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AP EAMCET · Maths · Three Dimensional Geometry

If \((\alpha, \beta, \gamma)\) are the Direction cosines of an angular bisector of two lines whose Direction ratios are \((2,2,1)\) and \((2,-1,-2)\), then \((\alpha+\beta+\gamma)^2=\)

  1. A \(3\)
  2. B \(2\)
  3. C \(4\)
  4. D \(5\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(2\)

Step-by-step Solution

Detailed explanation

Given, direction ratio are \((2,2,1)\) and \((2,-1,-2)\) Now, angle between the lines is given by \(\cos \theta=\frac{4-2-2}{\sqrt{9} \cdot \sqrt{9}}=0 \Rightarrow \theta=\frac{\pi}{2}\) So, direction cosines of two lines are…