Parabola

Focus

The fixed point on a parabola.

Directrix

The fixed line of a parabola.

Vertex

The point on the parabola which is halfway from the focus to the directrix.

Axis of Symmetry

The line passing through the focus and perpendicular to the directrix.

Lactus Rectum

A chord connecting two points of the parabola passing through the focus and perpendicular to the axis of symmetry.

a

distance from vertex to the focus or from vertex to directrix.

2a

distance from focus to the end of the latus rectum.

4a

length of the latus rectum.

e

symbol for eccentricity.

What is the General Equation of Parabola with vertex at (0, 0)?

right

What opening is the following:

• y²= 4ax

left

What opening is the following:

• y²= -4ax

up

What opening is the following:

• x²= 4ay

down

What opening is the following:

• x²= -4ay

What is the General Equation of Parabola with vertex at (h, k)?

right

What opening is the following:

• (y - k)² = 4a (x - h)

left

What opening is the following:

• (y - k)² = -4a (x - h)

up

What opening is the following:

• (x - h)² = 4a (y - k)

down

What opening is the following:

• (x - h)² = -4a (y - k)