Q39 / 90 · JEE Main 2023 (13 Apr Shift 1) · Mathematics

Let PQ be a focal chord of the parabola y2=36x of length 100, making an acute angle with the positive x-axis. Let the ordinate of P be positive and M be the point on the line segment PQ such that PM:MQ=3:1. Then which of the following points does NOT lie on the line passing through M and perpendicular to the line PQ?

  • A
    -6,45
  • B
    6,29
  • C
    3,33
  • Correct answer
    D
    -3,43

Solution

We have been given the length of focal chord PQ=100.

Figure 

Length of focal chord at t=at+1t2=100

Where a=9

t+1t=±103

∴t=3,13,-3,-13

Since ordinate of P is +ve

Figure

∴t=3 or 13

(t=3 as slope of PQ is positive)

∴M(21,9)

Required line:y-9=-8060(x-21)

⇒4x+3y=111

-3,43 does not lie on line.

Hence this is the correct option.

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

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