Gregory series


The Gregory series is an alternating sum whose value is a quarter that of π:

π4=i=0(-1)i12i+1=1-13+15-17+19-

(The approximate decimal value of this expression is 0.7853981633974483…)

More generally, a Gregory series for a given n is

i=0(-1)in2i+12i+1.

The Gregory series is named after the Scottish astronomer and astrologer James Gregory.

Title Gregory series
Canonical name GregorySeries
Date of creation 2013-03-22 17:35:33
Last modified on 2013-03-22 17:35:33
Owner PrimeFan (13766)
Last modified by PrimeFan (13766)
Numerical id 4
Author PrimeFan (13766)
Entry type Definition
Classification msc 11-00
Classification msc 51-00
Classification msc 01A16
Classification msc 01A20
Classification msc 01A25
Classification msc 01A32
Classification msc 01A40
Related topic TaylorSeriesOfArcusTangent