Question

Find the sum of the series 1+2+3+4+5+...….. infinity

Answer 1

Answer:

Let infinity be the nth term

Given:a=1,n=n,d=1

Sn=n/2 (2a+(n-1)d)

=n/2 (2+(n-1)1)

=n/2 (2+n-1)

=n/2 (n+1)

= [ n(n+1)] /2

Hope it helps u.....

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