#help-38
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since it says there how many 3 balls... But my r (selected object) was 7 and my total objects were 7 as well which makes 1
everything is context dependent. Yes I would say the $765$ is also correct. The key thing is what you want
team132
I'm so confused 🥲🥲
Do you want combinations or something else?
Combinations since our teacher said so haha
then 1
but that's not in the choices I was given 😭
there was 536.25 I think then there was a 3000+ given... our teacher said we needed to add 7,5, and 3
I think it would be best if you clarify with your teacher
you're right but I looked up online, do you think this solution is right?
this was the given
The question is different now?
yes but I made it relevant since it's basically the same question with a different given so I can solve the first question in the same way this was solved
6C3 is the answer they want for the new question
but was 10 C 3 necessary as well?
then again if I solved them like that the answer would also be 1 lol
wait not 1 nvm
$(654)/(1098)$
team132
wth now im even mor confused 😭
Since they want probability of a hypergeometric distribution
ohh
My answer above is correct for the probability
The formula I am using is:
num_permutation * probability_of_single_event
The permutation of RRR is just 1
probability of event is fairly easy to calculate
idk any of those 🥲 but I get ur 7x6x5/3! now
Yes but she talked abt adding the 7 red balls, 5 white balls and 3 green balls..
I prefer the way I think about the content because formula I mention above can be use binomial distribution as well
Anyhow I will leave you to it
ty ig 🥲
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can anyone help on call
what is your doubt
i dont know how to do discriminant
!original
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.
Use the discriminant to determine the number and type of solutions of the following quadratic equation. 64x^2 −64x+16=0
do you know the formula of discriminant?
for a general quadratic $f(x) = ax^2+bx+c$, its discriminant is $b^2-4ac$
lgkoo
if the discriminant is positve, then two real solutions, negative then two complex solutions, and equal to zero means one repeated soln
thank you
you're welcome
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You have resources?
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what you mean?
Materials that you learn with, Eg books
i just go to class
but he did not teach us this yet
and i am trying to do it before he teaches it
Then you should read it from a book. When you have little understanding. Explanation is easier
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Use the square roots property to solve the quadratic equation (w+1/2)^2+4=21 nter exact answers in radical form. If there are multiple answers, list them separated by a comma, e.g.
1,2 . If there is no solution, enter
∅
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Use the square roots property to solve the quadratic equation (6x-7)^2+4=21 If there are multiple answers, list them separated by a comma, e.g.
1,2. If there is no solution, enter
∅
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Use the square roots property to solve the quadratic equation (6x-7)^2+4=21 If there are multiple answers, list them separated by a comma, e.g.
1,2. If there is no solution, enter
∅
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what is your doubt?
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Is there a formula for the nth composition of a second degree polynomial?
@scenic delta Has your question been resolved?
1 den n^2 ye kadar olan sayıların toplamını mı istiyorsun @scenic delta
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Hey
Somoene can Help me resolve this
I guet the result but I'm not sure about the step
Ty already
what step
@full moth Has your question been resolved?
When I need to find the constant
I already find the form of the general solution
But im struggling with the constants
the two pieces of information on the right are your friends for that part
I know but I don't remember how I have to do it 
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Given : cosα = 24/25, where 3π/2 < α < 2π and sinβ = 4/5 where π/2 < β < π
calculate:
a) sin 2α
b) cos 2α
c) sin(α-β)
d) tg (α-β)
double angle identity for first 2
These are going to help you
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is (n!) at the power of 2 -------) (n!)(n!) ?
okay yes thank you !
Just stick to the definition of power of 2, wich is x to the power of 2 equal to xx
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thanks!
It’s .close
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Suppose n > 1 is an integer such that 4((n − 1)! + 1) ≡ 0 (mod n). Prove that n = 4 or n is prime.
