Exam-style question
Try this first
What is the safest exam approach for locate roots of f(x) = 0 by considering changes of sign of…?.
- A.I1: justify each step using the relevant numerical methods rule
- B.Use any familiar GCSE calculation even if it ignores Locate roots of f(x) = 0 by considering changes of sign of…
- C.Write only the final answer without showing the mathematical method
- D.Change the notation or restrictions to make the algebra look simpler
Model answer
What a good answer should say
- The correct answer is I1: justify each step using the relevant numerical methods rule.
- This option is best because identify the mathematical structure, choose a valid method, and justify the final statement, then checks that the notation, restrictions and conclusion match the AQA A-level Mathematics objective.
This answer is tied to the objective: I1 Locate roots of f(x) = 0 by considering changes of sign of f(x) in an interval of x on which f(x) is sufficiently well behaved; understand how change of sign methods can fail..
Explanation
Why this works
Use the explanation to connect the worked answer back to I1 Locate roots of f(x) = 0 by considering changes of sign of f(x) in an interval of x on which f(x) is sufficiently well behaved; understand how change of sign methods can fail..
I1: justify each step using the relevant numerical methods rule is the correct option. It directly supports locate roots of f(x) = 0 by considering changes of sign of… by requiring the student to identify the mathematical structure, choose a valid method, and justify the final statement.
The other options are weaker because they hide the reasoning, ignore restrictions, or use a generic calculation that may not fit the objective.
Maths method check
- Topic focus: Pure Mathematics.
- Question style: practice.
- Reasoning demand: understanding.
- Check the operation, notation, units, and final answer form against the question before moving on.
Common mistake
No common mistake is linked to this question yet.