A Dissection Proof of Leibniz's Series for π/4

  title={A Dissection Proof of Leibniz's Series for $\pi$/4},
  author={Mits Kobayashi},
  journal={Mathematics Magazine},
  pages={145 - 150}
Summary Inspired by Lord Brouncker's discovery of his series for ln 2 by dissecting the region below the curve 1⁄x, Viggo Brun found a way to partition regions of the unit circle so that their areas correspond to terms of Leibniz's series for π⁄4. Brun's argument involved ad hoc methods which were difficult to find. We develop a method based on usual techniques in calculus that leads to Brun's result and that applies generally to other related series. 
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