Carlos Eugenio Thompson Pinzón
Reputation
2,261
Next privilege 2,500 Rep.
Create tag synonyms
Badges
4 22
Newest
 Caucus
Impact
~19k people reached

Feb
11
comment How do you define the derivative of a function without an argument?
@GitGud, I know. My point is that $f'$ is just the function generated by point-wise calculating $f'(x)$ in each point $x$. At least whenever $f$ is derivable in $x$. I might further declare a derivate operator but that does not define the derivative of a function.
Feb
11
comment How do you define the derivative of a function without an argument?
$f':\mathbb R\to\mathbb R$, $x\mapsto f'(x):=\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$
Feb
1
comment what can we say about $f(x)= |\cos x| + |\sin x|$
Note that if 4 is true, then 2 is false. Why?, also check $f(0)$
Feb
1
revised what can we say about $f(x)= |\cos x| + |\sin x|$
TeXing a little
Dec
10
awarded  Caucus
Dec
10
comment Suppose $A,B,C$ are sets. Prove that $A\mathbin\triangle B\subseteq C \iff A\cup C=B\cup C$.
@kuhaku I used Inkscape. I'm not sure if this apply as a rigorous proof. The one qualifying the proof should define what is rigorous enough.
Nov
2
awarded  Nice Answer
Oct
7
awarded  Yearling
Oct
1
comment How to transform the following logical expression into English
More like there is an engineer such as for every accountant who manages this engineer,there is a person who the accountant manages.
Oct
1
revised How to transform the following logical expression into English
TeXing a little
Oct
1
revised Proof about a subset of a metric space
TeXing a little
Oct
1
revised Determine whether {¬q∧(p→q)}→¬p is tautology
added 41 characters in body
Oct
1
revised Find the values of $a$ and $b$ so that f will be continuous on $(-\infty, \infty)$
TeXing a little
Oct
1
reviewed Approve A logic exercise (finite satisfiability)
Sep
30
revised Decimal expansion of a Cauchy sequence
minor corrections.
Sep
30
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.
Sep
30
awarded  Explainer
Sep
16
revised Recursive definition of multiplication
TeXing a little
Apr
22
awarded  Enlightened
Apr
22
awarded  Nice Answer