Question

Calcule a soma dos 6 primeiros termos da PG ( 4, 12, 36,.... )​

Answer 1

◼️ Encontrar a razão da PG

• $\small{q=a2/a1}$

• $\small{q=12/4}$

• $\small{q=3}$

◼️Calculando essa soma (s6)

• $\small{sn=a1.(q^{n}-1)/(q-1)}$

• $\small{s6=4.(3^{6}-1)/(3-1)}$

• $\small{s6=4.(729-1)/2}$

• $\small{s6= 2.( 728)}$

• $\small{s6= 1456}$

◼️A soma será igual a 1456