#help-39
1 messages · Page 88 of 1
Like, pick a random element of my set. The probability that that element exists
okey dokey
(I'm sorry but we may go back over some stuff that was said earlier but we shall see how this goes):
(I'm just working through some examples and ideas)
So in your set you can have some things that may not exist. Gotcha
Maybe this is a good way to explore it. I'm trying to understand the inference from the bottom up. So if we work with the assumption that there are more actually existing things than merely possibly existing things, and assume all outcomes are equally probable, then we're able to derive that the probability of actually existing is less than the probability of not existing. I've got some confusion on how that derivation goes. How would you write out the derivation?
surely its nonsensical to say that there are more things existing that possibly existing things. When you say that you are saying that your sample is larger than your set which doesn't make sense.
Sample is larger than your set? How do you mean
You said "if we work with the assumption that there are more actually existing things than possibly existing things.
ahh ok. So in this case are sample space is infinite?
(I've gone to make a drink but I'll be back haha. I want to answer this question now as well)
Maybe. It might be infinite or finite. Not sure. Sounds like a philosophical question.
true. Because my reasoning was going to be that if the sample space is infinite then the probabilities become negligible:
So I would say we have to assume that are sample size is finite
Yeah this makes sense. So lets proceed assuming te sample size is finite.
whooooah. This doesn't check with agreeing with what I said above when quoting you.
Unicorns have a possibiltity of existing but don't. Here, our set is all possible existing things and we are taking samples of what does exist
Here we are saying that there are more things than could possibly exist
there is quite a difference, do you see?
I don't quite see the difference.
that's fine, I'll try a different way of explaining
I think we can work with this interpretation & everything should go fine.
oki. So, our set is all possibly existing things and x is an item in this set. so why does this not work
I guess it's a meta-question. Like why are we setting the sample space as equal to the # of possible existing stuff, and not setting the sample space as equal to the # of possible existing stuff, and the # of psosible not existing stuff. Or another way to put it what are some problems with setting the sample space like the latter. Is it extremely weird to do or unconventional? Is there a reason for selecting the sample space like that? Is it the most representative, or something?
Like what would be wrong with doing this:
P(x exists) = # of total existing stuff / # of total possible not existing stuff.
Or: P(x doesn't exist) = # of total not existing stuff / # of total possible not existing stuff.
ooo o o o o . We set the sample space as the number of possible exiting things to avoid the infinity issues above. If we make our sample space the sum of possible existing things and the sum of possible non-existing things surley our sample space is infinitley large (jesus this is philosophical). If our sample space is infinite then all probabilities are 0 (or more specifically p(x) = 0 ).
Yeah I gather that. I guess I'm just saying, there are different sample spaces we can choose for p(x exists) that will yield different probabilities for p(x exists). So I'm just trying to figure out why we select one sample space rather than the other. Is it something to do with representative-ness of the sample space, or something? Just guessing here
ok so, (using your useful assumption of equal outcomes) the first one works. It makes logical sense that the probability that something exists is the ratio of existing things and total possible non-existing things. Now I need to wrap my head around what the 2nd one is saying
This one doesn't make sense? Or: P(x doesn't exist) = # of total not existing stuff / # of total possible not existing stuff.
I see your stuckness, I think I am on the same page as you know
Oh dope. Lol. But also not dope cos now we gotta brainstorm.
In this context this does make sense HOWEVER in practice I think there are some issues
lets take both these statements and say they are both talking about the same data set
and I am some abosulute mad man and have counted everything in the universe
with the second statement, we cannot count the total of non-existing things as we don't really know (assuming finite size) number of things that could be made
ahhhh nnopangnaposagihjol
now I'm going in circles
Yeah I'm not totally following you here
I want to say that this statement is identical to the previous statement
IF P(x exists) = # of total existing stuff / # of total possible not existing stuff.
then P(x doesn't exist) = # of total not existing stuff / # of total possible not existing stuff.
that is just a fact
Yeah I agree.
