Calculating e^x-1 on classic HPs

[Dieter]

(01-11-2016 10:20 PM)Dieter Wrote:  On a classic HP it could look like this:
(...)

The code shown in the initial post uses the complete stack, OTOH it returns both e^x and e^x–1 in Y and X.

The following version returns e^x–1 while it saves the Y-register. It also does not use R^ which is missing on some of the classic calculators.

Code:

e^x
ENTER
ENTER
LastX
x<>y
LN
-
x<>y
x
LastX
1
-
+
RTN

And using the 35s in equation mode (as well as one data register) it can even be done in a single line:

Code:

EXP(REGX)►U–1+(REGX–LN(U))*U

Dieter