#help-10
1 messages · Page 450 of 1
We only plug in if they are in a determinate form right
yes
that's where your table earlier comes in
because there was division of 0 giving undefined
Ohhh right
also, I recognize that text you showed earlier. who gave you that image, if I may ask?
oh, alright.
So when we’re not told where the discountuiny is, we just look at where the function changes definition
And that point will be where we test it
boundary points are always prime suspects for discontinuities.
When u say boundary point I thought it was the end points of the interval
I rarely use boundary point to mean endpoint.
if I do I will explicitly say what point I'm referring to.
and you can question me if I don't. that is fine.
yes if both functions are continuous separately, the only possibility for a break to occur is the boundary point
Could we just say point where the function changes definition to avoid confusion or is there any other name for it
you can say that
there is another name for it. it's called boundary point lol.
but I prefer not to type a bunch if it is understood what boundary points are.
I’ll just say boundary point alright 👍
i say breakpoint but it doesn't rlly matter ig
as long as you get the point
pun unintended
The limit are not equal to each other which means there won’t be a max min in the interval
As the max min states that it should be a closed interval and be a continuous function within the interval
Wait
I’m confusing my self
Actually yeah
if the function is not continuous, then the EVT (which is what your theorem is actually called, if I read the statement correctly) does not apply.
Min max thereoum
most people refer to it as the EVT.
Oh ok
just to confirm, your theorem statement is this:
If f is continuous in a closed interval [a, b], there exists points c, d in [a, b] such that f(c) \leq f(x) \leq f(d) for all x in [a, b].
correct?
or equivalently,
If f is continuous in a closed interval, f attains a maximum and a minimum in the interval.
Yea
then yes, it is more commonly known as the extreme value theorem (EVT).
Ah, I see
So after the limits are not equal to each other at x approaches 2 , there won’t be a max min?
It’s not going to be a continuous function from the start of the interval to the end of the interval
The limit as x->2 simply doesn’t exist
well then the theorem doesn't even apply to begin with.
it may happen that there is a max or min, but the conditions required for the EVT to apply are false, so it is not guaranteed.
we cannot guarantee their existence.
What does that mean
^
Like we’re unsure
yes.
is your native language not English? I can try to see if I speak your native language.
Do you speak Viet
@steel night 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 does the degree sign on top of A mean on the second equation?
Closed by @restive saffron
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.
Let $Q$ be a refinment of $P$. Then $L(g,P)≤L(g,Q)≤U(g,Q)≤U(g,P)$. But $U(g,P)=L(g,P)$. So $U(g,Q)=L(g,P)=U(g,P)$. Similarly $U(g,Q)=U(g,P)$. Thus as there exist a sequence of partitions such that $U(g,P_{\varepsilon})-L(g,P_{\varepsilon})<\varepsilon$ for all $\varepsilon>0$, $g$ is integrable
Wai
I think this is fine
But I dont think you even needed to define a refinement Q
You can do it directly with P
huh
I mean fair
consider the constant seqeunce of partitions P,P...
and we're done
.close
Closed by @versed stratus
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 help? For some reason i just cannot get my marginal profit to work as expected
I set revenue to be 2300u, because u is in thousands and we naturally want them all to be in similar units, and so i then set profit P(x) = 2300u minus the original given function C(u), which after some simplifying turns out to -0.0022u^2 + 2299.87u - 330
I then take the derivative of the profit and go from there
yeah but you need not multiply it by thousand as all units are givem in thousands already.
Did i misread it
Marginal profit of 307 thousand batteries
hmm ok
i suppose that the "the manufacturer plans to charge wholesalers $2.30 per battery" maybe was what got me
but thanks!!!! :)
.close
Closed by @wooden surge
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.
Guys I don't have a clue how to do this
how come the right side doesn't have an n
@final radish Has your question been resolved?
@final radish Has your question been resolved?
you are in the right way just seprate equations the constes alone, the x alone and the x^2 alone
I hope tha helped @final radish
@final radish Has your question been resolved?
You made a careless mistake when expanding (ax)^2
and also after what you've done so far, just group all the terms by constant, x, and x^2 and compare coefficients of these between LHS and RHS
you also have quite a number of presentation issues but i think you should get the right answer before addressing these
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.
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.
Can I grab another set of eyes to help me find my mistake?
