« first day (676 days earlier)      last day (4642 days later) » 

17:00
@Jeff angle EGJ = angle JFH by alternate interior angles
@Jeff angle GEJ = angle FHJ by alternate interior angles.
@AmithKK Owow, I'll watch that tonight. Seems really exciting or something. About what I would suggest to watch, I'm not sure if we share common interest. What kind of movie are you in the mood for right now?
@robjohn @robjohn that assumes BD is parallel to AC. this is supposed to be any quadrilateral
Oh, let me see if I can find something in my HD.
@robjohn ...and this assumes AB parallel to CD
@Gigili Uhh what?
17:02
@Jeff EG=FH by the midpoint rule
@Jeff they don't enter into it
@Jeff EG and FH are parallel by the midpoint theorem
@robjohn because they both parallel to AD.
@Jeff yes
@robjohn ok. i see now. AAS makes the triangles congruent (aka equal). and the rest is easy. cool solution! (@AmithKK fun quesiton, too)
Lol thanks
I'll tell our maths two teacher
@AmithKK Note that we haven't shown (or used) that J is on AD
@AmithKK J is the intersection of EH and FG
@AmithKK we used AD only to get that EG and FH were parallel and equal
17:08
@robjohn you sure? wasn't the first step that angle EJG equals angle FJH?
@Jeff that was by opposite angles.
...although that's only the angle between the two triangles, not necessarily point J
@Jeff once we have established that EG and FH are parallel and equal, we can remove AD and the proof goes through
BBT
Good NIght
@AmithKK good night
17:11
@robjohn yup! because EH intersects FG and the opposite angles of that intersection are the angles of congruent triangles. cool
now i have a geometry question (it's geometry day in mathchat!): I have a circle with inscribed quadrilateral. i know two angles of the quadrilateral (70 and 80 degrees). I need to find one other angle of the quadrilateral.
@Jeff The two are not opposite angles, because opposite angles add to 180°
@Jeff So that should be enough of a hint
the two known angles are next to each other.
@Jeff Yes, that is what I just said :-)
are you saying opposite angles of all quadrilaterals are 180 deg?
@Jeff that are inscribed in a circle, yes. Can you show that?
17:14
@robjohn as for this. i was just repeating it in my own words (that's how I remember things sometimes - I guess teach's don't like that).
@robjohn i'm just now going to think about how to show that. i'll let you know if i get it.
@robjohn thanks. i'm gonna try before i view that hint.
@Ilya: I'd suggest Avatar.
@robjohn got it. that was easy (once i read the title of the hint)
@Jeff :-)
@Gigili I'd suggest it, too. Why are we suggesting it?
17:24
@robjohn Hih. @Ilya wanted to watch a movie, I guess.
@Gigili I just saw Kung Fu Panda 2, and it was enjoyable, as well.
@Gigili Yes. Two in fact.
@robjohn kung fu panda 1 was def. fun
@Jeff Yes, I really liked that, too.
in fact, i'm gonna try to download it now to give to my niece and nephew (aka niblings) this afternoon.
17:33
@Jeff Arrrgh, matey!
is that a good "Arrrgh" or a bad one?
@Jeff or are you purchasing it online?
@Jeff it was a pirately arrrgh!
i'm looking for it, yes
oh. i get it! :D
i don't like to pirate too much stuff. only old music from my yout that's hard to find
@Jeff I've never had trouble finding music from my youth, and I bet that was a much longer time ago.
@Jeff 8 years longer ago :-)
i see. well, i've had some difficulty cuz not everything i liked was super popular. :D
but i pay for it if it's available cuz i was a programmer once upon a time so i understand it
17:37
@Jeff nor mine, but there was enough of a subculture for some of it that it has stayed around. I did buy CDs long ago with a lot of it though, and that helps.
I always buy my music on CDs. I rarely, if ever, download my music.
I did download the album with "Grandma got run over by a Reindeer" on it, because I could not get it any other way at one point.
i had a bunch of old CDs around somewhere, too. i used to like CDs, too. because i want to own what i buy (in a way) and not be at the mercy of renting from some company
When mp3 first came out, I got a player for my car and was amazed at being able to have 11 albums or so on a single disc. The iPod puts that to shame.
@robjohn yeah. you got that right.
ok. here's a fun question (not work or tutoring or anything). how did you get that vertical bar equals $\sqrt{ab}$?
@MattN Oops, sorry! Good luck.
