#help-39
1 messages · Page 309 of 1
its 2🙏
oh right, it's 1
For me it's correct. We know that all days=14 and day with people 13 if we use the formula.
Yeah.
Use that: $$\text{At least one} = S_1 - S_2 + S_3 - S_4 + S_5 - S_6$$
Ga³¹Br³⁵I⁵³9000✞
Here is correct to.
@smoky gull Has your question been resolved?
Do you have more questions about that?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
.brother that's what i thought when i first saw him
i tried making two cases of n being even and odd
the only thing i can comprehend is that , at $n=1 , a_n = odd$ which might make a change in things , other than that, all other numbers in the sequence must be even
parthisjoking
i have not studied these things formally
but i can tell you from intuition
that the first thing which needs to be proven
can be proved if u assume n is even
i proved it but obv i cant give u the solution
it didn't form a recursion for me
by using the formula of linear homogenous for 2 degree . i got the recursive relation
how did you do it then
those are some big words which i dont know
see
if n is even, let n=2k
then tell me, what will $a_{2k}$ be equal to?
Anshuman
2^2k + 2^k
Anshuman
2^2k-1 + 2^k
no
Anshuman
there is a floor function there as well
that will be k
will be equal to floor of { 2k/2 - 1/2}
which is floor of (k - 1/2)
which is equal to k-1
so now we have: $$a_{2k-1} = 2^{2k-1} + 2^{k-1}$$
Anshuman
no worries
now go ahead and multiply $a_{2k-1}$ by $2$ and see what you get
Anshuman
and compare it with other things
so a_2k = 2(a_2k-1)
Anshuman
so there are infinitely many
but the question says that we have to show that the terms can be expressed as a SUM of DISTINCT numbers in the sequence
im sure there are other individuals who could tell you properly as im just in class 10th and all this is intuition based
oh distinct
i didn't read that sorry
sure
no worries
imma study physics , prolly the chat will close on itself
@me if you wanna help
What can I help with
I actually haven’t done this type of problem before
@shadow elm Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Please don't occupy multiple help channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
How does -4xnm become +4mxn ?
,, \vec n \cross \vec m = -\vec m \cross \vec n
ghost
.close
Closed by @still dirge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
i found out that f(f(n)) = f(n) , can be proved using induction or smm
but idk how to prove the main ques
how are you not in the mods server
Mathematics olympiad discord server iirc
idk about that one
@shadow elm Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
what have you done broski
let me
ss
what i typed out so far
k i cant screenshot my tablett
for some reason so ill just type out what i got so far
for q2 we need at least n=6 verticies where the sum of degrees is 2(n-1) => 2(6-1) = 10 (Handshake Lemma)
but its basically
just this
i didnt get much done
beyond that
for q1 i have no clue where to begin
i watched some videos on isomorphic trees
and found some notes but not much else
from the notes i can understand is that two isomorphic graphs are just the same graph drawn differently
im also reading up on degree sequences which is where i got that number from^
additionally, I found this in the textbook, which is what im looking at for reference
@zenith trench Has your question been resolved?
@zenith trench Has your question been resolved?
when I see a problem like this, the first thing I notice are G and its "opposite" can be seen the other way, like G is also the opposite of "opposite G", they form a partition of all edges, if an edge is not in G its in opposite G and the reverse is also true
the other point is that n >= 5 is necessary
from this point, I know that a logical way to go is to assume G has no cycle and it should imply "opposite G" has one (or the reverse)
so graphs without cycles with n >= 5 have a certain property that we have to think of
first intuition, if a graph has too many edges, at some point it will have a cycle (so graph without cycle must have an upper bound of their number of edges)
so the fact that G and opposite G are a partition of edges will imply some problem with that
if one has very few edges, the other has a lot
and the n >= 5 must probably be necessary because you need at least that much vertices in order to have enough edges
I would say the problem is with the total number of edges, which is n choose 2 since it's the total of possible edges in a graph with n vertices
maybe in your book you've already done something about graph without cycles ? otherwise, try to figure out the upper bound
for your 2nd problem about trees, I would try to make trees big enough with an even number of vertices for each degree
so I can swap them somehow if needed and make a 2nd tree not isomorphic to the first
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@woven matrix took some time but i completed those two questions just now with ur advice :)
all option seems correct to me
my new question is this
@zenith trench Has your question been resolved?
