Epsilon Delta Proof of Limits Being Equal











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I have a question about this Epsilon-Delta Proof of Limits Being Equal
Why did the person that answered this assume that δ=δ0?



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  • He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
    – Hongyu Wang
    Nov 23 at 18:13






  • 2




    No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
    – Alex Vong
    Nov 23 at 18:19








  • 3




    Why is this question urgent, exactly?
    – Noah Schweber
    Nov 23 at 18:25






  • 1




    He's saying you can use the same $delta$ for the second limit as you did for the first.
    – saulspatz
    Nov 23 at 18:35















up vote
-3
down vote

favorite












I have a question about this Epsilon-Delta Proof of Limits Being Equal
Why did the person that answered this assume that δ=δ0?



Thank you!










share|cite|improve this question
























  • He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
    – Hongyu Wang
    Nov 23 at 18:13






  • 2




    No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
    – Alex Vong
    Nov 23 at 18:19








  • 3




    Why is this question urgent, exactly?
    – Noah Schweber
    Nov 23 at 18:25






  • 1




    He's saying you can use the same $delta$ for the second limit as you did for the first.
    – saulspatz
    Nov 23 at 18:35













up vote
-3
down vote

favorite









up vote
-3
down vote

favorite











I have a question about this Epsilon-Delta Proof of Limits Being Equal
Why did the person that answered this assume that δ=δ0?



Thank you!










share|cite|improve this question















I have a question about this Epsilon-Delta Proof of Limits Being Equal
Why did the person that answered this assume that δ=δ0?



Thank you!







calculus limits






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 23 at 18:37

























asked Nov 23 at 18:01









noam Azulay

11




11












  • He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
    – Hongyu Wang
    Nov 23 at 18:13






  • 2




    No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
    – Alex Vong
    Nov 23 at 18:19








  • 3




    Why is this question urgent, exactly?
    – Noah Schweber
    Nov 23 at 18:25






  • 1




    He's saying you can use the same $delta$ for the second limit as you did for the first.
    – saulspatz
    Nov 23 at 18:35


















  • He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
    – Hongyu Wang
    Nov 23 at 18:13






  • 2




    No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
    – Alex Vong
    Nov 23 at 18:19








  • 3




    Why is this question urgent, exactly?
    – Noah Schweber
    Nov 23 at 18:25






  • 1




    He's saying you can use the same $delta$ for the second limit as you did for the first.
    – saulspatz
    Nov 23 at 18:35
















He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
– Hongyu Wang
Nov 23 at 18:13




He chose $delta = delta_0$. This can be assumed because he originally assumed $lim_{x rightarrow 0} f(x) = L$ which ensures such $delta$ exists.
– Hongyu Wang
Nov 23 at 18:13




2




2




No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
– Alex Vong
Nov 23 at 18:19






No, the answerer didn't assume it, they simply set $delta$ to be $delta_0$. To do an $varepsilon$-$delta$ proof, you are given an $varepsilon$, and you need to find a $delta$ satisfying certain conditions depending on $varepsilon$ and $delta$. In the answer, the answerer first fixes some $varepsilon$, and then obtain a $delta_0$ using the limit, and after that take $delta$ to be the $delta_0$ obtained previously.
– Alex Vong
Nov 23 at 18:19






3




3




Why is this question urgent, exactly?
– Noah Schweber
Nov 23 at 18:25




Why is this question urgent, exactly?
– Noah Schweber
Nov 23 at 18:25




1




1




He's saying you can use the same $delta$ for the second limit as you did for the first.
– saulspatz
Nov 23 at 18:35




He's saying you can use the same $delta$ for the second limit as you did for the first.
– saulspatz
Nov 23 at 18:35















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