@Jeff The triangle with altitude $\sqrt{ab}$ is a right triangle, right?
17:50
yes
@meg1997: Hi, do you want me to answer your question here?
@Jeff $a:\sqrt{ab}::\sqrt{ab}:b$
ok :)
@meg_1997 ok?
hey that was for Gigili
17:51
@meg_1997 First, take a look at this
@meg_1997 didn't know; it wasn't linked or anything :-p
@robjohn why?
@meg_1997 In your case, $a,b=0$ and $r=1$
@Jeff do you see the similar triangles there? There are three right triangles, all similar
@robjohn there must be another congruent angle betwn those 2 triangles (they both have right angle, they both share the vertical line)
oh. i see now (now that you said three right triangles). lemme try to do that explicitly on paper.
17:54
@Gigili yes
@meg_1997 So it's a circle with $r=1$, center (0,0). Draw a circle like that, you'll have $-1 \leq x \leq y$ and solve $x^2+y^2 \leq 1$ for $y$
@Jeff legs $a$ and $\sqrt{ab}$, hypotenuse $a+b$, and legs $\sqrt{ab}$ and $b$
@meg_1997 $y^2 \leq 1-x^2$, so what's $y$? Can you solve it with you've learned about absolute?
@Jeff You only need the two smaller triangles, really
@Gigili ya i will try it now i got it
@robjohn are looking for how vertical bar equals $\sqrt{ab}$?
17:58
@meg_1997 Jeff and I were discussing that. Rather I was giving him hints.
ok..
@meg_1997 did you have some questions, or did you just know the answer?
ya i know it
@meg_1997 :-) don't spoil it for Jeff yet!
@Ilya: "psychological horror film", eh? Nonono, I'm not going to see that.
18:03
@robjohn hey ya ok.. :P
@Gigili is Ilya here? am I not seeing him for some reason?
Once I was watching a horror film, I skipped all the scary scenes. So I didn't understand much.
@robjohn but you get the two smaller triangles by making them both similar to the big one.
@robjohn Umm, He's invisible!
@Jeff Yes, you need to know that the two angles are complementary, and for that, you do need the right angle of the larger triangle.
18:07
ok. i'm off to celebrate father's day (yes, a week early). by all.
@Jeff later, have a good father's day!
@Gigili I just checked, and I am not ignoring anyone. I thought that perhaps I had accidentally ignored Ilya.
@robjohn (s)He's not here. (s)He asked a question and left. I am leaving comments for the time he gets back.
@Gigiliwill you please see again the second last comment you did to me
i hav a doubt is it $-1 \leq x \leq1$ ?
@meg_1997 Which one? It's referring to inside of the circle, so $-1 \leq x \leq 1$. What you have doubt about and why?
hey.. nothing (by mistake its 'y' instead of '1' above) thanks for your answer:)
18:19
Ah yes, $-1$ and $1$ must be excluded
@meg_1997 Oops, sorry!
@robjohn thanks
@robjohn I am at the harmonic analysis conference!
Talked to some cool guys.
18:32
@JonasTeuwen any names I might know?
Tao Mei? Mauceri?
They like Ornstein-Uhlenbeck.
@Gigili i am not getting that why should $-1$ and $1$ must be excluded as it has all points inside and on the circle
@JonasTeuwen Cool! so you are having a good time?
@robjohn Yes. I'm only here since a few hours
@JonasTeuwen how long are you going to be there?
@JonasTeuwen Tao Mei is one of the invited speakers. You've talked to him after only a short while there?
18:41
@meg_1997 They shouldn't, I was confused for a moment as to why Wolfram doesn't show $-1 \leq x \leq 1$ but then I saw it shows $x=-1$ and $x=1$ separately (as integer solutions). That's why I linked to it.
@Gigili ohh yes!
@robjohn For a week. I talked to him as first :). He has some interesting questions.
@meg_1997 Is everything clear now?
@Gigili then is there any correction for the answer you gave ?
@meg_1997 No, it's correct.
18:44
ok
thanks:)
@JonasTeuwen I see that it is June 11-15. Have a good time. Check in when you can :-)
I will :).
@JonasTeuwen If you get some interesting results or questions, let us know :-)
@meg_1997 Any time! I added that part to my answer and I assume you can delete your comment now that you got it.
i have to proctor tomorrow!
18:50
@Gigili ya sure
@Eugene How boring!
@robjohn can you close this please
@Eugene what would be the motivation to close? I don't think we close questions for being too hard. It seems that the OP is asking about a certain approach to the RH.
