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# 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

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