« first day (4 days earlier)      last day (348 days later) » 

10:00
Evaluate the following infinite sum:$$1 + 4x + 9x^2 + 16 x^3 + \cdots $$
Arithmetico geometric progress?
or waitI see squares!
Yeah, nothing too special about it.
$2^2x + 3^2x^2 +4^2x^3 $the series looks speical though :D
It does, but it's pretty simple.
I have a better idea for this one. It can be solved by differentiation too oo
Wait
10:03
Yup, you're differentiating $x + 2x^2 + 3x^3 + 4x^4 + \cdots$
D:
Well i guess nothing left to solve then xD
Haha, alright. Next question?
Yep
Given $\mathbf{F}=x^2\mathbf{i}+y^2\mathbf{j}$, evaluate $\nabla\times(\nabla\cdot F)$ ;)
If $a_i > )$ for $i = 1, 2, \cdots , n$ and $a_1 a_2 \cdots a_n = 1$, then the minimum value of $(1+a_1) (1 + a_2) \cdots (1+a_n)$ is?
10:06
Sure :D
0 hahaha
Maybe Don't remember those operator well @AndreaL. :(
It always made me laugh :D
xD
I have forgot vector calculus, did that before 1 year
@AndreaL. Scalar cross vector?
@ParthKohli doing :D
No
Gradient , curl and divergence operator
Ah, right.
10:08
@AndreaL. , I don't remember them now, could you do it xD
Basically the curl operator accepts a vector input, and as @ParthKohli noted, it's like giving the cross product between a vector and scalar. Nonsense
So that gives us $2x \hat i + 2y \hat j$?
Yep :D
I just go all the way to 0
xD
The standard answer ahahah
Oh so my interpretation was correct :D. Glad i didn't forget all lol
@ParthKohli ,still thinking about your question xD
is it $2^n$ I don't know really
10:11
Yes!
@Mann Yep, to be honest I was always puzzled by vector calculus (based on the work of Green, Stokes, Kelvin...) because at my uni (Politecnico di Milano - Chemical Engineering) it's very common to find such language to describe transport phenomena (heat, mass and momentum transfer) ;)
OH ok next then
Ahh the heat equation that pde I only know that one ^^
chemical engineering cool
I am not in college yet ^^
@ParthKohli in 11th standard
Find the sum of the products of every pair of the first $n$ natural numbers.
I remember this one :D You have to subtract $(\sum n^2 - (\sum n)^2)$
or viceversa
Yup! :D
10:14
kk nexty
Hmm, dunno. Here you go:
If $a_1, a_2, \cdots , a_n$ are in AP whose common difference is $d$, then:
$$\sin(d) \left[\sec a_1 \sec a_2 + \sec a_2 \sec a_3 + \cdots + \sec a_{n-1} \sec a_n \right]$$
Ap D:
I knew this question one min
IT becomes something like telescopic series
ah yes got it
$sin (a_2-a_1)$ for first term
Yup, you got it.
xD
And etc
Aha! I found one interesting, show that $$\sum_{n=0}^\infty\frac{n}{2^n}=\sum_{n=0}^\infty\frac{1}{2^n}$$
10:18
:OOO
This seems cool
That's AGP.
If you think about it.
Yes, seen that ^^
Let's find a cooler way to solve it :D
Its marvelous (for me, the first time I noticed that)! It's the exact reason on why series aren't infinite sums, but limits of partial sums!
Yes man! It indeed is! It's always wiser to consider these series as limits of p sums ^^
Btw what's your math syllabus in college? :O
I have always wondered
Aww man, I just want to get to college as soon as possible.
And study under good professors.
10:22
Hahahah :D , I have mostly studied myself though.
I may be too unpolite to ask... but how old are you?
I am 17 ^^
Fifteen.
Here I give a question
My age is $2^2+4^2$
10:24
I should sum it as a gp :D
Hehe ;)
$4\frac{(4^2-1)}{4-1}$
I like vectors always, lets see this
@Mann How would you evaluate $4^2$? Maybe like this:$$4^2 = \dfrac{4(4+1)(2\cdot 4 + 1)}{6} - \dfrac{3(3+1)(2\cdot 3 + 1)}{6}$$
Wooo this is some nice form :D
You have to evaluate $4$ too
Next year I'll turn $3^3-3!$
10:27
@Mann Hmm, seems tough.
