If a, a1 , a2 , a3 , ..........,a2n, b are in AP and a, g1 , g2 , g3 ,

1.	If a, a1 , a2 , a3 , ..........,a2n, b are in AP and a, g1 , g2 , g3 , .....................g2n, b are in G..P. and h is the single harmonic mean of a & b, then a1 + a2n/g1g2n + a2 + a2n - 1/g2g2n -1 + an + an + 1gngn + 1 is equal to(a) 2n/h(b) 2nh(c) nh(d) n/h
Answer» Correct option (a) 2n/h Explanation: a₁ + a_2n = a₂ + a_2n–1 =......................= a_n +a_n+1 = a+b and g₁g_2n = g₂.g_2n–1=.....................= g_n.g_n+1 = ab Also h = 2ab/ a + b Given expression = a + b/ab + a + b/ab + ........a+b/ab(n times) = n a + b/ab = n.2/h = 2n/h

If a, a1 , a2 , a3 , ..........,a2n, b are in AP and a, g1 , g2 , g3 , .....................g2n, b are in G..P. and h is the single harmonic mean of a & b, then a1 + a2n/g1g2n + a2 + a2n - 1/g2g2n -1 + an + an + 1gngn + 1 is equal to(a) 2n/h(b) 2nh(c) nh(d) n/h

Answer»

Correct option (a) 2n/h

Explanation:

a₁ + a_2n = a₂ + a_2n–1 =......................= a_n +a_n+1 = a+b and g₁g_2n

= g₂.g_2n–1=.....................= g_n.g_n+1 = ab

Also h = 2ab/ a + b

Given expression = a + b/ab + a + b/ab + ........a+b/ab(n times)

= n a + b/ab = n.2/h = 2n/h