I found out that my first step is wrong lmao. What did I do wrong?
$$ 4((n-1)!+1) \equiv 0 (mod n) $$
thiccyoshi4568
$$ \frac {4(n!)}{4n} + 4 = nk $$
thiccyoshi4568
$$ (n-1)! = \frac {n!}{n} $$
thiccyoshi4568
You shouldn’t put 4 in the denominator
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where a and b are just trivial integers to represent p for the purposes of another question
in spherical coordinates $\odif V = \rho^2 \sin \phi \odif{\rho,\phi,\theta}$
pnoןɔ
tysm
@deft oyster Has your question been resolved?
the same thing for sin there now that i mentioned it
shouldnt it be sin phi?
why are they both in theta
as per this definition of dV even, it should be sin tau, not sin theta as given here
seems to be a mistake, they write it as sin φ in the next line
you are absolutely right and i just clocked that myself, the rest is Fubini theorem
thank you so much for your helkp
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Can i work on this with someone
Do you know the probability that an ace is drawn out of the 52 cards?
@terse cipher Has your question been resolved?
Calculate probability for when you draw Ace then a 'ten' value,
calculate probability for drawing a 'ten' value then an Ace
then combine the probabilities
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help
I tried taking moments but i kind of forgot how to
can someone walk me through it?
@frigid lark Has your question been resolved?
<@&286206848099549185>
I have to go to class in a minute so I won't be able to respond to follow up questions for a bit but I still need help on this question
<@&286206848099549185>
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Super confused on where to start on this
should i be splitting the intergral into 2?
okay and then like one is for up to pi/2
and the other is for pi/2 to pi
and i add the answers together
yeah
so for 0 to pi/2 integral you integrate sinx
then for pi/2 to pi you integrate cosx
idek why i asked that all i needed to do was stare hard enough lol
ohh okay and id do like anti derivative
make it nice and easy
Thanks Jaxx!
👍
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I'm on this problem, now I get to P = e^(Gt)
which gives me P = e^(-λt λt λt -λt)
Then I use Maclaurin series, but it's hard to that for matrix
some notes.. take it but don't understand
<@&286206848099549185>
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@shrewd otter Has your question been resolved?
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Hello
I just have a quick question,
If the x needs to be five units bigger to compensate from being subtracted by 5, would that not make it the same as the first function f(x)=1.2^x
It’d be the same shape, but shifted right 5 units
Since x = 5 is the new x = 0 and blah blah blah so forth
So, does the -5 have no effect on anything?
It does have an effect
It shifts the graph 5 units
Then, what is the x there for?
In 1.2^x, when x = 1, y = 1.2
In 1.2^(x-5), when x = 6, y = 1.2
It reaches the same values, just 5 units later than the original
Okay, this makes a lot of sense now
behaviour and asymptotes remain the same.
👍
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...
i need help with surface areas
do you know the formula for surface area of a cylinder
yes SA = 2nr2+ 2nrh
um
i get what you mean
but please write pi as pi, not n
and the r in the first term is squared
oh sorry
فطر
so what are you waiting for? just apply the formula
okay give me a minute
SA= 2 πr(14)²+ 2π(14)(6)
SA= 392π+168π
SA=560π
now i multiply 560x3.14 right?
@orchid wagon
remind me what r is in the formula
radius
and do you think 14 is the radius?
no
so...?
the radius is 6
6 is the height
huh
A line that runs directly from the middle to the edge of a circle or sphere.
cylinder*
<@&268886789983436800> um sus link
but anyway
this checks out
and what about the diameter?
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Why isn’t the 1/2 distributed to the C in step 3?
Because 1/2 times a constant is another constant
this might be crazy but (1/2)*C = C
I think you might be right
You can think of them as different C’s
1/2 = 1 confirmed

Yes and then they let D = c/2
Then they rename D to C
Where’s that
It’s a bit bad notation but it’s commonly done
Hidden in the background
naw cuz in really complex integrals that C is gonna be messed with a lot
You can say $C_1 * \frac{1}{2} = C_2$ and then say C_2 = C. It‘s just another constant
ℑμΤ𝛄𝛗θ
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“c/2 is another constant” is saying let d = c/2 then d is a constant then let’s call it c instead
slappin a C at the end of an indefinite integral is usually good
Yeah I see but I feel like it’s being manipulated so it should at least be put down
Eh, not everyone explicits everything in their work
Especially when it‘s a common thing
Alr well I get it thanks
It should, but it is acknowledged to be what we mean
And it isn’t a main idea of indefinite integration
So we don’t put much weight on writing that explicitly
Alr
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if x is an eigen value of a real skew symmetric matrix then prove that |1-x|/|1+x| = 1
If u add the 2 by 1 and multiply the 6 divide the 8 you will get the answer
it can be proven that for a matrix A, A and A^T has the same eigen values. if x is an eigen value of A, x is also an eigen value of A^T. again as x is an eigen value of A, -x is an eigen value of -A and also A^T = -A, so actually -x is also an eigen value of A^T. idk if i am dum but can we say x = -x in that case? or x = 0 actually
bro what
<@&268886789983436800>
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hmm
can you use lhopital?