Closed by @zenith trench
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Image 1 integrates to image 2.... however, I'm getting a slightly different answer,
instead of -1/4a, I'm getting -1/2a.... I want to know where I mada the mistake....
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
show your workings
can I just tell you what I did?
My handwriting is in hindi?
Not english
I mean numbers are numbers fr
ax + b = u
du = a dx
dx = du/a
integral (sinu cos u du/a)
1/a taken out of integrand
I use identity sin2x = 2 sin x cos x
and get 1/2a outside intgerand and 2sin u cos u du inside
= 1/2a integral(sin 2u du)
I integrate
do a k sub
and get 1/2a -cos(2ax + 2b)
Okay
If you are done with this channel, please mark your problem as solved by typing .close
.close
Closed by @small barn
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
can someone teach me how to solve a second order homogenous DE?
Sure
Matter of fact, what you are essentially solving is a quadratic in disguise

I will let u 
no im in game
😭
this makes sense
<@&268886789983436800>
u r a snitch
Take a day off
bro tryna promote his soundcloud 😭 🙏
ode?
ordinary differential equation
is that the same as first order?
what does independent variable mean 😭
like you know a function y=f(x)
x is independent it can be anything we want it to be, but y depends on the value of x
hmm?
that doesnt make sense, x cant be both
f(x) is the same as y; what value you will get for it will depend on x
yes
when you solve the linear homogeneous diff eq of order 2 here, you can have 3 cases
2 real solutions, 1 real solution or 2 complex solutions
after all you are solving a quadratic equation
yes
Now depending on p and q you get real or complex solutions
You can try to figure that out
keqae
for real solutions
Yes; I believe you can case-by-case it depending on that inequality
Notice that in the = case λ1=λ2, so one vector falls out.
Instead we need to do the following
We need to account for the multiplicity
okay wait
sorry
i understand that
for the second order homogenous DE
your two general solutions are $e^{\lambda_1}x, e^{\lambda_2}x$
keqae
uh
formatting mistake
assume the x is in the exponent
but how does this lead to
yes
ae^... + be^...
i could try to explain it in terms of algebra, suppose we have solutions y1 and y2 then one could show that any linear combinations is a solution as well
in fact in terms of linear algebra we have a subspace
Easy example: y'=y
so basically for my preuniversity ahh i should just remember the cases 😭
i mean yeah if you havent taken linear algebra its hard to understand why the theory works, but it's worth it because it is well thought out concept
Yes and you can prove that
thats interesting
in fact i have the proof myself
you use the fact that the differential operator is linear
whats the differential operator?
d/dx
in simple terms you use the fact you can pull out scalar or distribute differentiation
hmm okay
i understand that
this is why any combination is also a solution
and are the distribution properties an exclusive feature of linear operators?
yes
whats an example of a nonlinear operator?
maybe for example taking the square root
i wouldnt say therefore but yes squaring is also not linear
and any logarithmic function
logs have some similar properties but they are not linear
okay cool
this all
how does the different numbers of solutions
you learn that in linear algebra
affect your
solution
or does it not change
say for example the roots to $\lambda \in \mathbb{C}$
keqae
uhm not sure how to answer that but have you heard of vectors before?
