Answer:
the distance from pole to directrix is 4 units
Explanation:
Rewritten to the form ...
r = ed/(1+e·cos(theta))
you find ..
ed = 4/-2 = -2 . . . . . where d is the distance from the pole to the directrix
e = -1/-2 = 1/2 . . . . . the eccentricity
so d = ed/e = -2/(1/2) = -4 and the ellipse has the equation ...
r = (1/2)(-4)/(1 + 1/2·cos(theta))
The directrix is a vertical line 4 units from the focus in the -x direction.