Let F be a planar vector field and again consider an annular region A as in the previous problem. Suppose that F has no equilibria and that F points inward along the boundary of the annulus, as before. (a) Prove there is a closed orbit in A. (Notice that the hypothesis is weaker than in the previous problem.)(b) If there are exactly seven closed orbits in A, show that one of them has orbits spiraling toward it from both sides.