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5.1.31 extgcd

Syntax:
extgcd ( int_expression, int_expression )
extgcd ( bigint_expression, bigint_expression )
extgcd ( poly_expression, poly_expression )
Type:
list of 3 objects of the same type as the type of the arguments
Purpose:
computes extended gcd: the first element is the greatest common divisor of the two arguments, the second and third are factors such that if list L=extgcd(a,b); then L[1]=a*L[2]+b*L[3].
Note:
Polynomials must be univariate (in the same variable) to apply extgcd.
Example:
 
  extgcd(24,10);
==> [1]:
==>    2
==> [2]:
==>    -2
==> [3]:
==>    5
  ring r=0,(x,y),lp;
  extgcd(x4-x6,(x2+x5)*(x2+x3));
==> [1]:
==>    x5+x4
==> [2]:
==>    1/2x2+1/2x+1/2
==> [3]:
==>    1/2
See gcd; int.