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 .