The distance of the point Q(0,2,–2) form the line passing through the point P(5,–4,3) and perpendicular to the lines =(-3 i+2 k)+λ (2 i+3 j+5 k),λ ∈…
JEE Main 2024 — Mathematics Vectors & 3D Geometry
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The distance of the point Q(0,2,–2) form the line passing through the point P(5,–4,3) and perpendicular to the lines r=(−3i^+2k^)+λ(2i^+3j^+5k^),λ∈R and r=(i^−2j^+k^)+μ(−i^+3j^+2k^),μ∈R is
Official previous-year question
Held on 31 Jan 2024 · Verified 6 Jul 2026.
Options
A
86
B
20
C
54
D
74
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Solution
Plotting the diagram of the given data we get,
Now, let a,b,c be the DR's of the line perpendicular to (−3i^+2k^)+λ(2i^+3j^+5k^)and(i^−2j^+k^)+μ(−i^+3j^+2k^).
⇒2a+3b+5c=0,−a+3b+2c=0
Now, solving 2a+3b+5c=0&-a+3b+2c=0 we get,
⇒−9a=−9b=9c
⇒1a=1b=−1c
So, the equation will be,
⇒1x−5=1y+4=−1z−3...(i)
Let R be the foot of perpendicular from Q(0,2,−2)to(i).
⇒1x−5=1y+4=−1z−3=k
⇒x=k+5,y=k−4,z=−k+3
⇒R≡(k+5,k−4,−k+3)
So, DR's of QR are (k+5,k−6,5−k).
Now, using perpendicular condition we get,
⇒1(k+5)+1(k−6)+(−1)(5−k)=0
⇒k=2
⇒R≡(7,−2,1)
⇒QR=49+16+9
⇒QR=74
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