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Write the Direction Cosines of the Line X − 2 2 = 2 Y − 5 − 3 , Z = 2 .

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Question

Write the direction cosines of the line \[\frac{x - 2}{2} = \frac{2y - 5}{- 3}, z = 2 .\]

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Solution

We have 

\[\frac{x - 2}{2} = \frac{2y - 5}{- 3}, z = 2\]

The equation of the given line can be re-written as 

\[\frac{x - 2}{2} = \frac{y - \frac{5}{2}}{- \frac{3}{2}} = \frac{z - 2}{0}\]

\[ \Rightarrow \frac{x - 2}{4} = \frac{y - \frac{5}{2}}{- 3} = \frac{z - 2}{0}\]

The direction ratios of the given line are proportional to 4,-3,0. 

Hence, the direction cosines of the given line are proportional to

\[\frac{4}{\sqrt{4^2 + \left( - 3 \right)^2 + 0^2}}, \frac{- 3}{\sqrt{4^2 + \left( - 3 \right)^2 + 0^2}}, \frac{0}{\sqrt{4^2 + \left( - 3 \right)^2 + 0^2}}\]

\[ = \frac{4}{5}, \frac{- 3}{5}, 0\]

 

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Chapter 27: Straight Line in Space - Very Short Answers [Page 41]

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R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 27 Straight Line in Space
Very Short Answers | Q 7 | Page 41

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