Question

Determine a soma dos numeros pares de 2 a 60

Answer 1

a₁ = 2

an = 60

r = 2

60 = 2 + (n - 1) . 2 ------- 60 - 2 = (n - 1) . 2 ------ 58 = (n - 1) . 2

58/2 = n - 1 ------ 29 =  n - 1 ----- n = 29 + 1 ----- n = 30



S₃₀ = [(2 + 60) . 30]/2 ------ S₃₀ = (62) . 15 ---- S₃₀ = 930