Question

determine o oitavo termo da PG (1800, -180,...)

Answer 1

a₁ = 1 800

q = a₂ / a₁

q = - 180 / 1800

q = - 1 / 10

An = a₁ * qⁿ ⁻ ¹

A₈ = 1 800 * ( - 1/10 ) ⁸ ⁻ ¹

A₈ = 1 800 * ( - 1/10 ) ⁷

A₈ = 1 800 * ( - 1/10 000 000)

A₈ = - 18 / 100 000

A₈ = - 9 / 50 000

Answer 2

Resposta:

a₁=1800

a₂=-180

q=a₂/a₁=-180/1800=-1/10

an=a₁*qⁿ⁻¹

a₈ = 1800 * (-1/10)⁸⁻¹ =1800 * (-1/10⁷)

a₈ =-1800 * 10⁻⁷ = -1,8 * 10⁻⁴