- #1
AxiomOfChoice
- 533
- 1
Let [itex]\{h_n\}[/itex] be ANY sequence of real numbers such that [itex]h_n \neq 0[/tex] and [itex]h_n \to 0[/itex]. If [itex]f'(x)[/itex] exists, do we have
[tex]
f'(x) = \lim_{n\to \infty} f_n(x),
[/tex]
where
[tex]
f_n(x) = \frac{1}{h_n} (f(x+h_n) - f(x))
[/tex]
?
This seems to express the derivative as the pointwise limit of a sequence of functions...right? Do we know, in addition, that the convergence is uniform?
[tex]
f'(x) = \lim_{n\to \infty} f_n(x),
[/tex]
where
[tex]
f_n(x) = \frac{1}{h_n} (f(x+h_n) - f(x))
[/tex]
?
This seems to express the derivative as the pointwise limit of a sequence of functions...right? Do we know, in addition, that the convergence is uniform?