Equation of Plane Passing Through Intersection of Two Planes
In R3, consider the planes P1:y=0 and P2:x+z=1. Let P3 be a plane, distinct from P1 and P2, which passes through the line of intersection of P1 and P2. If the perpendicular distance of the point (0,1,0) from P3 is 1 and the distance of a point (α,β,γ) from P3 is 2, then which of the following relations is (are) true?
To find the equation of the plane P3, we use the family of planes passing through the intersection of P1:y=0 and P2:x+z−1=0.
The general equation of such a plane P3 (where P3 is distinct from P1) can be written as:
(x+z−1)+λy=0
Rearranging the terms, we get:
x+λy+z−1=0
The perpendicular distance from the point (0,1,0) to the plane P3 is given to be 1:
12+λ2+12∣0+λ(1)+0−1∣=1λ2+2∣λ−1∣=1
Squaring both sides:
(λ−1)2=λ2+2λ2−2λ+1=λ2+2−2λ=1⟹λ=−21
Substitute λ=−21 back into the equation of P3:
x−21y+z−1=0
Multiplying the entire equation by 2, we obtain the equation of plane P3:
2x−y+2z−2=0
Now, it is given that the perpendicular distance from the point (α,β,γ) to P3 is 2:
22+(−1)2+22∣2α−β+2γ−2∣=24+1+4∣2α−β+2γ−2∣=23∣2α−β+2γ−2∣=2∣2α−β+2γ−2∣=6
This leads to two possibilities:
2α−β+2γ−2=6⟹2α−β+2γ−8=0
2α−β+2γ−2=−6⟹2α−β+2γ+4=0
Thus, the relations that can be true are given by options (B) and (D).