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a=0; 
b=1; 
TOL=10^(-4); 
N=200; 
%自适应求积法 
% f=inline('(100*sin(10/x))/x^2','x'); 
f=inline('4./(1+x^2)','x'); 
APP=0; 
i=1; 
TOL(i)=10*TOL; 
a(i)=a; 
h(i)=(b-a)/2; 
FA(i)=feval(f,a); 
FC(i)=feval(f,a+h(i)); 
FB(i)=feval(f,b); 
S(i)=h(i)*(FA(i)+4*FC(i)+FB(i))/3; 
L(i)=1; 
while(i>0) 
     FD=feval(f,a(i)+h(i)/2); 
     FE=feval(f,a(i)+3*h(i)/2); 
     S1=h(i)*(FA(i)+4*FD+FC(i))/6; 
     S2=h(i)*(FC(i)+4*FE+FB(i))/6; 
     v1=a(i); 
     v2=FA(i); 
     v3=FC(i); 
     v4=FB(i); 
     v5=h(i); 
     v6=TOL(i); 
     v7=S(i); 
     v8=L(i); 
     i=i-1; 
     if(abs(S1+S2-v7)=N) 
       fprintf('超出范围'); 
       break; 
     else 
       i=i+1; 
       a(i)=v1+v5; 
       FA(i)=v3; 
       FC(i)=FE; 
       FB(i)=v4; 
       h(i)=v5/2; 
       TOL(i)=v6/2; 
       S(i)=S2; 
       L(i)=v8+1; 
       i=i+1; 
       a(i)=v1; 
       FA(i)=v2; 
       FC(i)=FD; 
       FB(i)=v3; 
       h(i)=h(i-1); 
       TOL(i)=TOL(i-1); 
       S(i)=S1; 
       L(i)=L(i-1); 
end 
end 
APP