hp40g+.book Page 51 Friday, December 9, 2005 1:03 AM

NEXTPRIME

NEXTPRIME(n) returns the smallest prime or pseudo-prime

 

greater than n.

 

Example

 

Typing:

 

NEXTPRIME(75)

 

gives:

 

79

PREVPRIME

PREVPRIME(n) returns the greatest prime or pseudo-prime

 

less than n.

 

Example

 

Typing:

 

PREVPRIME(75)

 

gives:

 

73

Modular menu

 

All the examples of this section assume that p =13; that

 

is, you have entered MODSTO(13) or

 

STORE(13,MODULO), or have specified 13 for Modulo

 

in CAS MODES screen (as explained on page 15-16).

ADDTMOD

Performs an addition in Z/pZ.

 

Example 1

 

Typing:

 

ADDTMOD(2, 18)

 

gives:

 

–6

 

ADDTMOD can also perform addition in Z/pZ[X].

 

Example 2

 

Typing:

 

ADDTMOD(11X + 5, 8X + 6)

 

gives:

 

6x – 2

Computer Algebra System (CAS)

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