function LR2
function y=f(x);y=x*x; end
N=[10 20 50 100 1000]
a=0;b=1;Sa=[1/3 1/3 1/3 1/3 1/3];
for i=1:5
h=(b-a)/N(i);S1(i)=0;S2(i)=0;S3(i)=0;S4(i)=0;
x=a;
for j=1:N(i)
S1(i)=S1(i)+f(x);x=x+h;
end
S1(i)=S1(i)*h;
x=a+h;
for j=1:N(i)
S2(i)=S2(i)+f(x);x=x+h;
end
S2(i)=S2(i)*h;
x=a+h;
for j=1:N(i)-1
S3(i)=S3(i)+f(x);x=x+h;
end
S3(i)=(f(a)/2+f(b)/2+S3(i))*h;
x=a+h;
for j=1:N(i)-1
if mod(j,2)==1
S4(i)=S4(i)+4*f(x);
else
S4(i)=S4(i)+2*f(x);
end
x=x+h;
end
S4(i)=(f(a)+f(b)+S4(i))*h/3;
end
format bank
[N' Sa' S1' S2' S3' S4']
plot(N,Sa,N,S1,N,S2,N,S3,N,S4)
end
Результат выполнения
N Ia I1 I2 I3 I4
10.00 0.33 0.28 0.39 0.33 0.33
20.00 0.33 0.31 0.36 0.33 0.33
50.00 0.33 0.32 0.34 0.33 0.33
100.00 0.33 0.33 0.34 0.33 0.33
1000.00 0.33 0.33 0.33 0.33 0.33
ПРИМЕР4.. Лабораторная работа 3.
Решение дифференциальных уравнений