Let a and b are positive real numbers. If a, A_1, A_2, b are in arithmetic progression a, G_1, G_2, b are in G.P. and a, H_1, H_2, b are in H.P. show that \frac{G_1 G_2}{H_1 H_2}=\frac{A_1+A_2}{H_1+H_2}=\frac{(2 a+b)(a+2 b)}{9 a b}: Sequence & Series (Mathematics) | DivineJEE