Oxford Entrance Exam Problem 5

Geometry Level 3

The reflection of the point $(1, 0)$ in the line $y = mx$ has coordinates

(1-m,m)

\left(\frac{m^2+1}{m^2-1},\frac{m}{m^2-1}\right)

\left(\frac{1-m^2}{1+m^2},\frac{2m}{1+m^2}\right)

(1-m^2,m)

(1,m)