Question

Numa P.G a1=1/4 e a9=128.calcule a razão
Dessa P.G.

Answer 1

Resposta:

Explicacão passo;

ç1)  n = ?

    a1 = 1/2

   q= 2

an = 128

an = a1 . q ^n - 1  

q^ n-1 = an/a1 = 128 /1/2 = 256

2^ n -1 = 2^8

n - 1 = 8

n = 9

2) An = 125

   A1 = 1/ 125

   q = 5  

An = A1  q "n - 1

125 = 1/25  5"n-1

125 .  25 = 5" n-1

5"3  5^2 = 5^ n/5

5^3 .  5^2 . 5 = 5 ^n

5^6 = 5n

n=6

3)   x . x = 24 . 6

    x¨2 = 144

   x = V144

  x = 12

portanto a sequencia ´{6,12,24}