HP 40gs - Manual (Page 237)

Computer Algebra System (CAS) 14-55
SUBTMOD Performs a subtraction in Z/pZ or Z/pZ[X].
Example 1
Typing:
SUBTMOD(29, 8)
gives:
–5
Example 2
Typing:
SUBTMOD(11X + 5, 8X + 6)
gives:
Polynomial menu
EGCD Returns Bézout’s Identity, the Extended Greatest Common
Divisor (EGCD).
EGCD(A(X), B(X)) returns U(X) AND V(X) = D(X), with D,
U, V such that D(X) = U(X)·A(X) + V(X)·B(X).
Example 1
Typing:
EGCD(X 2 + 2 · X + 1, X 2 – 1)
gives:
AND
Example 2
Typing:
EGCD(X 2 + 2 · X + 1, X 3 + 1)
gives:
AND
3x 1 –
1 – 1 – 2x 2 + =
x 2 – ( ) – 1 3x 3 + =
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