The problem for solving equation f ( x ) = 0 , where f : d c x y is nonlinear operation , is very important in view of theoretics and practice . not only professional numerical researchers devote themselves to it , but also many engineers and mathematicians study it according to their own demands and interest . some are the spokesmen among them , whose work reflects the features of the mathematics in their times 几个世纪以来，许多工程技术人员，还有许多纯粹的数学家，他们都曾从自己的需要或兴趣出发，去对它做了不同角度的研究，在研究这个课题的数学家中，不少还是他们时代的数学的代表人物，他们在这个课题上的工作，也反映了各个时代的数学面貌。
