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location Lima, Peru
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visits member for 2 years, 4 months
seen 12 hours ago

Curiosity-driven organism doodling in the intergalactic infinity.


Dec
13
comment Solving cubic with a nice real solution
@DavidH Yup, that would give us the depressed cubic $y^3=42y+105$. But I don't see an obvious way to suppose that $y=\sqrt[3]{a}+\sqrt[3]{b}$.
Dec
13
revised Solving cubic with a nice real solution
added 7 characters in body
Dec
13
asked Solving cubic with a nice real solution
Dec
12
accepted Generating functions and central binomial coefficient
Dec
12
comment Generating functions and central binomial coefficient
@MarkoRiedel Hm, that's a more general case, but it linked to this. Also, sorry for the wrong previous title, copy-and-paste error. So, close because dupe?
Dec
12
revised Generating functions and central binomial coefficient
edited title
Dec
12
comment Students who see ears of another student
@BrianM.Scott Interesting, it also works with $n=2$! So now we have the bound $n\le f(n) \le n+2$ in the general case, a proof doesn't seem very far away...
Dec
12
asked Generating functions and central binomial coefficient
Dec
11
comment Students who see ears of another student
Also, a possible regular(ish) arrangement: $$\begin{matrix} \downarrow&\leftarrow&\leftarrow&\leftarrow&\leftarrow\\ \downarrow&\downarrow&\downarrow&\downarrow&\uparrow\\ \downarrow&\downarrow&\downarrow&\downarrow&\uparrow\\ \downarrow&\downarrow&\downarrow&\downarrow&\uparrow\\ \rightarrow&\rightarrow&\rightarrow&\rightarrow&\uparrow \end{matrix}$$
Dec
11
awarded  Caucus
Nov
21
accepted Trigonmetric sum of inverses
Nov
21
revised Trigonmetric sum of inverses
added 6 characters in body
Nov
21
comment Trigonmetric sum of inverses
@EdwardJiang Sorry, it was a $1$.Edited!
Nov
21
revised Trigonmetric sum of inverses
added 490 characters in body
Nov
21
asked Trigonmetric sum of inverses
Nov
20
comment Integer solution for $Rx^2+Sy^2=1$ .
This is pretty much what we know about quadratic diophantines
Nov
18
comment A High School Math Question dealing with coordinate geometry
@EricStucky It is likely because of the vague wording, but I don't think that all choosings of points $E$ would result in a shape with the same area.
Nov
18
comment $a+b+c+d+e$ divides $a^5+b^5+c^5+d^5+e^5-5abcde$
$a=-b-c-d-e$ doesn't yield $0$, so it won't be that easy.
Nov
18
comment A High School Math Question dealing with coordinate geometry
You have infinitely many options for choosing $F$ and $E$. Each way of choosing $F$ and $E$ produces a point $E'$. The problem asks: If we graph all possible E', what area will that graph have?
Nov
13
comment How find this real value $x+y+z $ if such this equation
@Amzoti Wolfram alpha finds only two . But yes, there are two different real values of $x+y+z$