passwella.
Menu

WAEC Further Mathematics 2026 Question 31

Question 31

Trigonometry

Evaluate (4/(3√2)) cos 75° in surd form (radicals)

  1. A.⅓(√3 − 1)
  2. B.⅔(√3 − 1)
  3. C.⅓(√3 + 1)
  4. D.⅔(√3 + 1)
Show the answer and explanation

Answer: A (⅓(√3 − 1))

Explanation

cos 75° = cos(45° + 30°) = (√6 − √2)/4. So (4/(3√2)) × (√6 − √2)/4 = (√6 − √2)/(3√2) = (√3 − 1)/3.