Q29 / 53 · NTA Abhyas (JEE Main) 2020 · Mathematics · Ellipse

If the circle whose diameter is the major axis of the ellipse x2a2+y2b2=1 a>b>0 meets the minor axis at point P and the orthocentre of ∆PF1F2 lies on the ellipse, where F1 and F2 are the foci of the ellipse, then the square of the eccentricity of the ellipse is

  • Correct answer
    A
    5-12
  • B
    3-1
  • C
    12
  • D
    32

Solution

Figure

mF1B⋅mPF2=−1⇒a-00-ae×b-00--ae=-1⇒b2a2=e2⇒e4+e2−1=0
∴e2=5-12

Hence, the correct answer is option: 'A'.

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