Question

The equation of the plane containing the line $ r=i+j+\lambda (2i+j+4k) $ is

• A. $ r.(i+2j-k)=3 $
• B. $ r.(i+2j-k)=6 $
• C. $ r.(-i-2j+k)=3 $
• D. None of the above

Answer 1

Answer: (A)

The position vector of any point on the given line is
$ i+j+\lambda (2i+j+4k) $
or $ (2\lambda +1)i+(\lambda +1)\hat{j}+4\lambda k $
which lies on $ r.(i+2j+k)=3 $
Hence, the plane
$ r.(i+2j-k)=3 $
contains the given line.