Réponse:
[tex] \frac{ \frac{ {7}^{n + 1} }{n + 2} }{ \frac{ {7}^{n} }{n + 1} } = \frac{ {7}^{n + 1} }{n + 2} \times \frac{n + 1}{ {7}^{n} } = \frac{n + 1}{n + 2} \times {7}^{n + 1 - n} = 7 \times \frac{n + 1}{n + 2}[/tex]
[tex] \frac{4 \times {0.5}^{n + 1} }{4 \times {0.5}^{n} } = {0.5}^{n + 1 - n} = 0.5[/tex]
