R: Zeros of a Polynomial

solve.polynomial {polynom} | R Documentation

## Zeros of a Polynomial

### Description

Find the zeros, if any, of a given polynomial.

### Usage

    ## S3 method for class 'polynomial'
    solve(a, b, ...)

### Arguments

`a` | A polynomial object for which the zeros are required.
`b` | a numeric value specifying an additional intercept. If given, the zeros of `a - b` are found.
`...` | Not used by this method.

### Details

This is a method for the generic function `solve`.

The zeros are found as the eigenvalues of the companion matrix, sorted according to their real parts.

### Value

A numeric vector, generally complex, of zeros.

### See Also

`polyroot`, `poly.calc`, `summary.polynomial`

### Examples

    p <- polynomial(6:1)
    p
    ## 6 + 5*x + 4*x^2 + 3*x^3 + 2*x^4 + x^5
    pz <- solve(p)
    pz
    ## [1] -1.49180+0.0000i -0.80579-1.2229i -0.80579+1.2229i
    ## [4]  0.55169-1.2533i  0.55169+1.2533i
    ## To retrieve the original polynomial from the zeros:
    poly.calc(pz)
    ## Warning: imaginary parts discarded in coercion
    ## 6 + 5*x + 4*x^2 + 3*x^3 + 2*x^4 + x^5

[Package polynom version 1.3-9 Index]