@Jasper no not at all

amwhy and some other guy were fighting

and I told the other guy to back off because <insert something here that amwhy did in the past>

and amwhy said they didnt

Oh OK. I didn't want to probe. I was just concerned about you @Typhon =D

so we were talking about the fact that it was probably one of the people using amwhy's username in the past to impersonate

but a mod said

"yer not allowed to talk about what past users might have did"

even though amwhy was one of the people discussing it

hence why I told ted to not do that

plus, it was pretty rude

anyways nope

no fight

Anyway, it seems that Simply Beautiful Art will be teaching calculus this Saturday.

@Jasper I know

i cant go

in fact i better leave

i just got a message from the mods telling me im not allowed to be in chat for the next month

|How do i prove that if n is composite, then $2^n -1$ is composite?

so im taking my leave

Take care @Typhon.

@Faust is that even true? :/

it is

according to my prof

@Typhon Can I know why?

@Jasper spam

i spammed

@Typhon But I didn't see any from you. =D

it was last night

A month will be over soon. Don't worry about it @Typhon

months seems extreme less u were spamming porn or something

@Faust uuuh. it was a bit innapropriate.

Can someone help me get started on integrating 7x*sqrt(6+x)?

I think I need to use integration by parts

uh

I was given a 'hint' that said x = u - 6, but, I tried U = x+6 and I didn't get anywhere

i can look in my book

one sec

@10Replies you did it wrong

rip.

I know that lol. Not sure where I fd up tho

replace x with u - 6

I can do that?

why can't you?

then what is du?

It uh, doesn't make any sense...

nvm im an idiot

why?

do what he says

is it violating something mathematical?

u is a variable you just created

it can be whatever you want

u = x + 6 is equivalent to x = u - 6

so just replace x with u - 6

If I have four bins, and the chance of any individual bin being filled is 2%, what is the chance of any one in those 4 bins being filled? Is it just 8%?

there is a formula in my book for it but ur ways easier

differentiating both sides dx = du

But u substitution is like f(u)du..

omfg

that formula

is like... shit

@logical123 i dont belive so

We called integration by parts ultraviolet voodoo in my ap calc class like 7 years ago

Faust, neither do i

Ok. But, thats what I was taught... idkhtf to do the other thing

My friend thinks it's 8%. I'm not sure what it is, but I don't think it is that lol

@10Replies it's not a different thing

it's u substitution

you're being too rigid

u need to use PIE

i belive

I have only learned what I was taught in class... I can't pick this shit up through osmosis

But, ok, I substitute x for u-6

but thats long and i dont rember the bettwer way for at least 1

@10Replies yeah....

ok?

so what's so hard now?

I now have 7(u-6)*sqrt(u-6+6)

yeah

now integrate

How?

expand it

write it all out

@10Replies power rule....

you know power rule, right?

Thats for derivitives tho rite

sigh

inverse power rule

sorry

Thats u substitution...

$(7u -42) (u^{\frac{1}{2}}) $

@10Replies what are you talking about

you clearly need to review a lot in your textbook

$(7u -42) (u^{\frac{1}{2}}) $ = $ (7u^{\frac{3}{2}}) -42(u^{\frac{1}{2}}) $

can u integrate now?

@10Replies

How do you get to that second bit.

with the 3/2

nvm

XD

add

you cant just look at a problem and expect the answer to bite you

if you confused try expanding or manipulating it

indeed

this isn't algebra where all you do is reduce, reduce, reduce

Well, I survived AP calc and got a 5 without needing to do any work, so I just assumed calc II would be the same

you had the answer the whole time you just didnt exspand it

HA!

If only I got a 5 on BC instead of a 4 :/

@10Replies integration methods are by far the most creative aspect of mathematics at your level

you have to be creative about it

Creativity in mathematics confuses me

I don't like factoring. I prefer just to use the quadratic formula

you just have to come up with a way to rewrite the function as something you know how to integrate

i dont know the quadratic formula

for instance

weird question

i just complete the squares and force factor

There is even a Cubedratic formula

I don't remember it though

its a few pages long

but if I take a shape and move it to the right by 6 units, does it retain its area?

its not that long...

