POLYDER POLYDER Polynomial Coefficient Differentiation

Usage

The polyder function returns the polynomial coefficients resulting
from differentiation of polynomial p. The syntax for its use is either

 pder = polyder(p)

 for the derivitave of polynomial p, or

 convp1p2der = polyder(p1,p2)

 for the derivitave of polynomial conv(p1,p2), or still

 [nder,dder] = polyder(n,d)

for the derivative of polynomial n/d (nder is the numerator
and dder is the denominator). In all cases the polynomial 
coefficients are assumed to be in decreasing degree.
Contributed by Paulo Xavier Candeias under GPL
