1. On the top right, click on the "rotate" icon between the magnet and the cube to rotate the diagram (you can also change the speed of rotation). 2. The first three sliders [color=#c51414][b]n[/b]x[/color], [color=#0a971e][b]n[/b]y[/color] and [color=#1551b5][b]n[/b]z[/color] represent the components of [b]n[/b], the normal vector of the plane Π. 3. Use the fourth slider to change the value of a in the equation of the plane Π: [b]r[/b].[b]n[/b] = a. 4. Click the checkboxes to display the normal vector [b]n[/b] as well as point V, a point outside the plane. 5. The three sliders [color=#c51414]vx[/color], [color=#0a971e]vy[/color] and [color=#1551b5]vz[/color] represent the coordinates of V. 6. Click the checkbox to display F, the foot of the perpendicular from V to Π. 7. Click the next checkbox to display [b]n[/b], the normal to Π through V. 8. Use the slider to determine the value of λ such that the vector [b]VF[/b] = λ[b]n[/b]. 9. Click the last checkbox to display VF', the reflection of V in Π. 10. Use the slider to determine the value of λ such that the vector [b]VV'[/b] = λ[b]n[/b].