Question

Which of the following are G.P. ? If they are G.P, write three more terms,

-2, -6, -18, ……

Answer 1

Given: t₁ = -2, t₂ = -6, t₃ = -18

∴ -2, -6, -18, is a G.P. 

where a = -2 and r = 3 

a_n = a . r^n-1 = 

a₄ = a . r³ = (-2) × 3³ = -2 × 27 = -54 

a₅ = a . r⁴ = (-2) × 3⁴ = -2 × 81 = -162 

a₆ = a . r⁵ = (-2) × 3⁵ = -2 × 243 = -486