It does

@10Replies it only goes up to fifth order. Beyond that, you're SOL.

@10Replies ok. you just scooted the function in that integral 6 units to the left.

so you move it over

get it's area

and move it back

That actually makes sense

it was a trick question

indeed

tbh, at some levels having a substitution of the form x = u - b is considered trivial enough that you just ignore it

for instance

sin(x - 6)

So I don't really need to use U? Could I just keep it as X and subtract 6 from each x

welll....

that would be a "different" x

you could call it smiley face doesnt matter

cause it's no longer the same function

just not x

so using another variable makes it clear that it is the same function is a different coordinate system

it's just a really easy coordinate system

btw smiley face is a terrible variable to use

one where the y-axis has moved 6 units

@10Replies in geometry you might've heard of the concept of a rigid motion

Once I integrate the 7u^(2/3)-42(u^(1/2)) what do I do?

that preserves angles, area, etc. for polygona

@10Replies substitute x back in using the equation you had relating u to x

let me tell you something

u substitution is actually of the form f(u) = g(x)

where f and g can be whatever

ok

then you would differentiate both sides and try to write the derivative of u in terms of x

and dx

if you can successfully replace some expression of x times dx with something in terms of just u and du, then you can replace everything according to those equations and integrate accordingly

note: not all substitutions are useful

but you can still perform them

in your case the book or assignment told you what to substitute by

@10Replies to be more precise you would replace u by x + 6

@10Replies sometimes it helps to think about the shape of what you are integrating and/or remember that shifting a function by any amount preserves area so long as you take into consideration that sorting. For instance, if that were a definite integral you could just shift the bounds as well. After all, moving a polygon or curve does not change the area within it.

similarly if you know the concept of a scaling transformation

f(ax)

then you might know that scaling and stretching a polygon has the effect of multiplying its area by the scaling factor

those together lead to a lot of trivial ways to handle integrals of the form f(ax + b)

@10Replies I hope that helps you. You're more in the realm where it's not just about knowing how to solve integrals. You sometimes have to devise your own algorithms to solve tricky ones. That's where a healthy knowledge of geometry is essential.

good luck!

@Typhon Just trying to understand this. Are you talking illegal as in copyright violations, or super illegal as in you get fired if it appears on your screen for a split second with anyone looking?

(Also, there was a room made earlier for the discussion of the offensiveness or not of certain words. I think this further discussion of it should be moved, too.)

@Wildcard illegal as in it's a site where people pirate thousands of textbooks and you might go to jail for going to the site.

@El'endiaStarman ^^^^ my last comment.

@Wildcard that discussion was created due to a mass flagger running amuck. That's irrelevant. ALSO, I was talking to ted about his rude accusation.

@Typhon Thank you for clarifying.

it has no relevance there

@Wildcard it's not porn though if that's what you meant.

@Typhon the comments immediately preceding this are what suggested it was a continuation of the same discussion.

@Typhon Good.

definitely an insult to academics though and not acceptable in a math chat.

in other news, irma is scary as hell

@Typhon (I would think that would be insta-ban worthy, so yeah, good.)

@Wildcard fair enough, but then that being moved should be the deciding factor

@Wildcard nobody was banned ironically but still...

@Typhon I'll shut up about it now. Yay math! :)

yes indeed

thanks

@Semiclassical irma?

what is that? is it a terrorist group?

...

I forget. Do you live in the US?

@Typhon rolls eyes

Hurricane

@Typhon Well done on avoiding the "news," actually. It's mostly all bad news. But you should know about this one.

i didn't know the name of the hurricane

sorry

(My previous two comments were not related in any way.)

Can I ping @Bernard here? Let's see.

