### 2.24.3 Coefficients of a polynomial: `coeff coeffs`

`coeff` or `coeffs` takes three arguments : the polynomial,
the name of the variable (or the list of the names of variables) and
the degree (or the list of the degrees of the variables).

`coeff` or `coeffs` returns the coefficient of the polynomial
of the degree given as third argument.
If no degree was specified, `coeffs` return
the list of the coefficients of the polynomial, including 0 in the
univariate dense case and excluding 0 in the multivariate sparse case.

Input :

`coeff(-x``^`

`4+3*x*y``^`

`2+x,x,1)`

Output :

`3*y``^`

`2+1`

Input :

`coeff(-x``^`

`4+3x*y``^`

`2+x,y,2)`

Output :

`3*x`

Input :

`coeff(-x``^`

`4+3x*y``^`

`2+x,[x,y],[1,2])`

Output :

`3`