class RealPolynomialFunction1D extends DoubleFunction1D {

  @Override
  public RealPolynomialFunction1D derivative() {
    final int n = _coefficients.length - 1;
    final double[] coefficients = new double[n];
    for (int i = 1; i <= n; i++) {
      coefficients[i - 1] = i * _coefficients[i];
    }
    return new RealPolynomialFunction1D(coefficients);
  }

  public  RealPolynomialFunction1D(final double... coefficients);

}