A number α\alphaα is a root of f(x)=0f(x)=0f(x)=0 if [...]\text{[...]}[...].
A number α\alphaα is a root of f(x)=0f(x)=0f(x)=0 if f(α)=0\boxed{f(\alpha)=0}f(α)=0.
The graph touches the xxx-axis and turns back upwards.
For a continuous function, a sign change is sufficient but not necessary for a root.
The function takes every intermediate value, including zero.
1.12.1 Locating roots by change of sign (A-level only) Flashcards
Flashcards for AQA A Level Maths 1.12.1 Locating roots by change of sign (A-level only), covering the key formulae, methods and definitions you need to recall for Paper 1, Paper 2 and Paper 3. 22 cards, matched to the AQA A Level Maths (7357) specification. Recall questions account for roughly 50% of marks at A Level Maths, so these target the marks you can secure before the paper starts.