Answer:
The correct answer is A. y = 2cos(3x)
Step-by-step explanation:
To find this, first note that it is a cosine wave. We can determine this by the fact that it starts at the amplitude and not 0 (as a sine wave does).
Next, find the amplitude. We can determine this by taking the highest y value and subtracting the lowest y value, then dividing by 2.
2 - -2 = 4/2 = 2
The amplitude is then put in front of the cosine function as such.
y = 2cosx
Next, we find the period. To find the period, determine how long it takes the cycle to repeat (2pi/3). Now divide this by 2pi and take the reciprocal.
(2pi/3)/2pi = 1/3
Reciprocal of 1/3 = 3
We then use this for the coefficient of x along with the other information taht we got.
y = 2cos(3x)
