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WAEC Mathematics 2023 Question 31

Question 31

Trigonometry

Find the value of α in the equation: cos (α + 14)° = sin (4α + 6)°.

  1. A.14
  2. B.16
  3. C.13
  4. D.15
Show the answer and explanation

Answer: A (14)

Explanation

cos A = sin B when A + B = 90°: (α + 14) + (4α + 6) = 90, so 5α = 70 and α = 14.