4 The \(n\)th term of a geometric series is \(u _ { n }\), where \(u _ { n } = 48 \left( \frac { 1 } { 4 } \right) ^ { n }\).
- Find the value of \(u _ { 1 }\) and the value of \(u _ { 2 }\).
- Find the value of the common ratio of the series.
- Find the sum to infinity of the series.
- Find the value of \(\sum _ { n = 4 } ^ { \infty } u _ { n }\).