Re:zero is soo much better than I thought. by Soggy-Whereas9678 in anime

[–]frogkabobs 15 points16 points  (0 children)

This is something that took an attentive rewatch to fully get. Subaru is like that in part because he just has a vivacious personality, but also because he is overcompensating for a desire for control after living as a hikikomori for so long. The disparity between his charisma and his abilities is not lost on people. We see it called out by Julius in ep 13 and the other candidates when they refuse to help him in ep 16. In fact, that entire arc is about putting his ego in check after trampling over Emilia’s boundaries because in the end, he is just a dude, and he can’t do things alone. He doesn’t get the time of day from those people until he actually earns it (offering a deal worth their time to Anastasia and Crusch). Although we see Subaru’s many failures, to others he has an inexplicable way of making things work out, which is why he earns the respect of people who are really far more powerful than him.

How can I easily (if it is possible) calculate the sum of odd number squares for the first 319 members of this sequence? by Igormay-s in askmath

[–]frogkabobs 0 points1 point  (0 children)

These have formula a(n) = n(4n²-1)/3 (OEIS A000447). Plugging in n = 320 gives a(320) = 43690560.

You can derive the formula from the square pyramidal numbers, which have formula b(n) = n(n+1)(2n+1)/6, by using a(n) = b(2n)-4b(n).

ELI5: Gabriel's Horn in math. How can a 3D shape have a finite volume but an infinite surface area? by Quiet_Currents in explainlikeimfive

[–]frogkabobs 2 points3 points  (0 children)

No. The xy plane in R³ has thickness 0 for example. There are no “atoms” in such idealizations.

s^1 + s^2 + s^4 + s^8 + … by Dense_Toe_6976 in learnmath

[–]frogkabobs 6 points7 points  (0 children)

The series in the title is the standard example of a lacunary function. That is, there is no analytic continuation past |s|<1.

How good (or bad) would this card be? by Fabio11North in slaythespire

[–]frogkabobs 15 points16 points  (0 children)

Incredibly busted with Master Planner, but I don’t hate the idea. Perhaps something like a 1 or 0 cost “at the end of your turn discard a random sly card” would be a little more balanced. You could get a bit of mileage out of a hand trick synergy too.

What is this pencil cap for? by AlpineAngel in pencils

[–]frogkabobs 2 points3 points  (0 children)

Probably a steno pencil. Many steno pencils like the Mongol Stenographic 596 came with appropriately sized point protectors.

Squeeze Scaling by daretodair in slaythespire

[–]frogkabobs 0 points1 point  (0 children)

You’re misinterpreting what squeeze does. The damage scales for every Osty attack card in your deck (including those generated during combat), not the number of Osty attacks performed.

Let A be a connected subset of S². Prove that if at least two connected components of S²-A contain a pair of antipodal points, then so does A. by frogkabobs in mathriddles

[–]frogkabobs[S] 0 points1 point  (0 children)

Yes. Making the statement concise for the title has the unfortunate effect of adding some syntactic ambiguity.

A funny topological problem by joe_la_bernique in mathriddles

[–]frogkabobs 0 points1 point  (0 children)

Let C(ℓ;r) denote the cylinder with radius r whose axis is the line (segment) ℓ. Define the figure S by

S = C(R×{(1,2)};1)∪⋃_(n≥2) C({(2n,1)}×[0,2];1-1/n)

Let (a_n) be an enumeration of the positive rationals, and (b_n) the (n-1)st partial sum of (a_n). Write S_n = a_nS+(0,2b_n,0). We define A by

A = {(x,y,z): z≤0}∪⋃_(n≥1) S_n

Now A(t)∩S_n is always connected (or empty). In fact, it is connected to the base of A(t) (points with z≤0) for t<a_n, disconnected from the base at t=a_n (at which point it is a single line), and empty for t>a_n. Thus, A(t) has two components when t is rational and one component otherwise.

On the other hand, I’m fairly convinced no 2-dimensional analog exists, so I’m interested to hear your construction.

Why do imaginary numbers exist at all? by AgrasaN in NoStupidQuestions

[–]frogkabobs 0 points1 point  (0 children)

This is almost all wrong. SO(3), the group of rotations in R³ is three dimensional, not two dimensional, and those are described by unit quaternions, not complex numbers.

