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Theorems · Theorem · real analysis

Real.tendsto_sum_pi_div_four

Filter.Tendsto (fun k => ∑ i ∈ Finset.range k, (-1) ^ i / (2 * ↑i + 1)) Filter.atTop (nhds (Real.pi / 4))

Leibniz's series for `π`. The alternating sum of odd number reciprocals is π / 4, proved by using Abel's limit theorem to extend the Maclaurin series of arctan to 1.

Defined in
Mathlib.Analysis.Real.Pi.Leibniz
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Foundations
Depth 277 from the axioms · uses propext, Classical.choice, Quot.sound

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