2,184 reputation
320
bio website blog.chlewey.net
location Bogotá
age 41
visits member for 11 months
seen 1 hour ago

Human being, or so they say.

Electronics Engineer who has rather worked in Datacom and IT, freelance developer, former IMO contestant who could not solve 1988's 6th problem, and MSc in Mathematics dropout.


1h
revised Decimal expansion of a Cauchy sequence
minor corrections.
1h
comment Decimal expansion of a Cauchy sequence
@ChristianBueno The second $b_n$ sequence is pretty close to the decimal expansion of $a$, although in some cases the $n$th digit might be off by 1.
5h
awarded  Explainer
Sep
16
revised Recursive definition of multiplication
TeXing a little
Apr
22
awarded  Enlightened
Apr
22
awarded  Nice Answer
Feb
13
revised parametrization of plane in $\mathbb R^3$
TeXing a little
Feb
11
comment Interior of the sum of two sets?
No. Let $A=\mathbb Q\cap[0,1]$, then $\operatorname{int}(\operatorname{cl}(A))=(0,1)$ while $\operatorname{int}(A)=\emptyset$.
Jan
20
reviewed Reject suggested edit on Inequality $\frac{1-3ab}{1-2ac}+\frac{1-3bc}{1-2ba}+\frac{1-3ca}{1-2cb}\geq 0$
Dec
23
revised component of a vector $\mathbf a$ onto vector $\mathbf b$
TeXing a little
Dec
23
comment Derivative change sign
By extremum do you mean a local minimum or maximum?
Dec
23
revised how to show $\frac{\partial\hat\sigma}{\partial\hat u}\times\frac{\partial\hat\sigma}{\partial\hat v}$ (cross product)
TeXing the title
Dec
23
reviewed Approve suggested edit on how to show $\frac{\partial\hat\sigma}{\partial\hat u}\times\frac{\partial\hat\sigma}{\partial\hat v}$ (cross product)
Dec
23
revised determine basis for given vector space
TeXing the image
Dec
23
answered Inequality in triangle involving medians
Dec
23
comment Prove using induction : $n < 3^n$
Write: “R.H.S. $= 3^{p+1}$” and go on.
Dec
23
comment Prove using induction : $n < 3^n$
Hint: What does $3^n$ means when $n=p+1$?
Dec
23
revised Prove using induction : $n < 3^n$
TeXing a little
Dec
23
comment A bijection between (0,5) and (10,20)?
Proving that it has inverse (and that inverse is a function, meaning that it is well defined to each point in the domain) is usually enough.
Dec
23
comment A bijection between (0,5) and (10,20)?
Hint: prove that $f(x)=2x+10$ is a bijection.