,rccw
Just to clarify the answer is…. 16/sqrt 377
is that not what you got
also like.... what's the question?
assuming given sinA = 5/sqrt(29) and cosB = 3/sqrt(13) find cos(A-B). assuming this is the question based on what questions he did before
That is- I just wanted to make it more obvious
The system said it wasn’t
why are we taking the sin of 5/√29?
do you mean something like: sinA = 5/√29?
if so, write that. you have two angles flying around here
It’s a whole big thing
@polar fossil read my last message in #serious-discussion thatll explain
I don’t even….
She would rather me separate and write it all by triangle and- idk it’s weird
that's fair enough, triangles are helpful, but like.... can you write something like a table then? or like
A
sin: 5/√29
cos: 2/√29
tan: 5/2
idk
it's just really hard to figure out what you've done
we've got
cos(A - B) = cosA cosB + sinA sinB
Yes
oh maybe it wants you to rationalise the denominator
Maybe
rationalizing marked you wrong on the last question, i was gonna say yeah your work is right though
multiply it by the square root on top and bottom
you just multiply by √377 / √377
Wait nvm I know what you mean now
was it marked correct by the system?
@round island Has your question been resolved?
.close
Closed by @round island
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.
heyyyy how shoudl i go abt practicing loops for python
write loops of your own if I had to guess
like just make up your own examples of functions/operations whose computation likely involves a loop
Can you not abuse math help channels with non math questions
oops im so sorry i ddint mean to "abuse" them
thank uuuuuuu
do coding practices
little projects can be nice, i remember one of the first thing I did with loops was to verify the Collatz conjecture up to n=1000000, with that you get a while and a for loop for sure. A lot of thing could be good practice Fibonacci, matrix multiplication etc…
any useful websites or resources?
thank uuuuuu
got u
what about a function that prints the first n rows of pascal's triangle?
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
etc.
if that's the level you're looking for
if you want something that uses while or do-while loops as well, maybe you can try implementing Newton's method for finding square roots with a set precision goal as the condition, if you want to challenge yourself a little bit.
loops are sums 
sums are loops you mean
$\prod$
Yukari
print("1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
etc.")
ah yes, the YanSim method when all else fails.
yansim 😭😭😭😭
products are sums

you have a point.
I was making a point in terms of functionality
I took my first c++ course before taking calc 2
it can go both ways tbf
@timid silo Has your question been resolved?
Closed by @placid crow
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 i get help with this [
for part a you can start by finding the critical points in the triangle
xy-x-3y is what shape
hyperbolic paraboloid
im just lost bruh
on what the extrema thing is in this regard
i mean last thing i did was finding critical points on curves
but this is totally different
so idk how what i did earlier relates to any of this
for a triangle, the extreme points are usually on the boundary OR inside the region where gradient=0 (or derivative doesn't exist)
so you should check both cases
this is to find possible extreme points IN the region (when you set gradient to 0)
can we start from the terms, so when they say find the absolute extreme, whats that supposed to mean here
like intuitively i mean
you can probably just think of a 2d graph, with a curve
find the extreme points of it while the x value is bounded
kinda same thing here
here you're finding the highest/lowest value that f reaches over the triangle
what does this mean exactly
@quiet condor Has your question been resolved?
i dont understand
what do you not understand about it
im just not understanding what we want here
it is similar to this where you plug every possible (x,y) in this curve into your f(x) and find the extremes
in the triangle case, your bounds are
x=0 for 0≤y≤4
y=0 for 0≤x≤5 and
y=4-(4/5)x for 0≤x≤5 (hypotenuse with line through (0,4) and (5,0))
so you take every possible point in this bounded triangle and plug it into f(x) and find the largest/smallest value f produces
@quiet condor 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.
$$ \int_0^{infinity} e^(-x^2) dx $$ I want to prove that with Laplace method
\int
William James Moriarty
If power is using ^{}
and infinity is \infty iirc
$$ \int_0^{\infty} e^{-x^2} dx $$
William James Moriarty
I just started learning latex that's why
Np bro
$$I=\int_0^{\infty} e^{-x^2} dx $$
We square I
$$ I^2=\int_0^{\infty} e^{-x^2} dx \int_0^{\infty} e^{-y^2} dy$$
William James Moriarty
$$I^2=\int_0^{\infty}\int_0^{\infty} e^{-(x^2+y^2)} dxdy $$
William James Moriarty
Here I want help to get the right substitution
What do you think you should use?
