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Brevan Ellefsen

Urbana, IL, USA

PhD candidate working on low dimensional topology and dynamics, with an emphasis on 3-manifolds.

I can be reached at [email protected]

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Top Questions
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64
Is it possible to represent every irrational number as a (limit of) an infinite sum of rational numbers?
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32
Where is the absolute value when computing antiderivatives?
math.stackexchange.com

25
Factorial question: number of trailing zeroes in 125!
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19
Is there a way to insert Log base-something into Google Calculator?
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14
What is the minimum area of a rectangle containing all circles of radius $1/n$?
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14
Rather weird integral
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14
Why does Wolfram Alpha say that $\infty^\infty$ results in "complex infinity"?
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14
Can a polynomial be expressed as an infinite sum of non-polynomial functions?
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13
List of old books that modern masters recommend
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12
Reverse Triangle Inequality in vector space
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12
What is the sum of all the Fibonacci numbers from 1 to infinity.
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12
what operation repeated $n$ times results in the addition operator?
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11
Need a hint for this integral
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11
Evaluating the integral $\int_0^{\infty} \frac{\sin(x)}{\sinh(x)}\,dx$
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11
Why do we care about multiple proofs of the same theorem?
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9
Approximating the Digamma function
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9
Express "if true, then 1 else 0" in a formula suitable for Desmos calculator
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9
Why can't calculus be done on the rational numbers?
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9
Derivative of a large product
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9
Approximation of a summation by an integral
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9
Euler Limit of $\frac{x^x-x}{1-x+\ln(x)}$ Without L'Hopital
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9
Algebra Polynomials Problem 1
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8
Finding the shortest distance between two Parabolas
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8
Why is $\cos^2(\arccos(x)) = x^2$ instead of $\cos(x)$?
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8
What counts as a "known" function
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7
sum of the digits of the number $(5^{2015})(2^{2018})$
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7
How to compute $\int_0^{\frac{\pi}{2}}\frac{\arctan(\sqrt{\tan(x)})}{\tan(x)}dx$
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7
Show $\sum_{k=m}^n {k \choose r} = {n+1 \choose r+1} - {m \choose r+1}$
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6
Find the value of $S$, sum of some Harmonic Numbers
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6
Reciprocal basis in same vector space vs dual basis in its dual space
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