@Eugene It's unclear whether the OP was taken in by the joke exercise or is asking a serious question about the relative merits of a quasicrystal approach to the RH. Even if he was taken in, he may change the question to be the more serious question and it will end up more respectable.
my motivation to close it that as it stands it is a crank question.
oh well if i'm overreacting i guess never mind then.
19:00
Though it seems Mahmud really was taken in by the joke.
i'm a bit concerned though by his past question history
what about it?
well take a look here at one his answers of my questions at mo
Ah, so he should have known better.
@Gigili sorry to interrupt..But i have a last doubt :in the answer you gave is it $-1 \leq x \leq 1$ instead of $-1 \leq x \leq 0$ for the union of last two cases?
19:06
well i downvoted it. i think this is enough of a trend to be labeled crankness.
I reserve the label crank, beyond just ignorance or pedestrian familiarity with math, for those who claim expertise and understanding far beyond their actual state of such.
fair enough. i can't close so i'll just downvote then
So e.g. if someone has no idea what they're talking about, and indeed is talking about silly nonsense, but has no qualms admitting this, I wouldn't call them a crank. I also think cranks tend to be stubborn and hard-headed in the face of community response.
@anon i respect your opinion then.
I remember when this guy came on to MSE. He didn't last long :P
19:14
@anon yikes that is scary.
i don't know. there's just so many out there so I take a leaf from Will Jagy's book. When you see someone trying to prove RH or BSD my hackles go up.
Jose Garcia often pushes the line there. I do however remember there being one attempted proof at RH that was met warmly on MSE. Someone found an error and the author thanked that person.
No wait, it wasn't RH, it was Navier-Stokes.
ah... i see
@meg_1997 Yes, you're right. I edited it again. Hope it's all correct now!
@anon have you heard of de branges?
Oh yes.
Ah, here it is, and it was even on vixra.
19:17
he's certainly not a crank but is displaying crank like behavior
@Gigili: yup perfect:)
Wow, just wow. Tell me how long did it take to ask that question
Ha, I've already answered two manifestations of that very question.
Time to get some rep!
lol
i noticed answering harder questions get you less rep.
they sure are fun to solve though.
That's exactly so.
19:20
Hello
huh. your suspension ended?
Yes, just today, it was only a week
i see.
19:36
@Eugene Ithought de Branges approach was not crankish
brian conrey (once his grad student) proved that his approach could not possibly work
but de branges is a legit mathematician
he proved bieberbach
my brain parses that as Beiber + Bach
and then BSODs
@Eugene What is that?
@anon hahaha.
@PeterTamaroff this
@Eugene I'm reading it.
Its so awesome when you get something named after yourself...
(When it is a legit results, obviously...)
19:43
it is cool
@anon should i delete this?
delete what?
lol
sorry
nah, I'd let it be
@Eugene You didn't see that question when you typed the title?
@Gigili i really didn't. also a search of "poincare" revealed no similar questions on the first page.
19:53
The titles are exactly the same. That's weird.
It should have shown you.
Let me try it.
Well, the original version is the third, yours is fourth.
i see. hmm...
@meg1997: I wonder what that user meant by those comments! But we will wait for him to respond. I checked it again but found nothing. The picture clearly shows that final answer.
yaa..well he is taking too long for his next comment!
20:10
Well I can't figure this out, can anyone point me in the right direction? $\int \frac{t}{t^4+2}$
Well, you get the following:
Don't forget the differential!!
I tried that already
You get this:
I know what you get, I already did that but it didnt help
$$\int {\frac{{tdt}}{{{t^4} + 2}}} = \frac{1}{2}\int {\frac{{du}}{{{u^2} + 2}}} $$
You can integrate that with the arctangent.
20:13
that is what I have
...
Well, then let $\sqrt 2 m = u$
$$\int {\frac{{tdt}}{{{t^4} + 2}}} = \frac{1}{2}\int {\frac{{du}}{{{u^2} + 2}}} = \frac{{\sqrt 2 }}{4}\int {\frac{{dm}}{{{m^2} + 1}}} $$
Huh, your favorite user @Eugene.
@Gigili who is?
$$\int {\frac{{tdt}}{{{t^4} + 2}}} = \frac{{\sqrt 2 }}{4}\arctan \frac{{{t^2}}}{{\sqrt 2 }}$$
@Eugene You edited his question.
