(HP35S) Lambert W Function

[Roberto Volpi]

Here some little example:

Find L(w) of e, even if, by inspection, we already know it is 1.
Use the subroutine W with e^x in the 2nd line

- press 1; e^x to obtain the numerical value of e
- press XEQ L
- stack y will display e and stack x will display 1

Find L(w) of 3

- press 3 and XEQ L
- stack y will display 3, and stack x will display 1.04990889496

It is the same result we can obtain with Wolfram Alpha, but with more significant decimal digits.

Find L(w) of 4

- Our HP35S will give 1.2021678732
- Wolfram Alpha will give 1.202167873219...
- the approximation given by our calculator is satisfactory.

Examples with the "general form" (or whatever the name) maybe tomorrow.