Based on the solution to univariate cubic equation,this paper puts forward a rigorous coordinate conversion method from geocentric system to geodetic system.

Based on the solution to univariate cubic equation,this paper puts forward a rigorous coordinate conversion method from Cartesian system to geodetic system.

In the light of solution of predicted fire point of antiaircraft gun,on the basis of graphic method,by use of sulving the equation,the paper put forward solutions on precision higher:"adjust-coefficient method","graphic approach mehtod" and "quartic equation method".

In this paper, we discuss when a quartic equation has no real roots, and obtain a necessary and sufficient condition on a quartic equation which has no real roots.

Two algorithms on solving quartic equation are introduced,and their accuracies and stabilities in numerical computation are analyzed in this paper.

The algorithm for determining all roots of general polynomials;

This paper introduces the method from generality to standardization of the simple cubic equation,and shows the illustrated distribution of standardized real root,solving the distribution problem of optional simple cubic equation s real root.

The method that simple cubic equation was changed from general to standard was introduced and the distribution of standardized real root was illustrated, which solved the problem of the distribution of any real root for simple cubic equation.