Does it also follow here?
IF P(x exists) = # of total existing stuff / # of total possible not existing stuff.
then P(x exists) = # of total existing stuff / # of total possible existing stuff.
@void sandal
this is slighlty different
Here, our numerator is changing. What we want to find / know the probability of is changing and that relationship works
Here, HOW we are finding the probability is changing and these 2 statements are not the same
I see
Right the denomintor is changing in the second, numerator changes in the first.
So now I'm trying to figure out which expression makes more sense:
P(x exists) = # of total existing stuff / # of total possible existing stuff
P(x exists) = # of total existing stuff / # of total possible not existing stuff
So you need to redirect your question to be what is your sample space?
I would argue in this case your actual sample space is T
Okay. So the actual equality should be:
P(x exists) = # of total existing stuff / # of total possible existing & not existing stuff?
Not quite with that wording. P(x exists) = # total existing stuff/ # total existing stuff + total non-existing stuff
of total possible existing stuff IS total existing+ total non-existing
Wow
Formatting
BIG STATEMENT
OHHH
Wait is that true?
Total possible existing stuff = total existing + total not existing?
I would say so yes
How are you reasoning to that
Unfortunately intuition ATM but I'll try it with some actually reasoning. In this case our sample space is everything, all objects. An object can either exist or not. There is no probability in an objects existence at a given moment. Since an object can either exist or not it must fall into either of those categories and so all objects is the sum of those categories
Yeah I agree with that.
All objects is the sum of the total existing & total not existing. But how are you getting to the further step of saying total possible existing stuff = all objects?
Total not existing might include an object that's impossible to exist
Right?
At that point it is a philosophical question
But I could say that if you take this to be true then surely we have infinite objects
Looks like it. Is there a way to get to Total possible existing stuff = total existing + total not existing avoiding any philosophical question.
^. And this would break our assumption that the set is finite
But bare in mind, just because the Probability of something is 0 doesn't mean is can't happen.
(if we accept infinity)
Yeah. Should keep that in mind
So the assumption is really quite important for it to all work. If we don't allow the assumption then we get the problems
I need to go to sleep but I've read this again:
Basically summarising: the "of Possibly existing stuff" gives the whole set T (sum of non existing and existing). The bottom equation saying "of possible stuff" is more ambiguous about it's set and says that we must consider things that are possible but can't exist which I would argue is contradictory to the definition of possible
I agree it's contradictory to the definition of possible. I don't exactly know if T is equal to possibly existing stuff. I'd have to think about that more.
@shadow monolith Has your question been resolved?
@shadow monolith Has your question been resolved?
@shadow monolith Has your question been resolved?
My question is:
Given all outcomes are equally probable,
I'm trying to figure out why this equality is correct:
Pr(x exists) = # of actually existing stuff / # of possibly existing stuff
Rather than this other equality:
Pr(x exists) = # of actually existing stuff / # of possibly not existing stuff
In other words: Which is the correct sample space to use for this calculation?
I.... don't get the question. Is this your own hypothetical question?
What are the 'outcomes that are equally probable'?
Yes it's my own hypothetical question. Maybe 'outcomes that are equally probable' is improper language.
Really what I'm trying to do is figure out how this inference works, under the stated assumption. How would you guess this inference formally follows?
I think they are saying that if you think of some random thing, for example an animal with a crocodile's head and a cow's body, and assuming you are sufficiently imaginative, it would be more likely that you think of something which doesn't exist.
Not sure I follow. How'd you write that out in a more formal way if you had to?
I'm not sure I can, sorry...
I thought I answered this question a few days ago
It's a distinct deeper question #help-46 message
This really isn't formalizable
As for your original question I don't think there's a difference really between "possibly existing" and "possible"
I'm thinking about it like "possible" includes "possibly existing" & "possibly not existing". To make my question concise: How are we deriving this equation?
p(x exists) = # of existing stuff / # of possibly existing stuff
OP seems to assume this equality & I don't understand how we're getting to this equality.
