Question

calcula arazão muma P.G conhecendo a1=4/25; a9=62500

Answer 1

$a_n=a_9=62500\\ a_1={4\over25}\\ \\ n=9\\ q=?\\ \\ a_n=a_1.q^{n-1}\\ \\ 62500={4\over25}.q^{9-1}\\ \\ 62500\div{4\over25}=q^8\\ \\ 62500\times{25\over4}=q^8\\ \\ simplificar~~~ 62500\div4=15625\\ \\ 15625\times25=q^8\\ \\ q^8=390625\\ \\ q=\sqrt[8]{390625} \\ \\ q=\sqrt[8]{5^8} \\ \\ q=5$

Answer 2

resolução!

a9 = a1 * q^8

62500 = 4/25 * q^8

62500 ÷ 4/25 = q^8

62500 * 25/4 = q^8

1562500/4 = q^8

390625 = q^8

5^8 = q^8

q = 5