Exercise 4.  Show that  ,  thus completing the proof of  Theorem 1.3.  

Solution 4.

See text and/or instructor's solution manual.

    For   and ,  let  .  Then    for some and some  .  

Thus,  ,  and  .  

This gives  ,  so that  .  

Therefore,  .

This solution is complements of the authors.

(c) 2008 John H. Mathews, Russell W. Howell