15. Given that \(z = 2 - 2 \mathrm { i }\) and \(w = - \sqrt { 3 } + \mathrm { i }\),
- find the modulus and argument of \(w z ^ { 2 }\).
(6) - Show on an Argand diagram the points \(A , B\) and \(C\) which represent \(z , w\) and \(w z ^ { 2 }\) respectively, and determine the size of angle \(B O C\).