public void DerivativeTest1()
{
// x - sin(x)
IExpression exp = new Sub(new Variable("x"), new Sin(new Variable("x")));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("1 - (cos(x) * 1)", deriv.ToString());
}
public void DerivativeTest2()
{
Number num1 = new Number(2);
Variable x = new Variable("x");
Mul mul1 = new Mul(num1, x);
Number num2 = new Number(3);
Mul mul2 = new Mul(num2, x.Clone());
IExpression exp = new Sub(mul1, mul2);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("(2 * 1) - (3 * 1)", deriv.ToString());
num1.Value = 5;
num2.Value = 4;
Assert.AreEqual("(5 * x) - (4 * x)", exp.ToString());
Assert.AreEqual("(2 * 1) - (3 * 1)", deriv.ToString());
}
public void PartialDerivativeTest4()
{
IExpression exp = new Sub(new Variable("x"), new Number(1));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("0", deriv.ToString());
}
public void PartialDerivativeTest1()
{
IExpression exp = new Sub(new Mul(new Variable("x"), new Variable("y")), new Variable("y"));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("(x * 1) - 1", deriv.ToString());
}