find the sum of the series?

sigma notation (( (-1)^n * pi^2n)) / (6^2n * (2n)!) as n=0 goes to ininity

robust2008-04-29T00:21:23Z

Favorite Answer

The maclaurin series for cos x is

1 - x^2/2! + x^4/4! - x^6/6!....

If we let x = pi/6 in the above expansion we recognize that your series is the series of cospi/6

√3/2

latassa2016-10-31T12:33:15Z

Find The Sum Of Series

Anonymous2008-04-29T00:18:21Z

It's a cos expansion evaluated at Pi/6 =>

=cos(Pi/6)=Sqrt(3)/2

kevin b2008-04-29T00:15:13Z

(-1)^n (Pi^2n)/(6^2n*(2n)!) use ratio test

(Pi^2(n+1)/6^2n*(2(n+1)!))*(6^2n*(2n)!)/(Pi^2n)

Pi^2*(2n)!/(2n+2)(2n+1)(2n!)

Pi^2/(2n+2)(2n+1)=Pi^2/INFINITY

=0