.. yes 😭
ok peep this
thats the same as y=x to understand that
yeah
now imagine we found the solution (1,1)
that point is on the line
but so is (2,2) or (π,π) etc
this is what we call a space of solutions
or just any (x, x)
okay
x(1,1) that is also a linear combination
you can now think the same of this, you have two vectors that form a plane of solutions so thats why we have the A + B thingy
i... dont see that
hmm okay
so does complex solutions for $\lambda$ change the form of the general solution?
keqae
Its the same concept but u take the real and imaginary parts
oh so it doesnt matter?
ye
Closed by @violet prism
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
why x multiplies the first column
If mult you have two rows ax+by and cx+dy
Ax and cx here can be expressed as x mult by vector a c
Similarly to y and vector b d
but shouldn't this step be done first?
Which one
arent they matrixes?
if you know matrix multiplication, the number of column should be equal to number of rows
why did you tell me the final solution right away?
They are the same lol
.
these are matrix multiplications
Thats the way you multiply, not the answer.
Like you ask me what is 2x2 i tell you 4 then you ask why tell answer
but I didn't mean the next step after that
They are equivalent
You can choose, depending on the context, which way to write the result
They are equivalent, albert said that
This sheds light on the fact that the application of a matrix to a vector can be expressed as the linear combination of the two columns, which might be useful for some cases (such as linear systems)
I hope this clears your doubt
If that was your doubt 😅
the number one matrix is 2x2 matrix, 2nd one is 1x2 matrix hence, the matrix multiplications says," when matrix A and matrix B has equal columns and rows respectively then they are multiplied by these steps:
in some sense this should be taken to be the definition of matrix multiplication
fr
Don't you agree that $\begin{bmatrix} ax + by \ cx + dy \end{bmatrix} = x\begin{bmatrix} a \ c \end{bmatrix} + y \begin{bmatrix} b \ d \end{bmatrix}$ ??
Alberto Z.
work it out in terms of algebra and youll see why
.
do you know bow to multiply matrices
I already explained broski
he doesnt know thats why he is confused
ah i see
he must have seen "matrix multiplication" concept on youtube
but why is it true?
cmon man ;-;
I think it would be better at this point to accept it as a definition for the time being
you could refer to this vid I suppose for intuition, but I'm not sure how much that would help you.
Multiplying two matrices represents applying one transformation after another.
Help fund future projects: https://www.patreon.com/3blue1brown
An equally valuable form of support is to simply share some of the videos.
Home page: https://www.3blue1brown.com/
Full series: http://3b1b.co/eola
Future series like this are funded by the community, th...
Why do you bring up this now? 😅
Do one thing at a time
Especially if you haven't solved the previous doubt!
I think this is the same thing as above
I don't think so at all
@green aurora
I mean it's true because that's what we mean when we write these symbols down
Kind of like asking "why is a dog called a dog"
Can you answer this, for the third time? @green aurora
Do you agree with that step?
Yes or no?
but then why does everyone say different things?
No, we are not
yes
Then where is your doubt?
If you agree with that, and you know how to multiply two matrices, your doubt should be now solved
but I didn't ask for that thing
Mmhh
this 🙁
Do you know HOW to multiply two matrices? In particular, a matrix with a vector?
YES
or
NO
????
for example why don't I also multiply y by a and c?
Just because that's not what we mean when we multiply two matricies
What is the basis for doing this?
None. Common vote.
.
We all have to use the same matrix multiplication, so this is the one we use.
There's no reason why a "dog" is called a "dog" but it would be very confusing if I just started calling them cats.
I’m not asking how to compute the product once the definition is given. I’m asking why matrix multiplication is defined that way in the first place, instead of some other rule
You’re explaining how to apply the definition. My question is more basic: why is matrix multiplication defined in that specific way at all?
Like, let's say historically they did decide on another rule. Call it "Rule B"
Then you'd be asking "why do we use rule B and not rule A?"
You might be wondering "why have a matrix multiplication at all?" Which has some interesting answers, but at the moment you're asking "why does matrix multiplication look like that?" Which was decided by popular vote at the time.
