JEE Advanced 2015 · Introduction to Three Dimensional Geometry
In R3, consider the planes P1:y=0 and P2:x+z=1.
Let P3 be the plane, different from P1 and P2, which passes through the intersection of P1 and P2.
If the 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?
In R³, consider the planes P₁: y = 0 and P₂: x + z = 1. Let P₃ be the plane, different from P₁ and P₂, which passes through the intersection of P₁ and P₂. If the 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?
P1:y=0,P2:x+z=1P3 passes through P1∩P2,P3=P1,P2
dist((0,1,0),P3)=1,dist((α,β,γ),P3)=2
Find P3, then test which of (1)–(4) holdP1:y=0(xz-plane),P2:x+z=1P1∩P2:y=0,x+z=1(a line)P3:(x+z−1)+ky=0⇒x+ky+z−1=0,n=(1,k,1)1+k2+1∣0+k(1)+0−1∣=1k2+2∣k−1∣=1(k−1)2=k2+2k2−2k+1=k2+2⇒−2k=1⇒k=−21P3:x−21y+z−1=02x−y+2z−2=0,∣n∣=4+1+4=33∣2α−β+2γ−2∣=2∣2α−β+2γ−2∣=62α−β+2γ−2=6⇒2α−β+2γ−8=0(4)2α−β+2γ−2=−6⇒2α−β+2γ+4=0(2)True relations: (2) and (4)(1),(3):β sign and γ coefficient do not matchP3:2x−y+2z−2=0,true: (2),(4)
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