JEE Main & Advanced JEE Main Paper (Held On 11 April 2014)

  • question_answer
    The plane containing the line \[\frac{x-1}{1}=\frac{y-2}{2}=\frac{z-3}{3}\]and parallel to the line\[\frac{x}{1}=\frac{y}{1}=\frac{z}{4}\]passes through the point:   [JEE Main Online Paper ( Held On 11 Apirl  2014 )

    A) \[(1, - 2, 5)\]                           

    B) \[(1, 0, 5)\]

    C) \[(0, 3, -5)\]

    D) \[(-1, -3, 0)\]

    Correct Answer: B

    Solution :

    Equation of the plane containing the line \[\frac{x-1}{1}=\frac{y-2}{2}=\frac{z-3}{3}\]is \[a(x-1)+b(y-2)+c(z-3)=0\] ..(i) where \[a.1+b.2+c.3=0\] i.e.,\[a+2b+3c=0\]    .... (ii) Since the plane (i) parallel to the line \[\frac{x}{1}=\frac{y}{1}=\frac{z}{4}\] \[\therefore \]\[a.1+b.1+c.4=0\]i.e., \[a+b+4c=0\] ... (iii) From (ii) and (iii), \[\frac{a}{8-3}=\frac{b}{3-4}=\frac{c}{1-2}=k\](let) \[\therefore \]\[a=5k,b=-k,c=-k\] On putting the value of a, b and c in equation (i),\[5(x-1)-(y-2)-(z-3)=0\] \[\Rightarrow \]\[5x-y-z=0\]   ... (iv) when x = 1, y = 0 and z = 5; then L.H.S. of equation (iv)    \[=5x-y-2\] \[=5\times 1-0-5\] \[=0\] = R.H.S. of equation (iv) Hence coordinates of the point (1, 0, 5) satisfy the equation plane represented by equations (iv), Therefore the plane passes through the point (1,0,5)


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