Given that sin (5x-28)° = cos (3x-50)", 0°≤ x ≤ 90°, find the value of...
MATHEMATICS
WAEC 2022
Given that sin (5x-28)° = cos (3x-50)", 0°≤ x ≤ 90°, find the value of x.
- A. 39
- B. 32
- C. 21
- D. 14
Correct Answer: C. 21
Explanation
using the trial method by inserting each option in the equation.
Inserting 21º: sin([5 x 21] - 28) = cos([3 x 21] - 50)
sin(105 - 28) = cos (63 - 50)
sin 77º = cos 13º
where:
sin 77º = 0.9744
cos 13º = 0.9744
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