20:17
GAH! You're right!!
he still hasn't accepted my answer!
that is a really complex solution to that problem, I don't think I can do that on a test
the critical idea is to factor $u^2+2 = 2\big((u/\sqrt2)^2+1\big)$
That way, up to scalings, it is something squared plus one in the denominator
@Eugene You shouldn't have asked him directly. You must have said, "consider accepting answers to some of your questions, especially this one".
especially this one lol
I have to memorize the 20 basic integral forms, simpson's rule, trapezoidal rule, area of a surface of revolution formulas and arclength formulas, so much to have memorized
20:21
@Gigili i shouldn't? i'm kind of annoyed with him
I can never figure out these factors either
$x^2 - 4x +5$
derp!
you get conjugate nonreal zeros
@Eugene "directly".
so how do I do $\int \frac{x-1}{x^2 - 4x +5}$
@Jordan Stop whininning, and we'll move on.
20:25
@Gigili oh well what's done is done i guess. i hate that he asked me a whole bunch of questions after answering and after all that showed no gratitude.
Jordan: you could factor and use partial fraction decomposition and then integrate with shifted logarithms, or you could complete the square and use an affine-linear substitution to integrate $1/(u^2+1)$
I am not whining
"I have to memorize the 20 basic integral forms, simpson's rule, trapezoidal rule, area of a surface of revolution formulas and arclength formulas, so much to have memorized"
I don't know anything that you said anon
It is a lot to have memorized, statement of fact
actually you probably know a bit of it but don't realize it :)
completing the square gives $(x-2)^2+1$ in the denominator. set $u=x-2$ and then integrate...
wait, did you edit?
well, the methods I listed still apply, so we're still good
although it's a slight bit more work either way
20:29
I didn't edit
@Eugene I'm saying for your future. At least he said "thanks"! Some users even don't bother saying it.
@Gigili i see. thanks for the advice.
The integration tables are really hard to memorize though since they all look so similar, I think I just need to do flash cards
Should this be straightforward?

$$(a,b)=1\text{ and } d|(a+b) \Rightarrow (a,d)=(b,d)=1$$??
@PeterTamaroff ?
please stop using wedges for your "and". I keep on thinking hodge operator
20:35
@Eugene I got it, nevermind.
seems clear to me
I use the fact that
@anon it's clear by division
@anon $d|a$ and $d|b$ then $d|ma+nb$ right?
@PeterTamaroff yup
so $d \mid 1$
20:36
you also have to rule out the cases $d\mid a, d\not\mid b$ and $d\not\mid a,d\mid b$ I think
@anon Sure, but that is trivial
I think-
ruling out $d|a,b$ is just as trivial
@anon Haha, true!
I have no clue how to do this $\int (1 + \sqrt{x})^8 dx$
@anon I think it is not necessary.
Look at this
"proof"
20:39
I know u subsitution won't work, I am about to try trig but that will take me a very, very long time
@Jordan Put $dx$ in there mate!
Suppose $d \mid a$ and $d \mid b$
Then $d \mid (an+bm)$ for any $m,n$.
Chose $n=x,m=y$ from $ax+by=1$ (ie $(a,b)=1$)
Then $d\mid 1$
Thus $d = \pm 1$
@PeterTamaroff yup
What I'm wondering is what "Suppose $d|a,b$" has to do with your original desired implication.
@anon easy gcd
Thus $(a,d)=(d,b)=1$.
20:41
@Jordan binomial theorem unless there's a clever trick I'm not seeing
What is binominal theorem?
@Eugene can you elaborate?
@anon Let $x^{1/8}+1 = u^{1/8}$
isn't $d$ the gcd?
or it is any old divisor?
@Eugene Any $d$ such that $d \mid (a+b)$
20:42
well it doesn't matter
@Eugene the gcd of what?
let $d$ be the gcd of $(a,b)$
then $d \mid a$ and $d \mid b$.
since $d$ is the gcd
sure but what does that have to do with $(a,b)=1,d|(a+b)$?
then any divisor must divide the gcd
you can have (2,3)=1 and d=5 if you want
certainly 5 is not the gcd of 2 and 3
20:44
Isn't my proof clear?
oh i see i see
@PeterTamaroff then no
you can't suppose $d$ is the gcd of $a,b$, or that $d|a,b$, out of thin air - it's not even necessarily the case
Any hints on this? $\int \frac{dx}{1+e^x}$
@anon I don't assume it is the $\gcd$
I assume it is a number that divides them both, not necessarily $\gcd$.