What's something in the set "possibly not existing" but not "possibly existing"
Married bachelors.
Really it's whichever one you want it to be
As far as which set is the universal one
Whether you want to allow logically impossible things or not
Don't the two ratios yield different probabilities?
One could argue they both yield 0
Oh cos the denominator's infinity. I guess.
Is it more proper to have the universal set be the union of possible existing things, and possible not existing things?
Depends on what your goal is ig
If it's to make statements about the probability of a "possibly existing" thing actually existing then no
In this context, maybe a thing is an arbitrary combination of descriptors/properties?
Sure.
Then as defined yes
Ah, I see. So if we're interested in the probability of something existing conditional on it possibly existing, then we'd wanna find the ratio of actually existing things to possibly existing things.
But if we're interested in just finding the probability of something existing, then we'd wanna find the ratio of actually existing things to the total number of possible worlds (which includes possibly existing things & possibly not existing things)?
Yeah
Dope. Last question. So to get the equality:
Pr(x exists | x possibly exists) = # of existing stuff / # of possibly existing stuff
Do we need to assume all outcomes are equally likely?
So "all outcomes are equally likely" would be like all the possibly existing entities have equally likelihood of occuring?
yeah
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whats happening here
they're basically doin the same thing again tbh
the goal of all the subsitution technique qs is to substitute the appropriate thing, and find a derivative which is basically rearranged and is in the question
so that you work it easily
this one looks sm harder
yeah true
they just took the bigger one and substituted it
and found its derivative
why do u need to find its deriv
then made the du / 2 look in such a way that they can rearrange it to replace (x+2) dx
but i thought that came from the big one
they find the derivative so that they have a 'du' in the equation to integrate bc we substituted the big one to 'u'
yeah it did, it just became smaller when they found its derivative, and then they rearranged
yes
how?
will you expand the whole function and integrate all of them or use a substitution that converts the integral into minimal form and lets u integrate quickly
i'd choose the latter
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.close
So you have a weight call it w and its remainder is 2 when divided by 5, so you can write w=5x+2, similarly w = 7x+5
this would give a negative weight which is impossible
this is a chinese remainder theorem problem, do you know how to apply it?
the x's are not the same that was my bad, use thee fact they are both equal to W so you have sosmthing of the form 5a + 2 = 7b +5
then rearranging youll get 5a - 7b = 3
yes crt is nothing but a linear combination of congruences
which is what we are constructing from the infomation given
our linear combination is now 5a - 7b = 3
we just need to solve for a and b simultaneously
and since we are living in modulus land we know we are specifically interested in integers, so my wisdom to you is to focus on a and plug and chug until an interger for a yields an integer for b when solving
these numbers are nice enough where you can do that
yeah its following the crt formally using the derived equations, crt can be applied to as many congruences as you want, in this case it is just 2 congruences
yeah
im gonna use = as congruent btw
if you have p = ai mod ni which is just i number of congruences youll want to follow these steps
also as a prereq you should know how to find multiplicative inverses
but anywaay given p = ai mod ni, youll first wnt to calculate the product of all of your moduli which is N = n1 * n2 * ...
next youll need to find Ni = N/n1 so baasically N1 = N/n1, N2 = N/n2, ...
this is where youll find the multiplicative inverses
call it yi = (Ni)^-1 mod(ni)
where each yi is the multiplicative inverse of each N/ni = Ni
its handy to make a table to organize all of these values
but then our solution p from earlier is just a linear combination of
p = (b1N1y1 + b2N2y2 + ...) mod N
where b is the remaainder from the original congruences, that will be given from the problem, and then you calculate each Ni as N/ni and lastly yi is the multiplicative inverse of each Ni mod ni
so b wil, be given thats a W, Ni is easy to calculate its just a product of each modulus, the only problem child is finding each multiplicative inverse
yes, try it yourself and we can compare answers, like most things with number theory its all just an algorithm
start with w = 2 mod 5 and w = 5 mod 7
yeah the multipllicative inverse is just an application of the euclidean algorithm, it is called the extended euclidean algorithm
yeah so lets do the example y1 = N1 mod n1 which is y1 = 7^-1 mod 5
are you following that?