nop
aw :/
i only can use transformations
alright, lemme check then
will x + pi/4 = t work? 
i do this
thinking about it
but i stuck after it
it can be theoretically simplified to this limit $\frac{\cos\left(9x\right)+\sin\left(9x\right)}{\sin\left(4x\right)}$ times some constants
MethIsAlwaysRight
rewriting tan(4x) as sin(4x) / cos(4x)
then just putting the cos(4x) in the front of everything
ok
and it's just -1
so you can treat it like a constant
and also take 3 from the too
top
$\frac{3+3\cos\left(9x\right)+3\sin\left(x\right)-3}{\tan\left(4x\right)}=\frac{3\cos\left(9x\right)+3\sin\left(x\right)}{\frac{\sin\left(4x\right)}{\cos\left(4x\right)}}=3\cos\left(4x\right)\frac{\cos\left(9x\right)+\sin\left(9x\right)}{\sin\left(4x\right)}=-3\frac{\cos\left(9x\right)+\sin\left(9x\right)}{\sin\left(4x\right)}$
MethIsAlwaysRight
it uses the limit of product is product of limits rule
what if you try multiplying by (cos(9x)-sin(9x))/(cos(9x)-sin(9x))
Would it simplify it?
idk
thats the problem
It's 4x
if it was 9x it would be solved by now
and no lhop for me
i suppose not even taylor expansion can be used
and after this?
not sure yet
substituion the variable?
might be worth a try
$\frac{\cos\left(9\left(t-\frac{\pi}{4}\right)\right)+\sin\left(9\left(t-\frac{\pi}{4}\right)\right)}{\sin\left(4\left(t-\frac{\pi}{4}\right)\right)}=\frac{\cos\left(9t-\frac{9\pi}{4}\right)+\sin\left(9t-\frac{9\pi}{4}\right)}{\sin\left(4t-\pi\right)}$
MethIsAlwaysRight
limit as t -> 0
right
aight done ig
how
$\frac{\sin\left(9x\right)}{\sin\left(4x\right)}$
MethIsAlwaysRight
uh
but since im idiot i still cant solve that
mine is different
mine is multiplied by few constants
its not exactly like this
where's the missing }
Dyssrupt
ok done
similar to my approach ig
now multiply and divide by that numerator
and apply cos double angle
Dyssrupt
cos9x+sin9x=√2 cos((pi/4)-9x),
Then we put x+pi/4=t, giving us,
√2cos(5pi/2-9t) or just √2 sin (9t)
And in the denominator we just have sin(-4t)
And another -1 due to the cos π
mine was similar
$\frac{3+3\cos\left(9x\right)+3\sin\left(x\right)-3}{\tan\left(4x\right)}=3\cos\left(4x\right)\frac{\cos\left(9x\right)+\sin\left(9x\right)}{\sin\left(4x\right)}=-3\frac{\sqrt{2}\cos\left(9x-\frac{\pi}{4}\right)}{\sin\left(4x\right)}=-3\frac{\sqrt{2}\cos\left(9t-\frac{10\pi}{4}\right)}{\sin\left(4t-\pi\right)}=3\sqrt{2}\frac{\sin\left(9t\right)}{\sin\left(4t\right)}$
MethIsAlwaysRight
t = x + pi/4
the answer is right
what apened here?
@main sigil
it's some kind of identity
cos(x) + sin(x) = sqrt2*cos(x-pi/4)
cos x+ sinx= sin(pi/2-x)+ sinx
And then apply sinC+sinD
To arrive here
Quite useful to remember this as an identity
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how to solve for x? i moved 4^2x to the other side. i forgot how to do this with exponent rules, do i cross out the 4s?
oh ok, thanks sm!
