Question

A Soma dos termos da PG (5, 50,...500000) é

Answer 1

$A_{n} = a_{1} . Q^{(n -1)}$
500000/5 = 10⁽ⁿ ⁻¹⁾
100000 = 10⁽ⁿ ⁻¹⁾
10⁵ = 10⁽ⁿ ⁻¹⁾

5 + 1 = n
6 = n

$S_{n} = \frac{a_{1} . (q^n -1) }{q -1}$
s6 = 5 . (10⁶ -1)/10 -1
s6 = 5 . 999999/9
s6 = 5 . 111111
s6 = 555555