diketahui barisan geometri 960,1920,3840,7680,.. rumus suku ke-n barisan tersebut adalah

a=960 r=1920/960=2
[tex]un = ar {}^{n - 1} [/tex]
= 960.2n-1
= 1920n-1
[tex]sn = a \times \frac{(1 - rn)}{1 - r} [/tex]
=
[tex] \frac{960(1 - 2n)}{1 - 2} [/tex]

=
[tex] \frac{960(1 - 2n)}{- 1} [/tex]
=-960(1-2n)
=-960+1n
=1n-960