brainjam

Member for 13 years, 3 months
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brainjam.ca
Toronto, Canada

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geometry

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Answers

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22

Does there exist a circle with EXACTLY two rational points, no more, no less?

Jan 7, 2021

7

Dandelin's proof of Pascal's theorem

Oct 12, 2021

6

An ellipse inside a heptagon

Mar 23, 2021

6

Convexifying a Concave Polygon by Reflections

Nov 21, 2021

5

On a Geometric Proof (Ahlfors) that the Cross ratio is real if and only if four points lie on a circle or straight line

Aug 19, 2021

Questions

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7

Is there a name or a reference for these aperiodic rhomboidal tilings?

May 17, 2018

7

Is there a geometric construction that finds the intersection of two conics, given only five points on each?

Aug 7, 2019

7

For a recursion based on $x+y+z+2\sqrt{xy+yz+zx},$ does what happens in $\mathbb Z\left[\sqrt n\right]$ stay in $\mathbb Z\left[\sqrt n\right]$?

Dec 17, 2020

7

Show that the locus of a point in this geometric construction is a conic

Oct 27, 2021

5

Is there an explanation for the patterns formed by the binomial coefficients $\binom{n+d-1}{d}\pmod{512}$?

Sep 22, 2010

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geometry

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euclidean-geometry

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circles

54

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Reputation

+10

On a Geometric Proof (Ahlfors) that the Cross ratio is real if and only if four points lie on a circle or straight line

+30

References for a formula generalizing the "cross ratio = -1" characterization of harmonic division.

+35

Enclosing a lamp in space via Minkowski's theorem

+10

Collinearity in bicentric pentagon

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