Question

Determine o número de termos de cada p.a finita (1,3,...9)

Answer 1

a1 = 1
an = 9
r = 2

an = a1 + ( n-1).r
9 = 1. + ( n - 1) .2
9-1 = ( n-1).2
n - 1 = 8/2

n = 4+1

n = 5 termos.


att: Jhonny ♥

Answer 2

a1 = 1
a2 = 3
an = 9
r = 3 - 1 = 2 ***
9 = 1 + ( n -1)2
9 = 1 + 2n - 2
9 - 1 + 2 = 2n
2n = 10
n = 5 ****