bessl1u.m

主要阐述的是使用差分法解一类Bessel方程在不同边界条件下的离散解

clear;
Q=1,a=2,u=[30,7,2,0.9,0.5,0.01];
b=1-a;
for i=1:6
    w=sqrt(u(i));
    A=0;
    B=Q/(a*besselk(0,w)-b*w*besselk(1,w));
    x=-3:0.03:3;
    y=A*besseli(0,w*x)+B*besselk(0,w*x);
   switch i
        case 1,
            plot(x,y,'k');
        case 2,
            plot(x,y,' . k');
        case 3,
            plot(x,y,' > k');
        case 4,
            plot(x,y,' * k');
        case 5,
            plot(x,y,' + k');
        case 6,
            plot(x,y,' < k');    
        end;
        hold on;
    end;
    hold off;
    axis([-1 1 -10 10]);
    legend('u= 30','u= 7','u= 2','u= 0.9','u= 0.5','u= 0.01',0)
    title('第一种边界条件下不同u值的图象','FontSize',12,'FontName','隶书');