#help-36
1 messages · Page 267 of 1
The value you get in the red part you wrote isn't defined in the real numbers since you have ln(**-**sqrt(2)/2)
Well cosh is even, so its inverse is only defined on half the domain.
It's kind of like solving $x^2 = c$, you need to take $\pm$ the solution you end up with
Azyrashacorki
so there's only one solution?
No what I mean is that your arccosh (your log formula) only spits out the answer which is >= 0, but there is another answer <= 0
ohhh
So in other words, $arccosh(cosh(x)) = \abs{x}$
Azyrashacorki
So if you solve for $\cosh(x) = c$, then the answer (provided $c \ge 1$) is $x=\pm arccosh(c)$
Azyrashacorki
so u could just simply make the second solution be the negative version of the first solution?
Yes
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during the last two lines can someone explain to me why p and q switched signs?
did the book make a mistake or is there something I'm not seeing?
oh wait im dumb they multiplied everything by -1
yes
mhm
i swear i started at the answer sheet for 5 minutes and couldn't figure it out
as soon as i post it here i figure it out smh 🤦♂️
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Infimum = 1, Supremum = e. Am I missing something?
I just need clarification
the math ping is too big
yes
yes
ok, so my answer is correct right?
wtf happened to the serv icon
lmaooo
no its the icon ig
wrong channel guys
lol
MB
@odd rivet what did I miss?
guys...did the server face change in ur dc too?
like theres a big one written over there?
so do you know what you need to change if you intersect the set with the rational numbers?
y'all talking here like its #general
keep in mind that exp(sqrt(x)) is a continues function
april fools
wait I just realized rational is not same as real number
ow silly me
!redir
This channel is only for on-topic discussion. Please take casual conversation to #discussion or #chill.
im sos orry
rational is the number that can be represented as m/n with m,n being integers right? @odd rivet
yes
(And n is non zero)
yes
What subject does this require to solve this , id like to learn it
9/10, 10/11, 11/12, 12/13, ... 999/1000
math analysis
Real analysis you mean?
no
its like introductory lesson before real
im lost @odd rivet , won't the limit tend to e at x = 1
how ddoes it change anything
I'm not tobi, but yes it should
yea idk if he is complicating things or what, but i gotta listen first
I just want to make sure you understand the question correctly
and there is probably a reason why its intersection with Q and not R
a
I understood no worries
yes to formally understand it you need to think about epsilons
and that Q is dense in R
and that you have a continues function here
yes
notice that it is part a, part b is absolute hell lol
or I just do not have the energy to solve at the moment
I will go sleep
thanks guys
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ofc ik
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Find a number 𝑡 such that
(3, 1, 4), (2, −3, 5), (5, 9, 𝑡)
is not linearly independent in 𝐑3
Okay
make matrix?
no
I can't work with that
I am using LADR
I am unsure on whether the linear dependence lemma works
for this
I am sure it is a nice way to solve it
I just do not know how to solve it
which is ?
I am thinking on rewriting the last vector with the other vectors
I do not know how to solve this
I could not solve this yesterday
I have not taken any computational courses
what does it mean for the three vectors to not be linearly independent
that I can get their sum to be 0 with scalars not all zero
That is not a problem
Then it is linearly dependent
yeah
you would have
aA + bB + cC = 0
so aA + bB = -cC
but they are nonzero scalars so divide by -c
you still get something like
aA + bB = C
I am thinking of making $$\forall a_1, a_2, a_3 \in \mathbb{F},$$ not all zero,
$$a_1(3,1,4) + a_2(2,-3,5) + a_3(5,9,t) = (0,0,0)$$
Hmm why need a3 though
you don't know whether c can be nonzero or not
it's at least one of them nonzero
not necessarily all
guys any one have 6month + weechat account?
