Theorem (Vieta's Formulas).   Consider a polynomial of  [Graphics:Images/GraeffeMethodProof_gr_1.gif]  of degree  n  with roots  [Graphics:Images/GraeffeMethodProof_gr_2.gif]   

        [Graphics:Images/GraeffeMethodProof_gr_3.gif],  
        
        [Graphics:Images/GraeffeMethodProof_gr_4.gif].  
        
Let  [Graphics:Images/GraeffeMethodProof_gr_5.gif]  be the  [Graphics:Images/GraeffeMethodProof_gr_6.gif] elementary symmetric function or symmetric polynomial for the variables [Graphics:Images/GraeffeMethodProof_gr_7.gif],    

        [Graphics:Images/GraeffeMethodProof_gr_8.gif]  
        [Graphics:Images/GraeffeMethodProof_gr_9.gif]  
        [Graphics:Images/GraeffeMethodProof_gr_10.gif]  
        [Graphics:Images/GraeffeMethodProof_gr_11.gif]  
        ...  
        [Graphics:Images/GraeffeMethodProof_gr_12.gif]  
        [Graphics:Images/GraeffeMethodProof_gr_13.gif]  
then
        [Graphics:Images/GraeffeMethodProof_gr_14.gif].  

Moreover, we have the important identities relating the coefficients of  [Graphics:Images/GraeffeMethodProof_gr_15.gif]  

        [Graphics:Images/GraeffeMethodProof_gr_16.gif]    for   [Graphics:Images/GraeffeMethodProof_gr_17.gif]

Exploration

[Graphics:../Images/GraeffeMethodProof_gr_18.gif]


Now we can proceed to explore Vieta's Formulas  for  polynomials of  [Graphics:../Images/GraeffeMethodProof_gr_19.gif]  of degree  [Graphics:../Images/GraeffeMethodProof_gr_20.gif].

[Graphics:../Images/GraeffeMethodProof_gr_21.gif]

[Graphics:../Images/GraeffeMethodProof_gr_22.gif]

 

 

 

[Graphics:../Images/GraeffeMethodProof_gr_23.gif]

[Graphics:../Images/GraeffeMethodProof_gr_24.gif]

 

 

 

[Graphics:../Images/GraeffeMethodProof_gr_25.gif]

[Graphics:../Images/GraeffeMethodProof_gr_26.gif]

 

 

 

[Graphics:../Images/GraeffeMethodProof_gr_27.gif]

[Graphics:../Images/GraeffeMethodProof_gr_28.gif]

 

 

 

[Graphics:../Images/GraeffeMethodProof_gr_29.gif]

[Graphics:../Images/GraeffeMethodProof_gr_30.gif]

[Graphics:../Images/GraeffeMethodProof_gr_31.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2005