Answer:
The correct answer is:
x = 0°, 30°, 150°, 180°
This is because the sine function equals 0 at 0° and 180° and equals 1/2 at 30° and 150°.
Explanation:
The frequency of a sound wave is the number of cycles it completes in a given amount of time. In this case, we can find the frequency of each sound wave by looking at the period of the functions.
The function y = 2sin2x has a period of π (since 2sin(2x) has a period of π/2, which is then compressed horizontally by a factor of 2). The function y = sinx has a period of 2π.
If the frequencies are the same, then the two functions must complete an equal number of cycles in the interval [0°, 360°), which is the same as the interval [0, 2π) in radians.
Let's first look at the function y = sin x. It completes one cycle in the interval [0, 2π), so we can say that it completes n cycles in the same interval, where n is an integer.
Now let's look at the function y = 2sin2x. It completes two cycles in the interval [0, π), so it completes four cycles in the interval [0, 2π). Therefore, we can say that it completes m cycles in the interval [0, 2π), where m is an integer.
For the frequencies to be the same, we need to find values of n and m such that:
n = m
Solving for n and m, we get:
n = m = 2
So both functions complete two cycles in the interval [0, 2π). We can find the times when this occurs by setting the angles in radians equal to multiples of 2π/2, or π:
2sin2x = sin x
2sin2x - sin x = 0
sin x (2sin x - 1) = 0
sin x = 0 or 2sin x - 1 = 0
sin x = 0 when x is an integer multiple of π.
2sin x - 1 = 0 when sin x = 1/2, which occurs when x = π/6 or x = 5π/6.
Therefore, the frequencies of the sound waves are the same at x = π/6, x = π/2, x = 5π/6, and x = 3π/2.
The correct answer is:
x = 0°, 30°, 150°, 180°
This is because the sine function equals 0 at 0° and 180° and equals 1/2 at 30° and 150°.