Question

sendo a Pg (1,2,4...) determine a 10

Answer 1

a10 = a1 * q⁹
a10 = 1 * 2⁹
a10 = 1 * 512
a10 = 512

Answer 2

veja..

$a_n=a_{10}=? \\ a_1=1 \\ q=2\div1=2 \\ n=10 \\ \\ a_n=a_1.q^{n-1} \\ \\ a_{10}=1.2^{10-1} \\ \\ a_{10}=1.2^9 \\ \\ a_{10}=512$