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11128
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location Boston, MA
age 64
visits member for 2 years, 10 months
seen Jan 25 at 18:57

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Jan
15
revised How to prove that the Nested Interval Theorem fails to hold in $\mathbb Q$?
added 9 characters in body; edited title
Jan
15
answered Is there a linear operation such that $F(1,1,1) = (1,2,3),F(1,2,3) = (1,4,9),F(2,3,4) = (1,8,27)$?
Jan
15
comment Concatenation of integers
@ErickWong From the problem statement, I supposed that each $x_i$ was a single digit. If it's not, obviously you have to take its log to figure out how long it is (or use some other method).
Jan
14
answered Concatenation of integers
Jan
12
comment The field mouse population satisfies the differential equation $dp/dt$ = 0 .5p - 450
If $p_0 = x+900$, then $x = p_0 - 900$. You got that sign backwards.
Jan
3
comment Topology on ideles
@KCd Oh, I can read it just fine. But at least the question should have been posted rather than linked to on the site...
Jan
3
reviewed Close How to show result in terms of $\pi$ in Mathcad?
Jan
3
reviewed Leave Open How to pronounce the complexity of an algorithm
Jan
3
reviewed Leave Open if $x = \sqrt{x+1} + \sqrt{x+2} + \sqrt{x+3}$ then x =?
Jan
3
reviewed Leave Open Convergence of series/absolute convergence
Dec
31
comment Proving the inequality $ \left|\prod_{i=0}^n \left(x - \frac{i}{n}\right)\right| \le \frac{n!}{4n^{n+1}}$
Two perhaps trivial comments. 1) The given inequality is the same as $\left\lvert \prod_{i=0}^n (nx-i)\right\rvert \le \frac{n!}{4}$. 2) From some experimentation, it appears that the maximum value of this polynomial as a fraction of $\frac{n!}{4}$ declines, perhaps to zero, as $n$ increases, so this is really not a sharp bound at all. For example, when $n=25$, the ratio is about $0.36$; at $n=100$, it is about $0.27$. This makes sense, since the larger $n$ is, the more opportunities there are for $nx$ to be close to an integer.
Dec
31
awarded  Enlightened
Dec
31
awarded  Nice Answer
Dec
31
answered Show that the equation $x^{4} + rx + s = 0$ has at most two distinct real roots.
Dec
30
answered Newton's method convergence criteria
Dec
30
revised Newton's method convergence criteria
added 2 characters in body
Dec
30
comment Integration with absolute value
I think you meant $x\in \left[0,\frac{\pi}{2}\right]\cup \left[\frac{3\pi}{2},2\pi\right]$.
Dec
30
comment Solving $x^2 \equiv a (\text{mod }6)$
Are you looking for a method other than just squaring the integers from $0$ to $5$?
Dec
30
answered Factorizing a polynomial of degree 4 that has complex roots
Dec
28
comment Find the Asymptotes of the function $f(x)=3^x / (3^x+1)$
Try $x\to -\infty$.