Question

Determine a fórmula do termo geral de cada PG.

a) (2,8,...)
b) (3,9,...)
c) (2,1,...)

Answer 1

a) (2,8,...) = 

r = 8/2 = 4  

an = a1.q^(n-1) ==> an = 2.4^(n-1)
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b) (3,9,...)

r = 9/3 = 3  

an = a1.q^(n-1) ==> an = 3.3^(n-1)
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c) (2,1,...)

r = 1/2   

an = a1.q^(n-1) ==> an = 2.(1/2)^(n-1)