// tan(a) = -1 / sin(a) ^ 2
public static Entity Derive(List <Entity> args, VariableEntity variable)
{
MathFunctions.AssertArgs(args.Count, 1);
var a = args[0];
return(-1 / a.Sin().Pow(2) * a.Derive(variable));
}
// arccotan(x)' = -1 / (1 + x^2)
public static Entity Derive(List <Entity> args, VariableEntity variable)
{
MathFunctions.AssertArgs(args.Count, 1);
var a = args[0];
return(-1 / (1 + MathS.Sqr(a)) * a.Derive(variable));
}
// (a * b)' = a' * b + b' * a
public static Entity Derive(List <Entity> args, VariableEntity variable)
{
MathFunctions.AssertArgs(args.Count, 2);
var a = args[0];
var b = args[1];
return(a.Derive(variable) * b + b.Derive(variable) * a);
}
// log(a, b) = (ln(a) / ln(b))' = (ln(a)' * ln(b) - ln(a) * ln(b)') / ln(b)^2 = (a' / a * ln(b) - ln(a) * b' / b) / ln(b)^2
public static Entity Derive(List <Entity> args, VariableEntity variable)
{
MathFunctions.AssertArgs(args.Count, 2);
var a = args[0];
var b = args[1];
return((a.Derive(variable) / a * MathS.Ln(b) - MathS.Ln(a) * b.Derive(variable) / b) / (MathS.Ln(b).Pow(2)));
}
/// <summary>
/// Derivation over a variable (without simplification)
/// </summary>
/// <param name="x">
/// The variable to derive over
/// </param>
/// <returns></returns>
public Entity Derive(VariableEntity x)
{
if (IsLeaf)
{
if (this.entType == Entity.EntType.VARIABLE && this.Name == x.Name)
{
return(new NumberEntity(1));
}
else
{
return(new NumberEntity(0));
}
}
else
{
return(MathFunctions.InvokeDerive(Name, Children, x));
}
}
// (a ^ b)' = e ^ (ln(a) * b) * (a' * b / a + ln(a) * b')
// (a ^ const)' = const * a ^ (const - 1)
// (const ^ b)' = e^b * b'
public static Entity Derive(List <Entity> args, VariableEntity variable)
{
MathFunctions.AssertArgs(args.Count, 2);
var a = args[0];
var b = args[1];
if (b.entType == Entity.EntType.NUMBER)
{
var cons = (b as NumberEntity).Value - 1;
var res = b * (a.Pow(cons)) * a.Derive(variable);
return(res);
}
else if (a.entType == Entity.EntType.NUMBER)
{
return(a.Pow(b) * MathS.Ln(a) * b.Derive(variable));
}
else
{
return(a.Pow(b) * (a.Derive(variable) * b / a + MathS.Ln(a) * b.Derive(variable)));
}
}
/// <summary>
/// See Substitute instead
/// </summary>
/// <param name="x"></param>
/// <param name="value"></param>
/// <param name="inPlace">
/// If no need to copy, we do it in place
/// </param>
/// <returns></returns>
public Entity Substitute(VariableEntity x, Entity value, bool inPlace)
{
Entity res;
if (inPlace)
{
res = this;
}
else
{
res = DeepCopy();
}
if (res == x)
{
return(value);
}
for (int i = 0; i < res.Children.Count; i++)
{
res.Children[i] = res.Children[i].Substitute(x, value, true);
}
return(res);
}
public Set SolveNt(VariableEntity v, int precision = 30) => SolveNt(v, (-10, -10), (10, 10), (10, 10), precision: precision);
/// <summary> /// Attempt to find analytical roots of a custom equation /// </summary> /// <param name="x"></param> /// <returns> /// Returns Set. Work with it as with a list /// </returns> public Set SolveEquation(VariableEntity x) => EquationSolver.Solve(this, x);
/// <summary> /// Returns a value of a definite integral of a function. Only works for one-variable functions /// </summary> /// <param name="x"> /// Variable to integrate over /// </param> /// <param name="from"> /// The down bound for integrating /// </param> /// <param name="to"> /// The up bound for integrating /// </param> /// <returns></returns> public ComplexNumber DefiniteIntegral(VariableEntity x, (decimal Re, decimal Im) from, (decimal Re, decimal Im) to)
/// <summary>
/// Will be soon!
/// Solves an inequality numerically
/// </summary>
/// <param name="inequality">
/// This must only contain one variable, which is var
/// </param>
/// <param name="var">
/// The only variable
/// </param>
/// <param name="sign">
/// ">", "<", ">=", "<="
/// </param>
/// <returns></returns>
public static Set SolveInequalityNumerically(Entity inequality, VariableEntity var, string sign)
{
throw new NotSupportedException("Will be added soon");
return(NumericalInequalitySolver.Solve(inequality, var, sign));
}
/// <summary> /// Returns an entity in polynomial order if possible /// </summary> /// <param name="expr"> /// To parse from /// </param> /// <param name="variable"> /// Polynomial is a function of a variable /// </param> /// <param name="dst"> /// To return to /// </param> /// <returns> /// true if success /// false otherwise (do not access dst in this case, it's undefined) /// </returns> public static bool TryPolynomial(Entity expr, VariableEntity variable, out Entity dst) => Functions.Utils.TryPolynomial(expr, variable, out dst);
/// <summary> /// Solves one equation over one variable /// </summary> /// <param name="equation"></param> /// <param name="var"></param> /// <returns></returns> public static Set SolveEquation(Entity equation, VariableEntity var) => EquationSolver.Solve(equation, var);
public static Entity InvokeDerive(string typeName, List <Entity> args, VariableEntity x)
{
return(deriveTable[typeName](args, x));
}
public static Entity Quack(Entity expr, VariableEntity x) => CommonDenominatorSolver.FindCD(expr, x);
/// <summary> /// Substitute a variable with an expression /// </summary> /// <param name="x"> /// A variable to substitute /// </param> /// <param name="value"> /// The value we replace variable with /// </param> /// <returns></returns> public Entity Substitute(VariableEntity x, Entity value) => Substitute(x, value, false);