also just setting up the system like andre did, it's exactly the same thing as setting up a matrix like you suggested
=(0,0,0) tho
then solve for a1 a2 a3
andre
and hopefully there's a t for which you get solutions other than a1=a2=a3=0
this is what you're looking for
I was stuck at this bit yesterday
my intuition is that I can just get scalars that span the last vector since I can just solve for t at the end
and that is exactly the problem; I don't know how to 
$$
3a_1 + 2a_2 = 5 a_3 \implies a_1 = \frac{2a_2 - 5a_3}{3} $$
andre
Am I in a good path here?
you've never done gaussian elimination then ?
no
if you say you never had a computational class
sadly
you better remedy that then
it's like the algorithm of intro lin alg
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$\oint_L{(xy+x+y)dx + (xy+x-y)dy}$, $L: x^2 + y^2 = 4x$
Bakoles
What's your question?
i need help?
hm
wdym
what is it then
it's parametric
1+1 = 3
polar has rho and phi
<@&268886789983436800> troll
@hallow yarrow please don't use help channels to troll.
not the place for such idle meanderings
yeah this isnt modular arithmetic anyway rn
if you use my sub what is rho at most
2
ye
ok
you can also do default polar sub and get something in terms of cos(theta) but thats not so elegant
So you used the standard sub
no it seems correct
hmm
check your phi
yeah
you forgot the jacobian it seems
phi should be correct
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I would appreciate help on this question! Not the answer, but I don't know how to go about solving it. The first time I answered, I got it wrong. I answered A'=(2,4) B'=(1,1) and C'=(4,2). I kinda was just guessing.
Well do you know the definition of vertices?
like do you need an explanation or just a clear answer?
your answer is dilated with respect to the origin, not with respect to D
you are translating it so that D becomes the origin, scaling, then translating back
what's with the weird pictures 
Where the two points/lines meet?
Yes
Explanation
The answer is doesn't involve D tho
So now try solving
Ill explain in a moment after you attempt it
I'm just not sure how to dialate with D and not the origin. I was taught this at the very beginning of the unit and theres been a lot of stuff so i forgot how to do it lel..
if you move the origin to D, what do the coordinates become?
im still confused 
Yea that lol
You beat me to it
the coordinates of A,B,C
b is 4,4 a is 6,10 c is 10,6?
yeah
Yes
It's tricky to understand the question but its simple in practice
Do a few more and you'll be clearing these questions no problem
soo if i dilate it by 1/2 it would become 2,2 3,5 and 5,3 but those werent in the answer choices iirc
because that's when D is the origin
then you have to rememeber to switch the origin back
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOH wait a minute
You are talking D as the beginning point. You gotta reverse it
Move back to origin after
wouldnt that just give me the same answer
im so lost
i dont think i understand what you guys are saying
uuuuuuuufgjhdsfgjhglirghlkdjcnpojhrf
looked thru our notes and my teacher did not teach this ever lol no ownder idk how to do it
after which step? after i get the 4,4 6,10 10,6 coordinates?
is B (0,0)?
because the coordinates from D are 4,4 but it a dilation of 1/2 and if you count 2,2 from D it lands on 0
or am i completely making that uo
up
<@&286206848099549185>
once you got this,
these coords were with respect to D as origin
well now when switch out origin back, they would change too right?
Right well then you just need to shift them back!!
Oh i see where your confused
You agruement would be that they just come back as when they were not reversed due to D and dilation?
aaargh im just not seeing how my answer is going to change because when i try to do it the way someone tells me i get (2,2) or (4,4) for B
i just dont know what im doing
ive been doing schoolwork for 8 hours lol my brain is fried
Could you maybe explain to me how to get the B' coordinate? like the steps
if thats allowed im not sure if it is
yes this
because if i count to 4,4 for b after i do the dilation it would just be 2,2 again
i feel like im going in circles
Sorry, was lil busy
its alright im just very stuck
One sec am helping somelse really sorry,
you could try another helper in the time being
its okay!! no rush, im the one asking for help after all
i need to do something real quick anyways
Hey sorry about that
b is 4,4 a is 6,10 c is 10,6?
