The truth of the statement depends on the specific interval being discussed, as the cosine function has intervals where it is both increasing and decreasing within each period.
The statement 'The graph of y = cos x is decreasing on the interval' cannot be classified as true or false without more specific information about the interval in question. The graph of the cosine function is periodic and has multiple intervals where it is increasing and decreasing. It decreases from 0 to π (0 to 180 degrees) and increases from π to 2π (180 to 360 degrees) within each period. Thus, if the specified interval falls within the decreasing region of the cosine graph, the statement would be true; if not, the statement would be false.