此程序为符号计算程序，自变量为 x ，能够进行多次循环求导，程序主要包含三个部分reduction、dfferentiate和check。

　　Reduction部分的作用是对于所输入的函数表达式进行化简；differentiate部分的作用是对于输入的函数表达式进行求导；Check部分的作用是对于输入的函数表达式进行括号的添加、化简以及纠错；-This procedure for symbolic computation program, since the variables x, the derivative can be recycled many times, the program consists of three parts reduction, dfferentiate and check. Reduction part of the role is to carry out the input function expression simplification　differentiate part of the role is a function of the input expression derivation　Check part of the role is a function of the input expressions in parentheses are added, as well as simplification correction