This 👆 was correct!
correct!
No see, thats where your going wrong, you are not dilating the entire coordinate system, only the traingles point ABC
So after this step, all you gotta do is shift the D(new origin) back to the old origin.
So in short, just subtract 2,2 to each point (ABC)
similar method applied as what you did here too!
@hot pawn Has your question been resolved?
need help in math
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Ik what x is
I also know
There’s a correlation between x and y that I’ve forgot
Or y and 65
X is 130
u got x right
How do I get y
u have to use ABCD
ABCD is a cyclic quadrilateral
Idk how to get y
whats the problem translated to english
use properties of this
what is do you know about it s opposite angles
Find x and y
they're supplementary
but what am i supposed to do
how do i translate problem to english
use that
what language u speak
y is 130 as well?
english
no
it looks obtuse but apparently its 50
I thought it was so I checked and it’s not
Swedish
is it 50
Its 115
...
so the ADC is opposite to ABC
is M the center of the circle ?
then 65+y =180
that is a priority of cyklisk fyrhörning
A figure with four corners
Oh I think I’ve heard it before
Just forgot it
What’s the correlation between the opposite corners
Motsatta vinklar i en cyklisk fyrhörning summerar till 180∘.
you are welcome
I remember I’ve heard that I just forgot it
The opposite corners make 180 together so 180- the corner we know which is 65
Anyway thanks again
.close
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So i basically only know that one corner is 90
is that all they tell you on this problem?
as it is, you dont have enough to figure this out
Yep they say deside all the angles
I tried doing this hold on
then you have that, not very useful but it's there
!xy
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.
I thought opposite angles in a figure with four corners make 180*
nope idts thats true for all quardilaterals
what did you apply?
Wdym
well take a trapezium for example
draw line from centre to that other point
isosceles triangles
idts means "i dont think so"
they arent isosceles
but its all same radius
um sry? did i say smth wrong😭
idts
I figured the radius needs to have smt to do with it
replacing idts with I dont think so in your message gives "nope I dont think so thats true for all quadrilaterals" which is the opposite of what you intended
it's what it's
Opposite angles in a cyclic quadrilateral sum to 180 degrees
so this is 135 according to the rule u have it and the right angle ends on the sam point on the circle so $frac{360-90}/{2}$
NoX
Ohh thank you
-# Oh i see, so in mathematical terms i just put two negatives
is M even the centre
It is
thats not correct either
Yes it is
-# okay just leave me alone😭😭😭
Ohh
why is that?
oh you meant those two points
Yeah that seems solved then!!
😟
Kiwi help
Looking at that annotated diagram, can you see how introducing the line MB gives us two isosceles triangles?
you have isosceles triangles now, since the radii of a circle are the same
triangle with 2 lengths that are the same
du har likbenta trianglar nu, eftersom radierna för en cirkel är desamma
Oooooohhhh
OH
YES
I see it now
And how does that help me..
Omg should I give up
it turns out theres nothing immediately interesting happening anywhere else
I am going to say
Can you deduce what the angles around B are?
yall are missing an easy way to find this missing angle
deduce = härleda
just MAB+MCB
Idk tbh
you need to consider the "cyclic" version of this quadrilateral
you mentioned it earlier
if you were to move point M but keep A, B, C fixed, you can prove it that way
Remove M?
i sse your point being, but wouldnt that be more lenghty
oh yes mtt is correct
it is a grand total of 2 steps
i know but circles properties arent that well easy to grasp
-# Kay go ahead then🙏
you first have to use one thats taught as one of the "first" circle properties
Move - not remove
Move the point M onto the circumference (call this point M'), and keep A, B and C where they are
then after that, use that cyclic thing youve heard about to turn this angle M to angle B
Where am i moving it
What could you say about angle AM'C (compared to angle AMC)?
oh right, "circumference" = "edge of the circle"
"omkrets"
Ohhhhh
wait yall are talking about ||inscribed angle thm|| right
lower-left works
So if I move it
Who needs help
yeah ||1/2*270 for ABC||
oh I wonder given the channel name, truly a difficult question /s

Where I put the arrow?
