The continuous random variable \(X\) has probability density function \(f\) given by
\(f(x)=\left\{\begin{array}{ll} \frac{3}{16}(2-\sqrt{x}) & 0 \leqslant x\lt 1 \\ \frac{3}{16 \sqrt{x}} & 1 \leqslant x \leqslant 9 \\ 0 & \text { otherwise } \end{array}\right.\)
(a) Find \(\mathrm{E}(X)\).

The random variable \(Y\) is such that \(Y=\sqrt{X}\).
(b) Find the probability density function of \(Y\).