Question

c语言求积分

c语言求积分 ∫sinxdx(x的积分区间为0-π)，要求编写一个函数double integral(double a,double b,int n)求积分，在主函数中输入积分上、下限与积分分段数目n。

Answer 1

#include<stdio.h>
#include <math.h>
double integral(double a,double b,int n)
{
double x,y,dx,sum=0.0;
int i;
dx = (b-a) /(double) n;
for (i=0;i<=n;i++){
y = sin(a+dx * i);
sum = sum + y;
}
y = sum / (double) (n+1) * (b-a);
return y;
}

void main()
{
double a,b;
int n;
printf("Enter a,b,n\n");
scanf("%lf %lf %d",&a,&b,&n);
printf("%lf", integral(a,b,n) );
}