Polynomial.java

public class Polynomial{
    double [] coefficients;

    public Polynomial(){
        coefficients = new double[0];
    }
    public Polynomial(double[] args){
        coefficients = args;
    }

    public Polynomial add(Polynomial p){
        int len = Math.max(p.coefficients.length, coefficients.length);
        double[] arr = new double[len];
        for (int i = 0; i < len; ++i){
            if (p.coefficients.length > i) arr[i] += p.coefficients[i];
            if (coefficients.length > i) arr[i] += coefficients[i];
        }
        Polynomial output = new Polynomial(arr);
        return output;
    }

    public double evaluate(double x){
        double result = 0;
        for (int i = 0; i < coefficients.length; ++i){
            result += coefficients[i] * Math.pow(x, i);
        }
        return result;
    }

    public boolean hasRoot(double x){
        return evaluate(x) == 0;
    }
}