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Grigory Merzon

@g-merzon.mathstodon.xyz.ap.brid.gy

[bridged from mathstodon.xyz/@g_merzon on the fediverse by fed.brid.gy ]

Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 12/07/2026

Long time ago I've made a web-version of slides about sliding ladder & Copernicus' thm. Now I'm uploading an English translation: dev.mccme.ru/~merzon/mirror/mp-cat/… (Math is from the book 'Lines and curves', pics were made by M.P.)

A kitten sitting on a ladder leaning against a wall

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 11/01/2026

a part of the English translation of our book «Basics of Mathematics in Problems (with solutions and comments)» is now freely available at dev.mccme.ru/~merzon/pscache/v08eng… «In the mathematical classes of School #57, the well-know Moscow […] [Original post on mathstodon.xyz]

title page «Basics of Mathematics in Problems»

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 21/12/2025

in quaternions conjugation is a 'polynomial' function: bar q = -1/2 (q + iqi + jqj + kqk) it doesn't contradict anything (and it's easy to prove) but still looks very weird (to me)

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 01/11/2025

just playing with manim

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 22/08/2025

take an arbitrary polynomial P(x) with non-negative coefficients and raise it to a large power we'll get a lot of monomials with various coefficients… let's look not at the individual coefficients but at the plot of all coefficients what will we see? (one can type e.g. something like […]

mathstodon.xyz

Original post on mathstodon.xyz

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 04/01/2025

how to compute (an approximation to) π? one recipe I like: take a couple of iterations of x→x+sin(x) if x=π+ε then x+sin(x)≈π+ε³, so this converges really fast: after just 4 iterations the error is just about 10^{-100} (!) (compare to, say, 1-1/3+1/5-… — where even with 2000 terms the […]

mathstodon.xyz

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 08/12/2024

y=x³+px+q for different (p,q)

a table showing plots of y=x^3+px+q for different (p,q)

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Grigory Merzon @g-merzon.mathstodon.xyz.ap.brid.gy · 27/11/2024

The sum of two cubes, X³+Y³ is divisible by X+Y. What about the sum of three cubes? Well, modulo X+Y+Z we have X³+Y³+Z³=X³+Y³-(X+Y)³=-3X²Y-3XY²=-3XY(X+Y)=-3XYZ. So X+Y+Z divides X³+Y³+Z³-3XYZ. In fact, since X³+Y³+Z³-3XYZ is invariant under (X,Y,Z)→(X,wY,w²Z) with w³=1, we get a complete […]

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