public void DerivativeTest2()
{
IExpression exp = new Cos(new Mul(new Number(2), new Variable("x")));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("-(sin(2 * x) * (2 * 1))", deriv.ToString());
}
public void DerivativeTest1()
{
IExpression exp = new Cos(new Variable("x"));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("-(sin(x) * 1)", deriv.ToString());
}
public void DerivativeTest3()
{
// cos(2x)
Number num = new Number(2);
Variable x = new Variable("x");
Mul mul = new Mul(num, x);
IExpression exp = new Cos(mul);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("-(sin(2 * x) * (2 * 1))", deriv.ToString());
num.Value = 7;
Assert.AreEqual("cos(7 * x)", exp.ToString());
Assert.AreEqual("-(sin(2 * x) * (2 * 1))", deriv.ToString());
}
public void PartialDerivativeTest3()
{
IExpression exp = new Cos(new Variable("x"));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("0", deriv.ToString());
}
public void PartialDerivativeTest2()
{
IExpression exp = new Cos(new Mul(new Variable("x"), new Variable("y")));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("-(sin(x * y) * (x * 1))", deriv.ToString());
}