The focus of the parabola is and parabola opens down.
Parabola contains .
Standard form of the vertical parabola is .
Where
\Vertex : ,
Focus : ,
Here and
Substitute and
in standard form.
and
.
Since the parabola opens down, then .
Therefore, .
Vertex of parabola : .
Axis of symmetry : ,
Axis of symmetry : ,
Directrix : .
Directrix : .
Write the equation for the parabola in standard form using the values of , and
.
Substitute the values of ,
, and
in standard form.
Therefore, the standard form of the equation is .
Graph :
\Graph the vertex, focus, axis of symmetry, and directrix.
\Construct a table values to graph the general shape of the curve.
\Graph of :
The standard form of the equation is .
Graph of :
.