Trigonometric identity — Different upper limit with identity

Step by step

1. Set up the solution: apply the named identity first and simplify before integrating or solving.(i) Same identity proof as the exam.
2. Finish the calculation, then check that the result meets the question’s conditions.(ii) .
3. State the final answer clearly in the form the question requested.Answer: .

Common mistake: changing so many features that the new example no longer tests the same mathematical idea.

Verification: Same reduction; new upper limit introduces .

Any mark labels are a TestMum study aid, not an official NESA marking allocation.