The amplitude of the function y = 2cosx + 4 is 2.
The general form of a cosine function is y = A cos(Bx - C) + D, where A is the amplitude. In this case, A = 2, so the amplitude of the function is 2.
The amplitude of a function represents the maximum displacement from the mean or center value of the function. In this case, the mean or center value of the function is 4, so the maximum displacement from this value is 2 (i.e., the function oscillates between 2 and 6).