otherwise.
Apr
24
comment Why Are Some Sets Not Measurable?
$m(B)$ is decidedly not supposed to be zero. A ball of positive radius has positive volume.
Apr
22
comment Solving the Gobblet game
The rules you linked say there are 24 pieces total, are there actually 32 in the version you're considering?
Apr
21
comment Sinusoidal function from $4$ knowns
then pick whichever single formula is easiest for you to find. You can get an answer by starting with sine or cosine, and assuming that the coefficient of the trig function $a$ is positive or negative. Try manipulating the variables in my other comment to see if you can adjust the locations of the trough and peak to be what you want, and edit your question with your attempts/observations if you don't get all the way there.
Apr
20
comment Sinusoidal function from $4$ knowns
Because of what you noted about sine and cosine, it could be either. $a*\cos(bx+c)+d$ is the same bunch of functions as $a*\sin (bx+c)+d$
Apr
20
comment Sinusoidal function from $4$ knowns
The period can't be 2 if it goes from min to max in 2 units.
Apr
20
comment Index set of dyadic partition
Have you been able to make any observations/notice any patterns?
Apr
18
comment A Combinatorial Game: the Snake and the Hunter
Here is a source for the problem: colombiaaprendiendo.edu.co/eventos/gathering-for-gardner-10
Apr
18
revised Define Grundy values
deleted 83 characters in body; added 5 characters in body
Apr
18
comment Define Grundy values
@RossMillikan, good catch! I was following a formal definition closely without thinking. The argument "since B can only move to [something which can move to zero], its value must be zero" does work in general.
Apr
17
answered Define Grundy values
Apr
17
comment Counterexample to $V=Range(A)\oplus Nullspace(A)$
@Ryles2014 In that example, there is no internal direct sum, so the direct sum in the isomorphism is external. I'm having trouble finding a great source explaining just this distinction, but the first page of mathdoctorbob.org/LinearReview3.pdf only has a little extra stuff.
Apr
17
comment Pictures of curves over finite fields with many points
Incidentally, it looks like manypoints is down now, but you can get a lot of info from web.archive.org/web/20160324153533/http://manypoints.org/… and perhaps contact one of the moderators listed at web.archive.org/web/20160324063313/http://manypoints.org/…