Q.

Let PQ be a chord of the parabola y2=12x and the midpoint of PQ be at (4, 1). Then, which of the following point lies on the line passing through the points P and Q          [2024]

1 (2, –9)  
2 (32,–16)  
3 (12,–20)  
4 (3, –3)  

Ans.

(3)

y2=12x

Chord PQ having mid-point (x1,y1)≡(4,1)

Equation of chord PQ

T=S1

yy1–12(x+x1)2=y12–12x1

⇒ y–6(x+4)=1–12×4

⇒ y–6x–24=–47 ⇒ y–6x+23=0

From the options, point (12,–20) lies on the chord.