### 5.34.4 Exact bounds for positive real roots of a polynomial: VAS_positive

The VAS_positive command takes one argument, a polynomial.
VAS_positive returns a list of intervals which contain the positive real roots of the polynomial using the Vincent-Akritas-Strzebonski algorithm. Each interval will contain exactly one interval.
Input:

VAS_positive(x^3 - 7*x + 7)

Output:

[[1,3/2],[3/2,2]]

Input:

VAS_positive(x^5 + 2*x^4 - 6*x^3 - 7*x^2 + 7*x + 7)

Output:

[[1,3/2],[3/2,2]]

Input:

VAS_positive(x^3 - x^2 -2*x + 2)

Output:

[1,[1,3]]