Since the final expression is proportional to the total angular momentum , Kepler's equal area law will hold for any system that conserves angular momentum. Since any radial force will produce no torque on the planet's motion, angular momentum will be conserved.
Since the final expression is proportional to the total angular momentum  Kepler's equal area law will hold for any system that conserves angular momentum Since any radial force will produce no torque on the planet's motion, angular momentum will be conserved