That’s not quite the same. I’m not asking about a bare convention; I’m asking which definition is mathematically justified by the properties we want matrices to have
You are asking about a bare convention.
the reason this one is called matrix multiplication is that it is the unique natural rule that makes matrices represent linear maps and makes composition correspond to multiplication. In that sense it is not a bare convention; it is mathematically motivated
Sure, but there's a ton of ways this could have been represented
You're asking "why this particular representation"?
The answer: "No particular reason"
If we did have y multiply by [a c] that would not have changed anything
Yes, there are many representations. But for the standard coordinate-matrix representation, row-by-column multiplication is not a free choice; it is the rule induced by composition of linear maps
I'm sorry you're so steadfast in your mistaken impression.
I think we’re talking past each other: I’m not denying that other conventions are possible; I’m saying that once the standard coordinate convention is fixed, the multiplication rule is forced.
And I'm telling you that's not correct
Unless you mean the convention itself is the multiplication rule we're telling you is a convention
No once the basis and coordinate convention are fixed, the rule is not arbitrary. The columns of the matrix are, by definition, the images of the basis vectors e1,e2,... and linearity then forces the action on any vector. So if you change the multiplication rule, you are no longer using the same representation of the same linear map
You'd just need to permute the columns to fix it
The Georgia Tech linear algebra text explicitly says that the definition of matrix multiplication is justified because it corresponds to composition of linear transformations, and even calls that the “one and only reason” for defining it that way. MIT 18.06 also explains that once a basis is fixed, a linear map is determined by the images of the basis vectors, and the columns of the matrix are exactly those images in coordinates. So with the standard coordinate convention fixed, the multiplication rule is not arbitrary; changing it changes the represented map or the convention.
Where "fix" means get from one arbitrary convention to another arbitary convention
The columns of the matrix are definitely not defined as the image of a basis vector, btw. That's a result
Closed by @green aurora
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
x^2 + y^2 =2y
how can i say this a circle
try subtracting the 2y from both sides and then complete the square
the general procedure is grouping all the x things together, then the y things together and then completing the squares
so in this case, you need to move that 2y term to the left side, so that its together with the y^2 term
Closed by @violet kraken
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Please don't occupy multiple help channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
when doing partial fractions
why can you sub in x = -2/5 and x = 1/2
when they are restricted
cz u would get a fraction where 0 is the denominator
what do you mean
du u mean can't?
yeah
no liek
but he said "in part a" so even im confused
you can do 50x^2 + 38x + 9 = A(1-2x)(5x+2) + B(1-2x) + C(5x+2)^2
and then sub in x = 1/2 and x = -2/5 and solve
and you get the correct A, B, C values
in the original equation you cant because thats a division by 0, but when we cross multiply it gives a polynomial true for all x
nice
.close
Closed by @blissful brook
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
In what sense can I take the abstract Mellin Transform of a function where the integral diverges?
@elfin stirrup Has your question been resolved?
Closed by @elfin stirrup
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
A few questions
Here isn't (x)=Q[x,y]
Well,,,
it doesn't need to have identity I suppose
no then 1 would have to be inside (x)
Got it
and stuff like y^2 + 1 either, bc that would imply x times f(x, y) = y^2 + 1 -> therefore stuff like that's invertible, and it isn't
so just sums of kx^ij^j
Cool
the prime ideal thing is easy enough to prove :3
yea, from defn even
ye
(x)≠(x,y) though right
ah right
yep
🤦
ahahaha
is okay
don't beat urself up
buuuut the prime ideal idea is the same
can you see how to show it's maximal
probably wanna show Q(x)/(x,y) is a field?
well \ but discord doesn't display that
ooh right, I keep getting confused with set diff.
yeah
*much
Closed by @sharp smelt
Use .reopen if this was a mistake.