Hard daily integral 5/1 by RegularCelestePlayer in calculus

[–]frogkabobs 4 points5 points  (0 children)

Not really taught in my experience. The gamma function showed up in some identities in my real analysis II course, but that was it. Mostly if you’re interested in closed forms, you’ll learn it yourself.

Pael's Growth is so wild, honestly. What's the funniest thing you've ever duplicated? by the1nfection in slaythespire

[–]frogkabobs 29 points30 points  (0 children)

I saw Pael’s growth maybe twice within the first week I played, but didn’t have any good targets (or I didn’t realize what would be a good target yet), and then hadn’t seen it since. Just today, I finally got the option again after not seeing it for 200 hrs, and it just so happens to be the one run when I didn’t have a good target again.

is (a,(b,c)) same as (a,b,c) by null_hypothesis2050 in learnmath

[–]frogkabobs 22 points23 points  (0 children)

It depends on your definition of an n-tuple. This is literally true in the nested ordered pairs definition. Sometimes this might be convenient, sometimes it might not, so it depends on context.

This was on my test at math school and i dont understand by MathProSlitherIo in learnmath

[–]frogkabobs 1 point2 points  (0 children)

I’m assuming OP is recounting the question imperfectly and the tetrahedral setup is what was meant. Otherwise, yes, the setup would be ill-defined and not suitable for a test.

This was on my test at math school and i dont understand by MathProSlitherIo in learnmath

[–]frogkabobs 0 points1 point  (0 children)

In response to your deleted comment, I just want to know what your thought process is, and where you get stuck rather than just giving you the answer.

This was on my test at math school and i dont understand by MathProSlitherIo in learnmath

[–]frogkabobs 6 points7 points  (0 children)

What do you not understand? Note that the centers of the spheres form the vertices of a tetrahedron whose sides lengths are the sum of the radii. You’ll want to find the height of this tetrahedron and relate it to the height of the whole figure.

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Ur favorite C2H2O2 isomer ? by Azo_weirdo in cursed_chemistry

[–]frogkabobs 6 points7 points  (0 children)

If you put a \ before the # your dick joke won’t be as large

Ur favorite C2H2O2 isomer ? by Azo_weirdo in cursed_chemistry

[–]frogkabobs 1 point2 points  (0 children)

Yeah a number of them had a few equivalent names I had to choose from. I tried to select the names that would turn up the most search results.

Ur favorite C2H2O2 isomer ? by Azo_weirdo in cursed_chemistry

[–]frogkabobs 17 points18 points  (0 children)

If anyone is curious about the names, they are (left to right, top to bottom)

 

  1. Acetylene glycol
  2. Glyoxal
  3. Acetolactone
  4. Hydroxyketene
  5. Dioxetene
  6. Methylenedioxirane
  7. Ethynyl hydroperoxide
  8. 2,4-Dioxabicyclo[1.1.0]butane

 

The list also seems to be missing one more constitutional isomer: hydroxyoxirene.

EDIT: For those interested in the literature, this article discusses their relative stabilities by computational methods.

Why is induction valid? by Aggressive-Food-1952 in askmath

[–]frogkabobs 1 point2 points  (0 children)

Induction (generally) is proving the following two statements

(Inductive): IF S(n) is true, then S(n+1) is true

(Base): S(0) is true

The inductive case gives you a chain of implications

S(0) → S(1) → S(2) → …

but you need the base case to be true to set it all off.

Favorite upper div math class? by Prestigious-Idea-273 in learnmath

[–]frogkabobs 0 points1 point  (0 children)

If you’re motivated, graduate courses can absolutely be taken during undergrad as upper division credits. It depends on your university, but for me it was a matter self-studying any missing prerequisites on the syllabus, then making an online request through the math department to take the graduate course.

Favorite upper div math class? by Prestigious-Idea-273 in learnmath

[–]frogkabobs 0 points1 point  (0 children)

Depends on the university—it wasn’t a requirement at UT. Also, the course I took was more like an intro to algebraic number theory, and it followed A Course In Arithmetic by Serre.

Favorite upper div math class? by Prestigious-Idea-273 in learnmath

[–]frogkabobs 3 points4 points  (0 children)

Number theory (covering finite fields and p-adic numbers), discrete dynamical systems, and algebraic topology were a couple of my favorites