Q38 / 40 · NTA Abhyas (JEE Main) 2020 · Mathematics · Hyperbola

The equation of a hyperbola is x2a2-y2b2=1. If P2,5 is a point from which perpendicular tangents can be drawn to the hyperbola and distance between both the foci of the hyperbola is 10, then its eccentricity is

  • A
    32
  • Correct answer
    B
    54
  • C
    169
  • D
    43

Solution

∵P lies on director circle x2+y2=a2-b2
∴ a2-b2=7 …(i)
Also, 2ae=10⇒ae=5 …(ii)
Now, e2=a2+b2a2⇒a2+b2=25 …(iii)
From (i) & (iii), we get,
 a2=16,b2=9
e=2516=54

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

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