We will see that the solution in the given interval is: x = 0.349 radians.
How to solve equations with the variable in the argument of a cosine?
We want to solve:
cos(3*x) = 1/2
Here we must use the inverse cosine function, Acos(x). Remember that:
cos(Acos(x)) = Acos(cos(x)) = x.
If we apply that in both sides, we get:
Acos( cos(3x) ) = Acos(1/2)
3*x = Acos(1/2)
x = Acos(1/2)/3 = 0.349
So x is equal to 0.349 radians, which belongs to the given interval.
If you want to learn more about trigonometry, you can read:
https://brainly.com/question/8120556
