Question

The plane ax + by = 0 is rotated about its line of intersection with the plane z = 0 through an angle α. Prove that the equation of the plane in its new position is 

Answer 1

Given planes are: ax + by = 0 …. (i) and z = 0 …. (ii)

Now, the equation of any plan passing through the line of intersection of plane (i) and (ii) is

(ax + by) + kz = 0 ⇒ ax + by + kz = 0 …. (iii)