Arctan I think
You need to subtitute something for x and y as functions of some other two variables.
x^2 + y^2 is a certain value with a specific meaning
I know this you want to say polar coordinates
But there are another way
Okok well yeah polar coordinates is the usual way there's probably some other way
I think y=tx
dy=xdt
e^(-(x^2+y^2))=e^(-x²(1+t²))
Okay that's will be easy
@shut lagoon thank you
.close
Closed by @zealous haven
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 would i start with this prove? im not too sure where to begin...
What is Q_n?
n-dimentional hypercube
Investigate Q_4 first, and then you should be able to argue about the other ones from how they're constructed inductively.
would i do induction on the number of vertices?
If you show that Q_4 is non planar, then it has a k_3,3 minor and from the construction of Q_n from Q_{n-1}, you should be able to argue that Q_5 does as well and so on
im having a hard time seeing Q_4 having any edges crossing xD
wait nevermind im looking at a 3d Q_4 not 2d
.close
Closed by @stiff citrus
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.
so for this, do i find the value of signum for every quadrant?
oh nvm got it
.close
Closed by @halcyon shuttle
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'm reading something on field theory right now and the author casually remarked, that if $K$ is a field with $\text{char} K = p$, we know that $K$ has $q := p^n$ elements for some $n \in \mathbb{N}$. Thus the multiplicative group has order $q - 1 = p^n - 1$ and every element in it satisfies $a^{q-1} = 1$. I got all that, but I didn't get the next part:
``Thus the polynomial $f = X^p - X \in \mathbb{F}p[X]$ has exactly $q$ distinct roots. We obtain $f = \prod{a \in K} (X - a)$ and $K$ is the splitting field of $f$ over $\mathbb{F}_p.$.''
(To be more percise, I don't get why the polynomial has exactly $q$ \textit{distinct} roots and why the other identity for $f$ holds.)
Ruby
.close
Closed by @brittle trail
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.
Let ABC be a triangle and let D be some point on the line segment AB which is neither B nor C. The circle of ABD intersects AC at an interior point E. The cricle ACD intersects AB at an interior point F. A' is the reflect of A about the line BC, such that the rays of A'C and DE meet at P and the rays of A'B and DF meet at Q. Prove that AD, BP and CQ are either concurrent or all parallel.
really lost but heres what i got: AD is the radical axis of the two circles,
since ABDE and ACDF are cyclic quadrilaterals, ∠CDE = ∠BAC = ∠BDF and reflecting it about BC, this is also = ∠BDP
dont really know how to continue
Could you provide the diagram which you drew
okay hold up ill try to draw a nicer one cuz i freestyled it 😭
What is angle chasing?
Math slang
basically finding or equating angles using properties or relationships
wait my drawing is not much better than it was before
i dont have my compass which is why LOL
I am not good enough for English
Use something round
A cup or sth
I think you can uh use Menelaus or Ceva's Theorem for this
also ABDE and ABCF is a cyclic qudrilateral no?
menelaus is for collinearity and i dont see ceva here
-# kiểu đi tìm góc bằng cách dùng các tính chất bằng nhau của các góc, không dùng tỉ lệ hay j khác
Oge
I was thinking of like the sine version of it
i tried but its hard to trace it out such that abde and acdf are concyclic*
You can use Ceva here using Sine tho
In any triangle $\triangle ABC$, three lines $AD$, $BP$ and $CQ$, are concurrent if and only if $$\frac{\sin(\angle BAD)}{\sin(\angle CAD)} \cdot \frac{\sin(\angle ACQ)}{\sin(\angle BCQ)} \cdot \frac{\sin(\angle CBP)}{\sin(\angle ABP)} = 1$$
MxRgD
Also note that ABDE is cyclic
yes ABDE and ACDF are cyclic quadrilaterals, ∠CDE = ∠BAC = ∠BDF and reflecting it about BC, this is also = ∠BDP
yep but where does this come into play here
Can you do reflection A' here
wdym
like the reflection of A across BC
mhm
oh wait
BDF and CDE are equal so DE and DF are images of each other about σ
i think i know how to do this now this is desargues
sorry!
.close
Closed by @meager trench
Use .reopen if this was a mistake.
No need to sorry btw, good luck!
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.
<@&268886789983436800>
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.
