Question

Сумма членов геометрической прогрессии равна 441, b1=224, q=0.5, найдите n.

Answer 1

b1•(q^n–1) 224•(q^n–1)
Sn = --------------- = ------------------ =
q–1 -0,5

= –448•(q^n–1)

–448•q^n+448 = 441
–448•q^n = –7
q^n = 1/64
(1/2)^n = (1/2)^6
n=6