#help-10
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The probability it's marked A isn't .92
that's P(A|Orange)
You want to look at all the A marbles
so it would b .92*.13?
P(Green A)=.13*.22
Yes.
yes.
so it will be .9622 at the end?>
oh nvm It's still wrong because it's not on the option 😦
omg... im so sorry
one of the option was .96
it was a scrolling answer so I didnt see 😦
sorry about that!
thank you so much for helping me!
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my brain is not working right at 1am I have no idea where to even begin, I think its neutons first law but with vectors but I am unsure
@subtle quiver Has your question been resolved?
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I'm a little lost as to why you cant just times a11 by B11
wdym times a11 by B11
so 1 times 2
ab11=2
Times the corresponding numbers with the corresponding locations
that's not how we define matrix multiplication
I know but, why because i'm really having hard time wrapping my head around it
if the matrices aren't the same dimensions, that logic fails
imagine a=3x2 matrix
b=2x3 matrix
there's no b3,2
Yes fair, but even if it was the same dimensions we cant do it
i think fighterman0 is asking about why we define matrix multiplication the way it is
exactly so it won't work
Yea
eh thats a bit deeper. You might just want to look up a proof about matrix multi
i think axler has a few
Matrix vector multiplication
How do you this? I got the answers but i still cant wrapp my head around it
isnt it 2*1?
?? A = 2x3 but B = 2x1
yet some how my tutur got 3*1
I mean he says it DNE in your first pic
yea but he still works it out??
Look, the first picture has A as a 2x3 matrix
your second picture has A as a 3x2 matrix
The matrices aren't even the same
ooo yea, I think he just rearranged it?
no, they are completely different questions
look at the numbers
This rule defines matrix multiplication
oooo yes yes, you right
Just to clarify we always times rows by columns?
like there is no exception to that rule?
yep. if you want the reason matrix multiplication is defined like this, maybe watch https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab. (it's also much easier to remember LA formulas with this intuition)
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how can i get the period
Period is the peak to peak or trough to trough measurement
@dreamy ember Has your question been resolved?
so what is the period here
You can determine that. I told you what you needed to know
ohhh
Can I get a source for that pls
Because what you've stated sounds like wavelength
And im wondering why its the same as period
You can look up period of sine/cosine and it'll say what I stated
And FYI, period is the time it takes to complete a cycle, and wavelength is the distance during one period
I was confusing physics terminology where the wavelength is the distance from peak to peak or trough to trough and the period is wavelength/velocity
Wavelength is distance, period is time
@dreamy ember Has your question been resolved?
Were you not able to determine period with the info I gave?
@dreamy ember Has your question been resolved?
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I'm having trouble with solving this AOPS question: If a^3 - b^3 = 24 and a - b = 2, then find all possible values of a + b.
so far I've tried factoring a^3 + b^3 into (a-b)(a^2+ab+b^2
well its a^3-b^3
Oh wait
yes, but the book tells me a different answer
True.
I get (a+b)^2 -ab = 12
From here, you can get the value of ab.
ab is 8, yes.
Now you have
(a-b)^2=a^2-2ab+b^2
Get the value of a^2+b^2
Then use it to calculate (a+b)^2
can't I just use this tho?
How'd you get that?
What no.
but the answer in the book doesn't match my answer
$$(a+b)^2 -ab = a^2+ab+b^2$$
$$(a-b)^2+ab=a^2-ab+b^2$$
ah
Sakata Yaksha
Uh huh.
thank you
You're welcome.
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how to do the induction? or is this correct/enough?
@compact shadow lmao last one last one
@lone blade Has your question been resolved?
It is already written in your picture
so it is correct?
Yes
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circles have radius 1
how do i find the length of the square
the line is straight, top 2 points are tangent
(a,2a) is on the cycle (x-1)^2+(y-1)^2=1
(a-1)^2+(2a-1)^2=1, quadratic, solve a, the answer is 2a
Two roots then rule out one root
Edited
👍

@lusty palm Has your question been resolved?
all good
wait wdym
Use coordinates
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Yo I have a physics question I dont get
‘An object (with mass 40 kg) is lifted through a rope. Its acceleration is 2 m/s^2 (to the bottom). What is the force that the rope applies to the object?’
And the answer is 232 N. Im not getting it tbh
What I did is
Fy = (40*2) - (40*9.81)
But its completely wrong 
yo what does it mean by the acceleration is 2ms^-2 downwards
isnt the downwards acceleration the weight force
as the mass is being lifted shouldnt it mean that the net acceleration of the body is 2 ms^-2 upwards
I have no idea
I thought that just meant that the lifting is getting slower but idk
hmm
ah ok i got it
so you need to use two formulae
when it says the acceleration is downwards that is your first formula
You know that the net vertical force is equal to the tension in the rope minus the downwards force.
