Answer: n/(n+1).
- A n/(n+1)
- B 1/(n+1)
- C n(n+2)
- D 1/n
Correct answer: A. n/(n+1)
Explanation: Each term 1/(k(k+1)) = 1/k - 1/(k+1) (partial fractions). Sum telescopes to 1 - 1/(n+1) = n/(n+1).
Bar heights for AP 2, 5, 8, 11 with the common difference d=3 marked between consecutive terms.
Concept context
Arithmetic progressions, geometric progressions, and sums