Next year, I'll turn $4^2$.
$Let \vec A , \vec B , \vec C$ be three unit vectors , suppose that $\vec A . \vec B = \vec A .\vec C=0$ and the angle between $\vec B$ and $\vec C$ is $\pi /6$ then $\vec A = k (\vec B \times \vec C)$ and k is equal to.
@Mann here you can have a look, the programme isn't quite "rich" though (I have a nonzero component of self taught material)
Cool :D
Hah, that's the best thing if there's isn't enough you can actually learn more of what you like
$k=2$
Nice :D but can be -2 aswell
Close
10:31
hang on
$|k|=2$
Yep ^^
Yup.
Hang on, try this one. I'm sure you've seen it though.
Could you find the area of the triangle in $\mathbb{R}^3$ with vertices $(1,0,0)$, $(1,-1,1)$ and $(2,0,0)$?
Finding question .-.
Hmm I think so with vectors
If $\cos(x-y), \cos(x), \cos(x+y)$ are in HP, then find $\cos x \cdot \sec\left(\frac{y}{2}\right)$
10:34
$\frac{1}{2}|\vec a \times \vec b + \vec b \times \vec c + \vec c \times \vec a|$
Nice ^^
Oh yay :D
Ok trying :D
In a more compact way $A=1/2|(\vec{b}-\vec{a})\times(\vec{c}-\vec{a})|$
Ah yes , or that one :D But here in my place you usually have to deal with variable vector so i am more used to that form ^^
Wait, a bit more D: can't find a nice identity to apply
getting close now
$\pm \sqrt{2}$
wait
one wrong thing .-.
@ParthKohli k
10:46
$\pm \sqrt{2}$
That one secret identity :D
$cos(a+b)cos(a-b)=cos^2a - sin^2 b$
Yes.
Underrated identity!
Ikr :D
@AndreaL. got it?
Ooh! Wait, if I use it
10:48
Yep, easier then ^^
It should work out as two solutions $\sqrt{2}$ and $-\sqrt{2}$
Yep!
Well I wasn't that rusty apparently (whew :))
@BalarkaSen Hello.
10:50
No you are great :D
It's a clone of The Root of Math, isn't it?
apparently so.
What? :O
@Mann Thank you very much, you sure are too. :D
@BalarkaSen I'm going to meet a math professor tomorrow.
I don't even know how I'd be able to handle him.
I'm not your kind.
10:51
Hehe lies, I am just a "mann" :D
what's his name/what does he work on?
Got a question
Find the image of parabola $y^2=4ax$ in the plane $x+y+z=0$
@ParthKohli For what I can tell about two years at uni, professors are (a bit eccentric) humans, just be natural and show your passion and motives. Remember, they are not unhappy to see one person interested in their fields (whether conservative or not ;))
10:54
Cool , I wish i was a little bit more interactive with teachers ^^, I actually used to do all my work myself or google ofcourse lol
@ParthKohli interesting. good luck!
don't be too nervous.
@user223679 I'm not in Aakash, goddammit!
2
Gotta star those message :D
oh, i see he's an algebraic number theorist. nice.
@BalarkaSen Yes. What field are you working on?
Oh, it's right there on your profile.
10:57
eh, bit of this and a bit of that. studying, more like.
Right. Have you thought about your college?
@AndreaL. , can't remove answer from parametric form S:
Not even a little?
Well it's like this
11:00
Actually there colud be a way, if I'm getting it right
What have you chosen for the next two years? Science?
I haven't got over my secondary examinations yet.
$$\left(\frac{5at^2}{6}-\frac{at}{3},\frac{-at^2}{6}+\frac{5at}{3},\frac{-at^2-2‌​at}{6}\right)$$
Oh, WBBSE.
yes. all kinds of crazy schedule.
11:01
What would you choose?
Three equations one, parameter. Won't be removeable
but of course I'll take science.
Just like an helix ahah
WBBSE, yes?
11:01
For the next two years as well?
OK.
