Exercise 3.  Prove that the following series converge uniformly on the sets indicated.  

3 (c).  [Graphics:Images/UniformConvergenceModHome_gr_151.gif]    converge uniformly on   [Graphics:Images/UniformConvergenceModHome_gr_152.gif],   where  [Graphics:Images/UniformConvergenceModHome_gr_153.gif].  

Solution 3 (c).

See text and/or instructor's solution manual.

Solution.   Here  [Graphics:../Images/UniformConvergenceModHome_gr_154.gif],  and  for a fixed  [Graphics:../Images/UniformConvergenceModHome_gr_155.gif],  choose  [Graphics:../Images/UniformConvergenceModHome_gr_156.gif]  large so that  [Graphics:../Images/UniformConvergenceModHome_gr_157.gif]  for all  [Graphics:../Images/UniformConvergenceModHome_gr_158.gif].  

Then, for all  [Graphics:../Images/UniformConvergenceModHome_gr_159.gif],  and all  [Graphics:../Images/UniformConvergenceModHome_gr_160.gif],  we have    

                    [Graphics:../Images/UniformConvergenceModHome_gr_161.gif],     
                  
so that  

                    [Graphics:../Images/UniformConvergenceModHome_gr_162.gif].
                    
Recall formula (1-24) in Section 1.3.  

(1-24)           [Graphics:../Images/UniformConvergenceModHome_gr_163.gif].  

In formula (1-24) we set  [Graphics:../Images/UniformConvergenceModHome_gr_164.gif]  and  [Graphics:../Images/UniformConvergenceModHome_gr_165.gif]  and get  

                    [Graphics:../Images/UniformConvergenceModHome_gr_166.gif].

Now use this, together with   [Graphics:../Images/UniformConvergenceModHome_gr_167.gif]  and obtain

                    [Graphics:../Images/UniformConvergenceModHome_gr_168.gif].  

Therefore, it now follows that  

                    [Graphics:../Images/UniformConvergenceModHome_gr_169.gif]    

      For  [Graphics:../Images/UniformConvergenceModHome_gr_170.gif]  and all  [Graphics:../Images/UniformConvergenceModHome_gr_171.gif],  we have    

                    [Graphics:../Images/UniformConvergenceModHome_gr_172.gif].   

The series    

                    [Graphics:../Images/UniformConvergenceModHome_gr_173.gif]  

is known to be convergent  (it is a geometric series).  

Therefore, by the Weierstrass M-test, the series   [Graphics:../Images/UniformConvergenceModHome_gr_174.gif]   converges uniformly on   [Graphics:../Images/UniformConvergenceModHome_gr_175.gif],   where  [Graphics:../Images/UniformConvergenceModHome_gr_176.gif].  

                    [Graphics:../Images/UniformConvergenceModHome_gr_177.gif]          [Graphics:../Images/UniformConvergenceModHome_gr_178.gif]

  

                    [Graphics:../Images/UniformConvergenceModHome_gr_179.gif]          [Graphics:../Images/UniformConvergenceModHome_gr_180.gif]

                    The image of  [Graphics:../Images/UniformConvergenceModHome_gr_181.gif] under  [Graphics:../Images/UniformConvergenceModHome_gr_182.gif]  for  [Graphics:../Images/UniformConvergenceModHome_gr_183.gif].

                    [Graphics:../Images/UniformConvergenceModHome_gr_184.gif]          [Graphics:../Images/UniformConvergenceModHome_gr_185.gif]

                    The image of  [Graphics:../Images/UniformConvergenceModHome_gr_186.gif] under the mapping  [Graphics:../Images/UniformConvergenceModHome_gr_187.gif].  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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