Leading coefficient of a polynomial : lcoeff

### 2.24.6 Leading coefficient of a polynomial : `lcoeff`

`lcoeff` takes as argument a polynomial given by a symbolic expression or by the list of it’s coefficients.
`lcoeff` returns the leading coefficient of this polynomial, that is the coefficient of the monomial of highest degree.
Input :

`lcoeff([2,1,-1,0])`

Output :

`2`

Input :

`lcoeff(3*x```^```2+5*x,x)`

Output :

`3`

Input :

`lcoeff(3*x```^```2+5*x*y```^```2,y)`

Output :

`5*x`