Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Additional Mathematics
Lesson Topic: Solve, for a given domain, trigonometric equations involving any of the six trigonometric functions, possibly using standard identities
Learning Objective/s:
  • Apply fundamental trigonometric identities to rewrite equations so that only one function of the same angle remains.
  • Solve trigonometric equations for a specified domain using algebraic techniques and identity substitutions.
  • Determine all solutions within the required interval by accounting for the correct period of each function.
  • Validate solutions against domain restrictions and express answer sets using proper notation.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheet with mixed trigonometric equations
  • Unit‑circle poster or digital diagram
  • Scientific calculators (or calculator app)
  • Trig‑identity reference cards
  • Teacher’s answer key
 Introduction:
Begin with a quick recall of the six trigonometric functions and their reciprocal identities, linking to previous work on the unit circle. Prompt students to predict the solutions of a simple sine equation to spark curiosity. Explain that by the end of the lesson they will be able to solve any trig equation in a given domain using identities and proper period reasoning.
Lesson Structure:
  1. Do‑now (5'): Solve sin θ = ½ for 0° ≤ θ < 360°; share answers.
  2. Mini‑lecture (10'): Review key identities and the general solving strategy; demonstrate rewriting an equation.
  3. Guided practice (15'): Work through Worked Example 2 together, prompting students to identify each step.
  4. Collaborative activity (15'): In pairs, solve a set of mixed‑type equations from the worksheet using the identity cards; teacher circulates.
  5. Check for understanding (10'): Quick quiz (Kahoot/exit ticket) with one equation; discuss common mistakes.
  6. Summary (5'): Recap the procedure, emphasise period considerations, and assign homework.
Conclusion:
Summarise the four‑step procedure for solving trigonometric equations and remind students to always verify domain restrictions. Collect exit tickets where each pupil writes the solution set for a given equation. For homework, assign three additional problems covering each equation type and require full working and justification.