Q.

Let (x,y) be any point on the parabola y2=4x. Let P be the point that divides the line segment from (0, 0) to (x,y) in the ratio 1 : 3. Then the locus of P is            [2011]

1 x2=y  
2 y2=2x  
3 y2=x  
4 x2=2y  

Ans.

(3)

Let A(x,y)=(t2,2t) be any point on parabola y2=4x.

Let P(h,k) divide OA in the ratio 1:3

 (h,k)=(t24,2t4)h=t24,  k=t2h=k2

 Locus of P(h,k) is x=y2