@PeterTamaroff can't assume that!
20:45
@PeterTamaroff like I said, you can't assume it divides both out of thin air
because that is not even necessarily true
@anon Right
Let me rephrase then.
@Jordan maybe u=e^x?
I tried but it only complicatred the problem
@Jordan Not really. You get $\int du/u(u-1)$
@PeterTamaroff use bezout!
20:47
which is separable in simple fractions.
@Eugene Well, I have that $ax+by=1$
And that
$d=am+bm$
but you also have $a + b = kd$
That doesn't look right
for Jordan ie $$\frac{1}{u(u-1)}=\frac{1}{u-1}-\frac{1}{u}$$
so $ax + bx = kxd$
I get $\int \frac{du}{e^x 1 + u}$
20:48
@Eugene Damn! I was writing $d=k(a+b)$
Yes yes
Now it closes
So many different conversations in chat
F**k me, dude.
so we're done
20:49
Does anyone like cheese?
@PeterTamaroff indeed!
@Jordan you mean $e^x(1+u)$, but you forgot to change the $e^x$ there to a $u$...
@Eugene Hahahha.
@anon should't it be $\frac{1}{u^2-u}$|
@Jordan that's the same thing!
20:49
@Jordan Yes.
But make it into partial fractions!
@PeterTamaroff i thought you meant $d = gcd(a,b)$.
how is it the same?
@Eugene Nay
@Jordan $u(u-1)=u^2-u$
20:49
@PeterTamaroff OH WELL
Why the heck are you all making that integral so complicated!
woops, I had a bad sign in one of my comments, sorry Jordan
@Eugene Wait, what?
Give me 5 sec to type up the easy solution
LEEEEEEEEEEEEEEEROOOOOOOOOOOOOOOOOOY
20:50
@PeterTamaroff what, wait?
JEEEEEEEEEEEEEEEEEEEEEEEEENKIIIIIIIIIINS
reading all this is just making me really sleepy, I can't concentrate on math homework
@PaulSlevin how's the template selection going on?
$$ \int \frac{1}{e^x+1}\,\mathrm{d}x = \int 1 - \frac{e^x}{e^x+1}\,\mathrm{d}x = x - \log\left( e^x + 1 \right) + \mathcal{C} $$
@Eugene hahaha nothing, I'm moving on the the other excercises. When I dominate them all (CH1) I'll move on to CH2.
20:51
recently i was thinking about this question
i enjoyed answering it a lot
@PeterTamaroff Are you taking elementary number theory now ? =)
@N3buchadnezzar he's reading apostol for his elementary number theory needs. lol
@Eugene Not true!
@Eugene I decided to use yours but combine leos header design
20:52
I'm interested in Anal too. Hhahahaha
@PeterTamaroff entirely true
@Eugene thanks again for the help
@PeterTamaroff oh. you like anal huh
I have one from David M, Burton.
@Eugene It is so awkward when people write Math. Anal. when taking notes.
Dude, don't do that, please!
20:53
@PaulSlevin no problem. glad i could. if you can i'd appreciate if you'd erase my stuff from the templates.
@N3buchadnezzar I have it to. Eugene reccommended it. Its good too.
@PeterTamaroff you like math anal huh
@Eugene yeah i deleted all the maths, and replaced it with my own
@PaulSlevin cool thanks.
20:54
@Eugene We'll get banned!
There are young people here too....
@PeterTamaroff lol
you said it
@PeterTamaroff The book really grew on me. I did not like it at all in the beginning, but after going to some lectueres, and doing some exercises I enjoyed it much more. Although some of the problems can be a tad hard sometimes.
@N3buchadnezzar Hm. They are cool. Since I read a little bit on congruences from Apostol, I solved some of the problems Burton poses with that.
Like
Our professor wrote Anal on the blackboard, then instantly went over to another board and started writing there instead.
Show the square of any integer is always of the form $3k$or $3k+1$
Same with cube, or fourth power.
20:56
@PeterTamaroff typo?
@Eugene Was it $\mod $ another one?
what is 3k3k+1??
3k OR 3k+1, jeez Eugene
He, sorry.
nothing^2=2 mod 3
20:57
@anon Hahahha true.
:)
The magic dragon!
@Eugene did you change any fonts in that template or was it just standard?
it's not the same with cubes. for example 2^3=8=3(2)+2

« first day (676 days earlier)      last day (4642 days later) »