@sour fiber how can I help
well it technically can be any one point on the circle
(meaning I need to draw in AM' and CM')
but yeah, what you drew works
yes
no, it has to be on major arc AC
What happens if u move it thre
oh yeah 💀 any point that forms a cyclic quad with vertices MABC
if you name it clockwise
can you find a way to now relate the original AMC and the new AMC?
(unless you just google translated the word in which case nvm)
Maybe that the opposite angles Make 180
dammit
@whole halo while your method is right i don't know why reject my method and they both gives the samethink + mine is faster
Incidentally - @sour fiber we're referring to this, if that jogs your memory:
-# congratz on 🟨
hmm, another property? have you heard about inscribed angle theorem before?
Ohhh but I don’t see one of those in this
sorry, I cant understand a word you said when you wrote down "(360 - 90)/2" which also isnt exactly correct either
im pretty sure helping in channels decreases your virtue 💀 i got yellow from sending a message here, hahha
We've built one - look at angle AMC and AM'C (where M' is that new point we've been making)
M' is the new M
Does that jus make a longer square
i think they mean major arc AC becomes 360-AMC because B is on minor arc AC
We have two m
the reflex angle at M angle, at the center should be 360-90 then it is the same from here just devide by two same, same but different
And the extra point we've made, which (at least I am, but) we're calling M**'**
Other way around
45
yea thats better explanation
Mb
ye
thats actually really good, thats one step instead of two
we can show that one later on after this one
Now look at the quadrilateral M'ABC
Yes
All points lie on a circle, so what have we got here?
For which angle, to check?
B
Yeeee
very nice
Yayyyy
now so far we've done it with 180 - 90/2
Now we have all four angles of our original quadrilateral MABC - now time for the algebra
Yes
oh right
This should hopefully be the smooth-sailing part
,rccw
Throw that in there pretend it’s there
You can check your answer by solving for x
...?
My fave thing to do on here is to click on people profiles and listen to the songs they listen to, Like Ve's
Solving for x IS what the question's asking for
Ohh I didn't read the question i assumed that's the answer
good job
YAY
So u don't need help anymore?
congrats! c:
TYYY
Nop
Wait
Check ur dms
Wdym
I haven’t done the like corners yet I only jus got x lemme check if it’s correct
It’s right
Dw
I checked answer
@sour fiber i sent u a dm, check, really important
Thanks moey but I’m good
oh wait, yh, you did say you were missing the 90 in the thing
Thanks for the concern though
nvm, you're good 
NP
ok if u dont need anymore help imma go
have a good day and dont forget to do .close when youre done
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Hi, how do you simplify -i over 2i?
You're probably expecting this, but i/i = 1
I got it wrong chat
I actually liked the suggestion that was deleted. Multiplying by i/i is an interesting thing you can do here
Note I am not answering your original question here, but a related idea
Wait was I supposed to put in 1? 😭
oh I thought it was silly haha
Okay guys, how do ya simplify 5i/-4i?
Ohh okay, thanks
How do ya simplify 4/3i? There's no other i
what is 1/i
how can u simplify that
ooh multiply by i/i
just i?
Careful
If you're multiplying top and bottom by i, the top becomes i, sure - but what does the bottom become?
-# Use \ to escape Discord formatting an initial - as a bullet point, if that ends up happening
Wouldn't the top be 4i?
@rain agate I believe we were first addressing this
-# We need to make sure this is down correctly before tackling the 4/3i one
So, as in, if we want to realise 1/i, we can multiply top and bottom by i
(cf. rationalising fractions with surds in the denominator)
What are surds?
hoo boy
https://www.bbc.co.uk/bitesize/guides/zg6vcj6/revision/1 (I'm hoping this can be accessed)
But you typically should have come across these before dealing with complex numbers, fwiw
My teacher never taught me abt surds
@rain agate Has your question been resolved?
