Reputation
Top tag
Next privilege 10,000 Rep.
Access moderator tools
Badges
7 28 91
Impact
~157k people reached

16h
comment How do I express logical connectives with Nand?
@MauroALLEGRANZA You can use $\uparrow, \rightarrow, \downarrow, \leftarrow, \triangle, \times ,\bigcirc, \times, \square, \triangle$ to attack with Akuma's combo on Street Fighter $V$.
Jul
28
comment What's the meaning of the $R(f(x),g(x))$ in $\int R(f(x),g(x))?$
See Apostol's: Calculus or Courant/Fritz': Introduction to Calculus and Analysis.
Jul
27
comment What would be interesting maps to use on that Eudoxus reals?
@lulu Yes. But I'm not sure of what $f$ would be useful for this construction of the Eudoxus reals. I'm reading this but it doesn't ring a bell.
Jul
27
comment What would be interesting maps to use on that Eudoxus reals?
@lulu I don't get it. If I take $f(x)=mx+b$, I'd have: $$f(x+y)-f(x)-f(y)=m(x+y)+b-(mx+b)-(my+b)=-b$$ That doesn't seems meaningful.
Jul
21
comment Minor mistake computing $\int \frac{1}{x^3+2x^2-3x} \; dx$?
Oh, thanks. When I expanded it in the board, I (wrongly) found $-3c$. Now I expanded it with Mathematica and obtained the right result but didn't pay attention.
Jul
17
comment Why $\frac{1}{9}$ becomes $\frac{1}{3}$ in $\frac{1}{3} \int \frac{1}{s^2+1} \, ds$?
Okay. But is it wrong to use the product rule? Or it's just more practical to use this rule?
Jul
17
comment Why $\frac{1}{9}$ becomes $\frac{1}{3}$ in $\frac{1}{3} \int \frac{1}{s^2+1} \, ds$?
I've added an edit. Could you take a look at it?
Jul
17
comment Why $\frac{1}{9}$ becomes $\frac{1}{3}$ in $\frac{1}{3} \int \frac{1}{s^2+1} \, ds$?
I don't understand why I have $ds=\cfrac{1}{3} du$. I don't understand how does $ds$ relates do $du$.
Jul
13
comment Statistics books with motivation and historical tidbits about the development of the concepts?
@MichaelHardy Yes. And I'm looking exactly to the mathematical motivation for them. I'm curious to know exactly what made them develop the concept (be it "mathematical" or not). I marked "mathematical" because sometimes in the development of mathematics, things were not really mathematically justified, such as Leibniz infinitesimals.
Jul
6
comment Is it a good practice to write this integral in this form?
@JohnMa I'm supposing I don't know it for a while. But I'll compute it a little later. Do you think this presents a big problem?
Jul
3
comment Reference Request: Regge Symmetry “Angle-Edge” Duality
I believe Bob Marley is a feasible reference to what you're looking for.
Jul
3
comment How to get rid of the term with $xy$?
One silly doubt: In the book I'm reading, it says about eliminating the linear terms, in another place I've read, it seems that the objective is to eliminate the term with $xy$. Are they equivalent? There is also another book I have that says that the objective seems to be to write the conic in the form $ax^2+bxy+cy^2$. I'm a little confused.
Jul
3
comment How to get rid of the term with $xy$?
I need to do a change of variable such that $xy=0$, right?
Jul
3
comment How to get rid of the term with $xy$?
@r9m What's the difference of them? I know that this matrix form is associated (can be expanded) to a quadratic form. But I'm not sure what your matrix does.
Jul
3
comment How to get rid of the term with $xy$?
@r9m There are two matrixes. This one you mentioned and: $$\begin{pmatrix} {x}&{y}&{1} \end{pmatrix}\begin{pmatrix} {a}&{b/2}&{d/2}\\ {b/2}&{c}&{e/2}\\ {d/2}&{e/2}&{f} \end{pmatrix}\begin{pmatrix} {x}\\ {y}\\ {z} \end{pmatrix}$$
Jul
3
comment Should the expanded expression of a quadratic form be equals to It's original expression?
@RoryDaulton That is also viable. But In my mind, they didn't seem valid for operations in equations. But I jsut checked Apostol's book and saw that they are indeed appropriate. Thanks for pointing it out.
Jul
3
comment What is the $1469^\text{th}$ derivative of $x^{532}-5x^{37}-4$?
@DavidRicherby I know. I just said it to enhance his mathematical culture.
Jul
2
comment Special Products of Transpositions
@Blue You could (should?) have asked it on Math Overflow. As it seems pretty exploratory: "Have these "special permutations" been studied in the literature?" - I guess they'll not close the question.
Jul
2
comment What is the $1469^\text{th}$ derivative of $x^{532}-5x^{37}-4$?
It might be good for you to know the existence of Faá di Bruno's generalization of the chain rule to higher derivatives.
Jul
1
comment When should I shift $a$ and $b$ in $\cfrac{x^2}{a^2}+\cfrac{y^2}{b^2}=1$?
@OfirSchnabel Oh. Then I probably made some mistake in the previous computations. Gonna try it now.