@Wildcard actually my ignorance of the news isn't because it is all bad news. I ignore the news because I am an incredibly selfish individual and do not want to be concerned with the needs of others. I would rather everyone else just sit down and quit whining all the time!

people vote for trump and complain cause he gets elected

people vote for hillary clinton and trow a fit

uh

honestly, who cares?

congress has far more say then the president

given that politics actually affects people's lives and livelihoods

@Typhon Let's not go there. At all.

many times in history the president was stubborn af and congress just voted around him.

i see no reason the same cannot happen now

#CongressTermLimits

sorry

Oh goodness. Politics in Math SE.

but it's really my only opinion on the matter

here's my simplest argument for why one should care about the Presidency: nuclear weapons.

I mean, you could at least discuss religion and make it interesting. It's more relevant to mathematics by far.

@Semiclassical that's only an issue if the president is suicidal or literally truly bonefied insane.

The relationship of infinity to God and the knowability or unknowability of the ultimate nature of the universe.

WAAAAY more interesting (and way more mathematical) than a political discussion.

> "I don’t know what predominates in Cantor’s theory - philosophy or theology, but I am sure that there is no mathematics there." (Kronecker)

@Wildcard I'll relate it to math then. Economics takes a long time to have an effect when decisions are made. Like... 30 years probably. Congressman and women sometimes stay in office for 30+ years. That's definitely far more catastrophic causing for the economy when (guess what) CONGRESS CONTROLS THE ECONOMY. So honestly I just laugh at people who complain.

you complain about the president not taking care of something he doesn't control. LOL!

@Typhon If you're going to be mathematical, at least start with some basic rigor. Define "control."

(You can use a natural language definition; I don't mind.)

:D

@Wildcard nah

i just mean it's not his jurisdiction

congress is on charge of regulating the economy

so it's them that need to answer for the economy in the toilet

that's really an oversimplification.

fair enough

@Semiclassical true but the president changes every 8 years.

at maximum

@Typhon Well, scope of jurisdiction is defined by law. But, the economy and the effects produced therein is not (and cannot) be defined by law. Most policy mistakes come from attempting to do so.

four years is a long time.

congress changes either when someone dies or when someone is no longer elected in.

@Typhon So that's not really sufficient as a definition.

It's not a definition

the unlimited terms do bother me, though.

did i say it was

@Typhon No. You said "nah."

:)

@Semiclassical I'd say they have more contributing of a factor into the economy failing or going wrong.

grantedf

If we want to have a productive conversation, we should start by defining the terms we want to use.

industry also has a large play

@Wildcard it's not math though

economics is math

@Typhon No it's not.

It's economics.

which is what I was hoping to prompt a discussion of

@Wildcard it's all math, pretty much

econ uses math based on assumptions

anyway

and those assumptions are as much a part of economics as the math

@Typhon It's all epistemology. Mathematics is a subfield of epistemology.

;)

oh god philosophy

i reject philosophy

Why?

ffs youtube wooork

@Typhon Philosophy lies behind mathematics, so you can't do that.

@Semiclassical Yes, Irma is scary.

man i gotta do my hw ill ttyl

@Typhon what's up?

@Shog9 Thanks. So evidently I don't understand something about chat moderation, because I see sometimes conversations are "moved to Trash" but they're still there and viewable. Whereas sometimes messages are actually deleted.

Just my $0.02 as a user in this chat room: I think everything from the first mention of Trump and Hillary onwards in this discussion could be "moved to Trash" without loss.

(But I don't think it needs to be deleted.)

@Wildcard trash is just another room

@Shog9 Okay. And I think it's only diamond mods who can move conversations there? And to actually delete a conversation, who can do that (and are there guidelines on when it should/shouldn't be done)?

@Wildcard Room owners can also move messages

typhoon is odd right?

@ACuriousMind Ah, I see. So for this room it's only the mods and Anon.

thats not just me right?

@ACuriousMind But for actual deletions, of course a poster can delete his own messages, but otherwise it's just diamond mods?

Aha, and I just realized that diamond mods can moderate chat network wide, am I right?

(Sorry to bug with questions, but I'm fairly new to the chat workings of SE.)

@Wildcard Yes (posters also can only delete their own messages during the 2 min edit period)

@Wildcard Yes

@ACuriousMind Thanks.

