The triangle PQR of area 'A' is inscribed in the parabola `y^2=4ax` such that the vertex P lies at the vertex pf the parabola and base QR is a focal chord.The modulus of the difference of the ordinates of the points Q and R is :

Options

A. A/2a
B. A/a
C. 2A/a
D. 4A/a

Answer

C

Explanation

(3) Difference of the ordinate
`d=|2at+(2a)/(t)|=2a|t+(1)/(t)|`

Now, area `(A)=(1)/(2)|(at^(2),2at,1),(a//t^(2),-2a//t,1),(0,0,1)|=a^(2)(t+(1)/(t))`
`or2a(t+(1)/(t))=(2A)/(a)`