Exams Joint Entrance Examination Mathematics 3D Geometry Question 192 Question 192 of 521 Medium MCQ
The shortest distance between lines L 1 L_1 L 1 and L 2 L_2 L 2 , where L 1 : x − 1 2 = y + 1 − 3 = z + 4 2 L_1:\ \dfrac{x-1}{2}=\dfrac{y+1}{-3}=\dfrac{z+4}{2} L 1 : 2 x − 1 = − 3 y + 1 = 2 z + 4 and L 2 L_2 L 2 is the line passing through the points A ( − 4 , 4 , 3 ) A(-4,4,3) A ( − 4 , 4 , 3 ) , B ( − 1 , 6 , 3 ) B(-1,6,3) B ( − 1 , 6 , 3 ) (and perpendicular to the line x − 3 − 2 = y 3 = z − 1 1 \dfrac{x-3}{-2}=\dfrac{y}{3}=\dfrac{z-1}{1} − 2 x − 3 = 3 y = 1 z − 1 ), is:
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\[ \begin{aligned}
& \mathrm{L}_2=\frac{\mathrm{x}+4}{3}=\frac{\mathrm{y}-4}{2}=\frac{\mathrm{z}-3}{0} \\
& \therefore \mathrm{S} . \mathrm{D}=\frac{\left|\[\begin{array}{|ccccccc|}\mathrm{x}_2-\mathrm{x}_1 & \mathrm{y}_2-\mathrm{y}_1 & \mathrm{z}_2-\mathrm{z}_1 \\ 2 & -3 & 2 \\ 3 & 2 & 0\end{array}\end{aligned} \]\right|}{\left|\overrightarrow{\mathrm{n}\_1} \times \overrightarrow{\mathrm{n}\_2}\right|} \\
\& =\frac{\left|\[ 5 − 5 − 7 2 − 3 2 3 2 0 \begin{array}{|ccccccc|}5 & -5 & -7 \\ 2 & -3 & 2 \\ 3 & 2 & 0\end{array} 5 2 3 − 5 − 3 2 − 7 2 0 \]\right|}{\left|\overrightarrow{\mathrm{n}\_1} \times \overrightarrow{\mathrm{n}\_2}\right|} \\
\& =\frac{141}{|-4 \hat{\mathrm{i}}+6 \hat{\mathrm{j}}+13 \hat{\mathrm{k}}|} \\
\& =\frac{141}{\sqrt{16+36+169}} \\
\& =\frac{141}{\sqrt{221}}
\] Answer the question to unlock