圆锥的立体几何定义：“以直角三角形的直角边所在直线为旋转轴，其余两边旋转360度而成的曲面所围成的几何体叫做圆锥。旋转轴叫做圆锥的轴。 垂直于轴的边旋转而成的曲面叫做圆锥的底面。不垂直于轴的边旋转而成的曲面叫做圆锥的侧面。无论旋转到什么位置，不垂直于轴的边都叫做圆锥的母线。”
Wikipedia上的定义如下：“A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base that is in a plane that does not contain the apex. Depending on the author, the base may be restricted to be a circle, any one-dimensional quadratic form in the plane, any closed one-dimensional figure, or any of the above plus all the enclosed points. If the enclosed points are included in the base, the cone is a solid object; otherwise it is a two-dimensional object in three-dimensional space. In the case of a solid object, the boundary formed by these lines or partial lines is called the lateral surface; if the lateral surface is unbounded, it is a conical surface.”
那么如何使用软件绘制圆锥的图形呢？
代码如下：
参考了以下文章：https://zhidao.baidu.com/question/97543462.html(用matlab怎么画圆锥体？)
z=cplxgrid(20);%在复平面上面得到一个21*41的网格，x，y分别为其实部和虚部
x=real(z);
y=imag(z);
fz=sqrt((x.^2+y.^2));%圆锥公式，z^2=x^2+y^2来求fz
cplxmap(z,fz)%作图
在Matlab中输入以上代码，就可以得到圆锥图了(这图确实漂亮！)