Question

Qual o 20 termo da PG (5,10,20...)?

Answer 1

Vamos começar calculando a razão:

$razao=\frac{a_2}{a_1}\\\\\\razao=\frac{10}{5}\\\\\\\boxed{razao=2}$

Agora, utilizando a equação do termo geral da PG, podemos determinar o 20° termo:

$a_n=a_1~.~q^{n-1}\\\\\\a_{20}=5~.~q^{20-1}\\\\\\a_{20}=5~.~2^{19}\\\\\\a_{20}=5~.~524288\\\\\\\boxed{a_{20}=2621440}$