function A=fun3(t,h,T)
%上機(jī)實(shí)習(xí)三隱式格式;
r=t^2/h^2;
D=100;E=5000;F=3000;L=1;
N=T/t+2;
J=L/h+2;
A(2,J)=0;         %另第一,二行為零
a(1:J-2)=-D*r/2;
b(1:J-2)=1+D*r;
c(1:J-2)=-D*r/2;
for i=3:N
    A(3,1)=0;
    A(3,end)=0;          
   for k=1:J-2
    A(3,k+1)=0.5*D*r*A(2,k)+(2-D*r)*A(2,k+1)+0.5*D*r*A(2,k+2)-A(1,k+1)+t^2*(E*(k)*h*(L-(k)*h)+F);
   end
   A(3,2:J-1)=(zuigan(a,b,c,A(3,2:J-1)'))';  %追趕法
   A(1,:)=A(2,:);
   A(2,:)=A(3,:);
end