Roboguru

Diketahui barisan bilangan geometri dengan dan . T...

Diketahui barisan bilangan geometri dengan begin mathsize 14px style U subscript 3 equals 48 end style dan begin mathsize 14px style r a s i o equals 4 end style. Tentukan :

a. Rumus rumus suku ke-begin mathsize 14px style n end style

b. begin mathsize 14px style U subscript 2 end style dan begin mathsize 14px style U subscript 7 end style

Jawaban:

Rumus barisan geometri

begin mathsize 14px style U subscript n equals a r to the power of n minus 1 end exponent U subscript 3 equals 48 comma space r equals 4 end style 

Menentukan suku pertama begin mathsize 14px style open parentheses a close parentheses end style

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell U subscript 3 end cell equals cell a r to the power of n minus 1 end exponent end cell row 48 equals cell a open parentheses 4 close parentheses to the power of 3 minus 1 end exponent end cell row 48 equals cell a open parentheses 4 close parentheses squared end cell row 48 equals cell 16 a end cell row a equals cell 48 over 16 end cell row blank equals 3 end table end style

a. Rumus suku ke-undefined

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell U subscript n end cell equals cell a r to the power of n minus 1 end exponent end cell row blank equals cell 3.4 to the power of n minus 1 end exponent end cell end table end style

b. undefined dan undefined

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell U subscript 2 end cell equals cell 3 open parentheses 4 close parentheses to the power of 2 minus 1 end exponent end cell row blank equals cell 3 open parentheses 4 close parentheses end cell row blank equals 12 end table end style

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell U subscript 7 end cell equals cell 3 open parentheses 4 close parentheses to the power of 7 minus 1 end exponent end cell row blank equals cell 3 open parentheses 4 close parentheses to the power of 6 end cell row blank equals cell 3 open parentheses 4.096 close parentheses end cell row blank equals cell 12.288 end cell end table end style

Jadi, begin mathsize 14px style U subscript 2 equals 12 comma space U subscript 7 equals 12.288 end style.

0

Ruangguru

RUANGGURU HQ

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

Coba GRATIS Aplikasi Ruangguru

Produk Ruangguru

Produk Lainnya

Hubungi Kami

Ikuti Kami

©2021 Ruangguru. All Rights Reserved