Question

Quantos termos têm a PA (6,12,18...2016). E qual a soma dos termos dessa PA?

Answer 1

an=a1+(n-1).d
2016=6+(n-1).6
2016=6+6n-6
6n=2016
n=2016/6
n=336

a P.A tem 336 termos, vamos a soma dos termos.
sn=(a1+an).n/2
sn=(6+2016)×336/2
sn=2022×168
sn=339696