Mathematics | VITEEE 2015 | Discussion Page

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The two liines x=my+n, z=py+q and x=m'y+n', z=p'y+q' are perpendicular to each other, if

$mm'+pp'=1$

$\frac{m}{m'}+\frac{p}{p'}=-1$

$\frac{m}{m'}+\frac{p}{p'}=1$

$mm'+pp'=-1$

Option D

Given lines are

x=my+n,z=py+q and x=m'y+n'. z=p'y+q'

Above equations can be rewritten as

$\frac{x-n}{m}=\frac{y-0}{1}=\frac{z-q}{p}$ and

$\frac{x-n'}{m}=\frac{y-0}{1}=\frac{z-q'}{p'}$

Lines will be perpendicular , if

mm'+1+pp'=0

$\Rightarrow$ mm'+pp'=-1

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