Odpowiedź:
[tex]a_{n} =a_{1}*q^{n-1} \\\\\left \{ {{a_{1}*q^{}=2} \atop {a_{1}*q^{3}=9}} \right. \\\left \{ {{a_{1}=\frac{2}{q} } \atop {a_{1}=\frac{9}{q^{3} } }} \right. \\\\\frac{2}{q} =\frac{9}{q^{3} } \\\\9q=2q^{3} //:q (q\neq 0)\\9=2q^{2} //:2\\q=\sqrt{4.5} \\a_1=\frac{2}{\sqrt{4.5} } =\frac{2\sqrt{2} }{2} \\a_n=\frac{2\sqrt{2} }{2}*(\sqrt{4.5})^{n-1}[/tex]
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