An open subinterval of the closed interval [a, b] is an open interval (c, d)

such that (c, d) subset of [a, b] (i.e. a <= c < d <= b). Give an example of numbers a < b and of a function f : [a, b] --> R which is increasing on

every open subinterval of [a, b] and is not increasing on [a, b]. Be sure

to justify your example (Hint: Choose f to be discontinuous.)

I am really bad at something that contains with intervals