Maybe better question is $y^2=4ax$ image in $x+z=0$
$t(t/4a,1,-1-t/4a)$
oo
I have not got that good imagination in 3d :D
It's because every point on the image has to satisfy $x+y+z=0$, hence if $y$ and $x$ are fixed on the relation, then it's game over: just plug in the value of $z=-x-y$ and you've got the projected image of the parabola on the plane. Moreover, if you want the intersection, just solve $y^2=4ax$ and $y=1-x$
Oh wait i made a big mistake in my calculation lol
I MADE WRONG MIDPOINT xD
11:06
We're humans after all ;)
I know I parametrised as $(at^2,2at)$ :d
ADG
ADG
@AndreaL. hello
@Mann hello, you've bringing new people evryday, hmm
Yo @ADG
@ADG Hi ;)
It's open group :D
ADG
ADG
11:10
It felt like: Both pounced at me quickly
good job
@AndreaL. are you indian
?
No , italy cool
:D
Italian! ^^
ADG
ADG
@Mann area 51 thing. any comments?
Lemme see I upvoted tho
ADG
ADG
@AndreaL. how come you came here [I want to say "Yahan kaise aana hua" maybe badly translated.]
11:12
What brought you here* He meant :D
ADG
ADG
@Mann yup you're great
i had a tragedy yesterday
How?
bitsat?
Just paid a visit, actually. I always hung up on TeX.SX and I wanted to see this room. Wasn't disappointed ;)
Oh that's great ^^. I'd be posting a lot more things after 24 may when exams end
ADG
ADG
@Mann well I got 345 and didn't knew about the mysterious bonus extra 12 questions which could bring my score easily above 380 as I had only left 3 questions and then cs pilani, but hmm :(
11:14
Aw man, but don't worry. It's still great :O
That score I'd never be able to get hehe
@ADG Impressive nonetheless
Hah yes, this exams in india are hard. Like lots of question very less time.
90 questions in 3 hours. MCQ lol
ADG
ADG
@Mann nope 150
ques in 3 hrs
I don't know but maybe his test had more
Yes 150 for his
See crazy lol
@ADG What?!
ADG
ADG
11:17
and I had half an hour left too, stupid me
Good golly
Indeed man.
This is like question fest. xD
And you have twelve more on top of the 150!
That's almost a question a minute!
ADG
ADG
I could've rechecked or attempted extra questions, but the stupid stupid stupid stupid me, just submitted the test
11:18
Don't worry ADG you'd do great
Dude don't worry. You will be fine
Take a look at me, I cant solve anything in that less time
Lol
Well, you're that fast, I wish we were taught to think that rapidly :/
ADG
ADG
I think of dropping this year so that I get CS in iit
Haha it's how it is here, just get the solution as quick as possible.
You still got jee advanced .-.
@AndreaL. you should check these paper
Jee advanced it's annual paper in india
Quite interesting ^^
Only though when you give it enough time, in 3 hours it's still retarded ha
@Mann I'm looking it up right now, didn't know of it :/
ADG
ADG
nope it's a paper you can score 90% but most people have 50-60% acuuracy and hence get 45-54 %
11:21
Np. you'd like it
ADG
ADG
@AndreaL. ranks in the top hardest exams in the qorld
More like that @ADG haha
@Mann Thank you for the material, guys :D
Not a problem :)
You can have atleast 20 years of these papers haha
or even further
ADG
ADG
btw other indian exams like scra and civil servise etc.
11:23
No way I won't spend my free time playing around with them: the more I look the more I seek with Math and Chemistry ;)
ADG
ADG
the acceptance level goes as low as 0.1%
In india there are more exams than subject xD
Haha, you'd love the math ^^
Chemistry well, since you are already in chemical engineering you won't find it that hard
@ADG 0.1% tho :D
ADG
ADG
and coaching industries earn thousands of crores ($10^3*10^7=10^10$) rupes (=$157$million Us dollars)
and schools just run as formalities
@Mann maybe,, since Organic is from 1st to last year of bachelor degrees
Don't know, I am not so much fond of chemistry hah
tbh I should go solve some paper too now ^^ 6 days xD
Be back later
Mann
Oh, never mind.
ADG
ADG
11:27
timepassing here after giving a 6hr exam from 8-11+12-3
@Just think that it's all down to the math, here
ADG
ADG
@AndreaL. I'll agree with another notion that it is a tool, a rather intersting one, that I'd call it a pure field maybe
Anmol, my friend is getting 387 and a friend in his school 400+ and other 20 toppers above me 380+
@Mann
ADG, did you attempt all questions?
