The complex numbers \(z\) and \(w\) are represented, respectively, by points \(P(x, y)\) and \(Q(u,v)\) in Argand diagrams and
$$w = z(1 + z)$$
- Show that
$$v = y(1 + 2x)$$
and find an expression for \(u\) in terms of \(x\) and \(y\). [4]
- The point \(P\) moves along the line \(y = x + 1\). Find the Cartesian equation of the locus of \(Q\), giving your answer in the form \(v = au^2 + bu\), where \(a\) and \(b\) are constants whose values are to be determined. [5]