public void PartialDerivativeTest1()
{
// (y + x ^ 2) / x
IExpression exp = new Div(new Add(new Variable("y"), new Pow(new Variable("x"), new Number(2))), new Variable("x"));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("(((1 * (2 * (x ^ (2 - 1)))) * x) - ((y + (x ^ 2)) * 1)) / (x ^ 2)", deriv.ToString());
}
public void DerivativeTest1()
{
IExpression exp = new Div(new Number(1), new Variable("x"));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("-(1 * 1) / (x ^ 2)", deriv.ToString());
}
public void DerivativeTest2()
{
// sin(x) / x
IExpression exp = new Div(new Sin(new Variable("x")), new Variable("x"));
IExpression deriv = exp.Differentiate();
Assert.AreEqual("(((cos(x) * 1) * x) - (sin(x) * 1)) / (x ^ 2)", deriv.ToString());
}
public void DerivativeTest3()
{
// (2x) / (3x)
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 Div(mul1, mul2);
IExpression deriv = exp.Differentiate();
Assert.AreEqual("(((2 * 1) * (3 * x)) - ((2 * x) * (3 * 1))) / ((3 * x) ^ 2)", deriv.ToString());
num1.Value = 4;
num2.Value = 5;
Assert.AreEqual("(4 * x) / (5 * x)", exp.ToString());
Assert.AreEqual("(((2 * 1) * (3 * x)) - ((2 * x) * (3 * 1))) / ((3 * x) ^ 2)", deriv.ToString());
}
public void PartialDerivativeTest4()
{
// (x + 1) / x
IExpression exp = new Div(new Add(new Variable("x"), new Number(1)), new Variable("x"));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("0", deriv.ToString());
}
public void PartialDerivativeTest3()
{
IExpression exp = new Div(new Variable("y"), new Variable("x"));
IExpression deriv = exp.Differentiate(new Variable("y"));
Assert.AreEqual("1 / x", deriv.ToString());
}
