Bosonic and fermionic entropy of a three-dimensional black hole

By using the quantum-statistical method, we derive the partition function of bosonic and fermionic fields in a three-dimensional black hole. Then via the unproved brick-wall method, the membrane model, we obtain that the entropy of bosonic and fermionic fields in the black hole is proportional to the area of the horizon. In our result, the stripped term and the divergent logarithmic term do not exist any more. The problem that the state density is divergent around the horizon doe, not, exist either. We also give the influence of the spinning degeneracy of particles on the entropy of the black hole. We offer a new simple and direct way of calculating the entropy of a lower-dimensional black hole.