public override Expression FindDerivative()
{
if (Arguments.Count == 1)
{
Expression topLevelDerivative =
FunctionName == "sin" ? Build("cos", Arguments) :
FunctionName == "cos" ? -Build("sin", Arguments) :
FunctionName == "ln" ? FractionExpression.Build(ConstantExpression.One, Arguments[0]) :
FunctionName == "sqrt" ? FractionExpression.Build(ConstantExpression.One, (Fraction)2 * this) :
null;
if (topLevelDerivative != null)
{
return(Arguments[0] is VariableExpression ?
topLevelDerivative :
topLevelDerivative *Arguments[0].FindDerivative());
}
}
throw new NotImplementedException($"Function \"{FunctionName}\" with {Arguments.Count} arguments has no defined derivation");
}
/// <summary> /// Binary division of expressions. /// </summary> /// <param name="first">Left-side expression.</param> /// <param name="second">Right-side expression.</param> /// <returns>Returns the result of dividing the first expression by the second expression. /// If immediate division is not possible, a fraction expression will be returned instead.</returns> public static Expression operator /(Expression first, Expression second) => FractionExpression.Build(first, second);