Find the first two terms, in ascending powers of \(x\), of the binomial expansion of
$$\left( 1 - \frac { x } { 2 } \right) ^ { \frac { 1 } { 2 } }$$
6
Hence, for small values of \(x\), show that
$$\sin 4 x + \sqrt { \cos x } \approx A + B x + C x ^ { 2 }$$
where \(A , B\) and \(C\) are constants to be found.