<    1      2    >

---

Formulas of Viète

With the formulas of Viète, the coefficients of a quadratic function can be expressed in the sum and the product of its zeros, by

     and     

 

---

Explanation

The general form of a quadratic function is

what you can also write as

because it applies that a ≠ 0, otherwise it would not be a second-grade function. If you factorize this function you get

A calculation then gives

so that

     and     

 

---

Additional information

The formulas were developed by the French mathematician François Viète.

 

---

Deutsch   Español   Français   Nederlands   中文