Meaning you have two unkowns
$F_y=T-ma$
you need to derive another formula to find the tension force in the string
note: the downwards acceleration took into account weight, that is why you can safely say the net force equals the tension take away the downwards force (F = ma) of the object, where a is given
does that make any sense 🤔, there is just one more formula you need to find T
OGC
@timid silo Has your question been resolved?
Im not sure why we need to remove ma from the found Tension
So what I did is
Fy = ma
Which means
F + 392,4 = -80
Where -80 is ma and 392,4 is 40*9.81
In which case I get F = 312
And 312 - 80 is indeed the solution
Tho I dont understand this last step
Ye, so this problem was set such that it directly gave you the net upwards force (the unkown) and the net downwards force... You know this, because when it says string attached to a mass, you clearly know tension is the only force up, however, when it gives you the acceleration it refers to the net downawards acceleration as the problem specifiically referred to. Given Newton's second law, you know that this net force can be expressed as F=ma
So you only have two forces to work with in the vertical direction, and taking the vector sum you end up with Fy = T - ma.
In this scenario you didnt take into account the tension force acting in the vertical direction.
you considered the net force as the net force of the entire system, whereas the question refers to the downward acceleration as downwards, hence, opposing the tension.
The difference between these forces is what generates the upwards force, so if the forces were equal you would have an equilibrium
Brb 5 min ill try to read everything very carefully lol
Thanks meanwhile btw very helpful 🙂
ye np take ur time 👍
just try to consider that there are only two forces: the tension and the downwards force, and the question made it easier for you in giving you the net acceleration, which allows you to find the net downwards force
@timid silo Has your question been resolved?
Oh wait I think I can see it now
Because the question wants us to find the force that is applied, which is the summ of all forces on the y axis
So since the acceleration is negative F == 40*-2 which is -80
But the weight force downwards is still the same as I calculated, which is 40*9.81
So the sum between -80 and (40*9.81) and then remove 80
$F_y=T-ma$
OGC
this is the net vertical force ye
Yeah that
so u have everything except T
find one more equation
it also would have ma in it
its a more general equation which u may be used to in tension/pulley problems
Got it now, thanks again 👍
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ye all good
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Who do you do b) it makes little sense. What I did was I found 2A, 3C and 4B
when By the look of it if i add 2A+3C it doesnt = 4B
Subtract the multiplication of 4 with B and multiplication of 2 with A
The divide the whole thing with 3
but why?
(4B-2A)/3
Firstly, the C that you calculated in question a or c is not applicable for b
the Matrix C in all the 3 questions a, b and c have different values
Okay I thought C would be the same for whatever reason. Thanks for clarifying
Since 2A+3C = 4B,
By solving algebraically,
3C = 4B-2A
C = (4B-2A)/3
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How does this converge at .75
I understand that the limit is 0 and therefore the numbers added get smaller
But I’m lost on how the numbers sum to 3/4
@misty temple Has your question been resolved?
Thats really strange, I dont know if thats right.
but then again I'm not the brightest in math so
I’m guessing that the summation series goes:
1/3 + 1/8 + 1/15 + 1/24 …
Right?
u can split that expression and express in terms of two partial fractions and proceed from that stage, it'll become more clear to you
But I’m not sure what to do next
my handwriting sucks so I can't send a pic
Aw :/
\begin{align*}\sum_{n=2}^\infty\frac{1}{n^2-1}&=\frac{1}{2}\sum_{n=1}^\infty \frac{1}{n}-\frac{1}{n+2} \
&=\frac{1}{2}\sum_{n=1}^\infty \left(\frac{1}{n}+\frac{1}{n+1}\right)-\left(\frac{1}{n+1}+\frac{1}{n+2}\right)\end{align*}
How did you get the 1/n - 1/n+2? Thank you btw
ScapeProf
Telescoping now
What changes when we do this?
Other than n
I’m not sure where the 1/n is from
If you plug in n=2 in 1/(n-1) it is the same as plugging in n=1 in 1/n?
Ohhhh yes thanks
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Can someone help me? How can I write the Euler-Lagrange equation in terms of generalized coordinates and velocities?
Question is very general
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How should I do this?
@timid silo Has your question been resolved?
@timid silo Has your question been resolved?
@timid silo Has your question been resolved?
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Hi
In the point of inflection I
it has the abscissa x = -2
and what is y?
