ECAT Maths XI : Chapter 11 TRIGONOMETRY IDENTITIES (test 1) Leave a Comment / By Afshan JAMAL / July 2, 2026 Welcome to your ECAT Maths XI : Chapter 11 TRIGONOMETRY IDENTITIES (test 1) 1. Which of the following is equal to cos⁴(40°) − sin⁴(40°)? cos 80° sin 80° 0 1 None 2. (sin⁴ θ − cos⁴ θ)/(sin² θ − cos² θ) = (a) (b) (c) (d) tan² θ (e) 1 sin² θ sin² θ − cos² θ sin⁴ θ/cos⁴ θ 1 None None Previous Start Quiz Next Time's up
