Find the coordinates of the foot of the perpendicular Q drawn from to the plane
. Also, find the distance PQ and the image of the point P treating this plane as a mirror.
The d.r's of normal to the plane are 2,-1,1
PQ is
to the plane so, its equation is:
The coordinates of any random point on the line PQ
Q lines on the plane so,
Foot of the perpendicular :
Distance
Let be the image of P in the plane
so, Q will be mid point of PM
ie
On comparing the coordinates, we get :
the image is