Question

If a₁, a₂, .........., $a_n$ are in H.P., then the expression a₁a₂ + a₂a₃ + .......... + $a_{n-1}a_n$ is equal to
(a) n(a₁ - $a_n$)
(b) (n -1)(a₁ - $a_n$)
(c) na₁ $a_n$
(d) (n -1)a₁ $a_n$

Answer 1

(b) (n -1)(a₁ - $a_n$)

is the answer of the question