yeah so basically what we are trying to do is solve 7x = 1 mod 5
we want to find an x such that when 7 is multiplied by x and divided by 5 the remainder is 1
well lets start with yi = (7)^-1 mod 5, if we multiply both sides by 7 we get 7yi = (7)^-1 * 7 mod 5 = (1/7)*7 mod 5 = 1 mod 5
so 7yi = 1 mod 5
yeah from what i said ealier to this example x = yi
just a palce holder for a variable
so we now want to solve 7yi = 1 mod 5, we can use the definition of mod to reqrite this as 7yi = 1 + 5k
now, what i did in undergrad was i would rewrite this as yi = 1+5k/7 and i would just plug in integers starting from 0 for k and see which k value gave me an integer solution for yi
so start at k=0, k=1, ...
you hsould find at k = 4 you get yi = 3
thus the multiplicative inverse is 3
so what we saaid earlier when we multiply 7 by 3 and divide by 5 our remainder should be 1
and 7*3 = 21/5 yields a remainder of 1
so we are good to go
oh you bet
so now youre solving 5x = 1 mod 7
sounds like a plan
yes but in this case i =2 since this is the second congruence
then multiply both sides by 5
so we haave 5y2 = 1 mod 7
i keep using x as a force of habit hahah myb if its confusing you
i got y2 = 3
k = 0 y2 = 1/5, k = 1 y2 = 8/5, k=2 y2 = 3
cause 5*3 = 15/7 yields remainder 1
so now we have b1 = 2, b2 = 5, y1 =3, y2 = 3, N1 = 7, N2 = 5
we are now ready to construct our answer in the form
w = n1y1N1 + n2y2N2 mod N
the original remainders from the problem statement
2mod5 and 5mod7
its the 2 and 5 respectively
yes sir
w = 117 mod 35 but we can simplify this down to w = 12 mod 35
well letss focus on 12
lets take 12 for w and see if it satisfiess our two other congruences
12 = 2 mod 5, 12 = 5 mod 7
12/5 yields remainder of 2, 12/7 yields remainder of 5
well we have 117 mod 35
117 mod 35 = 117 - 35 mod 35 = 117 -35 -35 mod 35 = 117 - 35 -35 -35 mod 35 = 12 mod 35
just reducing
yes
so 12kg is our answer
and we checked it by plugging it back in to the other equaations
but you asked for the answer of the form nk+a so it woukd be
w = 12 mod 35 => w = 35k + 12
but the questsion is asking for the weight in kg and it would be 12kg
yeah unfortunately so
its the same type of problem
like the exact saame aapplication of the theorem
yeah he is applying other theorems from number theory
sure
im not sure where youre starting at in this problem
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for this question
the solution says this:
but for delx/del t
shouldnt it be this:
af'(u) - ag'(v)?
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Im doing critical points and i dont understand where in what order should i detect those p1 p2 p3 p4
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i found delz/del r which is:
Z_xcos(theta) + Z_y sin(theta)
now i have to differentiate this again
saul
but I dont get how to do it
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I need help
!15m
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what don't you understand specifically that is stopping you from trying something?
Everything
do you understand how multiplication and substitution works?
Nope
If I told you to evaluate $x+y$ when $x=1$ and $y=2$, then you start with the expression $x+y$, and you replace $x$ with 1 and $y$ with 2. So you just need to evaluate $1+2$, which 3, and that would be your answer.
SWR
That is the concept of substitution
I was just giving you an example
where are you seeing this?
negative
Here
Oh you mean $3x^2$ when $x=-5$?
