Final answer:
The correct function is (y=3cos(4x) - 4)
Step-by-step explanation:
The correct function for a cosine wave with an amplitude of 3, a period of ((π)(2)), and a midline of y = -4 is (y = 3cos(4x) - 4). This is because the amplitude of the cosine function corresponds to the coefficient in front of the cos function, the period corresponds to the coefficient in front of the x, and the midline corresponds to the constant term at the end of the function. In this case, the amplitude is 3, the period is ((π)(2)), and the midline is y = -4.