1.9: Past-paper question 2

(a) Expand $\displaystyle \frac{2}{\sqrt{1+3x}}$ in ascending powers of $\displaystyle x$ up to and including the term in $\displaystyle x^3$

Express each coefficient as a fraction in its simplest terms where appropriate.

(b) State the range of values of $\displaystyle x$ for which the expansion is valid.