The orbit of a particle in a central field is known to obey the following relationship: r = A/(1+sin(theta)) a) determine the form of the central force F(r) that is responsible for this motion. b) What is the distance of closest approach between the particle and the point that acts as the origin of the force? What is the furthest distance that the particle can be found form the origin of the force? a) After applying the equation of motion, you get f(r) = -(A^3*l^2*m)/r^2 But for part b, how do I find the r-min? Also A is not mentioned as a constant so do I assume it is?