SWR
Say you had $2x$ when $x=-1$, then you just do $2\times -1=-2$
SWR
2x means you are multiplying 2 and x
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and in your $3x^2$ problem, you are multiplying $3$ and $x^2$
SWR
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A chocolate is wrapped in a box shaped like a triangular right prism. The end surfaces are equilateral triangles with sides of 50 mm. The box is 300mm long. How much chocolate is there room for?
<@&286206848099549185>
!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
3😔 🙏
Lemme see what you've tried!
first i used pytagaros to find the height and got 43 and than i took 4 x 50=2150 2150 x 43
V= A x H
g x h/2
It's an equilateral triangle
ye
Try again
🤔
[ \text{Area} = \frac{\sqrt{3}}{4} \times s^2 ]
Gaza
Where s=50mm
we have not learnt that formula
this is the conclusion in the book
but i dont understand how they got that
but why do they use the lenght as the height
$\frac{1}{2} \times \text{base} \times \text{height}$
It's this formula then
Gaza
It's equilateral
This is the base area
but they said that 300 was the lenght not the height
The height it's equal to the length of the box
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find k so that the function is continuous on any interval
i dont know where to start
Try to imagine what this would look like on a graph
Horizontal line? Not really.
what is the critical value of x in the interval where it might not be continuous
-3?
-3 is not even in that interval
you know for sure x+3 and kx are continuous functions, if you look at them separately, but if you define a piecewise function, then the only x value that is critical is the one, where you change functions
so at what x are you switching the from kx to x+3
1
4
𝔸dωn𝓲²s
i do
it's a trivial limit
My bad
and i am trying to show the concept on how to approach these piecewise function tasks
4?
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can someone help me setup the integral
I think i have the first two bounds
z goes from 0 to r
r goes from 0 to sqrt(2)
but not sure how to bound theta? My first thought was from 0 to pi/2 but i feel like thats wrong
@torpid nova Has your question been resolved?
it helps to consider what the graphs y = sqrt(2 - x^2) and y = |x| look like
(also x^2 + y^2 = r^2 not r)
semi circle and like a v shape
intersecting at x = -1, 1
with the inside of the v and circle being what we're integrating in the original integral
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x^2 - 12x + ? = (x - ?)(x-?)
how do i find out what the question marks are
Factorise the left hand side
how
are the question marks all intended to be the same thing?
no
well im not completely sure abt this
bc i did anotehr one and it was two different numbers
center term?
you can complete the square
12?
yes this is what i'm talking about
(on second thought, even if this was true then it wouldnt work either)
(x-6)(x-6)
ohh
im not working on that question anymore but can you tell me if (x-3)(x-4) is the same as (x-4)(x-3)?
is 2*1 the same as 1*2
@lyric helm Has your question been resolved?
yes
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Chapter of "Espece Vectorial", Couldn't understand How he could reach this result:
<@&286206848099549185>
Expand this out and see what it becomes - you should be able to identify the basis elements from there
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i sortve understand it but keep getting them wrong. any help?
what're you getting for each one?
Explain $\lim_{x\to0^+}f(x)=\infty$ to me
SWR
yes i dont understand
But it was your answer. How did you get it?
Oh. So your understanding is that you start at 0, and keep going right (because its 0+), and keep going until the infinite part?
right
Okay. At least now I understand your thought process. So let me correct it for you.
the examples dont make sense
$\lim_{x\to 0^+}f(x)$ is the value that $f(x)$ approaches as $x$ approaches 0, but only from the right side of 0. That is, you would consider what $f(x)$ approaches from the positive $x$ axis.
SWR
so + is the right side and - is left?
yep
ok, so 0+ would be -6 then?
Neither.
$\lim_{x\to0^-}f(x)$ is what $f(x)$ approaches as $x$ approaches zero from the left side. $x$ is going toward zero again, but you're only looking at the left side now, instead of the right.
SWR
expressed at 0? What do you mean?
on the left the only function i see could have the answer -4
nah its like you're going like this
omg
i completely forgot at the one on bottom
lmao
so 0- is also -6, then x 0 is inf?
