suatu deret geometri U3=4, U4=9,U 6 adalah

[tex] \frac{u4}{u3} = \frac{9}{4} \\ \frac{a {r}^{3} }{a {r}^{2} } = \frac{9}{4} \\ r = \frac{9}{4} [/tex]

[tex]u3 = 4 \\ a {r}^{2} = 4 \\ a { (\frac{9}{4} )}^{2} = 4 \\ a( \frac{81}{16} ) = 4 \\ a = 4 \times \frac{16}{81} = \frac{64}{81} [/tex]


[tex]u6 = a {r}^{5} \\ = \frac{64}{81} ( { \frac{9}{4}) }^{5} \\ = \frac{ {2}^{6} }{ {3}^{4} } { (\frac{ {3}^{2} }{ {2}^{2}}) }^{5} \\ = \frac{ {2}^{6} }{ {3}^{4} } \div \frac{ {3}^{10} }{ {2}^{10} } \\ = \frac{ {3}^{6} }{ {2}^{4} } = \frac{729}{16} = 45 \frac{9}{16} [/tex]