lim n^2/(1+2+3+...+n) n--> inf

We know that 1+2+3+...+n = n(n+1)/2

==> lim 2n^2/n(n+1) = 2lim n^2/ lim n^2+n

Let us divide by the highest power n^2

==> 2lim (n^2/n^2) / lim n^2(1+1/n)

Reduce similar:

==> 2 lim(1)/lim (1+1/n) when n--> inf

==> 2/1+0 = 2

## See eNotes Ad-Free

Start your **48-hour free trial** to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Already a member? Log in here.