Предмет: Алгебра, автор: love19971

Найдите сумму бесконечной геометрической прогрессии 9; -3 ; 1

Ответы

Автор ответа: dtnth

$b_1=9; b_2=-3; b_3=1$
$q=b_2:b_1=-3:9=-frac{1}{3}$
$|q|<1$
$S=frac{b_1}{1-q}=frac{9}{1-(-frac{1}{3})}=9:frac{4}{3}=9*3:4=27:4=6.75$

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