contestada

A parabola has a vertex at (0,0). The focus of the parabola is located at (4,0). What is the equation of the directrix?

Respuesta :

the equation is y^2=16x and the directrix is x=-4

Answer:

The equation of parabola is given by:

[tex](y-k)^2 = 4a(x-h)[/tex]

where,

(h, k) is the vertex.

Focus = (h+a, k)

As per the statement:

A parabola has a vertex at (0,0).

⇒[tex]y^2 = 4ax[/tex]

The focus of the parabola is located at (4,0).

⇒[tex](h+a, k) = (4, 0)[/tex]

⇒[tex](a, 0) = (4, 0)[/tex]

⇒a = 4

then, equation become:

[tex]y^2 = 16x[/tex]

We have to find the equation of directrix

The equation of directrix is, x = h-a

then;

x = 0-4 = -4

⇒x = -4

Therefore, the equation of directrix is, x = -4