Dev - C++ - Ayduda con tangente

#include<stdio.h>

#include<stdlib.h>

#include<math.h>

#include <iostream>

using namespace std;

double x;

double factorial(int m){

    if (m==0 ){

        return 1;

    }

    else {

        return m*factorial(m-1);

    }

};

double b[8]={1,(1/2),(1/6),0,(-1/30),0,(1/42),0};

int main(){

double tg = 0;

int n;

    cout<<"Ingrese un valor de x menor a 1,6 : "<<endl;

    cin>>x;

        for (n=0; n<=7; n++){

        tg=((b[n*2])*((pow(-4,n)*(1-pow(4,n)))/factorial(2*n)))*pow(x,((2*n)-1));

        cout<<tg<<endl;

}

    cout<<"math"<<tan(1)<<endl;

return 0;

};