And to follow up on inf1425's message you can just take the base 4 logarithm on each side.
log_4(1/16) should just be (-2)
oh ok, and how can u tell log_4(1/16) = -2 just by looking at it?
4^-1 = 1 / 4
4^-2 = 1 / 4^2
4^-2 = 1 / 16
makes sense. thanks u guys this was really helpful
You can also solve it without logarithms if you want by rewriting 1/16 as 4^-2
then the bases would cancel out and you're left with (-2) = 4x + 18
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I'm not sure I understand this table
So for the first two columns, are they N/A because there's no p coordinate?
No
The first box of the left column is asking what is the x component of something in polar coordinates if I understand the table correctly
Below that is the y component in polar form
@earnest breach Has your question been resolved?
I don't think I understand still.
The x coordinate would just be p
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for 9.4
I understand how to do it by induction, but i think my reasoning is off
based on the definition of N, you can repeatedly map it to another vertex
by mapping it to the vertex of it / 2 (which depends on if its even or odd)
and you can technically do this repeatedly
minus like 1/2 since its not in the domain
is there a flaw in my understanding
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what does the =sign with a slash threw it mean and what is the first step in solving this?
It means that x is not 0
It's very important because you can't divide by 0
oh
im lisining
2 step consider x>0
oh right
a≠b means that a 100% isn't b
okay so 0 is not a choice right?
k
The answer is A
thank you but what did you do to get that?
oh now i understand
Then you can just divide 3x2+2x by x because if x is negative it will not affect the result the same if x was positive
oh now this all makes sense
and you got -4(3x by spliting the 12 in two parts right?
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Does this look correct?
for b) why do we need to condition on $\mathcal{F}_S$ isn't it as straightforward as the solution I have posted?
Master Wanky
@true bridge Has your question been resolved?
<@&286206848099549185> anybody whos strong at probability can verify?
Ok not sure why hte hint says to use Strong Markov Property in order to deduce something about $E[B_T - B_S | \mathcal{F}_S]$
Master Wanky
oh
is it because you cant say $B_S$ and $B_T- B_S$ are independent if htey are stopping times...
Master Wanky
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,rotate
how do I do this 😭?
do you know any theorems related to angles being subtended at the circumference by the diamter
I dont think so
ok, the first and second one would be applicable
Ok. So where would I plug the numbers in?
apply angle on a line in combination with that
sorry for the late response. What is that?
180?
yes
so what would I do with that?
apply property one
wait so would I do 6x=180?
no
I dont really understand what your saying. Im sorry.
do you know the angle on a straight line
180?
apply that in combination with the first property in your list and show your diagram
by the first property do you mean the center one?
yes
180° will be your central angle
wait so will x be 180?
no
forget about x
for now
first mark the 180˜ on the line around the centre
then apply that centre property as shown
try drawing it and show me
numbers aren't in ideal locations
should the 180 in the middle be in the inside?
the second property in your list
wait so I would divide it by 2?
sorry if im still not understanding it or getting it wrong 😭
wait so just 360=6x?
no
I dont understand how to use that property to make an equation
what's your arc measure here
what's the expression of the angle here
plug those in
oh wait so 90=6x?
yes
yes
ok. Thank you for the help :)
combining those, this is a special case of the inscribed angle theorem
angle at the circumference subtended by the diameter is 90°
which also goes by thales' circle theorem
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Could someone help me with this problem?
Lagrange's Theorem does the trick.
This is what I have thusfar, what are your thoughts? "For any group of order 25, any nonidentity element must have an order that divides 25, thus the order of any nonidentity element must be 5, as it cannot be 1 (the order of the identity) or 25 (which would imply the group is cyclic)..."
good
@strong horizon Has your question been resolved?
I would reword that slightly, as the group G being cyclic is fine and one of the possibilities stated
Thank you! Can I share with you my solution for this problem as well?
Could I ask for your advice on problem 1 as well?
Sure
do you have any ideas for it so far?
I have this thusfar:
I think I'm happy with that so far, looks good to me 
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@copper acorn Has your question been resolved?
