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📐 Mathematics  ·  Straight Lines  ·  JEE

The ellipse x²/9 + y²/4 = 1 has a =

Answer: 3.

  • A 2
  • B 3
  • C 4
  • D 9

Correct answer: B. 3

Explanation: For x²/a² + y²/b² = 1, a = 3 (larger denominator under x²). Semi-major axis = 3.

Slope as Rise over Runxy(x₁,y₁)(x₂,y₂)run = x₂−x₁rise = y₂−y₁m = rise/run = (y₂−y₁)/(x₂−x₁) = tanθ

The slope of a line is the ratio of vertical change (rise) to horizontal change (run) between any two points on it - equivalently, the tangent of the angle θ the line makes with the positive x-axis.

Concept context

Points, lines, and curves on the Cartesian plane

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