## § Geometric proof of Cauchy Schwarz inequality

- All credit goes to
`p0a`

on `##math`

on freenode for teaching me this proof!

Here's one fun application of Cauchy-Schwarz. We can apply it to two vectors
$x=(\sqrt a, \sqrt b)$ and $y=(\sqrt b, \sqrt a)$ to derive the AM-GM
inequality: