Java Tutorial - Programming a symbolic derivative calculator for real functions

In this tutorial I am showing to how program a symbolic derivate calculator for real function.

The full project and the expression parser can be downloaded here:

The expression parser uses exp4j library, then builds an AST (abstract syntax tree). The abstract syntax tree can be used to perform different operations such as numeric evaluation, asymptotic calculus at a given point and differentiation.

[genki]

I couldn't have done my homework without you, thank you !!!

[VadimC]

Hello,
Thank you Ivan for your lessons.
I want you to search better next 4 formulas. Thank you!
1) Arctan: d/dx * arctan(g(x)) = g'(x) / (1 + g(x)^2)
new Division(op.getDerivative(),
new Addition(new Constant("1"),
new Pow(op, new Constant("2"))));




2) Arcsin: d/dx * arcsin(g(x)) = g'(x) / sqrt(1 - g(x)^2)
new Division(op.getDerivative(),
new Sqrt(new Subtraction(new Constant("1"),
new Pow(op, new




3) Acos: d/dx * arccos(g(x)) = - g'(x) / sqrt(1 - g(x)^2)
return new Negate(new Division(op.getDerivative(),
new Sqrt(new Subtraction(new Constant("1"), new Pow(op, new


4) Abs: d/dx * |g(x)| = ( g(x) * g'(x)) / |g(x)|
new Division(new Product(op, op.getDerivative()), new Abs(op));

[sadan]

How can this code be implemented for partial derivatives?

[angeld.almarzam.]

Omite elevar al 2 las funciones arcsin y arcos. Excelente aporte

[SantiagoRosales]

Thanks! Althought I think there may be something wrong with the results. If my expression is something like (3/(x+pi)) the derivative doesn't include the numerical value of pi and thus giving and incorrect result. It works if I put 3.14 instead of pi.

[aldogarciavaldez]

And how can I return to the drift in String? Example if I put 3x ^ 2 and I want to show in console 9x

[manolete]

Hi this code is perfect can I use it for an app I have in mind?