Newton Raphson

double f(double x){
    //sin(x) + x^2 -1
    //f(x)/f'(x)
    return (sin(x) + x*x - 1)/(cos(x) + 2*x);

}
double next(double Xi){
    //Xi+1 = Xi - f(Xi)
    return Xi - f(Xi);
}
double errorr(double next, double cur){
    return abs(next-cur);
}
int main(){
    double cur = 1;
    int i=1;
    double neww;
    double e=0;
    do{
        //cin>>prev>>cur;
        neww = next(cur);
        e = errorr(neww,cur);
        //cout<<i++<<"\t"<<cur<<"\t"<<neww<<"\t"<<e<<endl;
        printf("%d\t%.6f\t\t\t%.6f\t\t\t%.6f\n",i++,cur,neww,e);
        cur = neww;
    }while(e>0.01);
    return 0;
}