Question

Calcule a soma dos 11 primeiros termos da P.G. (2, 4, 8, 16,...).​

Answer 1

Sn= a1(q^n-1)/q-1

2(2^11-1)/1

2(2048-1)/1

2×2047/1

4094

Answer 2

A₁₁ = ?

a₁ = 2

q = a₂ / a₁

q = 4 / 2

q = 2

n = 11

An = a₁ * qⁿ ⁻ ¹

A₁₁ = 2 * 2¹¹ ⁻ ¹

A₁₁ = 2 * 2¹⁰

A₁₁ = 2 * 1024

A₁₁ = 2048

Sn = a₁ * (qⁿ - 1) / q - 1

S₁₁ = 2 * (2¹¹ - 1) / 2 - 1

S₁₁ = 2 * (2048 - 1)

S₁₁ = 2 * 2047

S₁₁ = 4 094