ADG
ADG
yup 3 left
aske me the meaning of indions? [what is that]?
secrilicious? [what is thatx2]
and another simlar
You have to attempt all questions to ask for bonus round.
ADG
ADG
11:33
I'm not good in english
Hey :D
ADG
ADG
@ParthKohli that's why I'm frustated I'm feeling like my 2 yrs were wasted :(
@Arpan read the transcript maybe?
too long :o
Fill me in :D
ADG, you have JEE Advanced.
ADG
ADG
@ParthKohli I get 200-276 in sample tests
11:34
@ADG In Advanced? :O
ADG
ADG
yes
in allen tests
276 out of 360 is very high! Congrats :D
@ADG 276 is really good though.
Two digit rank :D
ADG
ADG
nazar + luck =bad combo
nope 2K+
11:36
Last year, 278 was 100 rank.
@ADG Dont worry, it'll be good :)
@ADG You had BITSAT?
*gave
ADG
ADG
you're unaware of the various mysterious happenings by IIT, each year is different and I got 276 in only one of those, maybe by luck. I only want CS
@Arpan transcript
345?
ADG
ADG
@Arpan context lacking
What?
I dont want to read entire transcript D:
ADG
ADG
11:38
samajh nahi aaya 345 wala phir se bata na
koi ni
have you all read "The Last Lesson- [Franz?]"
yes
o.O
I'm not understanding anything..
Did you get 345 in english?
:21681841 Kisne bola English bolni zaruri hai?
ADG
ADG
nevermind
*345 in BITSAT lol :D
ADG
ADG
@ParthKohli sabse accha bach hai
remind me of virat kohli BTW
11:40
Virat Kohli achcha hai kya?
ADG, are you from Jaipur?
I'll come back when some one is willing to tell me how much ADG got in BITS.. .-.
ADG
ADG
OK @ParthKohli I don't watch cricket.
@Arpan 345
Well, thats quite good :D
@ADG Which school is the 400+ guy in?
A friend of mine got 379
ADG
ADG
11:41
@ParthKohli does my profile read jaipur?
Yes, yes it does.
Do you happen to know Ronak Agarwal?
@ADG Quite the scholar you are :D
Yep, from Brilliant
@Arpan Yeah, that guy.
@ParthKohli He gets 335 in FIITJEE AITS .-.
ADG
ADG
@ParthKohli don't rem he's from a school with anmol my friend with him
@ParthKohli yes heard about him but he's no big deal
11:45
@ADG How can you say that?
ADG
ADG
We have sheshansh agarwal the person who score 100 marks more than the second ranker almost everywhere
So much competition .-.
@ADG That guy is on Brilliant too. :|
ADG
ADG
3 times olympiad medalist
first indian to go in class 9th olmpiad senior
We have Bhavya Choudhary
:(
ADG
ADG
11:47
we'll sheshansh scores 176/180 in tests
So high .-.
ADG
ADG
and sometimes proves teachers teaching since two decades wrong.
I say he is AIR 1. mark my words
and we have 15 year old Pranay Agarwal.
@ADG There's no point betting on others.
ADG
ADG
Some toppers are cranky like pranay and kartik
WE have to do well.
ADG
ADG
11:48
hmm
@ADG Kartik?
What does it matter to you or me if the topper is from Allen or whatever?
ADG
ADG
maybe not?
Will it make you feel good if he's from Allen but you get really shitty marks?
ADG
ADG
KOed
dunnow, just telling you guys because you were praising me unnecessarily
11:49
No point thinking about others
Where's @Mann?
He left.
Okay.
ADG
ADG
hmm
Quick question:
first doer wins:
Lets do questions :D
ADG
ADG
$$\large \int_0^{1}(1+x^2)^n{\rm d}x$$
find $11I_5-10I_4$
done?
11:53
nope :(
i'm slow :O
Seeing question paper , very bored haha
Hi @Mann :D
On phone though I be back later
Hi @Mann, just finished giving a read on Jee Advanced 2014
@ADG How to do?
11:57
@AndreaL. He left. How'd it go?
@ParthKohli Not bad actually, most of Chemistry and Physics (90%) were quite accessible at my level, and about 60% of math questions were fine
ADG
ADG
@Arpan IBP
@ADG Ya I know
Wait doing

« first day (4 days earlier)      last day (348 days later) »