tentukan jumlah 8 suku pertama dari deret geometri 12+6+3+...
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Jawab:
Penjelasan dengan langkah-langkah:
Rumus
[tex]S_{n} = \frac{a(r^{n}-1 )}{r-1}\\[/tex]
ditanyakan jumlah 8 şükür pertama geo.
diketahui n = 8, a = 12, r = [tex]\frac{1}{2}[/tex]
jawab
[tex]S_{8} = \frac{12(1 - \frac{1}{2} ^{8} )}{1- \frac{1}{2} }\\\\S_{8} = \frac{12(1 - \frac{1}{256} )}{\frac{1}{2} }\\\\\\S_{8} = \frac{12(\frac{256}{256} - \frac{1}{256} )}{\frac{1}{2} }\\\\\\S_{8} = \frac{12(\frac{255}{256}) }{\frac{1}{2} }\\\\\\S_{8} = 12(\frac{255}{256}) . \frac{2}{1} }\\\\\\S_{8} = 12(\frac{255}{128}) }\\\\\\\\\\S_{8} = \frac{3060}{128} }\\\\\\\\\\S_{8} = 23,90625 }\\\\\\\\[/tex]
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