A function f : A ->R is increasing if f(x) <= f(y) for every x, y in A such that x <= y.

Suppose that f : [a, b] -> R is increasing and that a < c < b.

i want to shat that :

lim f(x) = sup{f(x) | a <= x < c} and

x->c-

limf(x) = inf{f(x) | c < x <= b}.

x->c+

and whether these limits are the same?

can anyone help with this...any guidance..or starting me off thankz