# Showing a matrix is 1-1

How do I show below is 1-1. I also know the natural basis is $$R^2$$

• What have you tried? Jan 18 '20 at 20:46
• I’m not sure where to even start. I think I’d need to change $R^2$ into a 2x2 matrix though Jan 18 '20 at 20:48
• Why do you want to calculate $R^2$? (I'm assuming you mean $R=R_{\pi/3}$) The question is about $R$, isn't it? Jan 18 '20 at 20:52
• You need to show the invertibility of $R_{\pi/3}$. The easiest way would be to calculate the determinant of $R_{\pi/3}$. Jan 18 '20 at 20:54
• Show that the determinant is not zero. Jan 18 '20 at 20:54