Baby Rudin exercise 7.12












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There is a standard solution posted for this problem(here is the link: Rudin's 'Principle of Mathematical Analysis' Problem 7.12). I understand everything except the last step(the inequality). I don't see why there exists an interval $[c,d]$ that the first term is less than $varepsilon/3$ for all $n?$










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  • 1




    $begingroup$
    If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
    $endgroup$
    – DudeMan
    Dec 28 '18 at 18:28










  • $begingroup$
    I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
    $endgroup$
    – aud999
    Dec 29 '18 at 8:35










  • $begingroup$
    I think I got it now.. It is because of the dominance of g
    $endgroup$
    – aud999
    Dec 29 '18 at 9:15
















1












$begingroup$


There is a standard solution posted for this problem(here is the link: Rudin's 'Principle of Mathematical Analysis' Problem 7.12). I understand everything except the last step(the inequality). I don't see why there exists an interval $[c,d]$ that the first term is less than $varepsilon/3$ for all $n?$










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
    $endgroup$
    – DudeMan
    Dec 28 '18 at 18:28










  • $begingroup$
    I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
    $endgroup$
    – aud999
    Dec 29 '18 at 8:35










  • $begingroup$
    I think I got it now.. It is because of the dominance of g
    $endgroup$
    – aud999
    Dec 29 '18 at 9:15














1












1








1





$begingroup$


There is a standard solution posted for this problem(here is the link: Rudin's 'Principle of Mathematical Analysis' Problem 7.12). I understand everything except the last step(the inequality). I don't see why there exists an interval $[c,d]$ that the first term is less than $varepsilon/3$ for all $n?$










share|cite|improve this question











$endgroup$




There is a standard solution posted for this problem(here is the link: Rudin's 'Principle of Mathematical Analysis' Problem 7.12). I understand everything except the last step(the inequality). I don't see why there exists an interval $[c,d]$ that the first term is less than $varepsilon/3$ for all $n?$







real-analysis






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share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 28 '18 at 18:53









AugSB

3,38921733




3,38921733










asked Dec 28 '18 at 18:21









aud999aud999

944




944








  • 1




    $begingroup$
    If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
    $endgroup$
    – DudeMan
    Dec 28 '18 at 18:28










  • $begingroup$
    I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
    $endgroup$
    – aud999
    Dec 29 '18 at 8:35










  • $begingroup$
    I think I got it now.. It is because of the dominance of g
    $endgroup$
    – aud999
    Dec 29 '18 at 9:15














  • 1




    $begingroup$
    If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
    $endgroup$
    – DudeMan
    Dec 28 '18 at 18:28










  • $begingroup$
    I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
    $endgroup$
    – aud999
    Dec 29 '18 at 8:35










  • $begingroup$
    I think I got it now.. It is because of the dominance of g
    $endgroup$
    – aud999
    Dec 29 '18 at 9:15








1




1




$begingroup$
If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
$endgroup$
– DudeMan
Dec 28 '18 at 18:28




$begingroup$
If you understood the argument right above that wherein it discuss bounding the difference of integrals of $phi$ for various choices of $phi$, then you just take $epsilon/3$ in that line rather than $epsilon$.
$endgroup$
– DudeMan
Dec 28 '18 at 18:28












$begingroup$
I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
$endgroup$
– aud999
Dec 29 '18 at 8:35




$begingroup$
I mean, there exists [c,d] for every n, but how do we guarantee that there is an interval [c,d] that exists for all n.( n approaches infinity. )
$endgroup$
– aud999
Dec 29 '18 at 8:35












$begingroup$
I think I got it now.. It is because of the dominance of g
$endgroup$
– aud999
Dec 29 '18 at 9:15




$begingroup$
I think I got it now.. It is because of the dominance of g
$endgroup$
– aud999
Dec 29 '18 at 9:15










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