Answer:
y = 5 cos ((2π/3)x - 2) + 2
Step-by-step explanation:
Cosine function takes a general form of y = A cos (Bx + C) + D
Where
A is the amplitude
2π/B is the period
C is the phase shift ( if -C, then phase shift right, if +C phase shift left)
D is the vertical displacement (+D is above and -D is below)
Given the conditions of the function to build and the general form, we can write:
** Note: period needs to be 3, so 2π/B = 3, hence B = 2π/3
Now we can write:
y = 5 cos ((2π/3)x - 2) + 2
first answer choice is right.
