Question

Calcule a soma dos 24 primeiros termos de cada PA a) 5,10,15...) b) 3,3,3...)

Answer 1

A) Razão = A2 - A1 ➡ 10 - 5 ➡ Razão = 5

PA de 24 termos:

(5, 10, 15... 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120)

Sn = (A1 + An) · n / 2

Sn = (5 + 120) · 24 / 2

Sn = 125 · 24 / 2

Sn = 3000 / 2

Sn = 1.500

B) Razão = A2 - A1 ➡ 3 - 3 ➡ Razão = 0

PA de 24 termos:

(3, 3, 3... 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3)

Sn = (A1 + An) · n / 2

Sn = (3 + 3) · 24 / 2

Sn = 6 · 24 / 2

Sn = 144 / 2

Sn = 72