!listpings
What
,help
A brief description and guide on how to use me was sent to your DMs!
Please use ,list to see a list of all my commands, and ,help cmd to get detailed help on a command!
Get your DMs
Yo I got to much trouble in learning those algebraic identities pls help
Ok
$(a + b)^2 = a^2 + 2ab + b^2$
1 divided by 0 equals Infinity
Like this one yeah?
Yea man
Yes😭
What about it
You know why this works?
I can't learn it
1 divided by 0 equals Infinity
Now try to expand this
So it might help to use it with numbers instead of letters first. Like uh (5+2)(5+2) = 7 × 7 = 49. But also theres 5(5+2) + 2(5+2) = 5×5 + 5×2 + 2×5 + 2×2 = 5² + 2(2×5) + 2²
Hopefully that helps
@full pelican Has your question been resolved?
Closed by @full pelican
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.
need help finding t value

humor me and try 1.693
I'm thinking that they used 2.4 as the mean instead of 2.38
even though you really shouldn't
yeah igot 1.693 too
oh actually, that would make sense lol
yeah sometimes people aren't the brightest with rounding
I can't check anymore but I'll just go with it
rip
Closed by @thin halo
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
as always, please state what you have tried and what you do not get.
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
1
in fact, state what you do not get from the start next time, please. so that helpers can directly read your questions from the get go.
State MVT
Is this original question, no crop?
this is unreadable for dark mode
yes no crop
I can read this
i swear I've seen this q like weeks ago 😭
Let's construct a function
haha
Since x here changes and the exponent doesn't change
What could be the function structure?
x^2/3
wheres f?
the function you just found
2/3x^-1/3
no
I MEAN
1/x^1/3
ye
im not sure
Of what?
finding the domain
...
@steel night
This doesn't make sense
so the domain of the original function, not the derivative
Wait, are you writing these things down on a piece of paper or tablet? Or are you just writing messages here without taking notes? @steel night
Blud always ask many questions and seems to not understand any, even though these questions are the same 🥀
im writig on the board
yeah Im not sure what the domain is
Well you are given two value of x in the function f you found
👀
And by MVT there is a point?
i see
This is MVT. Do you agree? @steel night
i dont understand the first line of the OP
Do you see those a and b?
yes
Can you tell what their values are for the exercise you're working on?
You are the OP
original post
first derivative value between a and b?
Ye
I dont understand the 2nd case
<@&286206848099549185>
what does the MVT state?
f(b) - f(a) = f'(c)(b-a) is a direct consequence of the above if you multiply both sides by b-a, is that what you mean?
there exists a point c on the open interval a,b such that (f'(c) = f(b) - f(a))/(b-a)
a,b such that (f'(c) = f(b) - f(a))/(b-a)
what about in in words?
you have an interval a to b yes
there exists a number between a and b such that it fulfils the condition (f(b) - f(a))/(b-a)
essentially, (f(b) - f(a))/(b-a) is the slope of the straight line connecting the points (a, f(a)) and (b, f(b)) (just like y2 - y1 all over x2 - x1)
we call this straight line the secant line
there is a point on the graph between a and b such that the derivative (the tangent line to that point) has the same gradient as that secant line
Thats the conditions
visually, it is something like this
Lagrange's MVT merely states that there exists this point c such that these two lines are parallel
how do we know the interval, if we are not given the interval
Just an extension of Rolle’s Theorem (or, Rolle’s Theorem is a special case of the Mean Value Theorem)
It’s an arbitrary interval (a, b)
You were given
so long as this interval fulfils the conditions of being continuous and differentiable
Ngl i started studying MVT just 1 week ago😂
yup
Exactly! Continuous on closed, differentiable on open
MVT is so fun u get to prove Taylor's theorem (which is arguably the best thing in calc)
YIPPIE!!
I have enough trauma after EVT and IVT 💀
Still havent able to fully understand sequences 😂
Think of sequences as like listing the outputs of a function
Instead of x’s they are indexes, positive integers based on ‘n’
so let me say what MVT is
Maybe i will make a help channel later to ask
MVT states that there is a point c, in a closed interval [a,b], where when differentaiated, it is parallel to the chord AB
The pipeline is just
Fermat's theorem -> Rolle's Theorem -> Lagrange's MVT (Standard MVT) -> Cauchy's MVT -> Taylor's Theorem
yup
anything else I should add to it
specify its continuity
Alright i dont understand fermat
Dont kill me 😂
wait maybe its differences in terminology but isnt it just there exists f'(c) = 0 if there is a local min or max between the interval (a,b) (continuous, differentiable)
L’Hopital’s is somewhere in there
lol
L'Hopital is after Cauchy's MVT
Yeah, Ik.
