5 A transformation of the \(x - y\) plane is represented by the matrix \(\left( \begin{array} { r r } \cos \theta & 2 \sin \theta
2 \sin \theta & - \cos \theta \end{array} \right)\), where \(\theta\) is a positive acute angle.
- Write down the image of the point \(( 2,3 )\) under this transformation.
- You are given that this image is the point ( \(a , 0\) ). Find the value of \(a\).