Question 11 unsaved find the domain, period, range, and amplitude of the cosine function. y = -6cos4x

For this case we have the following function:
 y = -6cos4x
 The function is defined for all values of x, therefore, the domain is:
 (-inf, inf)
 The range of the function is:
 For x = 0
 y = -6cos (4 (0))
 y = -6cos (0)
 y = -6 (1)
 y = -6
 For x = pi / 4
 y = -6cos (4 (pi / 4))
 y = -6cos (pi)
 y = -6 (-1)
 y = 6
 The range of the function is:
 [-6, 6]
 The amplitude of the function is:
 6
 
 Domain: (-inf, inf)
 Range: [-6, 6]
 Amplitude: 6