Find the equation of the plane passing through the intersection of the planes 2x + 3y – z + 1 = 0 and x + y – 2z + 3 = 0, and perpendicular to the plane 3x - y -2z -4 = 0.
Equation of plane through the line of intersection of planes in Cartesian form is
(1)
For the standard equation of planes,
So, putting in equation (1), we have
2x + 3y–z + 1 + λ(x + y–2z + 3)=0
(2 + λ)x + (3 + λ)y + (-1-2λ)z + 1 + 3λ=0 (2)
Now as the plane 3x-y-2z-4=0 is perpendicular the given plane,
For θ=90°, cos90°=0
(3)
On comparing with standard equations in Cartesian form,
Putting values in equation (3), we have
(2 + λ).3 + (3 + λ).(-1) + (-1-2λ).(-2)=0
6 + 3λ-3-λ + 2 + 4λ=0
5 + 6λ=0
Putting in equation(2)
7x + 13y + 4z-9=0
7x + 13y + 4z=9
So, required equation of plane is 7x + 13y + 4z=9.