polyder

Polynomial derivative

Syntax

`k = polyder(p)k = polyder(a,b)[q,d] = polyder(b,a)`

Description

The `polyder` function calculates the derivative of polynomials, polynomial products, and polynomial quotients. The operands `a`, `b`, and `p` are vectors whose elements are the coefficients of a polynomial in descending powers.

`k = polyder(p)` returns the derivative of the polynomial `p`.

`k = polyder(a,b)` returns the derivative of the product of the polynomials `a` and `b`.

`[q,d] = polyder(b,a)` returns the numerator `q` and denominator `d` of the derivative of the polynomial quotient `b/a`.

Examples

The derivative of the product

$\left(3{x}^{2}+6x+9\right)\left({x}^{2}+2x\right)$

is obtained with

```a = [3 6 9]; b = [1 2 0]; k = polyder(a,b) k = 12 36 42 18```

This result represents the polynomial

$12{x}^{3}+36{x}^{2}+42x+18$