9楼: Originally posted by 478107371 at 2014-05-12 19:05:12
边界条件也是二阶差分吗，是不是一阶差分？另外迭代过程呢？思路是不是用有限差分将二阶方程变成线性方程组，然后用的牛顿迭代法求解？...

%解析解
yy=dsolve('D2y-3*Dy+2*y=x','Dy(0)=1','Dy(1)=2','x');
x=0:0.01:1;hold on;plot(x,eval(yy),'bo')
%bvp 数值解
f1=@(x,y)[y(2);x-2*y(1)+3*y(2)];
solinit = bvpinit(linspace(0,1,20),[-1 1]);
f2=@(ya,yb)[ya(2)-1;yb(2)-2];
sol = bvp4c(f1,f2,solinit);
xint = linspace(0,1,25);
yint = deval(sol,xint);
hold on; plot(xint,yint(1,:),'rp-');