54,252 reputation
4114204
bio website
location
age
visits member for 4 years, 4 months
seen 4 hours ago

Don't have much time these days...


1d
comment Integer part of a sum (floor)
@CFG: Can you please also mention the name of the magazine? Thanks.
1d
answered Integer part of a sum (floor)
1d
comment Integer part of a sum (floor)
@CFG: What exact magazine is this? Did you change any part of the problem? Are calculators allowed or is a mathematical proof required?
2d
comment A finite sum over $\pm 1$ vectors
@Turbo: btw, I only asked because you edited the question asking for a short inductive proof. Is that a requirement?
2d
revised A finite sum over $\pm 1$ vectors
edited body
2d
comment A finite sum over $\pm 1$ vectors
@Turbo: Ok. There probably is, but this is quite short IMO. It only seems long because of the explanations.
2d
comment A finite sum over $\pm 1$ vectors
@Turbo: You mean shortest proof? I don't know. Why is this insufficient? Is this homework (or something which requires a specific approach)?
Dec
15
answered recursive sub-sequences of sequence , one is increasing and one is decreasing to same limit -> the sequence converge?
Dec
15
comment A finite sum over $\pm 1$ vectors
This method also allows you to get the sum restricting $u$ to $|\sum u_i| \le K$.
Dec
15
revised A finite sum over $\pm 1$ vectors
added 16 characters in body
Dec
15
answered A finite sum over $\pm 1$ vectors
Dec
15
comment Proving $2 ( \cos \frac{4\pi}{19} + \cos \frac{6\pi}{19}+\cos \frac{10\pi}{19} )$ is a root of$ \sqrt{ 4+ \sqrt{ 4 + \sqrt{ 4-x}}}=x$
@TitoPiezasIII: Thanks!
Dec
8
awarded  Caucus
Dec
5
revised How can I prove analytically the number $2^{100000}+1$ is not prime??
edited tags
Dec
5
revised 4th grade word problem
edited tags
Dec
5
comment Does anyone know about Ramanujan's method of solving the quartic?
I have removed the soft-question tag. This has a completely objective answer: the method used by Ramanujan.
Dec
5
revised Does anyone know about Ramanujan's method of solving the quartic?
edited tags
Dec
4
awarded  Nice Answer
Dec
3
revised combinatorics problem counting
edited tags
Dec
1
comment Does $\lim_{n\to\infty}\frac{1}{n}\sum_{t=1}^na_t=L$ imply that $\{a_t\}$ is bounded?
@Neal: Why don't you post it as an answer?