u_0 = 2
u_{n+1} = 3u_n - 4n
u_1 = 3u_0 - 4 \cdot 0 = 3 \cdot 2 - 0 = 6
u_2 = 3u_1 - 4 \cdot 1 = 3 \cdot 6 - 4 = 18 - 4 = 14
u_3 = 3u_2 - 4 \cdot 2 = 3 \cdot 14 - 8 = 42 - 8 = 34
Pour la deuxième suite :u_0 = 0
u_{n+1} = u_n^2 + \frac{1}{2n + 1}
u_1 = u_0^2 + \frac{1}{2 \cdot 0 + 1} = 0^2 + \frac{1}{1} = 0 + 1 = 1
u_2 = u_1^2 + \frac{1}{2 \cdot 1 + 1} = 1^2 + \frac{1}{3} = 1 + \frac{1}{3} = \frac{4}{3}
u_3 = u_2^2 + \frac{1}{2 \cdot 2 + 1} = \left(\frac{4}{3}\right)^2 + \frac{1}{5} = \frac{16}{9} + \frac{1}{5} = \frac{80}{45} + \frac{9}{45} = \frac{89}{45}
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