Q25 / 105 · NTA Abhyas (JEE Main) 2020 · Mathematics · Three Dimensional Geometry

The shortest distance between the line x=y=z and the line of intersection of 2x+y+z-1=0 and 3x+y+2z-2=0 is

  • Correct answer
    A
    12 units
  • B
    13 units
  • C
    14 units
  • D
    15 units

Solution

P1=2x+y+z-1=0
P2=3x+y+2z-2=0
The line of intersection is parallel to
i^j^k^211312=i^-j^-k^
For the point on the line, putting z=0, we get,
2x+y=13x+y=2x=1, y=-1
So, the required point is 1,-1,0
Hence, the equation of the line of intersection is
x-11=y+1-1=z-0-1
Let, a→=i^-j^
b→=i^-j^-k^
c→=0→
d→=i^-j^-k^
c→-a→=-i^+j^
b→×d→=-2j^+2k^
Shortest distance =c→-a→⋅b→×d→b→×d→
=-222=12

Hence, the correct answer is option: 'A'.

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