Level 3 Integration Walkthrough

2023 NCEA Level 3 Integration Question 1(e)

2023 Paper

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Question

The shaded region is bounded by the three graphs

\[ y^2=10-x,\qquad y=3x,\qquad y=-\sin\left(\frac{\pi x}{10}\right). \]
x y y^2 = 10 - x y = 3x y = -sin(pi x / 10) Diagram is not to scale

Find the area of the shaded region.

The diagram is shown in its initial state. JavaScript adds any interactive controls and later walkthrough visuals.

First walkthrough idea

Focus to try first

Follow the PDF strategy: find the key intersections, integrate the large curved region first, then subtract the small cap above \(y=3x\).

Step 1

Find the key intersection values

Those are the points where the boundary changes.

Show the first step’s working

Those are the points where the boundary changes.

Key result

\[ x=0,\ 1,\ 10 \]

Walkthrough overview

What this question practises

This 2023 walkthrough is part of AS91579 — Apply integration methods in solving problems.

Method: Combining curve intersections with a subtract-a-cap area strategy.

This is Question 1(e) from the 2023 NCEA Level 3 Integration paper for AS91579 — Apply integration 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 AS91579.

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Learning summary

Review the method, not only the answer

This walkthrough helps you practise combining curve intersections with a subtract-a-cap area strategy. Use the hints to plan the method, then repeat the question without hints and check each step.

Common mistake to avoid

Check intersections, signs, and whether the question asks for signed area or total geometric area.

Continue practising