1. The problem statement, all variables and given/known data Let s be the sum of the alternating series [tex]\sum[/tex](from n=1 to [tex]\infty[/tex])(-1)n+1an with n-th partial sum sn. Show that |s - sn| [tex]\leq[/tex]an+1 2. Relevant equations I know about Cauchy sequences, the Ratio test, the Root test 3. The attempt at a solution I really have no idea where i'm meant to start with this question. I didn't know whether I thne have to take more partial sums i.e. partial sums of the n-th partial sum and work with it from there, or something else. I would be really grateful if someone could help me out.