@copper acorn Here is an attempt to explain. The notation $A=(a_{ij})$ is used to describe A by its entries where $a_{ij}$ is the entry at row i, column j. This is just to emphasize the entries of A.
The other part is describing sub-matrices consisting of some subset of the rows and columns of A. Your professor defines $I$ to be the set of rows in the submatrix and $J$ to to be the set of columns. That is $A_{IJ}$ is a matrix with the rows in the set $I$ and columns in the set $J$. The, determinant is just the determinant of this matrix.
Here is an example. Let
$A = \begin{pmatrix}
1 & 2 & 3\
4 & 5 & 6\
7 & 8 & 9
\end{pmatrix} $
Then, if we set $I = {1, 2}$ and $J = {2,3}$ (assuming we index rows and columns from 1) then this gives the submatrix:
$A_{IJ} = \begin{pmatrix}
2 & 3\
5 & 6\
\end{pmatrix} $
Owen
Alright, I had that feeling but whenever we wrote $A = a_{ij}$ it gave me the feeling that $a_{ij} \in F^{nxn}$ rather than $\in F$
Bean Man
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Two trains left the two cities to meet each other the distance between the citys one goes in 3 hours second one 4 hours. What part of the entire road is left 1 hour after exiting? the road between the trains
Total distance - (distance covered by train 1 + distance covered by train 2)
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can someone help me prove a sequence that diverges to infinity or negative infity cannot converge for my analysis class
If you write the definition of convergence and divergence, you'll see by the later that there is M > 0 such that forall x, M < |f(x) - f(a)|. Hence if you take ε < M, you cannot satisfy the definition of convergence
ok
is there a general definition of convergence and divergence
that i could look up online
@wraith hinge
Yeah, have you learned about the ε-δ definition in class?
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@human sorry can you post the definition of convergence that you used here so I can take a look at both
@wraith hinge also maybe I will need to look it up and see
I am not super good with these kind of names because I am new to analysis
Assume that the sequence converges to a finite limit L. Then, by the definition of convergence, for any ε > 0, there exists an N such that for all n > N, |a_n - L| < ε. However, since the sequence diverges to infinity or negative infinity, it will eventually exceed any bound, contradicting the assumption of convergence. Therefore, the initial assumption is false, and the sequence cannot converge.
is this a good enough proof?
No
you basically just said
"assume the series converges.... but it diverges so this is a contradiction"
That's actually not direct since convergence is not defined as being the negation of divergence to ±infinity (which is not always true btw)
Yes that's exactly it !
What are you talking about?
What?
That's not a proof at all
^
@supple copper
How so?
That isn't a proof it proved nothing
Show that 1/2 is an integer
Suppose it wasn’t an integer, well it’s an integer so that can’t be right
Proof: assume that it is an integer, but 1/2 is a fraction which is not an integer, so a contradiction.
Hence it’s an integer
That's exactly the proof I sketched earlier
That’s your argument
Okay well it's wrong then
Its not a proof at all
Assume that the sequence converges to a finite limit L. Then, by the definition of convergence, for any ε > 0, there exists an N such that for all n > N, |a_n - L| < ε. However, since the sequence diverges to infinity or negative infinity, it will eventually exceed any bound, contradicting the assumption of convergence. Therefore, the initial assumption is false, and the sequence cannot converge.
This part
You claimed without proof
And used it in your proof
Also, this isn't even "your" proof
So you just claimed the statement to be true without proof
that was what mark wrote
Which statement?
the one in bold?
I’ve bolded it
That's the definition of divergence to ±infinity
That part is fine? You need to show it can’t both be a convergent and a divergent one
That’s true
But you don’t know that it’s divergent
It's an hypothesis
Well you can’t claim a proof on a hypothesis
What? That part is fine.
what's the hypothesis, assume a sequence is divergent and prove that it isn't convergent?
even if so, you did not prove that
The problem is he just says well divergent so can’t be convergent contradiction
What we want to show is:
Convergence => not divergence to ±infty
Not that you use your assumption that it is divergent
We are showing this by the absurd
Whats wrong then?
