Posted by alice on Monday, March 16, 2009 at 6:30pm.
how do you find the coordinates of the point (x, y, z) on the plane z = 1 x + 1 y + 2 which is closest to the origin

math  Reiny, Monday, March 16, 2009 at 7:44pm
the closest point is surely on a line from (0,0,0) meeting the plane at right angles.
but the normal to the given plane is (1,1,1)
so the line must have direction (1,1,1)
it's parametric equations would be:
x = k
y = k
z = k
sub that in to the plane to find the value of k, sub back in the parametrics
and voila, there is your point.