Diketahui suku ke-3 dan suku ke-6 suatu deret geom...

Diketahui suku ke-3 dan suku ke-6 suatu deret geometri berturut-turut adalah 48 dan 384. jumlah lima suku pertama dari deret tersebut adalah ...

Jawaban:

$R u m u s space s u k e space k e minus n space y a i t u U subscript n equals space a r to the power of n minus 1 end exponent r u m u s space j u m l a h space s a m p a i space s u k u space k e minus n space a d a l a h S subscript n equals fraction numerator a left parenthesis r to the power of n minus 1 right parenthesis over denominator r minus 1 end fraction colon space r space greater than space 1 D a n space u n t u k space m e n c a r i space r a s i o space a d a l a h space r to the power of m minus n end exponent equals U subscript m over U subscript n m a k a comma r to the power of left parenthesis 6 minus 3 right parenthesis end exponent equals space U subscript 6 over U subscript 3 equals 384 over 48 equals 8 r cubed equals 8 r equals 2 U subscript n equals space a r to the power of n minus 1 end exponent a equals U subscript n over r to the power of n minus 1 end exponent equals U subscript 3 over r to the power of 3 minus 1 end exponent equals 48 over 2 squared equals 12 S e h i n g g a colon S subscript n equals fraction numerator a left parenthesis r to the power of n minus 1 right parenthesis over denominator r minus 1 end fraction semicolon space r greater than space 1 S subscript 5 equals fraction numerator 12 left parenthesis 2 to the power of 5 minus 1 right parenthesis over denominator 2 minus 1 end fraction equals space 372 J u m l a h space s u k u space p e r t a m a n y a space y a i t u space 372$

Ruangguru

RUANGGURU HQ

Jl. Dr. Saharjo No.161, Manggarai Selatan, Tebet, Kota Jakarta Selatan, Daerah Khusus Ibukota Jakarta 12860

Coba GRATIS Aplikasi Ruangguru

Download di Google Play

Download di Appstore

Produk Ruangguru

Produk Lainnya

Bantuan & Panduan

Hubungi Kami

081578200000

[email protected]

02140008000

Ikuti Kami

Instagram

Facebook

Twitter

Youtube