Notes, Thoughts & Puzzles
Welcome to my digital garden. Here I share informal mathematical notes, historical curiosities,
solutions to interesting problems, and personal reflections on academic life.
Analysis
Golden Ratio
Dec 27, 2025
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8 min read
We usually think of differentiation and inversion as completely different operations.
But what happens if we force them to be the same? The solution to $f'(x) = f^{-1}(x)$ leads us unexpectedly to the Golden Ratio and generalized "Metallic Means".
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Calculus
Geometry Challenge
Dec 20, 2025
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6 min read
A classic optimization problem proposed by Jose M.: What is the largest ellipse that fits inside a circle of radius $r$?
By analyzing the tangency conditions of the curves, we derive the maximum area $A = \frac{2\sqrt{3}}{9}\pi r^2$.
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Number Theory
Problem Solving
Dec 10, 2025
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5 min read
Computing the sum $\sum_{k=1}^{n} \lfloor \sqrt{k} \rfloor$ term by term is inefficient for large $n$.
In this post, we derive an elegant closed-form formula by regrouping the terms based on the intervals between consecutive perfect squares.
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