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visits member for 2 years, 11 months
seen Aug 6 at 17:15

Aug
1
comment Confused by definition of an open set in “All the Mathematics You Missed”
That's what I thought, but I am not nearly confident enough of a reader to say "that's wrong". Thanks.
Aug
1
asked Confused by definition of an open set in “All the Mathematics You Missed”
Apr
16
awarded  Critic
Mar
26
awarded  Popular Question
Jan
9
accepted Average proportion for proportions with different denominators
Jan
9
accepted Limit of $1/x^2$ - Apostol 3.2, Example 4
Oct
29
awarded  Tumbleweed
Oct
22
asked Average proportion for proportions with different denominators
Apr
23
awarded  Scholar
Apr
23
accepted Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
Feb
15
comment Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
@BrianM.Scott Yeah, sorry. I looked through and I couldn't find it, but once gingerjin gave a proof I recognized it. I was too impatient, is all. Thanks anyways!
Feb
15
comment Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
Thank you. This is a really clear explanation!
Feb
15
comment Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
@JonasMeyer I'll see if I can find something about $e^u$. Maybe that will help me understand this.
Feb
15
comment Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
@HenningMakholm Apostol's "One Variable Calculus". If there is a proof, I'm missing it.
Feb
15
revised Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
edited body
Feb
15
asked Proof that $\int_1^x \frac{1}{t} dt$ is $\ln(x)$
Nov
29
comment Limit of $1/x^2$ - Apostol 3.2, Example 4
Oh! I think I get it. Any neighborhood N(0) will contain points such that 0<x<{1\over A+2}, and for those points f(x) > A+2. You can't get around that, no matter what δ you choose. What makes me sure that I get it is that now I don't understand why I didn't see that in the first place.
Nov
29
comment Limit of $1/x^2$ - Apostol 3.2, Example 4
On reflection, I'm not sure either. This is helping, though. Thanks!
Nov
29
comment Limit of $1/x^2$ - Apostol 3.2, Example 4
Thanks for the formatting. I briefly tried to get it into LaTex, but I gave up after nothing worked. Haha. I've tried to ask questions where I didn't explain as much, and the person I was asking either refused to help or started talking about a part of the problem that I wasn't asking about. In this case, I had already burned through all of my mathy friends, but they are all at least two years out from real analysis, and couldn't help very much. They did help me get this far, though.
Nov
29
comment Limit of $1/x^2$ - Apostol 3.2, Example 4
I think I get it. Is this like saying that for a given δ1 such that for 0 < x < δ1, if δ1 does not work, than no δ > δ1 will work?