eullb.m

数值分析各种公式的解法

function eullb(x0,y0,b,h)
n=fix((b-x0)/h);
x(1)=x0+h;
y1=y0+h*fa(x0,y0);
y(1)=y1;
y2=y1+h*(fa(x0+h,y1)+fa(x0+2*h,y0+2*h*fa(x0+h,y1)))/2;
for i=2:n
    x0=x0+h;
    y0=y1;
    x(i)=x0+h;
    y1=y2;
    y2=y1+h*(fa(x0+h,y1)+fa(x0+2*h,y0+2*h*fa(x0+h,y1)))/2;
    y(i)=y1;
    hold on
end
[x',y']
function fa=fa(x,y)
fa=y-2*x/y;