MVT states that there is a point c, in a closed interval [a,b], where when differentaiated, it is parallel to the chord AB at c
so there is only one point
c
lol this is shoddily drawn but it gets the idea across
nice point
My L'Hôpital is not touched in my course 😂
Look at your DM’s or message requests
L'Hopital stole it from Bernoulli
Oke
Anything else you need clarified?
it doesnt tell u the specific value of c, it just tells you c exists
which is why Fermat, Rolle, Lagrange's MVT and Cauchy's MVT are all theorems that are called Existence theorems, they merely describe the "existence" of something
You can find the c’s algebraically
are u sure?
But the theorem itself doesn’t tell you which ones
yes, you have to solve for c, the MVT did not give you the c
it merely states you could do that
yeah but it was possible to find c because of the formula of MVT
its just only rearranging
Correct
However
sure..? like once again it only tells u that there is some c not the specific value of c
its not a formula for that reason
Just saying you can do smth isn’t the same thing as doing the thing
If I were to tell you it is indeed possible to calculate 2 + 2
thats a good point
Could you calculate 2 + 2?
Of course you could
MVT tells you you can do this, MVT does not tell you how you can do this
But I never told you what 2 + 2 was
I see
Think about it. Did I ever tell you what 2 + 2 is? Or did I just merely state that it could be calculated?
Is this explanation good so far
before I proceed
I don’t get it
specify its continuity
It can be done =/= This is how it can be done
wdym?
the range
in our example
interval range
It's the [a, b]
the graph of [a, b] is continuous
Would you agree that just because I told you that something is possible, doesn’t mean I necessarily told you the outcome of doing that thing?
Answer this @steel night
yes
its 8 and 8.019
yes ik
which needs to be specified
when u said continuous, did u mean values of a, b?
Closed interval
where do u want me to put a to b
uh
^
bro.
are we given f(b) and f(a)
You can calculate them
f(8) & f(8.019)
Where
f(x) = x ²/³
ah
calculate
@steel night Has your question been resolved?
how do we know whats f(a) and f(b) respectively
because the order matters since its subtraction
I dont think we are required to do graph in exams, i mean we can if it helps
just from my professor
it is not required but you need something to visualise
$f(8^{\frac{2}{3}})$
ø
is that valid?
0.019
so f'(c)?
ok done
Correct
so is there something i need to do next
What else
just conclude that c does not lie in a, b
the question wants the range of error right
like the bound
Correct
I dont understand
what am i supposed to do next
<@&286206848099549185>
no sorry i dont know this 🥀
oh rip
gl , try pinging min back
I think hes busy but all good
you calculated the exact error
you were supposed to calculate the upper bound on error
f(b)-f(a) / b-a = f'(c)
where a<c<b
Do you understand that f(b)-f(a) is the error whose upper bound we want to calculate?
@steel night
isnt the upper bound the absolute error? which accounts for the lower bound too
upper bound means max possible absolute error
ohhh
thats the upper bound?
that's the absolute error
f(b)-f(a) is the error
we want to guess max to max how big this error can be
using MVT
no why would we add or subtract the error to function
we would apply MVT on f(x)=x^2/3 with a=8, b=8.019
because it says to calculate upper bound using MVT
I think i did that
my working out is here
you calculated the exact error
you understand this?
Don't think that you were ever mean to evaluate exponents best to keep 2/3, and manipulate to find the upper bounds, we are not interested in point c, whose gradient is the slope from the endpoints rather we find how well does 8^{2/3} approximates 8.019^{2/3}
similarly in the equation you get with MVT, you need to make f(b)-f(a), which is the error, the subject and calculate max[f(b)-f(a)] which is same as saying max[error] to calculate upper bound on error
i dont understand this because its trig combined with bounds and im not good with them 😭
upper bound on error = max[error]
since error = f(8.019)-f(8)
we need to calculate
max[f(8.019)-f(8)]
using MVT
you get it?
yes
In the equation you get with MVT, you need to make f(b)-f(a) the subject and calculate max[f(b)-f(a)].
