/**
 * The PolynomialI interface manages a polynomial.
 * <p>
 * Example: 4.3x^2 is a polynomial where 4.3 is the coefficient constant and the
 * degree is 2.
 */
public interface PolynomialI {
  /**
   * Return the coefficient constant used in the polynomial for the degree
   * specified.
   * <p>
   * The valid request values are 0 <= degree <= 3.
   * 
   * @param degree Coefficient constant degree to return
   * 
   * @return Coefficient constant
   *
   * @throws IllegalArgumentException if the degree greater than 3 
   * or degree less than 0.
   */
  public double getCoefficient(int degree);

  /**
   * Returns the result of the polynomial calculated with the given x.
   *
   * @param x The x to plug into the equation.
   * @return the result of the polynomial computed with x
   */
  public double eval(double x); 
}