Question 966131
Index____________Term
1________________1
2________________1+(n-1)
3________________1+(n-1)
4________________1+(n-1)
That much helps understand the absolute values of the terms,
but the given sequence ALTERNATES in sign.




Index____________Term
1________________{{{1*(-1)^(n+1)}}}------forces sign to be positive; n+1=1+1=2.
2________________1+(n-1)
3________________1+(n-1)
4________________1+(n-1)



EACH term will use the same formula:
Index_______________Term
1__________________{{{(1+(n-1))(-1)^(n+1)}}}
2___________________{{{(1+(n-1))(-1)^(n+1)}}}



{{{highlight((1+(n-1))(-1)^(n+1))}}}, still from the point of view of a simple arithmetic sequence altered to alternate in sign.  This can really be made simpler:


{{{highlight(highlight_green(n*(-1)^(n+1)))}}}