几何画图

代码说明：

  根据数学函数，如一次函数，二次函数画曲线，一元三次，圆锥曲线，三角函数，指数，对数函数等画曲线(According to the mathematical functions, such as the first function, the two function, the curve, one yuan, three times, conic, trigonometric, exponential, logarithmic function, etc.)