The 3 display modes

Most calulators provide the usual "FIX" and "ENG" mode... these are very classic.
RPNenh provide other non-obvious mode.

examples mode :	epsilon	cute	rational ()
behavior	everything displayed	may round if number too near an interget	like cute and try to make it rational or with pi..
1	1	1	1
3.000000001	3.000000001	3	3.
0.428571428571429	0.428571428571429	0.428571428571429	3/7
1.88495559215387	1.88495559215387	1.88495559215387	3*pi/5
2.44948974278318	2.44948974278318	2.44948974278318	sqr(6)
0.0000001	0.0000001	0.0000001	0.0000001

To see an example how the rational mode is usefull, just try the following : put this matrix on the staxk [[1 2 3][4 5 6][-1 2 3]] and use 1/x, in rational mode you will get the following :

[ [ 1/2 0. -1/2 ]
  [ -3. 1. 1. ]
  [ 13/6 -2/3 -1/2 ] ]

it's nice, isn't it ?

Epsilon

this mode just display number exactly as it is in memory. no rounding is applyed.

cute

The default mode is "cute", because it's fast.
Rational mode is more accurate but is a little bit slower.
"cute" in interresting to to avoid displaying computer error-round, for ex. system may gives 5.00000000112 instead of 5.

Rational

Rational try to find a combinaison with PI, technicaly it try to find "number = P*pi/Q" where P and Q are integer.
system also try some classic squares, technicaly it try to match with "number = R*sqr(S)" where R and S are integer.
system canot find for Q, P, R and S too high.
finaly it try to find N and M that match "number= N/M". if nothing is found, system just display "number" as it is.

That means rational cannot give things like "(1+sqr(5))/3" or "ln(2-sqr(2))"...
the reason is : it's just a digital calculator, not an algebraic one!

System changing mode

just click on small icons on upper-right of RPNEnh.
If you want to learn everything about user interface, just checkthis tutorial It also show you where you can find the mode buttons.

Goto : RPNEnh menu - ScreenShots - List of functions