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QJEEM22Ma44f8: JEE Main 2022 Mathematics - Class 12 JEEM22Ma44f8 Solution: If the system of linear equations. has infinitely many…

If the system of linear equations.

8x+y+4z=−28x + y + 4z = - 2

x+y+z=0x + y + z = 0

λx−3y=μ\lambda x - 3y = \mu

has infinitely many solutions, then the distance of the point (λ,μ,−12)\left( {\lambda ,\mu , - {1 \over 2}} \right) from the plane 8x+y+4z+2=08x + y + 4z + 2 = 0 is :

Multiple Choice Options

  • A 353\sqrt 5
  • B 4
  • C 269{{26} \over 9}
  • D 103{{10} \over 3}

Step-by-Step Verified Solution

Δ=|814111λ−30|

=8(3)−1(−λ)+4(−3−λ)= 8(3) - 1( - \lambda ) + 4( - 3 - \lambda )

=24+λ−12−4λ= 24 + \lambda - 12 - 4\lambda

=12−3λ= 12 - 3\lambda

So for λ=4\lambda = 4 , it is having infinitely many solutions.

Δx=|−214011μ−30|

=−2(3)−1(−μ)+4(−μ)= - 2(3) - 1( - \mu )+4( - \mu )

=−6−3μ=0= - 6 - 3\mu = 0

For μ=−2\mu = - 2

Distance of (4,−2,−12)(4, - 2,{{ - 1} \over 2}) from 8x+y+4z+2=08x + y + 4z + 2 = 0

=32−2−2+264+1+16=103= {{32 - 2 - 2 + 2} \over {\sqrt {64 + 1 + 16} }} = {{10} \over 3} units

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