@ACuriousMind Unless a "spam flag" is raised (by enough people?) in which case a single message is...auto-deleted?

I was surprised a "spam/offensive" flag review popped up for me earlier; I'm not a moderator.

@Wildcard A validated rude/offensive flag deletes the offending message and automatically suspends the user for half an hour. Such flags can be validated by vote by all users with more than 10k reputation total

A moderator's vote is binding and instantly validates/dismisses the flag

@ACuriousMind Ah, cross site 10K+. Makes sense.

@ACuriousMind Thank you for explaining!

So then, for conversation that has gone off the rails but isn't necessarily total spam/offensive (e.g. just a heated discussion with no swear words) would generally better be moved to "Trash" rather than bothering a diamond mod to delete every message in it.

(Especially since such deletions tend to lead to complaints about "censorship and blah blah blah" from some people.)

→ 32 messages moved to Trashcan

@Wildcard Yup

@ACuriousMind Oho, but that's...what, a private room you moved it to?

So I guess only diamond moderators can see it.

@Wildcard There's public trash and private trash ;)

@ACuriousMind As contrasted with a "hard" deletion such as would be used on a totally not-safe-for-work image. Which wouldn't even go into private trash.

@Shog9 Thank you!

[deleted]

@Wildcard The private trash is more convenient if one might want to look at the messages again later

iTunes has a minimum resolution for ablum covers of 3000x3000

@10Replies [deleted]

Just testing.

anyone else think that is ridiculous

@10Replies You mean maximum?

Max is 6000x6000 :/

@ACuriousMind <_< >_>

@10Replies Version?

@10Replies How else am I gonna print the cover as a giant wall-covering poster? ;)

No, its for posting songs to iTunes radio

@10Replies Ohhhhh.

That makes sense, actually.

why?

@10Replies Retina displays.

other sites seem to think that 160x1600 is good enough

nobody looks at album covers in full screen lol

Even on a nice af 5k apple retina screen 1600x1600 should be enough

@10Replies You don't know my life :P

The average consumer has the largest side of their screen at like 1300 pixels lol. My iMac only has 1920

@10Replies But then you're making iTunes do the image blow-up. Just do the blow-up on your side and feed in a low quality blow-up, if you really don't care about the quality you're giving to your listeners (or don't think it will affect them).

It's a vector album cover so I just went back to illustrator and rexported it

I had to do it twice though because it was origionally 1000x1000 and then spotify wanted 1600 so I exported it again, and then apple wanted 3000 so I exported at 3000 and 9001 just to be safe

@10Replies Cool. Good fix.

gr8 more trash

we should just rename this as "The Trolly Trash Room" instead of "Mathematics"

We should make a separate room to talk about how trash this room is. That way we don't add anymore. amirite?

how can you not add more trash to the infinite source of trash though

I am really confused

Some infinities are more biggerer than other infinities

<s> And while infinity is bad, infinity + 1 is even badder 0_0 </s>

@BalarkaSen surely then somebody will assume this is the new target room for moving messages to.

@10Replies We're on $\aleph_1$ amount of trash here; if you believe generalized continuum hypothesis the next infinity up on the line is $2^{\aleph_1}$

long way to go bruh

Other than that still studying diff geometry @BalarkaSen ?

@quid Haha. Yeah, still more or less working on Riemannian geometry.

I haven't in depth learned about infinities. I have no idea what I'm talking about, hence the sarcasm tags.

I should be looking at Riemann surfaces/1-dimensional complex geometry by now though.

How's it going with you? @quid

Terms starts. Lot's of stuff to do.

True.

Is Mike still around this room?

Yup, he is.

... integral of 7/(1+sqrt(5x))

I am hating calculus more and more. They didn't teach us half the stuff we actually need to do the homework during lectures...

i think you just need quotient rule and chain rule

integration

Lol

@10Replies Have you tried u-subbing? $u = \sqrt{5x}$ seems to be the obvious choice.

Welcome to college mate.

You really need to read your text book, thoroughly.