TS EAMCET · Maths · Three Dimensional Geometry
If the direction cosines of two lines satisfy the equations \(l+m+n=0\) and \(2 l m+2 l n-m n=0\), then the acute angle between those two lines is
- A \(\frac{\pi}{4}\)
- B \(\frac{\pi}{3}\)
- C \(\frac{\pi}{6}\)
- D \(\frac{2 \pi}{5}\)
Answer & Solution
Correct Answer
(B) \(\frac{\pi}{3}\)
Step-by-step Solution
Detailed explanation
We have, \[ \begin{aligned} l+m+n=0 \text { and } 2 l m+2 l n-m n= & 0 \\ \therefore \quad 2(-m-n) m+2(-m-n) n-m n= & 0 \\ & {[\because l=-(m+n)] } \end{aligned} \]…
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