Question 344 of 521MediumMCQ
The equation of the line passing through (−4,3,1), parallel to the plane x+2y−z−5=0 and intersecting the line −3x+1=2y−3=−1z−2 is:
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Official solution
The line L is parallel to the plane P and intersect with line 4 at point R.
Let the coordinate of point R is, (x1, y1, z1) and it passes through L2.
\[{{{x_1} + 1} \over { - 3}} = {{{y_1} - 3} \over 2} = {{{z_1} - 2} \over { - 1}} = t\]
\[ \therefore \] x1 = -1 - 3t, y1 = 3 + 2t, z1 = 2 - t
\[\overrightarrow {AR} = \left( {3 - 3t} \right)\widehat i + \left( {2t} \right)\widehat j + \left( {1 - t} \right)\widehat k\]
\[\overrightarrow n = \widehat i + 2\widehat j - \widehat k\]
As \[\overrightarrow {AR} \] and \[\overrightarrow n \] are perpendicular to each other, So
\[\overrightarrow {AR} \] \[ \cdot \] \[\overrightarrow n \] = 0
\[ \Rightarrow \] (3 - 3t) 1 + (2t)2 + (1 - t) (- 1) = 0
\[ \Rightarrow \] 3 - 3t + 4t - 1 + t = 0
\[ \Rightarrow \] 2 + 2t = 0
\[ \Rightarrow \] t = - 1
\[ \therefore \] point R = (2, 1, 3)
\[ \therefore \] DR of line L is
= (2 - (- 4), 1 - 3, 3 - 1)
= (6, - 2, 2)
\[ \therefore \] Equation of line is
\[{{x + 4} \over 6} = {{y - 3} \over { - 2}} = {{z - 1} \over 2}\]
or \[{{x + 4} \over 3} = {{y - 3} \over { - 1}} = {{z - 1} \over 1}\]
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