Question

determine o numero de termo da p.g 3.(1/3)(1/27)(1/19.683)

Answer 1

a1 = 3
a2 = 1/3
a3 = 1/27
an = 1/19683

q = 1/27: 1/3 = 1/27 * 3/1 = 3/27 = 1/9 ***
1/19683 =  3 * (1/9 )ⁿ⁻¹
( 1/9)ⁿ⁻¹  = 1/19683 : 3/1 =  1/19683 * 1/3 = 1/59049
[( 1/3)²]ⁿ⁻¹ = (1/3)¹⁰
( 1/3)²ⁿ⁻²  ( 1/3)¹⁰
2n - 2 = 10
2n = 10 + 2
2n = 12
n = 6 ****