用计算机语言编写ErlangB公式计算器，实现给定任意两个变量求解第三个变量的功能，掌握ErlangB公式的计算方法，培养数值分析计算与算法设计能力。-Write ErlangB formula calculator computer language, to achieve a given arbitrary function of two variables to solve the third variable, master formula calculation method ErlangB cultivate numerical analysis computing and algorithm design capabilities.