The polar equation is .
The equation has cosine function is symmetrical about polar axis.
Graph the polar equation in cartesian plane: on
.
Observe the graph:
\The equation is maximum at
and minimum at
.
The equation has cosine function is symmetrical about polar axis.
Substitute .
.
The remains unchanged, it is symmetrical about polar axis.
As increases from
to
,
decreases from
to
.
As increases from
to
,
decreases from
to
.
As increases from
to
,
increases from
to
.
As increases from
to
,
increases from
to
.
As increases from
to
,
increases from
to
.
As increases from
to
,
increases from
to
.
This means that the distance from increases from to
, but instead of being in the first quadrant this portion of the polar curve lies on the opposite side of the pole in the third quadrant.
The remainder of the curve is drawn in a similar fashion, with the arrows and numbers indicating the order in which the portions are traced out. The resulting curve has 12 loops and it called a 12-leaves rose.
\Graph the polar eqation:
\
Graph of the polar equation in cartesian plane:.