For every positive integer n, the nth term of sequence is given by an= 1/n - 1/(n+1). What is the sum of the first 90 terms?
Choose one:
A) 0 B) 1 C) 25 D) 89/90 E) 90/91
a1 = 1 - 1/2   a2 = 1/2 - 1/3   a3 = 1/3 - 1/4   etc...   a90 = 1/90 - 1/91   The sum of these terms is 1-1/91 = 90/91   The answer is 90/91.
<result>E</result>
For every positive integer n, the nth term of sequence is given by an= 1/n - 1/(n+1). What is the sum of the first 90 terms?