We assume that it's both convergent and divergent and grt a contradiction
This is the proof just with added filler words that do nothing
Nothing was shown
How is this not valid? He used the two hypothesis and found a contradiction. It's pretty straightforward to me
No contradiction was found. He just wrote it. Show it formally
That's a simple extra step I wrote for him earlier
ok hold up does this still ahve the same issue if i do this
Choose ε = 1. Since (a_n) diverges to infinity, there exists an M such that a_M > L + 1. But this contradicts the assumption that for all n > N, |a_n - L| < 1. Therefore, the sequence (a_n) cannot converge if it diverges to infinity.
Okay? Like it is not at all a proof
I am still not proving anything
I was supposed to add this before sorry
Now, assume by contradiction that the sequence (a_n) converges to a finite limit L. By the definition of convergence, for any ε > 0, there exists an N such that for all n > N, |a_n - L| < ε.
Mathematics always has a level of informality. What actually matters is that we know how to fill in the details
Yes now its better
I really don't get why people got upset for your proof. It trully was pristine, albeit not totally formal, but again no one can be totally formal, unless you wanna get involve in some serious set theory, which is ok to me
That's how implication works
Lmao it really wasn't.
yeah i am super new to proofs so I am really just trying to figure things out slowly
I have no idea whats good or not
Whatever
The proof was very bad
But no one was upset about the proof being bad
Actually no one is upset at all
We were just pointing out that you were calling his proof correct when it was very lacking
@lapis blade im sorry i really really needed to go to the toilet and didn't scroll up to see context because you didn't reply to anything i just read it out of context
It's all about how strict you want to be
You could have asked many more details, like the space where the sequence takes its values, whether it is well ordered, and so on
I mean if it can be that lax then why even call it a proof. You’re basically just saying well yeah if it converges then it can’t diverge really large, which is like heuristically correct but in no means a proof of anything
I'll have to disagree in regard of the fact that his argument combined to my sketch is sufficient enough of a proof in my book
@lapis blade just a comment on how you go about proofs like this, a sequence that diverges to infinity or negative infity cannot converge the keywords you want to look at is diverges to ±inf and converge
from here to look back to your notes on what these words mean, then construct the proof from those definitions
you consider what it means for a sequence to diverge, then what it means for a sequence to not converge, these will be 2 separate statements
The point of intro to real analysis is pretty much just learning to write proper proofs.
then what you want to do is construct arguments to go from the first statement, and chain implication signs until you reach the 2nd statement
I understand where this is coming from, but really there will always be lacking details in a proof at this point if you ask me
And I am definitely not against going full on technical details on set theory and predicate logic, but mathematics is also about drawing the line
It's crucial that the M that you find is greater than N, that's what yields the contradiction. But of course that's not an issue since if M is smaller than N, then you can just bump M up to N, i.e. choose M' = N, and that will suffice, since diverging to infinity does not guarantee just one M for which a_M > L + 1, but rather every M' >= M will have a_M' > L + 1
@lapis blade Has your question been resolved?
ok
I feel like a synthesis of all this discussion would be valuable, so here is a proof that I hope will satisfy everyone:
Let (a_n) be a sequence of real numbers that converges to some real number L. Suppose also that it diverges to ± infinity (WLOG to +infty). This means by definition that for any real number M, there is a rank N s.t. M < a_n forall n > N.
Since the sequence also convergences, we have that forall ε > 0 there is a rank N' s.t. forall n > N', |a_n - L| < ε, i.e. -ε < a_n - L < ε, in particular a_n < ε - L
If you take M > ε-L, you have M < a_n < M
As for the meta discussion, I think saying "the proof needs more detail/rigor in my opinion" is completely fair but saying "that's not a proof at all" is pretty discouraging in my opinion since you can certainly be on the right track, have the right picture in your head, even if your formal proof is missing a few steps. I don't see a reason to get hostile, there is no objectively right answer to what suffices as a good enough proof and I think there's plenty good reason to be encouraging by saying something like "I like your proof, but I would justify this and that in more detail"
For every n > max{N, N'}
@lean prawn could you write this M=N out fully so I could see it by chance
M'=N srryy
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like just the rephrasing of my statement
.reopen
@lapis blade Has your question been resolved?
are you still here @lean prawn if not its ok I might sleep soon
Feel free to go to sleep this is taking me a little longer than I was expecting
but it's a good exercise for me as well
ok yeah I will probably be up for like another 15 minutes because I am solving another proof so feel free to ping me or dm me if you figure it out
if not its ok
I can DM you the proof if I figure it out :p
We want to show that convergence => does not diverge to infinity (the minus infinity proof is similar)
We will show this by contrapositive, by showing that
diverges to infinity => does not converge
Since (a_n) diverges to infinity, we have that for any value K that we'd like to reach, we have an M such that n >= M implies a_n >= K
We will use this M for a special K to show that the sequence does not converge.
