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location Buenos Aires, Argentina
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Mar
17
comment Calculating $\int_0^\infty(\log t)^n e^{-t}\ dt$
Well, yes, that's where I got it from.
Mar
17
asked Calculating $\int_0^\infty(\log t)^n e^{-t}\ dt$
Mar
16
comment Looking for help with a proof that n-th derivative of $e^\frac{-1}{x^2} = 0$ for $x=0$.
Hint: show that all derivatives of $f$ are of the form $R(x)e^{-1/x^2}$ for some rational function $R$.
Mar
13
awarded  Notable Question
Mar
12
comment Order of calculation in all math equations
@AJMansfield: That could very well be interpreted as $6/(2/(1+2))$. The only unambiguous way is to use parentheses.
Mar
12
comment $\operatorname{im} A = \ker A$ for a $2 \times 2$ matrix $A$?
What makes you think they have to be different?
Mar
12
comment Is this proof about functions correct?
Try to format your question a bit better, it's really hard to read like this. Also, this has nothing to do with number theory.
Mar
12
revised Dividing matrices
edited tags
Mar
12
comment Dividing matrices
Short answer: You can't. Maybe there's a subset of the set of all matrices that allows division, but I'm not sure.
Mar
12
comment Evaluate each of the numeric expressions: $\sqrt{(-3)}$, $\sqrt{3}$, $\sqrt{-3}$
As far as I know, while the equation $x^2 = a$ has two solutions for $a > 0$, $\sqrt{a}$ is defined as the positive square root, not both. This only applies when working in $\mathbb{R}$, since in $\mathbb{C}$ you can't distinguish positive and negative.
Mar
10
comment How to find average rate of change
I don't think it's so straightforward, though, since he was given the velocity, not the position (not to mention it should be a function of $t$ and not of $x$).
Mar
10
comment A proof in Spivak on integration.
@sizz: Suppose you know that $|x-y| \lt \epsilon$ for all $\epsilon > 0$. If $x \ne y$, you can take $\epsilon = |x-y|$ (because $x-y$ is not $0$), and you get $|x-y| < |x-y|$, a contradiction which came from assuming $x \ne y$.
Mar
10
answered About vector addition
Mar
8
comment Can the following equation be solved for the unknowns?
But it doesn't say through the curve, it says through the point.
Mar
8
answered Partial Derivative of $f(x,y) =\ln(x^{2} + y^{2}) + \sqrt{x^{2}\cdot y^{3}}$
Mar
8
comment Partial Derivative of $f(x,y) =\ln(x^{2} + y^{2}) + \sqrt{x^{2}\cdot y^{3}}$
$\frac{x}{\sqrt{x^2}} \ne 1$.
Mar
8
comment Can the following equation be solved for the unknowns?
How did you get that $f''(-2) = 0$? The question doesn't say anything like that.
Mar
8
comment domain of trigonometric function with greatest integer
The domain of $\sin x$ is $\mathbb{R}$.
Mar
8
comment How do I obtain the derivative of $\frac{x^2}{x-y}$?
Derivative with respect to what?
Mar
7
comment What was the first bit of mathematics that made you realize that math is beautiful? (For children's book)
I've always thought that it's kinda cheating to teach this to someone who doesn't fully understand complex numbers. I remember I first heard about this when I was about 16, and I thought it was some miraculous numerical coincidence, when in reality this exponentiation doesn't work like the one you know, so this identity does not mean what you think it means at that age.