Question

Calcule o décimo termo da PG (1,3,9...)

Answer 1

$PG (1,3,9...)\\\\ a_{1} =1\\ a_{n} = a_{10} =? \\ q=3\\ n=10\\\\\\ a_{n} = a_{1} *q^{n-1}\\\\\\ a_{10} = 1 *3^{10-1}\to \\\\a_{10} = 1 *3^{10-1}\to \\\\ a_{10} = 1 *3^{9}\to \\\\ a_{10} = 1 *19.683\to \\\\ a_{10} = 19.683$

Answer 2

PG: (1,3,9...)

a1 = 1
a2 = 3
a3 = 9
a10 = ?
n = 10

q = a2/a1 
q = 3/1
q = 3

Termo Geral da PG:

                n - 1
an = a1. q 

                10 - 1
a10 = a1.q
               
               9
a10 = 1.3

a10 = 3⁹
a10 = 19683
***************************
   4
3     =  81

    5
3      =   243

   6
3      =   729

   7
3     =  2187

   8
3     =  6561

   9
3     =  19683