2,270 reputation
1316
bio website
location
age
visits member for 2 years, 3 months
seen 14 hours ago

Sep
30
awarded  Explainer
Sep
3
answered Spectral norm of a Hadamard product
Sep
3
revised Spectral norm of a Hadamard product
edited body
Aug
28
revised Prove that Frobenius matrix norm is compatible with the vector norm
added 1 character in body
Aug
19
answered How to prove this inequality without using Muirhead's inequality?
Jul
13
awarded  Yearling
Jul
11
revised IMO 2014 problem 3, first day
added 7 characters in body
Jul
11
revised IMO 2014 problem 3, first day
added 7 characters in body
Jul
11
answered IMO 2014 problem 3, first day
Jul
2
awarded  Curious
Jul
2
revised Spectral norm of a Hadamard product
added 30 characters in body
Jul
2
asked Spectral norm of a Hadamard product
Jun
20
revised QM-AM-GM-HM proof help
added 274 characters in body
Jun
20
comment QM-AM-GM-HM proof help
@jonnytan999 The way I know to prove this claim, requires taking one derivative, though. Do you need an elementary solution (i.e., without any calculus involved)?
Jun
20
comment QM-AM-GM-HM proof help
@jonnytan999 Yes, as I mentioned particular values of $M(p)$ give you the QM, AM, GM, and HM of the $x_i$s.
Jun
20
comment QM-AM-GM-HM proof help
QM = $M(2)$, AM = $M(1)$, GM = $\lim_{p\to 0} M(p)$, HM = $M(-1)$.
Jun
20
comment QM-AM-GM-HM proof help
@jonnytan999 What notation? I merely defined a function $M(p)$.
Jun
20
answered QM-AM-GM-HM proof help
Jun
16
comment Why am I getting a contradiction?
What have you considered as the "contradiction"? You need the entire epigraph of $f$ to be convex, not just one slice of it.
Jun
14
comment Proving $\forall x\in\mathbb R : \dfrac{e^x + e^{-x}}2 \le e^{\frac{x^2}{2}}$ with Cauchy's MVT
You want to prove $A + B \leq C$, where $B\geq 0$. It's not sufficient to prove $A \leq C$.