Number in HP Prime

[Joe Horn]

(09-19-2016 06:58 AM)ggauny@live.fr Wrote:  Again thank for the trick "a/b fraction. I was not knowing this.

Be careful when using the fraction button in Home. It doesn't always return a fraction exactly equal to the input. Its purpose is to display a fraction that is close to the input, and you can control its precision by changing the display mode. For example, in Home, in Fixed 2 mode, pi [a b/c] returns 22/7, but in Fixed 5 mode it returns 355/113. Standard display mode is similar to Fixed 11. Here's a trick that nobody has mentioned yet: Set Fixed display mode, then go into CAS and type HDigits:=12. That will set your machine to Fixed 12 mode(!), which returns fractions with even higher precision than Fixed 11.

When the fraction button is used in CAS, it uses the "exact()" function, whose precision is controlled not by the display mode, but by the value of the CAS setting called "epsilon" (see page 2 of the CAS Settings).