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Three Dimensional Geometry
Question
Find the direction ratios and the direction cosines of the lines joining the pairs of points:
(–2, 1, 0), (3, 2, 1).
Solution
The direction ratios of the line joining the points (–2, 1, 0) , (3, 2,1) are 3 + 2, 2 – 1, 1 – 0 i.e. 5, 1, 1.
Dividing each by
we get the direction cosines of the line as 
Dividing each by
we get the direction cosines of the line as
Some More Questions From Three Dimensional Geometry Chapter
If α, β, γ are the angles which a line makes with the axes, prove that sin2α + sin2 β + sin2γ = 2.
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Mock Test Series
Mock Test Series