Question

Calcule a som da P.G. de (1,5,25,125,...,1.953.125)

Answer 1

TEMOS
A1=1
Q=5
SN=A1XQ^N-1/Q-1
AN=A1XQ^N-1
1953125=5^N-1
5^9=5^N-1
N-1=9
N=10
S10=1X5^9/4
S10=1953125/4
S10=488.221,25

Answer 2

resolução!

q = a2 / a1

q = 5 / 1

q = 5

an = a1 * q^n - 1

1953125 = 1 * 5^n - 1

1953125 / 1 = 5^n - 1

1953125 = 5^n - 1

5^9 = 5^n - 1

n - 1 = 9

n = 9 + 1

n = 10

Sn = a1 ( q^n - 1 ) / q - 1

Sn = 1 ( 5^10 - 1 ) / 5 - 1

Sn = 1 ( 9765625 - 1 ) / 4

Sn = 1 * 9765624 / 4

Sn = 2441406