อืม น่าเห็นใจจริง ๆ
มิถุนายน 2012 บ้านเรา net ยังไม่ถึงไหนเลย
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Gregory's series, is an infinite Taylor series expansion of the inverse tangent function.
It was discovered in 1668 by James Gregory.
It was re-rediscovered a few years later by Gottfried Leibniz,
who re obtained the Leibniz formula for ฯ as the special case x = 1 of the Gregory series.[1]
The earliest person to whom the series can be attributed with confidence is
Madhava of Sangamagrama (c. 1340 โ c. 1425).
The original reference (as with much of Madhava's work) is lost,
but he is credited with the discovery by several of his successors in
the Kerala school of astronomy and mathematics founded by him.
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