MCQ
The direction cosines of a line which is perpendicular to both the lines whose direction ratios are -2, 1, -1 and -3, -4, 1 are ______ 
  • A
    $\frac{3}{\sqrt{155}}, \frac{5}{\sqrt{155}}, \frac{11}{\sqrt{155}}$
  • B
    $\frac{3}{\sqrt{155}}, \frac{-5}{\sqrt{155}}, \frac{11}{\sqrt{155}}$
  • $\frac{-3}{\sqrt{155}}, \frac{5}{\sqrt{155}}, \frac{11}{\sqrt{155}}$
  • D
    $\frac{3}{\sqrt{155}}, \frac{5}{\sqrt{155}}, \frac{-11}{\sqrt{155}}$

Answer

Correct option: C.
$\frac{-3}{\sqrt{155}}, \frac{5}{\sqrt{155}}, \frac{11}{\sqrt{155}}$
C

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