Question

Find the coordinates of the focus, axis of the parabola, the equation of directrix and the length of the latus rectum.

y² = – 8x

Answer 1

The given equation is y² = –8x.

Here, the coefficient of x is negative. Hence, the parabola opens towards the left.

On comparing this equation with y² = –4ax, we obtain

–4a = –8 ⇒ a = 2

∴ Coordinates of the focus = (–a, 0) = (–2, 0)

Since the given equation involves y², the axis of the parabola is the x-axis.

Equation of directrix, x = a i.e., x = 2

Length of latus rectum = 4a = 8