Level 3 Integration Walkthrough

2023 NCEA Level 3 Integration Question 2(d)

2023 Paper

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Question

\[ \text{Find } \int \frac{\cos 2x+\sin 2x}{\cos 2x-\sin 2x}\,dx. \]

First walkthrough idea

Focus to try first

Differentiate the denominator and then scale it so it matches the numerator.

Step 1

Differentiate the denominator

Both trig terms bring out a factor of \(2\).

Show the first step’s working

Both trig terms bring out a factor of \(2\).

Key result

\[ -2\sin 2x-2\cos 2x \]

Walkthrough overview

What this question practises

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

Method: Spotting a logarithmic quotient by differentiating the denominator.

This is Question 2(d) 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 spotting a logarithmic quotient by differentiating the denominator. Use the hints to plan the method, then repeat the question without hints and check each step.

Common mistake to avoid

Keep logarithm domain restrictions and any inner-function factor visible throughout the working.

Continue practising