Question

What does the line y=k-1/4a represent in y=a(x-h)^2+k, the standard form of equation for a parabola?

Answer 1

The answer should be the directrix because k represents the y-value of the vertex, and for this questions the parabola is probably facing upward, so the directrix is under the vertex.

Answer 2

The line y=k-1/4a represent in y=a(x-h)^2+k is:

Directrix.

Explanation:

Directrix of a parabola--

A directrix is a line which is perpendicular to the axis of symmetry of a parabola and it does not touch the parabola.

Also, for the standard equation of the parabola i.e.

`y=a(x-h)^2+k`

The equation of directrix of a parabola is given by:

`y=k-(1)/(4a)`