- (D) The sign diagram shows that f changes from increasing to decreasing at x = 4
and thus f has a maximum there. Because f increases to the right of x = 0 and decreases to
the left of x = 5, there are minima at the endpoints.
and thus f has a maximum there. Because f increases to the right of x = 0 and decreases to
the left of x = 5, there are minima at the endpoints.