HP 40gs User Manual page 235

FACTORMOD
GCDMOD
INVMOD
MODSTO
Computer Algebra System (CAS)
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
gives:
2
( ( ) ⋅ (
– 3x 5 – x
Calculates the GCD of the two polynomials in Z/pZ[X].
Example
Typing:
2
GCDMOD(2X
gives:
( )
– 6x 1 –
Calculates the inverse of an integer in Z/pZ.
Example
Typing:
INVMOD(5)
gives:
–5
since 5 · –5 = –25 = 1 (mod 13).
Sets the value of the MODULO variable p.
Example
Typing:
MODSTO(11)
sets the value of p to 11.
3 2
– 5X + 5X – 4))
) )
+ 6
2
+ 5, 5X + 2X – 3)
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