Question

Calcule o 1 termo de uma Pg cujo décimo é 243 e a razão,3.

Answer 1

$a_1=?\\ a_{10}=243\\ n=10\\q=3\\\\\\ a_n=a_1*q^{n-1}\\\\\\ 243=a_1*3^{10-1}\to \\\\ 243=a_1*3^{9}\to \\\\ 243=a_1*19683\to \\ \\ \frac{243}{19683} =a_1\to\\\\ a_1= \frac{1}{81} \\\\\\\\ PG( \frac{1}{81} , \frac{1}{27} , \frac{1}{9} , \frac{1}{3} ,1, 3, 9, 27, 81, 243)$