Answer
$\dfrac {12}{3-4\cos \theta }$
Work Step by Step
$r=\dfrac {ed}{1-e\cos \theta }=\dfrac {\dfrac {4}{3}\times 3}{1-\dfrac {4}{3}\cos \theta }=\dfrac {12}{3-4\cos \theta }$
(Becouse directix is negative in sign we take $r=\dfrac {ed}{1-e\cos \theta }$ not $r=\dfrac {ed}{1+e\cos \theta }$
