A) 3, 1, ? 2
B) 2, ? 4, 1
C) \[\frac{3}{\sqrt{14}},\frac{1}{\sqrt{14}},\frac{-2}{\sqrt{14}}\]
D) \[\frac{2}{\sqrt{41}},\frac{-4}{\sqrt{41}},\frac{1}{\sqrt{41}}\]
Correct Answer: A
Solution :
If l, m, n are direction ratios of line, then by \[Al+Bm+Cn=0\] For \[x-y+z-5=0,\,\,l-m+n=0\] ?..(i) For \[x-3y-6=0,\,\,l-3m+0n=0\] ?..(ii) or \[\frac{l}{0+3}=\frac{m}{1-0}=\frac{n}{-3+1}\] or \[\frac{l}{3}=\frac{m}{1}=\frac{n}{-2}\] \[\therefore \,\,\,\]Direction ratios are \[(3,\,\,1,\,\,-2)\]. Note : Option , \[\left( \frac{3}{\sqrt{14}},\frac{1}{\sqrt{14}},-\frac{2}{\sqrt{14}} \right)\] may also be an answer but best answer is \[A(3,\,\,1,\,\,-2)\] because in direction cosines are written.
You need to login to perform this action.
You will be redirected in
3 sec
