Question

If the number of terms of an A.P. be 2n + 3, then find the ratio of sum of the odd terms to the sum of even terms.

Answer 1

Given: Total number of terms = 2n + 3

Let the first term = a

and the common difference = d

Then, a_k = a + (k – 1)d …(i)

Let S₁ and S₂ denote the sum of all odd terms and the sum of all even terms respectively.

Then,

S₁ = a₁ + a₃ + a₅ … + a_2n+3