public Expression Factor()
{
// Check if there is a simple factor of x.
if (this[0].EqualsZero())
{
return(Product.New(variable, new Polynomial(Coefficients.Where(i => i.Key != 0).ToDictionary(i => i.Key - 1, i => i.Value), variable).Factor()).Evaluate());
}
DefaultDictionary <Expression, int> factors = new DefaultDictionary <Expression, int>(0);
switch (Degree)
{
//case 2:
// Expression a = this[2];
// Expression b = this[1];
// Expression c = this[0];
// // D = b^2 - 4*a*c
// Expression D = Add.New(Multiply.New(b, b), Multiply.New(-4, a, c));
// factors[Binary.Divide(Add.New(Unary.Negate(b), Call.Sqrt(D)), Multiply.New(2, a))] += 1;
// factors[Binary.Divide(Add.New(Unary.Negate(b), Call.Sqrt(D)), Multiply.New(2, a))] += 1;
// break;
default:
return(this);
}
// Assemble expression from factors.
//return Multiply.New(factors.Select(i => Power.New(Binary.Subtract(x, i.Key), i.Value)));
}