Răspuns:
Explicație pas cu pas:
[tex]a_{1} = \frac{1}{2} ,a_{2} = \frac{1\cdot3}{2\cdot4} = \frac{3}{8},a_{3} = \frac{1\cdot3\cdot5}{2\cdot4\cdot6} = \frac{5}{16},a_{4} = \frac{1\cdot3\cdot5\cdot7}{2\cdot4\cdot6\cdot8} = \frac{35}{128},\\ \\ a_{5} = \frac{1\cdot3\cdot5\cdot7\cdot9}{2\cdot4\cdot6\cdot8\cdot10} = \frac{63}{256}[/tex]
