1. Diketahui barisan geometri U3= 4, U9= 64 tentukan: a. Rasio dari U1 b. U10. 2. Diketahui barisan geometri U2

Kelas 11
Materi : Barisan dan Deret
Sub Materi : Barisan Geometri

1.]
Diketahui :
U3 = ar² = 4
[tex]u9 = a {r}^{8} [/tex]
Ditanya : r & U10

ar² = 4
[tex]a = \frac{4}{ {r}^{2} } \\ \\ substitusi \\ a {r}^{8} = 64 \\ \frac{4}{ {r}^{2} } \times {r}^{8} = 64 \\ 4 \times {r}^{6} = 64 \\ {r}^{6} = 16[/tex]

[tex]u10 \\ = a {r}^{9} \\ = \frac{4}{ {r}^{2} } \times {r}^{6} \times {r}^{3} \\ = \frac{4}{ {r}^{2} } \times {r}^{3} \times {r}^{6} \\ = 4r \times 16 \\ = 64r[/tex]