Mathematics

@tb You can learn some of the vocab that people use around here

@ClarkKent pfffff wth

australia is also said to be investing a lot on tourism

user19161

@BenjaminLim I thought my superman logo the last time would have given you a clue.

@tb For example an icebox is called an eskie. To get drunk = to get maggot. Salad = marijuana. Then there are phrases like "good on ya"

@SauravTomar well you could say that

and kangaroo is called a boomer, right?

or baby kangaroo

2:02 PM

@SauravTomar urh no. The only thing I can get from that term is something related to drugs.....

@BenjaminLim I must say that I'm a bit disappointed. You could have been a bit more helpful there, considering how much time you spend with asking people stuff here...

@BenjaminLim I saw it written in the back of my notebook, in "interesting facts" section.

@tb Sorry you mean to moshe? Yeah I guess so.

I found your reaction a bit ... brisk

@tb Sorry man, perhaps I should have helped him out a bit more, explained a bit more. I will try to do that the next time someone on chat asks for help, for example say Jordan.

2:04 PM

Please do :)

@tb Yeah I should have been a bit more

compassionate should I say

@Moshe Have you figured out your problem now?

Recall the binomial theorem:

$(x + y)^n = \sum_{k=0}^n \binom{n}{k} x^k y^{n-k}$

user19161

@BenjaminLim Yeah, Jordan has this amazing curve theorem. :-)

@Moshe In your case you have $y = 3x$ and $x = -2$, $n = 10$

so that:

$(3x - 2)^10 = \sum_{k=0}^n \binom{10}{k} (-2)^k (3x)^{10 - k}$

If we want the coefficient of $x^3$, this happens when $k = 7$ because $10 - 3 = 7$

hence the coefficient of $x^3$ is $\binom{10}{3}(-2)^7(3x)^{10 - 7}$

@MattN Not australia, but other places on the southern hemisphere.

(I didn't ignore, I went to another room)

@BenjaminLim - chat.stackexchange.com/rooms/3366/moshe-is-studying

2:11 PM

@Moshe What I explained above, do you get it?

Matt N.

@tb I can't think of anywhere bearable in the southern hemisphere apart from Australia : )

oh, the bear can bear many things... but not winter

@BenjaminLim Sec, reading it. (Just rendered the MathJax)

I have to leave now, bbl.

Matt N.

Bye!

2:13 PM

bye

@tb Please watch: youtube.com/watch?v=SYsRPh2n2x8

@BenjaminLim Yes, we covered all that in class.

@Moshe ok

so therefore

I was having an issue with my multiplication, apparently.

computing the coefficient of $x^3$

is simply then

$3^3 \times (-2)^7 \times \binom{10}{3}$ is this clear?

2:14 PM

Yea.

Got it now,

I'm going to do it again on paper.

right firstly the binomial coefficient is 120, do you know how I got that?

Yes, 10 choose 3 is 120

I can do that.

yeah

btw, whats the question being discussed here?

$3^3$ is 27

so 27 times 120 is...?

2:17 PM

3240

@Moshe $(-2)^7 = -128$

yeah

so now we just need to do 3240 times -128

It's not $-128$?

oh sorry yeah

and 3240 times -128 is

-414720

which is what wolframalpha gave me earlier @Moshe

Right, now it makes sense.

got it now?

@ClarkKent No annoying row reducing

2:18 PM

Yup, thank you. I was making 2 mistakes.

(Well, three, but one didn't make the difference here.)

@BenjaminLim No problem.

I'm an undergrad student, probably way out of my league here.

@Moshe go slow with the arithmetic. You wouldn't believe I nearly failed a first year exam due to making like a mistake in every question in the arithmetic

user19161

@BenjaminLim Calculus?

Ilya

@BenjaminLim I would :D

I hang out on StackOverflowhave been for about 2 years. Not a regular here.

glad to be able to help

@Moshe Way out of what league?

2:20 PM

@BenjaminLim Mathematically, I'm an undergrad. Most people here are into advanced studying and theory, no?

@Ilya Well I got 51 in that exam......and then after that for my ODE exam I freaked out and solved like 200 DEs before it to make sure I was not making such mistakes again

DEs?

@Moshe Well if you wanna call commutative algebra "advanced studying"

DEs = differential equations

Eh, ok.

Ah.

user19161

@BenjaminLim 51 is a nice number. It is 3 times 17.

2:21 PM

Ok, seriously, I have 4 topics on this test, just getting comfy with #1.

@Moshe I'm only second year first semester so you're not too "far behind" if that's what you would like to call it.

Binomial Theorem, Graph of Hyperbola or Ellipse (Shifted Conics), Log and Exponentials, Trig (reference angles, specifically)

@BenjaminLim Ah, where?

user19161

At first I thought you were a grad student @ben when you mentioned you like CA.

@Moshe ANU

@ClarkKent Are you nuts????? Why would you think that, have you seen my profile page?

In Australia?

2:23 PM

yes

Cool.

user19161

@BenjaminLim Well, I guess I forgot that!

user19161

@Moshe Ah, I learnt that in high school.

@ClarkKent Well how do you know about commutative algebra?

Anyone know where I can find example problems online?

user19161

2:24 PM

@BenjaminLim Well, it is just two words.

user19161

@Moshe Does your textbook not have examples?

@Moshe I don't really remember, it's been a while since i've tried problems like that! However if you like at the schaum's series books those are really good

@ClarkKent My Textbook only has answers to the odd examples. The Prof says he's going to ask a find the term in the expansion of, but the book seems to have every other kind of example on Binom theorem. But not that kind.

user19161

@BenjaminLim Yeah, they are pretty good for the lower undergrad courses. Proofs are included in many cases too.

user19161

@Moshe May I know what your TB is?

2:26 PM

ok bye guys!!!

user19161

@BenjaminLim Bye!

@ClarkKent TB? Oh, sec.

user19161

@Moshe textbook

amazon.com/Algebra-Trigonometry-Edition-Customized-Brooklyn/dp/…

user19161

@Moshe Hmm, I don't know of any books offhand to give you examples you need. Schaum's outlines are good for exercises but I am not sure the exact title you should look for.

user19161

2:30 PM

@Moshe Oh they spelt his last name wrongly. It's "Stewart" and not "Steward", haha.

user19161

His calculus texts seem very popular in the US.