Question

Determine o 65 termo da p.a (9,4,-1...)

Answer 1

(9, 4, -1, ...)

a₁ = 9

r = 4 - 9 --- r = - 5

an = a₁ + (n - 1) r   ---- a₆₅ = 9 + (65 -1) . (-5) ---- a₆₅ = 9 + 64.(-5)

a₆₅ = 9 - 320 ---- a₆₅ = - 311