god that reference is peak
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I need to find the largest number and provide proof
what have you tried
I tried squaring all of those and putting it into a^2-2ab+b^2 formula
conisder mutliplying by conjugate/conjguate
yes multiply and divide by conjugate
i hope he knows what conjugate means
seems so
.close
Closed by @kind lagoon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
In last 2nd line why it is 180 -60
Bcuz 180 - theta equals theta
So it should be like 180-120 = 120
Bcuz see the 2nd page attached here since 180 - 60 =sin 60
Ya ya i know
sin(120) = sin(180 - 120) = sin(60)
Can you post that again so I can rotate
they're applying supplementary identity for sec (and cos)
cos(theta) = -cos(180 - theta)
sec(theta) = -cos(180-theta)
See
Sec -60
Sec 180 - 120
Sec 120
Right
no
Ohk I got it
.close
Closed by @rose phoenix
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
someone gave a solution in the previous channel
but can we ignore the fact that it explicitly says SUM …
@proper nova i think it was u (sorry for pinging)
@shadow elm Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
for c how can I say anything about the relationship between f(n), f(n-2), and f(n+2). I found this stack exchange but there explanation is not clear. They just say tan can't take a value greater than 1 on (0,pi/4) and that implies two inequalites. https://math.stackexchange.com/questions/2368340/how-to-show-the-inequality-for-int-0-pi-4-tannx-dx
what step you don't understand ?
Is he trying to point to the fact that the height of any part of the tan curve is going to be some decimal value and by multiplying a decimial more times you make it smaller thus the height of the curve that is multiplied by itself more times is smaller and thus the area is smaller and because of that we can say the integral is less
Remember for $x\in(0,1)$ and $n < m$, we have $x^m < x^n$
π=√g
ye so the curve would have higher height
Yes i guess that is what you said, so yeah use that
Closed by @royal galleon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hello everybody, why is a+b not a^2 + b^2 but 2ab
Huh???
W question
!xyp
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
a+b not a^2+b^2
You probably meant to ask why is (a+b)^2 = a^2 + b^2 + 2ab, instead of just a^2 + b^2
One has ^2, the other doesn't
is that right?
Do you have more questions?
It's like asking:
why is 3+4 not 3² + 4²
😅
its 7
Lol
Because one have the ^2 and the other does not.
I guess you're trolling then!
trollin'?
It’s like 2+3 it’s not 2^2+3^2=13
a*a = a \therefore a=1
a*a = a^2 ;-;
is ts ragebaiting?
it can be equal to it for specific values of a and b, but it's not always equal, so it's not an identity
just like a^2 = a isnt always equal, but can be equal for specific values of a (namely 0 and 1)
get this man a true
thank you so much!!
partypooper
Do you have more questions?
nope :love:
!done
If you are done with this channel, please mark your problem as solved by typing .close
Closed by @ember rampart
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Which part does not make sense?
like how can u take y = root x along x axis
shouldn’t it go along z
as z is missing
from our equation
ykwim?
no
you are doing a rotation akin to the right
so in 3-dimensional space (with z-axis forward) you get a solid
ummm u integrated?
it's a random example so you understand what it means to rotate a func about x-axis
Wow
What
This is like what the answer key of my book says
I m confused what do they mean by y >= 0
like can’t y be negative or positive
but we square it in the end to make it positive
Oh my blud I misread the q totally
wow
trace in the xz plane is confusing me
Well when you rotate it or rather look at the picture, can you notice a symmetry?
no but I won’t have an image in the exam
you can derive that yourself in 5s
The point is your rotation has a constant radius sqrt(x), in 3d you will notice in the yz plane that you have traces in the form of circles, which gives you (sqrt(x))^2=x=y^2+z^2
@subtle phoenix Has your question been resolved?
you here?
you wont have a fancy image on the exam, but you can still draw it following a few steps
first, do you know what y = sqrt(x) looks like
yea
next what
then take the shape and spin it around the x-axis
you see the x-axis, right?
