public void PartialDerivativeTest4()
{
// (x + 1) * (3 + x)
IExpression exp = new Mul(new Add(new Variable("x"), new Number(1)), new Add(new Number(3), new Variable("x")));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("0", deriv.ToString());
}
public void DerivativeTest1()
{
IExpression exp = new Mul(new Number(2), new Variable("x"));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("2 * 1", deriv.ToString());
}
public void DerivativeTest2()
{
// 2x
Number num = new Number(2);
Variable x = new Variable("x");
IExpression exp = new Mul(num, x);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("2 * 1", deriv.ToString());
num.Value = 3;
Assert.AreEqual("3 * x", exp.ToString());
Assert.AreEqual("2 * 1", deriv.ToString());
}
