In an arithmetic sequence a1, a2, a3, . . . , we know a1 = 1 and an = 1/n for some integer n > 1.
(a) What is the common difference of this arithmetic sequence, in terms of n?
(b) Compute the value of an+1.
We have
1 , 1/2, 1/3, 1/4 , etc
a) the common difference is 1/ (n + 1) - 1/n = (n - (n +1)) / (n* (n+1)) =
-1 / (n(n+1))
b) an+ 1 = 1/n - 1 / (n(n+1)) = (n + 1 - 1)/ (n (n + 1)) = n / (n (n +1)) = 1/ (n +1)
+69 
