The coeff command finds the coefficients
of a specific degree of a polynomial. coeffs is a synonym for coeff.
coeff takes two mandatory and
one optional argument:
P, the polynomial.
vars, the name of the variable (or the list of the names of
variables).
Optionally, n, the degree (or the list of the degrees of the variables).
coeff(Pvars ⟨,n⟩) returns the nth
degree coefficient of P, or if n is not specified,
the list of the coefficients of P, including 0 in the
univariate dense case and excluding 0 in the multivariate sparse case.
