StreakPeaked· Practice

ExamsJEE AdvancedMaths

S1 and S2 are the foci of an ellipse whose major axis has length 10 units. For any point P on the ellipse, the perimeter of triangle P*S1*S2 is 15. Find the eccentricity of the ellipse.

  1. 1/2
  2. 1/3
  3. 2/5
  4. 3/5

Correct answer: 1/2

Solution

PS1 + PS2 = 2a = 10 and S1S2 = 2ae; perimeter 2a + 2ae = 15 gives 10 + 10e = 15, so e = 1/2.

Related JEE Advanced Maths questions

⚔️ Practice JEE Advanced Maths free + battle 1v1 →