8:35

The 3-square problem (classic geometry question)

12:41

A Complex System of Equations | Putnam & Beyond

14:47

THE FACT

32:04

easy derivative but it took me 32 minutes

13:00

The Moving Sofa Problem - Numberphile

7:16

how I remember all the trig and inverse trig derivatives

16:28

A very interesting differential equation.

7:27

Solving An Insanely Hard Problem For High School Students