poly

Scilab Function
Last update : 25/04/2007

poly - polynomial definition

### Calling Sequence

  `[p]=poly(a,"x", ["flag"])`

### Parameters

- `a` : matrix or real number
- `x` : symbolic variable
- `"flag"` : string ("roots", "coeff"), default value is "roots".

### Description

If `a` is a matrix, `p` is the characteristic polynomial i.e. `determinant(x*eye()-a)` , `x` being the symbolic variable.

If `v` is a vector, `poly(v,"x",["roots"])` is the polynomial with `roots` the entries of `v` and `"x"` as formal variable. (In this case, `roots` and `poly` are inverse functions).

`poly(v,"x","coeff")` creates the polynomial with symbol `"x"` and with coefficients the entries of `v` (v(1) is the constant term of the polynomial). (Here `poly` and `coeff` are inverse functions).

`s=poly(0,"s")` is the seed for defining polynomials with symbol `"s"` .

### Examples

    s=poly(0,"s");p=1+s+2*s^2;
    A=rand(2,2);poly(A,"x")

### See Also

`coeff` , `matrices` , `rational` ,