### 5.25.6 Leading coefficient of a polynomial : lcoeff

lcoeff takes as argument a polynomial given by a
symbolic expression or by the list of its 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