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Chapter 20 of 42
Revision Notes

Line and PlaneRevision Notes

JEE Advanced · Mathematics

Quick revision notes for Line and Plane — key concepts, formulas, and definitions for JEE Advanced Mathematics preparation.

Revision Notes — Line and Plane

Key concepts, formulas, and definitions from Line and Plane for JEE Advanced Mathematics preparation.

Key Topics to Revise

1

Direction Ratios and Direction Cosines

  • Direction cosines (l, m, n) are cosines of angles a line makes with coordinate axes
  • Direction ratios (a, b, c) are any three numbers proportional to direction cosines
  • Key relationship: l² + m² + n² = 1
2

Equation of a Line in Space

  • Vector form: r⃗ = a⃗ + λb⃗ (point a⃗, direction b⃗)
  • Cartesian form: (x-x₁)/l = (y-y₁)/m = (z-z₁)/n
  • Cross product form: (r⃗ - a⃗) × b⃗ = 0
3

Angle Between Lines and Distance Calculations

  • Angle between lines = angle between their direction vectors
  • cos θ = |b₁⃗·b₂⃗|/(|b₁⃗||b₂⃗|) for acute angle
  • Lines perpendicular if b₁⃗·b₂⃗ = 0
4

Intersecting and Non-intersecting Lines

  • Lines intersect if system of equations has unique solution
  • Lines are parallel if direction vectors are proportional
  • Lines are skew if they're neither parallel nor intersecting

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Key Concepts

Direction cosines (lThree main formsFor lines with direction vectors b⃗₁Distance from point P(p⃗) to lineLines can be

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Frequently Asked Questions

What topics are covered in Line and Plane for JEE Advanced?

Line and Plane is an important chapter in JEE Advanced Mathematics. It covers key concepts and formulas that are frequently tested in the exam. Key topics include: Direction Ratios and Direction Cosines, Equation of a Line in Space, Angle Between Lines and Distance Calculations, Intersecting and Non-intersecting Lines.

Line and Plane is a frequently tested chapter in JEE Advanced Mathematics. Questions from this chapter appear regularly in previous year papers. There are 90 practice questions available for this chapter.

Start by understanding the core concepts, then solve practice questions. Focus on formulas and their applications. Use revision notes for quick review before the exam.