public void DerivativeTest2()
{
IExpression exp = new Add(new Mul(new Number(2), new Variable("x")), new Mul(new Number(3), new Variable("x")));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("(2 * 1) + (3 * 1)", deriv.ToString());
}
public void DerivativeTest3()
{
// 2x + 3
Number num1 = new Number(2);
Variable x = new Variable("x");
Mul mul1 = new Mul(num1, x);
Number num2 = new Number(3);
IExpression exp = new Add(mul1, num2);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("2 * 1", deriv.ToString());
num1.Value = 5;
Assert.AreEqual("(5 * x) + 3", exp.ToString());
Assert.AreEqual("2 * 1", deriv.ToString());
}
public void PartialDerivativeTest3()
{
IExpression exp = new Add(new Variable("x"), new Number(1));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("0", deriv.ToString());
}
public void PartialDerivativeTest2()
{
IExpression exp = new Add(new Add(new Mul(new Variable("x"), new Variable("y")), new Variable("x")), new Variable("y"));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("(x * 1) + 1", deriv.ToString());
}