The Wallis product for pi, proved geometrically

A geometric proof of a famous Wallis product for pi.
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Here's a supplemental blog post, expanding some of the rigor of this proof, along with other interesting tidbits about surrounding topics that we didn't fit into the video:
https://www.3blue1brown.com/sridhars-corner/2018/4/17/wallis-product-supplement-dominated-convergence

Another approach to this product by Johan Wästlund:
http://www.math.chalmers.se/~wastlund/monthly.pdf

With more from Donald Knuth building off this idea:
https://apetresc.wordpress.com/2010/12/28/knuths-why-pi-talk-at-stanford-part-1/
Music by Vincent Rubinetti:
https://vincerubinetti.bandcamp.com/album/the-music-of-3blue1brown

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Видео The Wallis product for pi, proved geometrically канала 3Blue1Brown