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JEE Main202124 Feb 2021Evening ShiftMathematicsStraight LinesActual

Let a point P be such that its distance from the point 5 , 0 is thrice the distance of P from the point - 5 , 0 . If the locus of the point P is a circle of radius r , then 4 r 2 (in the nearest integer) is equal to __________.

Correct answer

0

Step-by-step solution

Let point is h , k So, h - 5 2 + k 2 = 3 h + 5 2 + k 2 8 x 2 + 8 y 2 + 100 x + 200 = 0 x 2 + y 2 + 25 2 x + 25 = 0 r 2 = 25 2 4 2 - 25 4 r 2 = 25 2 4 - 100 4 r 2 = 156 . 25 - 100 4 r 2 = 56 . 25 After round off 4 r 2 = 56

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