JEE Main20205 Sep 2020Morning ShiftMathematicsEllipseActual

If the co-ordinates of two points A and B are ( 7 , 0 ) and ( - 7 , 0 ) respectively and P is any point on the conic, 9 x 2 + 16 y 2 = 144 , then P A + P B is equal to :

Options

Correct answer

B. 8

Step-by-step solution

For ellipse x 2 16 + y 2 9 = 1 Comparing with, standard equation of ellipse x 2 a 2 + y 2 b 2 = 1 , we get a = 4 , b = 3 . ∴ e = 1 - 9 16 = 7 4 Since, A and B are foci Therefore, P A + P B = 2 a = 2 × 4 = 8 .

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