p1=[2,0,3,0,4,0];
p2=[0,0,-4,0,2,-1];

s=p1+p2

d=p1-p2

m=conv(p1,p2)



p2=[-4,0,2,-1];

m=conv(p1,p2)

[p,u]=deconv(p1,p2)


x=-1:0.05:1;
y=polyval(m,x);
plot(x,y)
refline(0,0);

format shortg
r=roots(m)

[abs(r),angle(r)]

[abs(r),radtodeg(angle(r))]

compass(r)