The equation for graph is either
or
,
.
Observe the graph:
\Since the graph is symmetric with respect to the polar axis, the polar equation is a cosine function.
\The polar equation is
.
Find the values of
and
.
The points on the graph are
and
.
Substitute
in
.


.
Substitute
in
.

.
Substitute
.

.
Substitute
and
in
.
.
The polar equation is
.
The polar equation is
.