Expression cannot be used as a function (POW)

Question

double aluminumWireResistance(double length, double wiregauge)
{
    const long double PI=(atan(1)*4);
    int a;
    double diam2;
    double numerator2=((4(2.82*pow(10,-8)))*length);
    double denominator2= (PI*pow(diam2,2));

    a=((36-wiregauge)/39);
    diam2=(.127*pow(92,a));
    diam2=(diam2/100);

  double alumWireResistance=numerator2/denominator2;
 return alumWireResistance;
}

I get the error: Expression cannot be used as a function on the double numerator2 line its supposed to be 4*(2.82*10^-8)*length

Answer 1

You said this:

double numerator2=((4(2.82*pow(10,-8)))*length);

Presumably you mean this:

double numerator2=((4 * (2.82*pow(10,-8)))*length);
//                    ^