The normal at a point on the parabola y 2 = 4 x passes through ( 5 , 0 ) . If two more normals to this…

The normal at a point on the parabola y2=4x passes through (5,0). If two more normals to this parabola also pass through(5,0),  then the centroid of the triangle formed by the feet of these three normals is
  1. 12,12
  2. (2,0)
  3. (5,0)
  4. (0,2)

Solution

The given equation of a parabola,

y2=4x

The equation of normal at a point P(5,0)

y=-tx+2t+t3

0=-5t+2t+t3

3t=t3

t2=3

t=±3,0

Here, a=1

Co-normal point

Pat12,2at1=(3,23)

Qat22,2at2=(3,-23)

Rat32,2at3=(0,0)

The centroid is,

C=3+3+03,23-23+03

C=63,0=2,0

Asked in: AP EAMCET 2019 (21 Apr Shift 2)

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