Question

qual o valor do primeiro termo de uma pg com 9 termos cujo razao seja 2 e onde o ultimo termo vale 256?

Answer 1

$a_1=?\\ n=9\\ q=2\\ a_n=256\\\\\\ a_n=a_1*q^{n-1}\\\\\\ 256=a_1*2^{9-1}\to \\\\256=a_1*2^{8}\to \\\\256=a_1*256\to \\\\ \frac{256}{256} =a_1\to\\\\ a_1=1\\\\\\\\ PG(1, 2, 4, 8, 16, 32, 64, 128, 256)$