now what does it means to spin something
but why is it going down too
around something else
the x-axis is not currently going down
its going right, as it always does
the picture youre looking at is in 3D
it does not mean the x-axis is going "down"
the y-axis is not going "down" either
the parabola is x = y^2 right
maybe you should ignore this picture for now
it seems youre not skilled enough in mentally spinning things, we will leave that for later
and my confusion is how is it possible to direct it along x axis if it’s
ok lets pause
have you spun something before?
like a beyblade
we can make do with a beyblade, sure, but itll be harder that way
ok then how do we spin
because then the next question is gonna be
what do we spin *
its clear the thing we're spinning is going to be the thing we're spinning
it could be the beyblade or the y = sqrt(x)
that we do know
now to spin it, youre already imagining a certain way to spin it
which is around the center, right?
yeah
I get that
on xy axis
we have a parabola
that keeps continuing
hey
Oh
we're not done yet
around which something spins
sure, is it a point or a line?
Center is a point
so for example
say I spin the beyblade sideways
thats going around the center too
but you know thats not correct
why not
why is it not correct
you know what I mean by spinning the beyblade sideways?
what
what am i seeing😭
Arey how did you know mein indian hun😭😭
Aisa kya hai mere naam mein😭
Explain kardo bhai
jee ka hai kya
ye gimme one sec
This is uni math
Thanku bhai
tum basically ek 2D mein parabola jiska axis is xais ko thoda ghumapge in 3D toh aisa ban jeyaga
Question ye hai kya
Yeh solution hai
Achaa
Question yeh hai
Yes
trace alag alag axis mein
kesi shape hoti
Hai
toh uss sab ko combine karke
But mujhse visualise nhi horaha
Acha toh basically aisa imagine karo lets say 2D ke parabola ko tumhe pi/2 se rotate kar diya
toh lets say xy plane horizontal hai, toh ab tumhara parabola xz mein aagya and vertical hogya right?
Tou like left side pe ek horizontal parabola ban gaya
xz mein
horizontal nhi hoga
Haan
Ab thoda visualize hua hoga like uska trace toh same hi aa rha hai
Wahi soln mein bhi bol rhe hain
Arey wo xz mein parabola ki equarion kya hoi
x = z^2
Badhiya
Ab hum koi general angle ke liye lete hain
Since wo hamesha 0,0,0 se pass hoga hi
Hum bas simply trace ko compare karke bol skte hain ki ye jo hai paraboloid
Iska toh simply xaxis equation rahega and y and z iske cross axis honge
How do we know origin se pass hoga
Arey x axis ke about kiya na rotate
y = sqrt (x) toh origin se pass hota hai
And x axis ke about rotate karenge toh point of intersection with x axis change nahi hoga na
yes boss
But why do we add y and z
kyunki jab rotate kiya x axis ke about toh phir wo 3D mein transform hua na
but add kyun karenge phir
Acha ruk waise samjhata hun
Hum basically saare parabolas lenge jinka shape is similar to y = sqrt(x)
Axis ki mkc abhi
shape pe chal
Shape sabka same hai yahan par
Achaaaaa
mein samjha tera point
multiply toh hoga nahi kyunki multiply se phir hyperbola jaise hoga
Arey tauba tauba kar diya tune toh🙏🙏
@subtle phoenix Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I need help with this i dont know what im doing wrong
try turning the row echelon form back into equations
@echo sandal Has your question been resolved?
maybe
yes
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
i will translate the problem one sec
Let $a_1,a_2,..,a_{2565}$ be positive integers for which [ \frac{1}{\sqrt{1+a_1}} + \frac{1}{\sqrt{1+a_2}} + ... + \frac{1}{\sqrt{1+a_{2565}}} = 100 ] Prove that there exists $i,j\in { 1,2,...,2565 }$ such that $a_i=a_j$
Copter
i'm stuck like halfway here
well if for contradiction all ai are distinct then a_j >= j for all j ≤ 2565
and it remains to show $\sum_{i=2}^{2565} \frac{1}{\sqrt i} < 100$
how do i show that?
have you tried AM-GM? It looks suspiciously like that.
