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Jika diketahui deret  , rumus jumlah suku ke- adalah …

Pertanyaan

Jika diketahui deret begin mathsize 14px style 4 plus 2 plus 1 plus horizontal ellipsis end style , rumus jumlah suku ke-begin mathsize 14px style n end style adalah …

  1. begin mathsize 14px style S subscript n equals 8 over 3 left parenthesis 2 minus 2 to the power of 3 minus n end exponent right parenthesis end style 

  2. begin mathsize 14px style S subscript n equals 8 minus 2 to the power of 3 minus n end exponent end style 

  3. begin mathsize 14px style S subscript n equals 1 plus 2 to the power of 3 minus n end exponent end style 

  4. begin mathsize 14px style S subscript n equals 8 over 3 left parenthesis 1 plus 2 to the power of n right parenthesis end style 

  5. begin mathsize 14px style S subscript n equals 8 over 3 left parenthesis 1 minus 2 to the power of n right parenthesis end style 

Pembahasan Video:

Pembahasan Soal:

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row r equals cell U subscript 2 over U subscript 1 end cell row blank equals cell 2 over 4 end cell row blank equals cell 1 half end cell row blank blank blank end table end style 

karena table attributes columnalign right center left columnspacing 0px end attributes row blank blank size 14px r end table table attributes columnalign right center left columnspacing 0px end attributes row blank size 14px less than blank end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank size 14px 1 end table maka:

begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell S subscript n end cell equals cell fraction numerator a open parentheses 1 minus r to the power of n close parentheses over denominator 1 minus r end fraction end cell row cell S subscript n end cell equals cell fraction numerator 4 open parentheses 1 minus open parentheses begin display style 1 half end style close parentheses to the power of n close parentheses over denominator 1 minus begin display style 1 half end style end fraction end cell row cell S subscript n end cell equals cell fraction numerator 4 minus 4 open parentheses 1 half close parentheses to the power of n over denominator 1 half end fraction end cell row cell S subscript n end cell equals cell 8 minus 8 open parentheses 1 half close parentheses to the power of n end cell row cell S subscript n end cell equals cell 8 minus 2 cubed times 1 over 2 to the power of n end cell row cell S subscript n end cell equals cell 8 minus 2 to the power of 3 minus n end exponent end cell row blank blank blank row blank blank blank end table end style 

Jadi, jawaban yang tepat adalah B.

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 12 April 2021

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