If the sequence were to converge, then there would be some L (that the sequence converges to) such that we would have some N such that n >= N implies |a_n - L| < 1 (this is with epsilon=1)
How do we find a contradiction?
Well, let's first try to understand our objective. We would like to have |a_n - L| >= 1 for sufficiently large n, since that would yield a contradiction.
By plotting L on the real number line (remember, it can be negative as well), we clearly see that if a_n >= L + 2 then that should work since you start two units to the right of L and keep going to the right. Let's try to show formally that it actually works.
So, by our assumption, for K = L + 2, there exists some M_big such that n >= M_big implies a_n >= L + 2.
Geometrically it is quite clear that
|a_n - L| >= 1 <=> a_n >= L + 1 OR a_n <= L - 1
Algebraically, the => direction is quite clear. The <= direction is what we need, though.
If a_n - L >= 1, then in particular it is positive, and thus we're clear. If a_n - L <= -1, then in particular it is negative, and thus we're clear.
Okay, good.
Since n >= M_big implies a_n >= L + 2 which is the same as a_n - L >= 2 we certainly satisfy the first inequality.
This means that we also satisfy |a_n - L| >= 1
...
Therefore, for n >= M_big, we have |a_n - L| >= 1, which is a contradiction IF n >= N
Well let's see.
If M_big >= N, then n >= N, and thus we find a contradiction.
If M_big < N, then we can choose M_bigger = N. Note that M_bigger > M_big, and therefore for n >= M_bigger, we can derive exactly the same results as for n >= M_big. Then, at the end, we find a contradiction if the index is greater than or equal to N. But it will be greater than or equal to N because M_bigger = N. Therefore, even in this case, we can derive a contradiction
I suppose I get a little handwavy near the end but I hope it clarifies the idea
no problem
hmm I think I overcomplicated that actually
because obviously if you just choose a large enough index, one larger than N and M_big, then obviously you reach a contradiction, and obviously you can do that
but yeah I need a break tbh so I'll just leave it here
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are both of these vectors considered points?
(1,0,0) and (0,-1,1)
Wait nvm, these two vectors make the basis set
I was trying to find a point from this simple example
Would RREF not be used to find a point?
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A particle moves along the curve x^2/9 + y^2/4 = 1, with constant speed v. Express its velocity vectorially as a function of (x,y).
Ik what the answer is
But question is
Here what is x?
Is it a function of t?
So can anyone frame question exactly similar to this
But but but
Kindly also provide the function of time for position in x and y axis so that i can but up and better understand it
as in the question, its the function of (x,y)
Can someone help me with https://discord.com/channels/268882317391429632/1230167216872489090
PLEEAse
its two variable function
!occupied
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Ofc but position of x and y would be also independently be function of time no?
wdym by that
someone just started spamming here
@wraith hinge Has your question been resolved?
<@&286206848099549185>
@wraith hinge Has your question been resolved?
Try differentiate both side of equation with respect t
That's what I said
I know the answer
But what x and y mean
Are they also individually functions of time for displacement is x and y axis?
Sorry
Given time what is x and y coordinate
You are right x and y are function
What you dont understand?
Hard for me to explain
Just that
Can u frame a simple problem like this one
Just that provide the functions for time too
So that i can put the values and understand
Try if it's like t^2 2t something simple
Because I have quite new to high school calculas
Parabola (t,t^2) ?
