The equation is where
and
.
Consider the equation .
.
The equation is in the general form of parabola where
is vertex, focus is
and directrix is
.
Compare the equation with general form.
\Here .
.
The equation of the parabola with vertix at and the axis of symmetry is about
-axis.
The focus is and the directrix is
.
The parabola is opens right when and opend left when
.
The equation of the parabola with vertix at and the axis of symmetry is about
-axis.
The focus is and directrix is
.