7. A sequence is defined by
$$\begin{aligned}
u _ { 1 } & = 3
u _ { n + 1 } & = 2 - \frac { 4 } { u _ { n } } , \quad n \geqslant 1
\end{aligned}$$
Find the exact values of
- \(u _ { 2 } , u _ { 3 }\) and \(u _ { 4 }\)
- \(u _ { 61 }\)
- \(\sum _ { i = 1 } ^ { 99 } u _ { i }\)
[0pt]
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