Răspuns:
[tex] \frac{1}{{3}^{2} } = \frac{1}{9} [/tex]
[tex] \frac{1}{ {3}^{3} } = \frac{1}{27} [/tex]
[tex] \frac{1}{ {3}^{4} } = \frac{1}{81} [/tex]
[tex]1 - \frac{1}{3} + \frac{1}{9} - \frac{1}{27} + \frac{1}{81} = [/tex]
Numitor comun 81
[tex] \frac{(81 - 27 + 9 - 3 + 1)}{81} = \frac{61}{81} [/tex]
[tex] \frac{61}{81} = aprox. \: 0.753...[/tex]
[tex] \frac{3}{4} = 0.75[/tex]
=>
[tex] \frac{61}{81} > \frac{3}{4} [/tex]
