Вычисление арифметического выражения

const float a = 0.5;
const float b = -1,7;
const float x = 1.69;
float s = 0;
 
s =
 
system("PAUSE");
return 0;

const float a = 0.5;
        const float b = -1.7;
        const float x = 1.69;
        float s = 0;
 
        s = a + x + 1.3;
        s = pow(fabs(s),1.0/5);
        s = sin(x - a);
 
        cout << "s = " <<  s << endl;
        system("PAUSE");
        return 0;

s = a + x + 1.3;
s = std::pow(std::abs(s), 1.0 / 5);
s *= sin(x - a);

int main()
{
    const double a = 0.5;
    const double b = -1.7;
    const double x = 1.69;
    double s = 0;
 
    s = a + x + 1.3;
    s *= std::pow(std::abs(s), 1.0 / 5);
    s *= std::sin(x - a);
 
    s += (1.0 + std::log(std::abs((x - a) / b))) / std::pow(M_E, x - a) * std::tan(a*x + 1.3);
 
    std::cout << "s = " <<  s << std::endl;
    system("PAUSE");
    return 0;
}

log: SING error
s = inf
Press any key to continue . . .
 
Модули вроде все есть
#include <vcl.h>
#include <math.h>
#include <iostream>
#pragma hdrstop
 
#include <tchar.h>
using namespace std;

s += (1.0 + std::log(std::abs((x - a) / b))) / std::pow(M_E, x - a) * std::tan(a*x + 1.3);

//code
s=pow(a*x+1.3,1./5)*sin(x-a)+(1+log((x-a)/b))/(exp(x-a)*tan(a*x+1.3));
//code

log: DOMAIN error
s = inf
Press any key to continue . . .

double t, u, s;
t=a*x+1.3;
u=x-a;
s=pow(t,1./5.)*sin(u)+(1.+log(fabs(u/b)))/(exp(u)*tan(t));