This is your entire task. Try to work on this.
@steel night is the question on how well does 8^{2/3} approximates 8.019^{2/3}?
hey, sorry even I do not understand, the maximum of a constant is the constant though?
But how does making the subject help with calculating max
You are really close to finishing it, no need to find max
Start from the equation f(b) - f(a) = f'(c) (b-a)
You know that c in (8, 8.019) i.e., 8 < c < 8.019
This is already a big hint
Try taking root 2/3 and manipulating to find the reciprocal! You will get the bound for it
8.019^2/3 - 8^2/3 = error
we are considering error is unknown and with that we are calculating max(error) that's why it's not max(constant)
No, the error is known, here we are assuming that one does not have access to a calculator hence the need to use algebraic tricks and MVT instead of computing the difference of 8^{2/3} and 8.019^{2/3} using your calculator
This is to illstrutate how people before that do not have access to calculator are able to approximate them
this is the question
Yes the bound is your answer to the question
(b-a)?
b = 8.019 and a = 8 in your case
f' means derivative
Ik
Oh I read wrong, how does your course define "error"?
Did they provide a definition for you?
Don’t worry about it
Anyways, error is most commonly defined to be absolute difference, i.e., |f(b) - f(a)|, in your case, 8.019^{2/3} > 8^{2/3} therefore we do not need to use absolute value here, so f(b) - f(a), I arrange it this way instead of saying frac{ f(b) - f(a) }{ b-a } is so that the LHS is talking about the error, and not the slope.
@steel night 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.
When applying the change of variables theorem for integrals, how can I apply it someting like $\int_a^b f(u(x)) dx$? and get some sort of intgeral in terms of $w = u(x)$?
LXDL
For example, to take a simple example, $\int_a^b f(c - 2x) dx = \int_{c - 2a}^{c - 2b} -1 \cdot f(u) du$
where $u(x) = c - 2x$
However when I do $\int_a^b f(c - x^2) dx = \int_{c - a^2}^{c - b^2} \frac{-1}{2x} \cdot f(u) du$
I'm not entirely sure if this is correct
LXDL
the normal change of variables always has $\int_a^b f(u(x)) u'(x) dx = \int_{u(a)}^{u(b)} f(u) du$
LXDL
but more oftne i see smthing like this instead
and I'm not relaly sure what the justification/proof behidn this is (assuming nomral hcange of variables theorem)
Would this proof look okay?
Assuming that $\forall x \in [a, b] u'(x) \neq 0$, then:
$\int_a^b f(u(x)) \frac{u'(x)}{u'(x)} dx = \int_{u(a)}^{u(b)} f(u) \cdot \frac{1}{u'(x)} du$
LXDL
Yes that's the idea.
okay yes, becasue for this step I was pretty unsure if that is the machinery they are using
In a way if you make the substitution $w = u(x)$, you get $\dd{w} = u'(x) \dd{x}$ and in this case it works like a fraction if you will. You get $\dd{x} = \frac{\dd{w}}{u'(x)}$, which you can plug in your integral
Azyrashacorki
hm, is there a reason we can jsut "plug in"?
i guess i was tryign to go for a more formal reasoning
This is the reason
for this example, this seems to be more like $\int_a^b f(c-2x) dx = -\int_a^b - f(c-2x)dx = - \int_{c-2a}^{c-2b} f(u) du$, is htis understanding correct? Since i dont think they need this heavy machinery, i.e. a special case where we are basiclaly multiplying a non zero constant and its recirpocal
LXDL
Yes indeed.
Sometimes you may be able to get something strictly in terms of u in the end.
But this depends on whether you can solve for u in terms of x.
Ah I see that makes alot more sense. Yes I think we can treat/I was sloppy with my notation, but what is happenign is that we define a function $h(w) := \frac{f(w)}{u'(u^{-1}(w))}$. Then we have $\int_a^b f(u(x)) \frac{u'(x)}{u'(x)} dx = \int_a^b h(u(x)) u'(x) = \int_{u(a)}^{u(b)} h(w) dw$.
