关于二维图像的初级问题 紧急！
 

均匀带电圆盘的电力线图 使用streamline
命令，画不出电力线，请问各位高手问题在哪里？？
对各种提示均表示感谢！

r=0.75;
[X,Y]=meshgrid(0:0.1:1);
p=sqrt(X.^2+Y.^2);
E1=0.5.*(1-p./(p.^2+r.^2).^0.5)-3./8.*X.^2./p.^2.*(2/3-2.*p./(p.^2+r.^2).^0.5+7.*p.^3/3./(p.^2+r.^2).^1.5-p.^5./(p.^2+r.^2).^2.5);
E2=3/8*2.*Y.*X./p.^2.*(2/3-p./(p.^2+r.^2).^0.5+p.^3/3./(p.^2+r.^2).^1.5);
Ex=E1.*X./(p+eps*(p==0))+E2.*Y./(p+eps*(p==0));
Ey=E1.*Y./(p+eps*(p==0))-E2.*X./(p+eps*(p==0));
Sx=(0:0.03:0.75);Sy=[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0];
streamline(X,Y,Ex,Ey,Sx,Sy)