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Mathematics
David C. Ullrich's user avatar
David C. Ullrich's user avatar
David C. Ullrich's user avatar
David C. Ullrich
  • Member for 9 years
  • Last seen more than a month ago
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About

(1954–2024)

Nothing about me is of any interest whatever.

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Top posts
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82
Are there theoretical applications of trigonometry?
May 2, 2016
63
Did Joseph Fourier ever make a pure mathematical mistake?
Jun 24, 2016
58
What is the average rational number?
May 28, 2016
50
Is every noninvertible matrix a zero divisor?
Jul 15, 2015
43
Problem of a slow thinker
Jul 14, 2018
40
Does every infinite field contain a countably infinite subfield?
Nov 7, 2015
32
Second derivative of $\det(\mathbb{1}+tA)$?
Jun 25, 2018
29
Reference for "distributional derivative being zero implies being constant"
Aug 15, 2015
28
If $f$ is a smooth real valued function on real line such that $f'(0)=1$ and $|f^{(n)} (x)|$ is uniformly bounded by $1$ , then $f(x)=\sin x$?
Jul 19, 2016
25
If every five point subset of a metric space can be isometrically embedded in the plane then is it possible for the metric space also?
Jun 17, 2016
Top Meta posts
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2
75
"What have you tried?"...
22
"... including any attempts you have made to solve it."
14
Reference Request not a request for a reference?
13
Etiquette dilemma
13
Are questions about history on topic?
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12
Finding all roots of a polynomial
6
Conditional \bye?