LXDL
Yep that's it
I see thank you, and usually for like the "constant" pull out trick one, its by lineartiy of the integral? i.e. don't need to very u'(x) =0 since in this case u'(x) = c for some $c \neq 0$ baically
LXDL
@icy wren 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.
find the domain of this function
here's what i did:
i cut out the function from the sqrt and compared it to 0
x^3+x^2 = 0
x^2(x+1) = 0
x = -1
but how do I know which one is correct?
just try a number more than -1 and less than -1
x^3 should never be negative and more than x^2
Closed by @lost lake
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 somebody help me to solve this using pumping lemma? I couldn’t figure out which string should I apply the lemma to.
@deep abyss Has your question been resolved?
ye ig
but a^n b a^(n! + n) b
and contradiction at i = 1 + (n! / y)
We need to find a contradiction somewhere
|y| <= n
Yea that works I guess
But how did you find that
just trying cuz n! is divisible by any number <= n
i thinking bout 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.
Hey what factoring method did I just use? And is there a simpler way of going about it.
that's not a factoring method, you just solved for x
Okay
you can get that form by completing the square of a quadratic btw
yes, if there was something else before this then that would be the case
Yeah but there’s many ways to solve
but if this was given then you can just directly solve for x
And my teacher wants me to use a variety
one of the easiest methods would be completing the square.
or, using the quadratic formula
or factorizing it
its just solving for x.
that’s not a factoring method
Closed by @digital charm
Use .reopen if this was a mistake.
just my side note u should write $|x-2|$
Nyxzore
.reopen
✅ Original question: #help-10 message
are you looking for help factoring it?
$|x-2| = \sqrt{4/3}$ so $x-2 = \pm \sqrt{4/3}$
x-2 is not sqrt(4/3), it's already +/- sqrt(4/3)
Annie Maqionde
its the absolute value
Nyxzore
Abosulte
the fact that u took the square root of a square
the +/- should have been written at this bottom step here
when you take the square root you automatically put the +/- there
Closed by @digital charm
Use .reopen if this was a mistake.
idk why this thread ragebaited me so hard
$\sqrt{4} = 2$, however if we say $x^2 = 4$ then $x = \pm 2$
Krish
idk something about it just ragebaited me can’t put my finger on it though
alr
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.
how do yall do algebraic expressions and factoring polynomials??
any specific problem ?
so that there is a reference point
where’d you get this? the answer should be n>12
that question is either cutting off an answer choice or really poorly put together.
i got this from modules / curriculum online in the philippines
did you crop this image? if so can you show the full page
go ahead
a couple of these are very oddly worded, which ones have you done so far?
none i js started
okay, in all honesty the wording of 1 and 4 are really throwing me off so I won’t be of much use there.
im still struggle with the first one💔
move on to 2 for now
kk
i also need help for measurement too can u also help me with that?
if u dont its fine , but if u do thx
lets move on to two
right now i have to go, if in 15 minutes nobody responds you can ping helpers
@humble hawk Has your question been resolved?
Closed by @humble hawk
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.
Need some help gang, i am trying to find an equation which was algebraic and its graph made a wave like structure … i remember seeing one it had no irrationals or anything complex just a simple function of x and numbers
Nah a single wave
could you draw it out?
A single upward bump
$\frac{1}{1+x^2}$?
Azyrashacorki
That has a bump
would be something along the lines of that
this is $y=\frac{1}{1+(x-2)^2}$
Johannes Kepler
you can do $\frac{1}{1+(x-h)^2}$
Krish
and h will move it left or right
!done
If you are done with this channel, please mark your problem as solved by typing .close
if you don't have any other questions
.close
Closed by @deft heart
Use .reopen if this was a mistake.
Thanks krish and everyone
you're welcome
cat
They did say thanks everyone
lmao
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 they say on a bearing of 310* is this what they mean visually?
Ik how to solve the question, im just trying to understand it
face north
turn 310 degrees clockwise
you are at a bearing of 310 degrees
it was useful when sailing long distances, using the mercator projection
"straight line takes me to where I want to go"
Isn't that what I drew?
Thanks for the clarification, I appreciate your help
.close
Closed by @desert pulsar
Use .reopen if this was a mistake.
.reopen
✅ Original question: #help-10 message
uhh i need help with another question, disregard the original please.
Why is the resultant force drawn in the middle between the vertical and horizontal components?
Here is how i solved the 1st question
You're resolving a vector. Think of it as a result of those two vectors combined.
so when im dealing with questions like these where two forces meet at a right angle the resulting vector will always come out the middle as shown in the diagram?
