9 (c).  Let    and    in part (a) to establish inequality  (4-17).  

Solution 9 (c).

See text and/or instructor's solution manual.

Solution.  From part (a) we have:



Observe that .

Using the inequalities     and  .  in part (b) this implies that

                       for   .

Thus   .  

Using this inequality we get inequality  (4-17):

                    

This solution is complements of the authors.

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