exm010306.m

来自「书本上的几个例子」· M 代码 · 共 17 行

a=-8;
r_a=a^(1/3)

p=[1,0,0,-a];	
R=roots(p)	

MR=abs(R(1));		
t=0:pi/20:2*pi;	
x=MR*sin(t);		
y=MR*cos(t);		
plot(x,y,'b:'),grid on		
hold on
plot(R(2),'.','MarkerSize',30,'Color','r')		
plot(R([1,3]),'o','MarkerSize',15,'Color','b')
axis([-3,3,-3,3]),axis square					
hold off