牛顿迭代

/*f(x)=cosx+sinx-4x*/#include<stdio.h>#include<math.h>#define e 1e-5double PF(double x)//原函数{    double ans;    ans=cos(x)+sin(x)-4*x;    return ans;}double DF(double x)//导函数{    double ans;    ans=-sin(x)+cos(x)-4;    return ans;}int main(){    int i;//精度 迭代次数    double pf,df,x0,x1;    x0=1.0,x1=1.0,i=1;    do    {        pf=PF(x0);        df=DF(x0);        x1=x0;        x0=x0-(pf/df);        i++;    }while(fabs(x1-x0)>e&&i<=100);    printf("x=%lf\n",x0);    return 0;}