# All Questions

348 views

### Reflecting a point by a line in $\mathbb R^3$

I would like to know if it's possible, given the vector equation of a line and the coordinates of a point, whether it's possible to reflect the point by the line.
119 views

### Symmetry in the line $x=y$

In the plane, why does the symmetry in the line $y=x$ sends the point of coordinates $(x,y)$ into the point of coordinates $(y,x)$ ? P.S. : does someone have a proof without linear algebra ?