function polyroots

Return the roots of a polynomial. The polynomial is defined as P(x) = P[1] + P[2]*x + P[3]*x^2 + ... + P[n]*x^(n-1)

Syntax
result = polyroots(P [, derivative])

Arguments

P:   The polynomial

derivative:   Optional, if an integer number is given, the nth derivative is returned.

Returns
A vector with the roots (or derivatives of) the polynomial

Examples
Calculate the roots of the polynomias 1 + x^2 = 0:
   print polyroots([1, 0, 1]), /values

P:	The polynomial
derivative:	Optional, if an integer number is given, the nth derivative is returned.