这是在codeproject下的老外的代码，没有工程文件（dsw、dsp），但有demo演示。对输入的函数（如log(x)，sign(cos(x))）都能在直角坐标系上画出相应的图，还有表达式分解的过程，很强大。-This is a foreigner under the codeproject code, there is no project files (dsw, dsp), but demo demo. A function of the input (such as log (x), sign (cos (x))) in the Cartesian coordinate system can be drawn on the map, as well as expression of the process of decomposition, it is powerful.