How're you getting $\lim_{x\to0}=\infty$? What's your thought process?
SWR
$\lim_{x\to 0}f(x)$ is what $f(x)$ approaches as $x$ approaches 0, regardless of the direction. As you get really close to $x=0$, what is $f(x)$ getting really close to?
SWR
-6
-6 for all besides f(0) which is und?
yup. $f(0)$ is undefined
SWR
ty!
Another important note: for any value $a$, if $\lim_{x\to a^-} f(x)$ exists and $\lim_{x\to a^+} f(x)$ exists, and $\lim_{x\to a^-} f(x)=\lim_{x\to a^+} f(x)$, then $\lim_{x\to a} f(x)$ exists and $\lim_{x\to a} f(x)=\lim_{x\to a^-} f(x)=\lim_{x\to a^+} f(x)$
SWR
Also, if $\lim_{x\to a^-} f(x)$ exists and $\lim_{x\to a^+} f(x)$ exists, but $\lim_{x\to a^-} f(x)\ne\lim_{x\to a^+} f(x)$, then $\lim_{x\to a} f(x)$ does not exist.
SWR
just good stuff to know
ok
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What have you tried?
i dont think theres enough info idk
They give you the radius.
Yes
If the angle is 84, then the area corresponds to 84/360 of the disk's area
the formula for the area of a circle is pi * r squared
so because we're given r = 3, the area = pi * 3 squared = 9 * pi
you then try to see what percentage or what fraction of the full circle that shaded area is by looking at the degrees
pi times 9
how
because 3 squared is 3 * 3 and not 3 * 2
if radius is 3
Yeah you're good
so the answer is like a ?
so the percentage of the full circle that 84-degree section makes up would be 84/360 because the full circle is 360 degrees
yes
yeah so the are of the cirlce is like 27 ish
divided by around 4
is around that
got u
around that yeah
it's best to keep the numbers exact until the end to round them but yeah
i see
usually notated as $pi*r^2$
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why are the signs cancelled
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????
sry wrong channel
its ok
the negative signs are cancelled because there are two negatives
but why
why do samw things get cancelled
whenever you are dividing or multiplying two negatives, they cancel out
why
just say u dunno smh
its so easy
dont ask irrelevant questions. the sign just moves in a different direction.
when you divide or multiply two negatives with each other they become a positive
literally what i said
when you divide or multiply one negative with a positive it will always be a negative
dont worry about that until you have to prove that a negative times a negative is positive in uni
qhy
yeah idk why they are saying we dunno
it just is.
aigh
it just kinda works like that
ikii
math = math
ikik
Why is negative times negative equal to positive? Let's answer this question in 5 levels, ranging from intuitive examples based on our daily experiences to a proof in Ring Theory that is often only seen by math majors.
they didnt har divison mann
but tysm
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rewrite (sect)^2 using an identity
how did u rewrite (sect)^2
1 + tan^t
ye ok 1 + (tant)^2
and after that u r very close to completing the proof
it helps to notice the similarities between the left side and right side
man i am stuck thats why
What have you done with the numerator
Isn’t that for 1-tan^2(x)
Yes the numerator
typo error sry
Actually instead of that
Rewrite everything in terms of sin and cosine
This is further from the solution
^
idk mann
yea
tan is sin/cos
no i mean i cant get the answer
Tan^2-1 / tan^2 +1
rewrite in terms of sin and cos
remember sin^2 + cos^2 is 1
oh wait maybe I don’t know the solution 😭 but I’d do that anyways
i got a test tmw 😭
are you trying to do anything with the problem
This is probably closer btw
rewrite in terms of sin and cos
If you want to practice you gotta do it yourself
without us just giving you the solution
I still thinking rewriting is a good step have you even tried it 😭
yea ofc man
Can you send it
@vital verge Has your question been resolved?
Oh wow the solution is a lot easier than it seems
Uhhhh my hint is dividing by tangent
somewhere
alr
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How do I answer this?
