Find the first 4 terms, in ascending powers of \(x\), of the binomial expansion of
$$\sqrt { 1 + 4 x }$$
giving each coefficient in its simplest form.
The expansion can be used to find an approximation for \(\sqrt { 26 }\)
Explain why \(x = \frac { 25 } { 4 }\) should not be used in the expansion to find an approximation for \(\sqrt { 26 }\)