The graph of a polar equation of the form is a conic, where e > 0 is the eccentricity and | d | is the distance between the focus at the pole and its corresponding directrix.
The conic section equation is .
To determine the type of conic, rewrite the equation as
Divide numerator and denominator by 10.
\Therefore, .
Since e = 1/2 (0 < e < 1), the conic section is ellipse. Sketch the upper half of the ellipse by plotting points from , as shown in figure. Then, using symmetry with respect to the polar axis, sketch the lower half.
\
For the ellipse in figure, the major axis is horizontal and the vertices lie at . So, the length of the major axis is
. To find the length of the minor axis, can use the equation e = c / a and
.