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I have no idea how to solve this, where do i start?
well what is required for f(x) to be differentiable
what are the necessary conditions
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if i had to represent this as a power series
could i just split it up into 3 * 1/(x+2) * 1/(x-1), and then turn the two fractions into power series and represent the final answer as a product of 2 power series
i know i can do it using partial fraction decomposition but just asking
You will need to rewrite that product as a power series
wouldnt that just be multiplying both the sequences of the series together
or
What do you mean exactly
like if im multiplying 2 power series
both going from n = 0 to inf
wouldnt i just multiply whatevers inside each of the power series together
Multiply each term? No, that's not it
if one series were to be like 3x^n
and another series were to be like 5x^2n
would the product of the 2 series be (3x^n)(5x^2n)
Like I said, it's not just multiplying each term
if you would multiply those two series together you would need 2 different indexes i believe
[ \left(\sum_{n=0}^\infty a_nx^n\right)\left(\sum_{n=0}^\infty b_nx^n\right) = \sum_{n=0}^\infty\left(\sum_{i=0}^na_ib_{n-i}\right)x^n ]
since its like multiplying polynomials, so you get a bunch of middle terms
A Lonely Bean
this you should probably approach with partial fractions
so going back to this if theres like a polynomial in the denominator i should go for factoring and partial fraction decomp
yes
are there any other techniques to use if there are polynomials in the denominator
If the polynomial is of the form 1 - x^n, then you don't need to factor
yeah i know but like if there are multiple terms with x
there are taylor series i suppose
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What do I do wrong here?
i set u = cos(41x)
du = -41sin(41x)dx
sin(41x)dx = -(1/41)sin(41x)
and then its -1/41 int(1/(1+u^2))du
and then its -1/41 ln(|1+u^2|)+C
and then i geet -1/41 ln(|1+cos^2(41x)|)+C
Int of 1/1+u^2 is not ln|1+u^2|
I do not believe $\int\frac{du}{1+u^2}=\ln|1+u^2|$
SWR
Well you sort of have to know this one
reach back into the recesses of your memories of previous calculus classes to recall the derivatives of inverse trig functions (or google them)
Try taking the derivative of arctan(x)
arctan
. . . into -1/41 cos(41x)^2/sin(41x) +C
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how would i solve this for N^2x?
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can someone explain how to solve this
@sage patrol Has your question been resolved?
<@&286206848099549185>
@sage patrol Has your question been resolved?
For x < 1, draw a line with an open dot at 1 and an arrow moving left
For x > 3, draw a line with an open dot at x = 3, and with an arrow right
As this statement is “or”, these two arrows should represent the answer
@sage patrol Has your question been resolved?
@midnight haven and I am
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Is there any necessity to move left to the left-most zero after changing a 1 to x?
or can the process just be "Move to 1, change to x, move to next 1, change to x, move to next 1, change to x, accept"
and anything outside that is rejected
More officially
- Move right until the first 1. Change to X. If none, REJECT
- Move right again until the next 1. Change to X again. If none, REJECT.
- Move right until next 1. Change to X. If none, REJECT.
- Move right to next 1. If none, ACCEPT. Else, REJECT
or do i have to move left to the left-most non-blank every time?
you can do whatever you want
you don't even really have to change to x as far as i can tell
i guess since it's the practise we're taught, it'd be good to maintain consistency
there's no reason to do it
yeah
this is a regular language so like
the turing machine is going to be very simple
for the transition diagram, do i just do for each step something like 1 -> 1, R
i just never added the writing to it yet
yeah that's how i'd draw it
you need to encode the information (state, value) -> (state, value, direction)
so that works
okay, so then for each reject it'd just be
wait i can't do the symbol
[ but flipped, basically blank space symbol
[ -> [, L
is this okay for each reject (apart from the last one)
I'd have to add a direction though right?
yeah
all spaces
because I don't want it to reject a string that has 0s in it
it can have infinitely many 0s
oh ok space is your end of string
just has to have three 1s exactly
that makes sense
and implicitly 0 transitions to itself?
