#include <stdio.h>
#include <stdlib.h>
#include <math.h>
double f1(double);
double f2(double);
double integ(double(*)(double),double,double);
int n=35;
int main(void)
{
    printf("first integral %lf\n",integ(f1,-1,3));
    printf("second integral %lf\n",integ(f2,1,5));
    system("pause");
    return 0;
}
double integ(double(*f)(double),double a,double b)
{
    double rez=0,h,i;
    h=(b-a)/n;
    rez = 0.5*(f(a) + f(b));
    for (i=1; i < n; i++)
        {
            rez +=f(a + i*h);
        }
      return  rez*=h;
}
double f1(double x)
{
    return 1/(3*x*x-2*x+4);
}
double f2(double x)
{
    return cos(x)/1+sin(x)*sin(x);
}