Solving x^y=y^x

[Erwin]

(10-28-2018 08:21 PM)Albert Chan Wrote:  Unless W function is built-in, it might be easier solve directly for infinite tetration.[...]

Of course you are right - its much easier in your case. The HP71b has the possibility to define systemwide new functions and use it in Calculator and BASIC mode (of course FORTH too) - that was the reason why I grab my calculator to try it :-)