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Question: Answered & Verified by Expert
If an angle between the line, x+12=y-21=z-3-2 and the plane, x-2y-kz=3 is cos-1223, then a value of k is
MathematicsThree Dimensional GeometryJEE MainJEE Main 2019 (12 Jan Shift 2)
Options:
  • A 53
  • B 35
  • C -35
  • D -53
Solution:
1577 Upvotes Verified Answer
The correct answer is: 53

cos90-θ=n1.vn1v

sinθ=i^-2j^-kk^.2i^+j^-2k^1+4+k24+1+4

θ=cos-1223cosθ=223sinθ=13

13=2-2+2k35+k2

2k=5+k2k=±53

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