Works
But it is not very interesting because you can express y by x
I don't even what interesting I just want to clear my concepts
That's why I asked
@stone kiln this answer is quite complicated
Very much actually
So if I had functions for x and y w.r.t to time
So I could cross check
I don't mean cross check
But yeah.. I. Wanna see how it works
You diff both parts and get relationship v_x and v_y
And you have another relation that it has constant v speed then v_x^2 +v_y^2=v^2
And just solve
well, a short explanation: he diff the equation then got a relation between Vx and Vy
then he used the fact that Vx and Vy is the x and y components of the velocity vector itself
so Vx^2 + Vy^2 = V^2
using this he got Vx in terms of x and y, the same with Vy
@wraith hinge Has your question been resolved?
Why?
Thanks a lot man!
Oooo
Got it!
he wrote some symbols wrong, like dz/dt = Vx
but eventually he fixed it and got the right answer
Real
Can u form a question like this
Because the velocity that came at last I wanna crosscheck it
So it would be great if similar question was there with function of time for x and y co-ordinates there
u can simply say that if u have y = f(x)
then say x= t
and y =f(t)
and what do u mean by question?
like u arent sure about the answer?
I am
But I want to check it
To see how it goes
The correctly understand the relationship between all
maybe some sort of visualisation for this system
we can set, x = 3cos(t) and y = 2sin(t)
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do all of these mean the same thing?
The last one is incorrect
v*u is a scalar
and so is ||u||
but the projection should be a vector
the third one rather gives the magnitude of the projection, not the projection vector
@lone mauve Has your question been resolved?
Yes, you left off the magnitude bars
would this formula be considered the same as the first two?
No
It’s the magnitude of the first two
Do you see the bars around proj in that?
| proj | instead of just proj
ya
The projection is a vector but that formula gives the magnitude of the vector
That’s an example of taking the magnitude of a specific vector yes
does absolute value really matter?
if the answer is 3 or -3 isn't it kinda the same thing?
distance cannot be negative, so 3 is the difference either way
for example:
I wonder if prof would be forgiving with marks if D was this
yes most people would mark you down for putting -3 because like you say a distance cannot be negative
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More of a general question, so I was sent this photo, could someone either tell me what noise type is and how it affects the degrees of freedom? Either that or point me to a resource.
Actually, if you could also point me to where this formula for chi squared comes from, that would also be appreciated
@frail yarrow Has your question been resolved?
<@&286206848099549185>
I'd ask for more context, but the person who sent me this is in a time zone where they should really be sleeping.
Can someone at least point me towards a resource for the formula used?
Someone at least tell me if I'm unlikely to get an answer?
@frail yarrow Has your question been resolved?
@frail yarrow Has your question been resolved?
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Is y^-3 = 1/3y ?
no
law of indices
Don’t know
Oh ok
for that question
what have you got so far
wtf
That’s how they taught us
it works but it's no tthe best way
Oh ok what should I do instead?
you can leave it how it is as 4x^5y^2 * (2x)/y^3
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
:( idk what to do
faiyrose
it's literally just calculation of the answer!?
my man, easy for you doesnt mean easy for others
basically exponent rules?
!nosols
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
last time i checked an infant can do addition
x^a+x^b =x^(a+b)
@zinc raft
which works for negative a or b, too
How would I combine y^2 and y^-3
,tex .freshman
how do you think?
@zinc raft do you know the index laws
No sorry
so many people here
Then why are u even asking
all good look at these
Ok ok I see
those are the main rules that you'll use
So I kind of combine like terms?
$y^2\cdot y^{-3} = y^{2-3}=y^{-1}=\frac{1}{y}$
Bob Goldham
when there's multiplication you add the powers if the base is the same
ur giving out
the answer-
that's what shes supposed to do herself
😭
no I'm explaining a general rule of algebra
you help op do the work, you do not do the work.
then use
a different example
oh lord its so cold
Ok
.close
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coudl someone help explai the logic of this step
so we want that left equation to look like the one in blue, so we add 2 onto the bottom, but we need to equate another fraction so it not like we added it out of nowhere
why is it 2x^2/x^2?
oh
so whats another example off it?
wait
if it need to be equivalent to 2, can't it just be 2?
you're basically making the number (2x^2) in the numerator and the denominator same
its more confusion that they added the 2 to the already x^2, why would you want to balance it out with an 2*x^2/x^2?