Differentiation of x^x returns wrong expression

[ronnycsharp]

Describe the bug
The differentiation of x^x returns a wrong result.

To Reproduce
Steps to reproduce the behavior:

var proc = new Processor();
var exp = proc.Parse("x^x");
var diff = proc.Differentiate(exp);

Expected behavior
The expected result should be x^2*(ln(x)+1)

Actual behavior
but it returns x*x^(x-1)

[sys27]

As I understand, the expected result should be: (x^x) * (ln(x) + 1).

[sys27]

Fixed. Thank you for reporting.