Question

Boa noite!
Socorro pifei

1 )Calcule o número de termos da PG (1/9, 1/3, 1 , ..., 729)


2) Qual o décimo termo da PG (-8,-4,-2,...)

Answer 1

Resposta:

Explicação passo-a-passo:

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1 )Calcule o número de termos da PG (1/9, 1/3, 1 , ..., 729)

729 = 1/9 . $q^{n-1}$

$3^{6} =3^{-2} .3^{n-1}$

6 = -2 + n - 1

n = 6 + 3

n = 9

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2)Qual o décimo termo da PG (-8,-4,-2,...)

$a_{10} = a_{1} .q^{9}$

$a_{10} = -8 . (2^{-1} )^{9}$

$a_{10} =-1.2^{3} .2^{-9}$

$a_{10} = -1 . 2^{-6}$

$a_{10} = \frac{-1}{64}$

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espero ter ajudado!!!