.close
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int of ln(4-x^2) dx from 0 to 1
Can you factor 4-x^2
Yes I can
What have you really tried
Sometimes it’s good to just try the obvious thing and see where that leads you
after doing this try thinking about what log property you can use
what is ln(0), beautifulsoap?
Do that and then this
yes with parentheses please
i started by going directly into ibp
is that wrong
-inf
I prefer the word counterproductive rather
ok
@chrome ermine Has your question been resolved?
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Ummm hlo
!da2a, please. just send your question!
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
@clever carbon do !close here
!close
.close, not !close.
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im used to ! lol
Ok yo so if I want to create a grafh lets say like a infinity symbol can I create it on my own?
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I'm trying to solve for ∠B. This is what I have gotten so far?
oh and ∠DEA is 100°
BDA is 130 btw
whoops, thank you for catching that
ah this is a sine rule problem i think
Where AE/sin50 = DE/sin30?
AD/sin(100deg) = AE/sin(50deg)
Thank you!
if we are never given the length of the lines it's impossible to solve it
yes
because ABD and BAD can be anything
ANYTHING
and the 130 degrees will stay the same
Are you sure?
Okay so ∠CEA = 80° and ∠ECA = 80°, so it's an isosceles triangle where AE = AC
∠DAC = 50° and ∠CDA = 50° so it's also an isosceles triangle where AC = DC
So AE = AC = DC
ok you extend the length of BD, will it affect the 130 degrees on BDA?
the answer is no
so confident yet so incorrect
-# Did you just contradict yourself?
BD = CE and DC = DE + CE
@still cradle Has your question been resolved?
Okay DC = DE + CE
And if we substitute CE for BD we get CD = BD + DE = BE
And AE = CD and CD = BE which means AE = BE
And that must mean ABE is an isosceles triangle
So ∠ABE and ∠BAE are equal
SO 180 = 130 + 2B - 30
isnt AC = CD
yup thats correct
oh nvm
now u only need angle AEB
which is 100deg
and since ABE is isosceles, the answer is just 40deg
2B = 80 which means B is 40 degrees
YIPPIEEE
YAYYYY
no need you did most of it on your own!
you helped guide me and motivated me 🙏🏽
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,tex So for Fourier analysis, there are two transforms you consider. The Fourier Transform and the Inverse Fourier Transform:
\e{align}{
x(t) &= \int_{-\infty}^\infty X(f)e^{j2\pi ft}\dd t \
X(f) &= \int_{-\infty}^\infty x(t) e^{-j2\pi ft } \dd t
}
I have an understanding of (1) in the sense of it saying that complex exponential signals can form a basis to describe any (most) functions, but I can't wrap my mind around of (2), especially the negative sign in the power of the exponential. Can we see it as the inner product of two functions
[
(f,g) = \int f(t)\overline{g(t)}\dd t
]
which makes the negative sign appear?
(2) is the inverse of (1)
Your explanation of (1) aligns with mine for the Fourier series but doesn't really describe the Fourier transform.
well the transform is just the continuous version of the series
so as far as intuition goes, it kinda translates
Okay fair!
Is there a similar intuition for (2)? I actually don't know it
for the fourier series you have $\hat f(n) = \int f(x) e^{-nx} dx$ modulo some constants which I dont wanna bother with and then $f(x)=\sum_n \hat f(n) e^{nx}$. so its kinda a continuous version of that I suppose?
Denascite
whoops forgot the i in the exponent. but you get the idea
but of course the inner product is a good observation and the fourier transform should also be viewed as an operator on some L^2 space
@rugged merlin Has your question been resolved?
aight thanks
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\textbf{Exercise 3.} Determine, for each $n \in \mathbb{N}$, the remainder of the division by $50$ of
[
3(-49)^n + 151^{3n+1} + \sum_{k=0}^{n} 2^k (2k)!
