Bonjour,
[tex]U _{n + 1} = \frac{U_{n} }{1 + U_{n}} [/tex]
[tex]U _{1} = \frac{U_{0} }{1 + U_{0}} = \frac{1}{1 + 1} = \frac{1}{2} [/tex]
[tex]U _{2} = \frac{U_{1} }{1 + U_{1}} = \frac{ \frac{1}{2} }{1 + \frac{1}{2} } = \frac{ \frac{1}{2} }{ \frac{3}{2} } = \frac{1}{2} \times \frac{2}{3} = \frac{1}{3} [/tex]
