Level 2 Calculus Walkthrough
2025 NCEA Level 2 Calculus Question 3(a)
2025 Paper — Find the point where the gradient is 3
Question
Find the coordinate of the point on the curve where the gradient of \(f(x)\) is equal to \(3\).
Differentiate first, solve \(4x-7=3\), then substitute that x-value back into the original function to get the full coordinate.
First walkthrough idea
Tip to try first
Differentiate the quadratic first so you can write the gradient function.
Step 1
Differentiate the function
Reveal the explanation and working for this step.
Show the first step’s working
Differentiate \(f(x)=2x^2-7x-20\).
Worked result
The derivative of \(2x^2\) is \(4x\), the derivative of \(-7x\) is \(-7\), and the constant disappears.
Walkthrough overview
What this question practises
This 2025 walkthrough is part of AS91262 — Apply calculus methods in solving problems.
Method: Differentiating, solving for the given gradient, and finding the coordinate on the curve.
This is Question 3(a) from the 2025 NCEA Level 2 Calculus paper for AS91262 — Apply calculus methods in solving problems. Use the guided hints to practise the method before revealing the full working.
Calc.nz is an independent learning resource. Compare questions, diagrams, and assessment information with the official NZQA resources for AS91262.
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Learning summary
Review the method, not only the answer
This walkthrough helps you practise differentiating, solving for the given gradient, and finding the coordinate on the curve. Use the hints to plan the method, then repeat the question without hints and check each step.
Common mistake to avoid
Check each step against the original condition, preserve signs and restrictions, and confirm that the final result answers the question asked.