]
Renato
what have you tried?
firstly, what do the first two terms become mod 50?
3 and 1
ok nice
then what
compute a couple of terms out and see if you notice a pattern
try for n=0, n=1, etc.
n = 0 is 1
who knows
well 10! = 10*...*5*...*1
ok so n >= 5 is 0
yup
the rest you just compute ig
i don't think there's a trick
the only trick i suggest is doing everything mod 50
dude shit seemed intimidating but it actually wasn't that big of a deal if you notice n >= 5 is 0
that's how they get you
i appreciate the help
ofc 
.solved
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What went wrong? What am I lacking here?
For correction, in last step
3/4(sin10 + sin70 - 1)
@rough nimbus Has your question been resolved?
<@&286206848099549185>
hi
you messed here
,, \sin \theta.\cos (\frac{4\pi}3) = \sin \theta.\cos(\pi + \frac{\pi}3) \
= \sin \theta(-\cos(\frac{\pi}3) )
professor paradox
AH- thanks for the help Prof 😭
itshould be 0 right?
the ans
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Need (b) and (c) checked
Let $x$ be rational. We then have $\frac{1}{q}≥ \frac{\varepsilon}{2}>0 \iff \frac{2}{\varepsilon}≥q>0$. Which is finite. At the same time we have $p≤q$. We thus find $D_{\frac{\varepsilon}{2}}$ is finite
Forgive me if I'm being thick, but what?
FUCK

Wai
Assuming that x=p/q in lowest terms, this is fine. Maybe briefly specify why you don't care about irrationals, but this should be fine.
ik you're probably just sketching things
thanks

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✅ Original question: #help-36 message
oh, that's easy
we make our partition of those points in $D_{\varepsilon/2}$ then the upper sum is less than $\varepsilon/2$
Wai
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It converges pointwise to $0$.
I suspect it's not uniformly convergent on $(0,
Wai
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Not quite sure about it converging pointwise to 0. For fixed x,
\begin{align*}
\lim_{n\rightarrow\infty}\left(\frac{nx}{1+nx^2}\right)&=\lim_{n\rightarrow\infty}\left(\frac{1}{1/nx + x}\right)\
&=\frac{1}{x}
\end{align*}
what
Uniform convergence isn't a property of a function at a point
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hello is anyone here?
yes
hi!
I'm going to ask if I graphed something correctly
what's your question?
!da2a
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
ask right away
woohoo da2aja
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o u h
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Each $f_n$ is continuous at $0$ as by the archemdian property there's $m$ such that $\frac{1}{m}< \frac{1}{n}$ giving us an interval in which the function can be brought arbitraily close to $0$.
Wai
sure
what about the rest
It doesn't converge uniformly
for fixed $n$ you can only get at most $\frac{1}{n}$ close
Wai
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<@&268886789983436800>
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\begin{enumerate}
\item Define $f_n=x^n$ where $x \in [0,1]$ , each $f_n$ is unioformly continuous, but $f$ is not continuous , let alone uniformly.
\item Define $f_n(x)=x ; x \in [0,n]$ , $0$ eveywhere else.
\item Define $f_n(x) = \frac{1}{x} \forall x \in [0,n]$ and $0$ elsewhere
\end{enumerate}
Wai
for (d) I can think of quite a few examples
but (e) seems to be tricky
hmm, I;ll basically want the discontinuities to cluser around every irrational
but that won't work
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really silly, but could someone pleas explain this simplification?
from the sum to the next line
wai
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What does it mean to write ds/dt?
Which would be v(t)
Derivative of s with respect to t, aka instantaneous rate of change of s with respect to t
Why does it mean how fast s changes?
Yes
Why?
Question: have you taken a physics class
Or any class dealing with kinematics or mechanics
Isn't the derivative the value to which the limit tends?
