In an AP Sn=n2-5.What is its tn ? – InterviewSolution

1.

In an AP Sn=n2-5.What is its tn ?

Answer»

GivenSn = n^2 - 5

Then sum of (n - 1) termsSn-1 = (n - 1)^2 - 5

tn = Sn - Sn-1 = n^2 - 5 - (n-1)^2 + 5 = n^2 - 5 - n^2 - 1 + 2n + 5 = 2n - 1

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