polyder
Derivative of a polynomial or a ratio of polynomials.
q=polyder(a)
[q,d]=polyder(a,b)
Inputs
a A vector of the coefficients of a polynomial, which is the numerator in case two inputs are specified.
b A vector of the coefficients of a polynomial, which, if specified, is the denominator.
Outputs
q The vector of coefficients of the numerator of the ratio of polynomials which is the derivative of the ratio of the inputs.
d The vector of coefficients of the denominator of the ratio of polynomials which is the derivative of the ratio of the inputs.


Example
>>polyder([2 3 4]) // derivative of 2x^2+3x+4 is 4x+3
          4
          3
>>// The derivative of (2x^2+3x+4)/(2x^2+4x+1) is
>>// (2x^2-12x-13)/(4x^4+16x^3+20x^2+8x+1) 
>>(q,d)=polyder([2 3 4],[2 4 1])
>>q
          2        -12        -13

>>d
          4         16         20          8          1