or rather each state transitions to itself on 0?
erm
this is where my understanding isn't great, because I'm following some examples our lecturer gave us
I'll send one
okay, that doesn't bother to define all possible transitions -- for example, what if it's at i and sees an X?
that's impossible because of the way the machine works
in your case though, you definitely have the chance of seeing the symbol 0
oh so i have to add another state in between i and S1?
i see what you mean now
i > S1 is the starting value only
well even in their example, what if they're in S1 and see an X
again, it won't because of how the algorithm proceeds
but the point is that you need to define what happens, in your case, if you're in any of your states and you see a 0
something similar to this?
every blank arrow is just bc too lazy to write [ -> [, L
it's an untidy version ik
just a quick sketch
yeah (why not just use i as s1 though?)
like, just loop through zero at i?
I'm not even joking when i say that my understanding of these rely on the visual examples because her notes don't explain them well
i felt like it was an illegal move lmfao
okay neater and updated one
good?
you're basically giving instructions for this machine
nahhhh you're free to go back to the initial state
just as long as it's clear where the start state is
which your incoming arrow does a good job of that
yes this one looks good
if you blur your eyes you can probably see the FSA hiding in there
the process of evaluation?
yeah, if you see i have to show how it processes an empty string, 01, 101, 01101, 0110110
right yeah
this way is decent i guess? but it's missing state information
sometimes i've done something like this
seems fine, i'd say that that's a partial trace because in the case of 01 you don't show the first step of seeing the 0 and moving to the right while staying in s1
but full traces are annoyingly long
yeah i dont know if they want it annoyingly long
there's another question on this that I've already answered, and just want to make sure that I've said enough for it
just want to see is my answer sufficient, then i'll finish up the processing of the strings and submit it
ok finished strings
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aha idk but thanks for the compliment but most importantly for the help!
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Q15
What do I do from here
I can’t factorise because of Y
@versed remnant
We haven’t covered that in class
Ohhhhhh
I didn tveen@
See that@
Omg
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can anyone help me with this problem
the topic is QUARTILES FOR GROUPED DATA
<@&286206848099549185> help me out please
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oh mybad
can you help me out?
but still can you help me out?
<@&286206848099549185> can someone help me out please
pleasee help me out <@&286206848099549185>
<@&286206848099549185> anyone pleaseee
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@wind linden Has your question been resolved?
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really a physics problem but yeah
where did xm1 and xm2 come from
also ycm1 and ycm2
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Is this correct?
translation:
ja...
really?
ja...
thank you
😂
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Hey was wondering how to do part (iii) of this question
Which one did you get as the partition?
Can you start by building one class?
2^0?
{1,2,4,8,16}
Cool. You have created one class. Can you do another?
maybe {3,6,12}
and {5,10}
Yup
Good work
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bit confused on how to do this
i differentiated and ended up with x = theta(k - 1) but i dont think it's right
@hoary meadow Has your question been resolved?
@hoary meadow Has your question been resolved?
@hoary meadow Has your question been resolved?
why do you think its not right
nvm it is
it's cz i was reading the markscheme wrong lol
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Is this correct?
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estimate f’(2) for f(x)=3^x . explain your reasoning
have u done anything similar before?
this is how far ive got
ive also used my calculator to compute this for small values of h like .003 etc
What kind of indeterminate is that?
and what did you get
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d/dx (sin x + cos x)/sin x
The book has some long answer by using quotient rule
And my question is
Can't you jsut cancel out the sin x and be left with 1 + cot x, or is that wrong because we have to worry about when sin x = 0?
sin x = 0 when x = 0 (0≤x<360) but in the limit definition of a derivative x tends to 0
cot is just cos/sin, you still have the problem of cot not being defined when sin is 0
in the limit definition of a derivative x tends to 0
not in general no
Yes, you can cancel out
yeah the difference in x's goes to 0
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