Jumlah tak hingga deret geometri -108+36-12+4-4/3+…adalah a.9 b.3 c.-9 d.-27 e. -81

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Jumlah tak hingga deret geometri -108+36-12+4-4/3+…adalah
a.9 b.3 c.-9 d.-27 e. -81

Jawaban Terkonfirmasi

A = -108
r = 36/-108 = -1/3
Maka:
displaystyle S_infty=frac{a}{1-r} \\ S_infty=frac{-108}{1-(-frac{1}{3})}=frac{-108}{frac{4}{3}} \\ S_infty=-108timesfrac{3}{4} \\ boxed{S_infty=-81;;[E]}

Jawaban Terkonfirmasi

A = -108
r =  -frac{1}{3}
S infty = displaystyle frac{a}{1 - r} \ S infty = displaystyle frac{-108}{1 - ( frac{-1}{3}) } \ S infty = frac{-108}{1 + frac{1}{3} } \ S infty = frac{-108}{ frac{4}{3} } \ S infty = -108 . frac{3}{4} = boxed{-81 = E}