hp40g+.book Page 53 Friday, December 9, 2005 1:03 AM

FACTORMOD

Factors a polynomial in Z/pZ[X], providing that p ≤ 97,

 

p is prime and the order of the multiple factors is less than

 

the modulo.

 

Example

 

Typing:

 

FACTORMOD(–(3X3– 5X2 + 5X – 4))

 

gives:

 

–((3x– 5) ⋅ (x2 + 6))

GCDMOD

Calculates the GCD of the two polynomials in Z/pZ[X].

 

Example

 

Typing:

 

GCDMOD(2X2 + 5, 5X2 + 2X – 3)

 

gives:

 

–(6x– 1)

INVMOD

Calculates the inverse of an integer in Z/pZ.

 

Example

 

Typing:

 

INVMOD(5)

 

gives:

 

–5

 

since 5 · –5 = –25 = 1 (mod 13).

MODSTO

Sets the value of the MODULO variable p.

 

Example

 

Typing:

 

MODSTO(11)

 

sets the value of p to 11.

Computer Algebra System (CAS)

14-53