The focus of the parabola `y^(2) = - `4ax is :

The focus of the parabola y ^(2) =4y -4x is

The focus of the parabola y ^(2) =4y -4x is

The focus of the parabola y^(2)-4y-8x-4=0 is

The focus of the parabola y^(2)-4y-8x-4=0 is

If a straight line passing through the focus of the parabola y^(2) = 4ax intersectts the parabola at the points (x_(1), y_(1)) and (x_(2), y_(2)) , then prove that x_(1)x_(2)=a^(2) .

Let S is the focus of the parabola y^(2) = 4ax and X the foot of the directrix, PP’ is a double ordinate of the curve and PX meets the curve again in Q. Prove that P’Q passes through focus.

If a straight line pasing through the focus of the parabola y^(2) = 4ax intersects the parabola at the points (x_(1), y_(1)) and (x_(2) , y_(2)) then prove that y_(1)y_(2)+4x_(1)x_(2)=0 .

The focus of the parabola y^(2)-4 y-8 x+4=0 is

The focus of the parabola y^(2)-4y-8x+4=0 is,