Cue Column:
- Both roots > k?
- Both roots < k?
- k between roots?
- Both roots in interval?
Note Column: For ax^2 + bx + c = 0, a > 0, roots alpha, beta:
- Both roots > k: D >= 0 AND f(k) > 0 AND -b/(2a) > k
- Both roots < k: D >= 0 AND f(k) > 0 AND -b/(2a) < k
- k between roots: f(k) < 0 (this alone is sufficient!)
- Both roots in (p,q): D >= 0 AND f(p) > 0 AND f(q) > 0 AND p < -b/(2a) < q
- Exactly one root in (p,q): f(p)*f(q) < 0
Summary: Location conditions combine three tools: discriminant, function value at key points, and vertex position. Condition 3 is the simplest — just one inequality.