Kuala Lumpur Trial 2025 Add Maths Paper 1, Question 6Trigonometric Functions

Solved on video in English · Form 5, Trigonometric Functions · 5:56 video

The question

(a)

Prove the identity tan θ + cot θ = cosec θ sec θ.

(b)

Solve the equation 4 cos x − sec x = 0 for 0 ≤ x ≤ 2π. Give your answer in terms of π.

Step 1

Write the left side in terms of sine and cosine: tan θ + cot θ = sin θ/cos θ + cos θ/sin θ.

Why this step

Turning tan and cot into sin and cos gives fractions we can combine. Keep working on the left side only until it becomes the right side.

3 more steps, each with the reason for it, in the full solution

Final answer

Proven

Where students lose marks

Watch out: reduce the left side to the right side, and quote sin²θ + cos²θ = 1. Don't work on both sides at once.

5 more steps, each with the reason for it, in the full solution

Final answer

x = π/3, 2π/3, 4π/3, 5π/3

Where students lose marks

Watch out: cos x = ±1/2, so solve both signs (four answers), and give them in terms of π, not degrees.

Watch every step of this question solved on video (5:56), with the reason behind each step and a box that checks your own answer.

No card. Every past-year question on video, in English and BM.