Question

5th,8th,11th terms of a g.p are in​

Answer 1

EXPLANATION.

5th, 8th, 11th term of a G.P.

As we know that,

Formula of :

General term of a G.P.

⇒ a + ar + ar² + ar³ + . . . . .

⇒ Tₙ = a.rⁿ⁻¹.

Using this formula in the equation, we get.

⇒ T₅ = a.r⁵⁻¹.

⇒ T₅ = ar⁴.

⇒ T₈ = a.r⁸⁻¹.

⇒ T⁸ = ar⁷.

⇒ T₁₁ = a.r¹¹⁻¹.

⇒ T₁₁ = a.r¹⁰.

                                                                                                                   

MORE INFORMATION.

Sum of n terms of a G.P.

The sum of first n terms of an G.P. is,

⇒ Sₙ = [a(1 - rⁿ)/(1 - r)]   when   r < 1.

⇒ Sₙ = [a(rⁿ - 1)/(r - 1)]   when   r > 1.

⇒ Sₙ = nr  when  r = 1.