C++用复合梯形法求积分

#include<iostream>using namespace std;const int N=10000;double func(double x);int main(){double a=-1.0;double b=1.0;double h=(b-a)/N;double sum=(func(a)+func(b))*h/2;for (int i=0;i<N;i++){sum+=h*func(a+i*h);}cout<<"result="<<sum<<endl;return 0;}double func(double x){return 2/(1+x*x);}

不知道怎么在博客里写入公式,知道的提醒下