Exercise 1.  Factor each polynomial as a product of linear factors.  

1 (c).  [Graphics:Images/LiouvilleMoreraGaussModHome_gr_37.gif].

Solution 1 (c).

See text and/or instructor's solution manual.

Answer.  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_39.gif].

Solution.  

                    [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_40.gif]

Therefore  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_41.gif]  is a factor of  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_42.gif],  and since the coefficients of  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_43.gif]  are all real

we know that  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_44.gif]  is also a factor of  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_45.gif].  Hence  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_46.gif]  is a factor of  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_47.gif].  

Now divide  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_48.gif]  by  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_49.gif]  and obtain

                    [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_50.gif].

Therefore  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_51.gif].   

Next use the quadratic equation to find the roots of  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_52.gif].  


[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_53.gif]  


[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_54.gif]  

Hence,   [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_55.gif].  

Combining this with the other factors  [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_56.gif]  we obtain

                    [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_57.gif].

We are done.   

Aside.  We can let Mathematica double check our work.

[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_58.gif]

[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_59.gif]



[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_60.gif]

[Graphics:../Images/LiouvilleMoreraGaussModHome_gr_61.gif]


          [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_62.gif]

          The roots of the polynomial   [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_63.gif],  

          [Graphics:../Images/LiouvilleMoreraGaussModHome_gr_64.gif].  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This solution is complements of the authors.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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