WAEC - Mathematics (2022 - No. 27)
Given that sin (5x-28)° = cos (3x-50)", 0°≤ x ≤ 90°, find the value of x.
39
32
21
14
คำอธิบาย
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