function3

代码说明：

   The DocPolynom to Character Converter The char method produces a character string that represents the polynomial displayed as powers of an independent variable, x. Therefore, after you have specified a value for x, the string returned is a syntactically correct MATLAB expression, which you can evaluate. The char method uses a cell array to collect the string components that make up the displayed polynomial. The disp method uses char to format the DocPolynom object for display. Class users are not likely to call the char or disp methods directly, but these methods enable the DocPolynom class to behave like other data classes in MATLAB. Here is the char method.