The gcd function computes the greatest common divisor of two polynomials A and B.

The optional argument x specifies the dependant variable.  If unspecified, findsym(A,1) or findsym(B,1) is used (whichever returns a non-NULL result first).  Note that if the input polynomials are multivariate then, in general, s and t will be rational functions in variables other than x.

The extended Euclidean algorithm is applied by gcd to compute unique polynomials s, t and g in x such that s*A + t*B = g where g is the monic greatest common divisor of A and B. The results computed satisfy degree(s) < degree(B/g) and degree(t) < degree(A/g). The greatest common divisor g is returned as the function value.

If A and B are arrays, the gcd(A,B) function computes the element-wise greatest common divisor of A and B.

If A is a scalar and B is an array then gcd computes the greatest common divisor of A and each element of B.

Arrays A and B must be the same size.