HP 40gs User Manual

Page 235

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Computer Algebra System (CAS)

14-53

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(–(3X

3

– 5X

2

+ 5X – 4))

gives:

GCDMOD

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

Example

Typing:

GCDMOD(2X

2

+ 5, 5X

2

+ 2X – 3)

gives:

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.

3x 5

(

) x

2

6

+

(

)

(

)

6x 1

(

)

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

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