In this video, we try to evaluate the Gaussian integral. Featuring some multivariable calculus, some graphs and my Paint illustrations.

Little background:
I first came across this integral in my quantum mechanics class a couple of months ago (see D. Griffiths' Introduction to Quantum Mechanics, 2nd Ed., Problem 1.3). I thought the way to solve this integral was rather cool, and had it in my list of tomake video for a while now. And here it is.