Parabola focus is at and vertex is
.
Since the -coordinates are equal, the parabola is horizontal.
Standard form of horizontal parabola is .
Where is vertex.
If then the parabola opens to the left and
parabola opens right.
Directrix is and focus at
.
Focus .
.
Substitute and
in
.
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The directrix is .
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Latus rectum is the line segment of a parabola perpendicular to axis which has both ends on the curve.
\Obtain the points define the latus rectum, let .
Then .
.
The two points that define latus rectum are .
Graph:
\Draw the coordinate plane.
\Plot the vertex, focus and the two points
Draw the directrix line.
\Connect the plotted points with smooth curve.
\The parabola equation is .
The two points that define latus rectum are
Graph of :
.