[tex]b_{n} = \sqrt{ b_{n-1}* b_{n+1} } \\ b_{n} = b_{1} q^{n-1} \\ b_{10} = \sqrt{ b_{9}* b_{11} }= \sqrt{768*3072} = \sqrt{2359296} =1536 \\ q= \frac{ b_{10}}{ b_{9} } = \frac{1536}{768} =2 \\ b_{10} = b_{1} q^{9} =\ \textgreater \ b_{1} = \frac{ b_{10} }{ q^{9} } = \frac{1536}{512} =3 \\ b_{2} =b_{1}q^{1}=3*2=6[/tex]
