Inverse of a linear transformation

Question

What is the inverse of the following linear transformation?

$T^{\theta}:R^2\rightarrow R^2$

a reflection in the line through the origin which forms an angle $\theta$ with the $x$-axis.

I have little idea how to approach this question, please provide an explanation of how I could answer this.

Thanks

Answer 1

It is the reflexion itself.

What is the image of the image of a point by a reflexion?