CBSE Class 12 Math 2018 Solved Paper
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Question : 28 of 29
Marks:
+1,
-0
Find the distance of the point (-1,-5,-10) from the point of intersection of the line
= + λ and the plane = = 5
= + λ and the plane = = 5
Solution:
Equation of line is = + λ
= (2 + 3λ) + (- 1 + 4λ) + (2 + 2λ)
This lies on the plane = = 5
⇒ [(2 + 3λ) + (- 1 + 4λ) + (2 + 2λ) ] . = 5
⇒ (2 + 3λ) + (- 1 + 4λ) (- 1) + (2 + 2λ) = 5
⇒ λ = 0
Coordinates are
(2 + 3λ , - 1 + 4λ , 2 + 2λ) = (2 , - 12)
Distance between (2 , - 1 , 2) and (- 1 , - 5 , - 10)
=
= 13 units
= (2 + 3λ) + (- 1 + 4λ) + (2 + 2λ)
This lies on the plane = = 5
⇒ [(2 + 3λ) + (- 1 + 4λ) + (2 + 2λ) ] . = 5
⇒ (2 + 3λ) + (- 1 + 4λ) (- 1) + (2 + 2λ) = 5
⇒ λ = 0
Coordinates are
(2 + 3λ , - 1 + 4λ , 2 + 2λ) = (2 , - 12)
Distance between (2 , - 1 , 2) and (- 1 , - 5 , - 10)
=
= 13 units
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