# Josué Molina

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bio website molinajosue.blogspot.com location Houston, TX age 24 member for 2 years seen 4 hours ago profile views 308

One Thousand Birds

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 Oct15 answered What is the meaning of $\frac{0}{0}$? Oct15 comment Parametric function differentiation problem Why are you differentiating $y$ with respect to $x$ when it is being expressed as a function of $t$? Oct15 comment Parametric function differentiation problem Welcome! Please include what you have already tried; this is not a homework-solving machine! Oct9 awarded Popular Question Oct7 answered Find an equation of the tangent line to the curve $y=x^3-3x+1$ at the given point $(2,3)$ Oct1 comment What is wrong with this proof of: $2+2 = 5$ I see this kind of "math" as being akin to wordplay. Sep30 answered Permutation vs Combination Sep30 answered Definite integral from $0$ to $t$ of $t$ wrt. $s$ Sep30 comment Prerequisites of general calculus Because an answer to this question would be subjective in nature, this question is unsuitable for this site. Sep30 comment If $A=\{1,2\}, B=\{1,2\}$, what is $A \cup B$? Is this kind of question allowed here? It is misleading, and its resolution lies in book definitions the author could have easily looked up. Sep29 awarded Popular Question Sep26 comment How should I begin when trying to determine a proposition whose truth value is unknown? Don't think of mathematics as having some sort of rule book, but pure logic instead. Things need to make sense before you proceed! Sep16 awarded Popular Question Sep12 revised How to integrate $\cos(\theta)\exp(i a \sin(\theta-\phi))$ The OP was fixed. Sep12 suggested suggested edit on How to integrate $\cos(\theta)\exp(i a \sin(\theta-\phi))$ Aug26 asked Simple Algorithm Running Time Analysis Jul23 accepted The union of a sequence of countable sets is countable. Jul23 comment The union of a sequence of countable sets is countable. I get your idea. :-) I am just trying to wrap my head around the technicalities. And thank you! Jul23 comment The union of a sequence of countable sets is countable. I was indeed trying to obtain $(1)$ but did not know how to. I am a little confused: if for $x_{k,l}$ I take $k=1$ and $l=1$, which is the first term of the sequence, then, according to your last expression, $x_{k,l}$ would be the $3$rd term? Jul23 comment The union of a sequence of countable sets is countable. @PeterTamaroff, $\mathcal S$ is an implementation of the diagonal argument.