Prove that $f(z)$ is analytic in $z_{0}$, then $f(z)in mathcal{C}^{infty}$ for some $mathcal{N}(z_{0})$.












0












$begingroup$


Given $f(z)$ a function of complex variable. Prove that if $f(z)$ is analytic in $z_{0}$, then $f(z)in mathcal{C}^{infty}$ for some neighborhood $mathcal{N}(z_{0})$.



Ok I've an idea, but I don't understand what excactly implies "$f(z)in mathcal{C}^{infty}$" or what I need to prove.
I know $mathcal{C}^{infty}$ means that $f$ is infinitely differentiable.
Someone can help me?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
    $endgroup$
    – Eric Wofsey
    Jan 13 at 7:06






  • 3




    $begingroup$
    "Ok I've an idea" Good, where is it?
    $endgroup$
    – Did
    Jan 13 at 12:56










  • $begingroup$
    Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
    $endgroup$
    – tajiri_numero_1
    Jan 13 at 15:51
















0












$begingroup$


Given $f(z)$ a function of complex variable. Prove that if $f(z)$ is analytic in $z_{0}$, then $f(z)in mathcal{C}^{infty}$ for some neighborhood $mathcal{N}(z_{0})$.



Ok I've an idea, but I don't understand what excactly implies "$f(z)in mathcal{C}^{infty}$" or what I need to prove.
I know $mathcal{C}^{infty}$ means that $f$ is infinitely differentiable.
Someone can help me?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
    $endgroup$
    – Eric Wofsey
    Jan 13 at 7:06






  • 3




    $begingroup$
    "Ok I've an idea" Good, where is it?
    $endgroup$
    – Did
    Jan 13 at 12:56










  • $begingroup$
    Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
    $endgroup$
    – tajiri_numero_1
    Jan 13 at 15:51














0












0








0


1



$begingroup$


Given $f(z)$ a function of complex variable. Prove that if $f(z)$ is analytic in $z_{0}$, then $f(z)in mathcal{C}^{infty}$ for some neighborhood $mathcal{N}(z_{0})$.



Ok I've an idea, but I don't understand what excactly implies "$f(z)in mathcal{C}^{infty}$" or what I need to prove.
I know $mathcal{C}^{infty}$ means that $f$ is infinitely differentiable.
Someone can help me?










share|cite|improve this question











$endgroup$




Given $f(z)$ a function of complex variable. Prove that if $f(z)$ is analytic in $z_{0}$, then $f(z)in mathcal{C}^{infty}$ for some neighborhood $mathcal{N}(z_{0})$.



Ok I've an idea, but I don't understand what excactly implies "$f(z)in mathcal{C}^{infty}$" or what I need to prove.
I know $mathcal{C}^{infty}$ means that $f$ is infinitely differentiable.
Someone can help me?







complex-analysis






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 13 at 7:04









Eric Wofsey

189k14216347




189k14216347










asked Jan 13 at 6:54









tajiri_numero_1tajiri_numero_1

115




115








  • 1




    $begingroup$
    The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
    $endgroup$
    – Eric Wofsey
    Jan 13 at 7:06






  • 3




    $begingroup$
    "Ok I've an idea" Good, where is it?
    $endgroup$
    – Did
    Jan 13 at 12:56










  • $begingroup$
    Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
    $endgroup$
    – tajiri_numero_1
    Jan 13 at 15:51














  • 1




    $begingroup$
    The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
    $endgroup$
    – Eric Wofsey
    Jan 13 at 7:06






  • 3




    $begingroup$
    "Ok I've an idea" Good, where is it?
    $endgroup$
    – Did
    Jan 13 at 12:56










  • $begingroup$
    Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
    $endgroup$
    – tajiri_numero_1
    Jan 13 at 15:51








1




1




$begingroup$
The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
$endgroup$
– Eric Wofsey
Jan 13 at 7:06




$begingroup$
The proof-writing tag for when you have a proof but have a question about how best to write it out. It is not for questions just about finding a proof.
$endgroup$
– Eric Wofsey
Jan 13 at 7:06




3




3




$begingroup$
"Ok I've an idea" Good, where is it?
$endgroup$
– Did
Jan 13 at 12:56




$begingroup$
"Ok I've an idea" Good, where is it?
$endgroup$
– Did
Jan 13 at 12:56












$begingroup$
Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
$endgroup$
– tajiri_numero_1
Jan 13 at 15:51




$begingroup$
Oh yes mmh my idea is: if $f$ can be wrote like a taylor series, i.e $f(z) = sum _{n = 0}^{infty}frac{f^{(n)}(z_{0})}{n!}(z-z_{0})^n$, then $f(z_{0})in mathcal(N)(z_{0})$. But I need prove that if $f$ is analytic then can be expressed like a taylor series and $f^{(n)}$ are smooth for every n.
$endgroup$
– tajiri_numero_1
Jan 13 at 15:51










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