24(a)

is defined on any interval

such that

Clearly

Then

could be any interval on which

e.g.,

or

...etc.
For


Both functions are continuous when

i.e.,

or

Then the domain of continuity of both functions is

21.
Since

belongs to the domain of continuity , then Theorem 1.1 guarantees the existence
of a unique solution.
22.
Since

is not in the domain of continuity, Theorem 1.1 does not guarantee the
existence or the uniqueness of a solution.