Answer: 2n+1 - 2.
- A 2n+1 - 2
- B 2n - 1
- C 2n+1
- D 2(2n - 1)
Correct answer: A. 2n+1 - 2
Explanation: GP with first term a=2, ratio r=2, n terms. Sum = a(rⁿ−1)/(r−1) = 2(2ⁿ−1)/1 = 2·2ⁿ−2 = 2n+1−2.
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