Yes
It is defined as a particular limit
So yeah, if you have, then you probably know the formula for average speed
Okay
I don't understand why it represents how much s changes
But a natural question is: how can we find the instantaneous speed. That is, the speed you’re traveling at an instant
Time cannot be 0 otherwise there is no speed
So they find the values in that very small interval ∆t
Yes
The value from right and left must be equal to exist
Since the intervals are very small, ds/dt comes out
CST (reply ping for help)
yes but this thing tells me the value I'm getting close to, it doesn't tell me how quickly it changes
What do you mean how quickly it changes
What’s it
Because if “it” is the position, then recall that the derivative is the instantaneous rate of change because it’s what the average rate of change approaches as the time difference approaches 0
<@&268886789983436800>
<@&268886789983436800>
…anyway…
Perhaps a practical example would be clearer
CST (reply ping for help)
Find the average speed between t=1 and t=2
(16-9)/(2-1)= 7
496?
Too big
6.01
∆t->0
Yes, and…
Yes
The derivative is the instantaneous rate of change specifically because it is the limit of the average rate of change
Graphically the rate of change can be represented as the slope of a line, and as the difference goes to 0, the line becomes more and more tangent to the graph
And so the slope of the tangent line is the instantaneous rate of change
So in our case v(t)=2t+4
Ye
So the tangent line to s(t) at the point t=1 has a slope of 6?
Yep
in the realm of kinematics, average velocity is the average rate of change of position with respect to time, hence instantaneous velocity is the instantaneous rate of change of position with respect to time, i.e. derivative of s with respect to time
(Speed is strictly nonnegative which is why velocity is the preferred term, since v(t) can be negative)
Instead at t=1.01 v=6.02
So the speed is increasing
And what can be said about s(t) instead?
From t=1 to t=1.01?
You can’t say the speed is increasing using the velocity function
Because we’re measuring the rate of change of position, not of speed
Since v is increasing there is an acceleration
Mmm yes but acceleration is a different function
I don't understand what v(t) tells me about s(t)
I can only say that if v(t) is >0 on an interval then s(t) is increasing on that interval
I understand
Thanks !!!
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Guys why cant i use area = base * height in this letter c?
This triangle does have the right ratios to represent cos(theta), but it's not the triangle with the height as its other leg
You need the green height here.
And in particular, you don't know the length of the leg at the bottom.. it's not 2, and the hypotenuse is not sqrt(62) as it's the length of BA.
BA is not the hypotenuse?
BA is the hypotenuse. What I'm saying is that its length isn't sqrt(62)
Why is it not the length?
3
Right, so it's not sqrt(62)
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part (b)
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ive seen that 1/89 equals the fibbonacci sequence shifted by 10 at each decimal place
i understand how it works fundamentally, but im not good enough at math to be able to reach the "compact" form
i also really want to know if there is any cool 1/x form for the fibonacchi shifted by 100 or 1000, (mostly because there are only 7 digits who are smaller than 10 in the sequence, then it gets all messed up)
(i added a cool explanation i found on reddit :p)
i also found another video explaining this, it mostly gets to the first step and then sets S to 1/10 (for some reason i dont understand)
where does this 1/10 come from???
so if i understand what you are asking correctly, you want to 1- understand how the image gets to 1/89 2- the version of the solution with 2-digit and 3-digit shifts?
yep!!!
hmm ok
my main issue rn is with the infinite sum
how do you get things in and out of it?!?!?
isnt it supposed to be infinite 😭
can you elaborate what you mean by highlighting it in your image?
okey
ill try
i dont understand why and how the guy added 2 extra terms on the infinite sum and what are the Sses doing
i also dont understand most of the forth and fifth line 😭
i can kind of imagine the Sses are cancelling out with the extra terms, but, how do you even come up with them???
ok so like
for a sum $S= \sum_{n=0}^\infty a_n$, we can do the following generally:
[
c\2S=\sum_{n=0}^\infty c\2a_n
]
can you accept this?
