三次方程求根及根的性质

EXTRACT A ROOT OF A CUBIC EQUATION AND THE NATURE OF ITS ROOT

给出实系数三次代数方程三个根的关系式定理。只要知道一个根，由该定理可方便地求出另外两根；对重根也适用，且更方便。

This paper gives the theorem by the actual factors of three algebraic equations having three roots,if known one of the roots the other two can be easily obtained by it. It is also adapt to the duplicated roots and is convenient.