# Linus Oey

## 12 Flips | 1 Magazine | 6 Followers | @linusoey | Keep up with Linus Oey on Flipboard, a place to see the stories, photos, and updates that matter to you. Flipboard creates a personalized magazine full of everything, from world news to life’s great moments. Download Flipboard for free and search for “Linus Oey”

### Learn Math Skills with Private Math Tutor (iPad & Online) | Thinkster Math

After starting Thinkster, Catelin earned distinguished marks in math on the KPrep test, placing in the top 95% of her school.<p>Carys was the only 4th …

Mathematics

### How many ways can you parenthesize an expression?

Mathematical diagrams are usually rectangles, sometimes triangles. So pentagonal diagrams are odd.<p>Here’s a pentagonal diagram from a paper by John …

### Quadratic reciprocity and Zolotarev’s Lemma

I want to explain a beautiful proof of the Law of Quadratic Reciprocity from c. 1874 due to Egor Ivanovich Zolotarev (1847-1878). Some time ago I …

Music Videos

### Numbers and Constructibility

This article follows my article on the construction of numbers where I introduced natural, rational, real and complex numbers. It’s not necessary to …

### math-a-magic:

<b>Solution by Radicals:</b><p>Solutions to the general equations<p>ax+b=0<p>ax^2+bx+c=0<p>ax^3+bx^2+cx+d=0<p>ax^4+bx^3+cx^2+dx+e=0<p>can be expressed through radicals.<p>There does not exist a general solution by radicals for equations of degree 5 or more - a fact that can be proved using Galois Theory and the fact that Sn is not solvable for n greater than or equal to 5.<p>I was reading about this again yesterday! I think I’ll put the proof up on here.

### Fun and Games

Vincent Aleven & Yanjin Long<p>For Carnegie Mellon University's Vincent Aleven, the claim was too good to be true.<p>"It only takes about 42 minutes to …