c5_3.m

这是我从一本基于MATLAB实现的数值分析算法的书中自带的光盘程序

%C5_3.m
%用高斯求积法计算定积分
function C5_3
a=input('Lower limit,a?');
b=input('Upper limit,b?');
n=input('Gauss点个数：n?');
h=(b-a);
xa=[];
%h=(b-a)/(n-1);x0=a+(0:(n-1))*h;
t=[-0.8611363116,-0.3399810436,0.3399810436,0.8611363116];
w=[0.3478548451,0.6521451549,0.3478548451,0.6521451549];
y0=(a+b)/2;
for g=1:n
    v(g)=y0+t(g)*h/2;
end
xa=[xa,v];
f=sin(xa);
fprintf('k        xa          f(xa)          w \n');
x=0;
k=0;
for i=1:n
    k=k+1;
    x=x+f(i)*w(i)*h/2;
    fprintf('%1d  %6.5e  %6.5e  %6.5e  \n',k,xa(i),f(i),w(i)');
end