Final answer:
The maximum value of y = cos (θ) for values of θ between −720° and 720° is 1.
Step-by-step explanation:
The maximum value of y = cos (θ) for values of θ between −720° and 720° is 1.
The cosine function oscillates between -1 and 1. In this range, the maximum value of the cosine function is 1, which occurs when θ = 0° or any multiple of 360°. Therefore, option b. 1 is the correct answer.