The lines (x-2)/1 = (y-3)/1 = (z-4)/-k and (x-1)/k = (y-4)/2 = (z-5)/1 are coplanar, if
The lines (x-2)/1 = (y-3)/1 = (z-4)/-k and (x-1)/k = (y-4)/2 = (z-5)/1 are coplanar, if
Option 1 -
K = 0, -3
Option 2 -
K = -1, 1
Option 3 -
K = -3, 3
Option 4 -
K = 0, 3
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1 Answer
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Correct Option - 1
Detailed Solution:| 1 -1 -1 |
| 1 -k | = 0
| k 2 1 |⇒ 1 (1 + 2k) + 1 (1 + k²) – 1 (2 – k) = 0
2k + 1 + 1 + k² − 2 + k = 0
k² + 3k = 0
k = 0, -3
Similar Questions for you
....(1)
Let
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Put l1 and l2 in (1)
α = 3
Given , ,
Dot product with on both sides
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Dot product with on both sides
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(a – 1) × 2 + (b – 2) × 5 + (g – 3) × 1 = 0
2a + 5b + g – 15 = 0
Also, P lie on line
a + 1 = 2λ
b – 2 = 5λ
g – 4 = λ
2 (2λ – 1) + 5 (5λ + 2) + λ + 4 – 15 = 0
4λ + 25λ + λ – 2 + 10 + 4 – 15 = 0
30λ – 3 = 0
a + b + g = (2λ – 1) + (5λ + 2) + (λ + 4)

Take
x = 2λ + 1, y = 3λ + 2, z = 4λ + 3
= (α − 2)
Now,
(α − 2) ⋅ 2 + (β − 3) ⋅3 + (γ − 4) ⋅ 4 = 0
2α − 4 + 3β − 9 + 4γ −16 = 0
⇒ 2α + 3β + 4γ = 29
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