- (a) Find the first 4 terms of the binomial expansion, in ascending powers of \(x\), of
$$\frac { 2 } { \sqrt { 9 - 2 x } } \quad | x | < \frac { 9 } { 2 }$$
giving each coefficient as a simplified fraction.
By substituting \(x = 1\) into the answer to part (a),
(b) find an approximation for \(\sqrt { 7 }\), giving your answer to 4 decimal places.