A particle moves in a potential V (r) = V0e2r2. (a) Given L, find the radius of

Question:

A particle moves in a potential V (r) = −V0e−λ2r2.
(a) Given L, find the radius of the stable circular orbit. An implicit equation is fine here.
(b) It turns out that if L is too large, then a circular orbit actually doesn’t exist. What is the largest value of L for which a circular orbit does indeed exist? What is the value of Veff (r) in this case?