Question

The coordinates of a point on the parabola $y^2=8x$, whose focal distance is $4$, is :

• A. $(2,\pm 4)$
• B. $(4,2)$
• C. $(4,-2)$
• D. $(2,4)$

Answer 1

The correct option is A $(2,\pm 4)$

consider the parabola $y^2=4ax$ are $(a,2a)$

a=focal distance from the origin = $4$

$x=a=4$

$y=+or-2a=2\times 4=+or-8$

$\Rightarrow points(x,y)=(4,+or-8)$ or which is equal to $(2,+or-4)$.