Copter
oh yea i changed some things mb
wouldnt i get >= with am gm?
for that you have to pre assume all are equal
also am gm is for real numbers so theres probably and easier way
denominator so $\frac{1}{\sqrt{1+a_i}}\le \frac{1}{\sqrt{2\sqrt{a_i}}}$ if im not wrong.
Annie Maqionde
Hint: bound it using calculus
try evaluating [ \sum_{n = 1}^{2565} \f 1 {\s {1 + n}} \le \sum_{n = 1}^{2565} \f 2 {\s {1 + n} + \s n} ]
how did u even think of this tho
i mean its a pretty well known bounding for 1/sqrt n
but i forgor
it's obvious
i see
Closed by @north talon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hey, I am trying to prove all three possible implications of the following statement:
Let G be an undirected graph on n nodes. Any two of the following statements imply the third:
- G is connected.
- G does not contain a cycle.
- G has n – 1 edges
I proved the 'if G is connected and has no cycles, it must have n - 1 edges' by induction and 'if G is connected and has n - 1 edges, it must not have a cycle' by contradiction
I am trying to do 'if G does not have a cycle and has n - 1 edges, it must be connected'
I am not sure how to do this one
@sweet lintel Has your question been resolved?
@sweet lintel Has your question been resolved?
<@&268886789983436800>
So you could try by contradiction (or direct depending on how you see it). Assume G has k connected components G_1 ,..., G_k for some k >= 1 (k > 1 if you're doing contradiction)
Every G_i can be applied a property that you've already proven...
Thanks!
.coose
.close
Closed by @bitter herald
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
how can we solve this system
no clue where to start from
Tu'es en Terminale ?
What ideas you have and what have you tried?
oui bac
nothing
i would lwky just try random numbers
What's that V supposed to mean?
cmon man
quel bac ?
smallest commun mulyiple
maroc
LCM alr
lwhats the L?
Lowest
aaaa ok tnx
Can you figure out what form a and b must have seeing the lcm?
oui l'arithmetique est exclusive au sm
what..?
try what
Prime factorisation of a and b
PGCD = 12
180=(2^2)×(3^2)x(5)
Hint, use this formula:
gauss?
Since 96 is a 12 multiple, both have atleast a 4 and a 3 multiple, but one of them has a 5 extra and one of them has a 3 extra
no
In what city you live though in morrocoo?
bro wants me to dox myslef💔
dm me
just tell (I am morrocan too)
why is gcd 12?
Nvm that just solves it
tanger
Alr then
why is the gcd 12 💔
wait
Using the formula: #help-39 message. 🙂
i dont see a ^ sign to apply it maaaan
$\begin{aligned}
&\text{Recall } a \vee b = \frac{ab}{\gcd(a,b)}. \text{ Let } d=\gcd(a,b) \text{ with } a=dx, , b=dy \text{ and } \gcd(x,y)=1. \[6pt]
&\text{Then } a \vee b = dxy. \text{ The system becomes:} \
&\begin{cases} d(x+y)=96 \ dxy=180 \end{cases} \[6pt]
&\implies d \mid \gcd(96,180)=12. \[6pt]
&\text{Hence } x+y=\frac{96}{d} \text{ and } xy=\frac{180}{d}. \[4pt]
&\text{Testing } d\in{1,2,3,4,6,12}, \text{ only } d=12 \text{ yields coprime integers:} \[4pt]
&d=12 \implies x+y=8, ; xy=15 \implies {x,y}={3,5}. \[6pt]
&\text{Therefore:} \
&\boxed{(a,b)=(36,60) \text{ or } (60,36)}
\end{aligned}$
YRIP_You
gl I am from Marrakech though
Closed by @wispy rapids
Use .reopen if this was a mistake.
You are welcome!
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello
hi, do you have a maths question
