code: public static void pow(ComplexPolar_F64 a , int N , ComplexPolar_F64 result )
      {
          result.r = Math.pow(a.r,N);
          result.theta = N*a.theta;
      }
docs: Computes the power of a complex number in polar notation
  
  @param a Complex number
  @param N Power it is to be multiplied by
  @param result Result