Define S(n) as the sum of the first n terms of an arithmetic sequence.

For some arithmetic sequence there exists positive integers m and n such that S(m) = n and S(n) = m.

What is S(m+n)?

(In reply to re: Solution by Steve Herman)

Yeah, I don't know why I called the first term a+d instead of just a.  I know it's probably not the obvious choice.  I realized this but decided not to change it.

Posted by Jer on 2021-10-07 12:31:44