Question

Em uma PG, A1= 4 e o A5= 324. Determine a razão?

Answer 1

Utilizando a equação do termo geral, temos:

$\boxed{a_n~=~a_1~.~q^{n-1}}\\\\\\\\a_5~=~a_1~.~q^{5-1}\\\\\\324~=~4~.~q^4\\\\\\q^4~=~\frac{324}{4}\\\\\\q^4~=~81\\\\\\q~=~\sqrt[4]{81}\\\\\\\boxed{q~=~3}$

Answer 2

resolução!

a5 = a1 * q^4

324 = 4 * q^4

324/4 = q^4

81 = q^4

3^4 = q^4

q = 3