Yep, when they're perpendicular (at right angle).
you said right angles as in plural, but there is only one right angle here?
Sorry, I think that's a minor error on my side.
like this right?
and the two angles on either side add upto 90?
Yep.
Closed by @desert pulsar
Use .reopen if this was a mistake.
.reopen
✅ Original question: #help-10 message
Hi back again with another question, disregard the original
How does Tx go from the top to the bottom? and something weird I've noticed is cos(60)*25 also gets the correct answer for the horizontal can someone explain why that is to me please?
<@&286206848099549185>
newton laws of motion
lmao
?
wdym top from bottom
its still in top
the force is acting horizontally
but to have better undrstanding and finding the Tx we horziontally move the vector below
to form a triangle
so that we can use trigo and find the required side = force
ahh so the bottom is just something we draw to make calculation and understanding easier?
yea
Ok but why does cos(6)*25 also get the right answer?
Also the second part of your question is simple
cuz cos(90 - theta) = sintheta
try to learn trigonometry i would say , it will help u better understand all these concept
so cos (90 - 30) = sin 30
ohh i didn't know that
i just checked in the calculator and you're right
yeah learn trigonometry it will be helpful,
cuz in these question u would need the help of it
well thats all the questions I have, thank you for your help @bright sedge
I know basic trig and trig graphs but I haven't gone too indepth
just go through basic trigonometric equations and formulae
didn't cover unit circle inverse trig functions yet
Yeah I'll be sure to revise, ty for ur help.
close
.close
Closed by @desert pulsar
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 are we allowed to move the vectors around like this? Is it like algebra where we can manipulate equations as long as the RHS and LHS are equal?
i think its mean N is opposite to that component , also F
so N its opposite to the vertical mg component , and F to the orizzontal mg component
Yeah! Vectors are not constrained to any point in space. They consist of just 2 properties, a magnitude and direction. No matter where the vector is positioned, it is the same vector. Moving the vectors tip to tail is actually the geometric way to sum vectors.
" No matter where the vector is positioned, it is the same vector " could you elaborate a little bit more on this?
hm
Well, in this context, the vectors are all forces
wait no that's a bad example
hm
Take your time explaining lol
You can imagine a vector like an arrow
if you use displacement as an example, if you are dispaced 2m north from like (0, 0) vs 2m north from (30, 0), it's still a displacement of 2 north
So if you are going 2m north and then 3m east
waits for desmos to load
well isn't that the literal definition of a vector? I was taught a vector is anything that can be drawn as an arrow because an arrow has magnitude and direction.
Yeah you got me a little bit lost here
I imagine trying to teach someone else a topic is much more diffucult than trying to learn it yourself.
Which is why I have big respect for all the helpers here, they're incredily helpful lol.
whether it's 2m north from the equator, or 2m north from my house, or 2m north from buckingham palace, it's still 2m north
do you know newton third law?
no matter where the arrow is, it's the same arrow
yeah lol
yeah force has an opposite or equal reaction
also known as the reaction force i think when drawing free body force diagrams
so N its opposite to vertical mg?
ahh i see looking at it that way makes much more sense
yeah
but N is not directly opposite its drawn at an angle in the diagram
vectors being arrows aren't tied to a specific point in space. you can always move around
I mean the vertical component with respect to the reference system
im gonna take a break from studying for now, i'll look back at this after dinner. Thanks for your help guys!
np!
@desert pulsar 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.
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.
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.
A small republic, consisting of six states, has 250 seats in the Congress. Find the apportionment of the republic using Jefferson's method.
How many seats are approportioned for State A B C D E F
I sent it and it says I have 2 wrongs among the 6 states idk which
ok
show your work
and the question
the first image seems to be for a different question (only has 4 states)
from the one you're asking about
you seem to be doing normal rounding rules instead of
what they wanted: Jefferson's method
oh, may I know how should I actually solve it hehe
did you get notes on jefferson's method?
I havent
you could look it up online but,
you should round your results down,
here adding those up will give 246
which is less than the desired 250
so in that case, you can reduce the divisor, 50k by a bit
and repeat until you sum to 250
ah so the overall should add up to 250
@cursive fox 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’ve confused myself on something to do with sketching gradient function 😭
ii
when i differentiate the function i get something different to mark scheme i don’t even know how i can mess that up
what you got?
1/2x 😭
No...