Does it f''(-2) ???
yes
let the point where the abcissa is be (x, y)
then at that point, f''(x) = 0
then, for that x, y = f(x)
So it should be f(-2) not f''(-2)
@fervent cradle is this true?
that's what i said
Ok thank you @fervent cradle
How to give an feedback? @fervent cradle
t!rep @fervent cradle
Mahdi has given @fervent cradle a reputation point!
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Good afternoon folks
Hello guys
growth of a spherical tumor modeled as a function of the population of germs (g in Million) in tumor, v(g) = 1.5 g?, When the diameter of the tumor is 2V15 , and population of germs is 20m and it is growing at a rate of 2m /day. How fast is the diameter of the tumor changing at that time?
My brain froze
1: Why did we need to calculate all those derivatives when we could just insert a = 1 into the taylor summation formula.
2: How did we go from the left side of the summation equation to the series?
Any help?
Sir this is wendy's
bruh
get outta here, someone else got here first
one question per channel at a time
K thx
what do you think the taylor summation formula is
you sum up all the derivatives?
??
yeah so you need the derivatives to calculate it
How can you capture the range (0 to infinity) with just 4 derivatives tho?
^
the zeroth derivative was 1
the first derivative was -1
the second derivative was 2!
the third derivative was -3!
the fourth derivative was 4!
so they say that the nth derivative is gonna be (-1)^n * n!
if you have the nth derivative, the general derivative for any n, then you can get all of them
Ok, so the point of derivatives is to see what values they return at a given x = a point
sure
you want to work out this
and you know this
so if you just substitute that into the first thing
then you get
so doing the derivatives lets you find out this component of the taylor series, correct?
yes
@fervent cradle sorry im jut lost on where each component fits
my line of thinking is
Given a fn and x =a, find the first nth derivative to find the circled component in blue, and use that to find the Taylor series of the fn.
yes
like you figured this out > (-1)^n * n!
no i don't understand the process rn
so this is the end result
this is still a series
the end result is a series
you're not finding an answer that doesn't have a sigma in it
like, there isn't gonna be any nice answer to 'what does this series of numbers equal'
there's not gonna be a more nice form than this last series
I guess my question is how the dude on the left became the dude on the right
I don't follow how the blue line happened
How are you able to just come up with an algebraic form like that
ok well if you ignore the minus signs
then it's just 1, 1, 2!, 3!, 4!
so it's just gonna be n!, right
now, considering the minus signs
it goes like +, -, +, -, +...
so that's gonna be (-1)^n
because (-1)^0 = 1, positive
I get the -1 part
(-1)^1 = -1, negative
but why ^n?
so yeah it's just a thing that works
right
this is why I get hooked on calc

the dopamine kick I just got from figuring out (-1)^n is better than cocaine caffeine
What about n!?
Who says that's true for all n?
they just took it for granted bc the pattern is so obvious
they just assumed
you can probs prove it explicitly
induction
Right but I'm a noob so I don't understand why it's taken for granted
like, I wouldn't be able to figure this out on an exam
well it's taken for granted bc it fits lol

because the 0th one is 0!
the 1st one is 1!
the 2nd one is 2!
the 3rd one is 3!
so they just assume it's gonna be like that always
yes
they just evaluate those at 1
they put 1 in, and it comes out as
0!
-1!
2!
-3!
4!
so they just assume it's gonna be (-1)^n * n! the whole time
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sin(180-2x) times 7.5 = 9 times sin (x)
how would i solve that?
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i got up to:
2^2x - 18^x = -8
wait im stupid its just a quadratic nvm
sorry
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How would you draw the point of, on a graph, something like..
Y is bigger than or equal to -2
× > 3
Y > 3x + 1
Also, because x > 3 and y > 3x + 1, you automatically get y > 10, which makes the y >= -2 condition redundant
@urban glen Has your question been resolved?
I'm confused lol
I think I get it nvm
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Find solutions for 11x+7y=200 in set of natural numbers, i got:
(x,y)=(400+7k,-600-11k);keZ
but how do i make it be in set of natural numbers
11 and 7 are coprime
There is a result about solutions of ax+by=c where a and b are relatively prime
if you find one solution (x_0,y_0) then all solutions are (x_0+bt,y_0-at) for all integers t. Use this
400+k>=0,-600-11k>=0
I see, so 0 isn’t in your version
wdym my version?
Wrong, k>=-57
k>-57,1428… right? So k>=-57
oh yes correct, i tought that it was -7k my bad
So -57,-56,-55
so that it would be negative
Yeah negative
thanks
Np
could you also help me with this (4x+10y)(8x+7y)=86, i have no idea how to do it
i can only think of writing 86 as a product of whole numbers
but thats too much work, there has to be a "smarter" way to do it
Thought the same
But don’t worry for each linear system there will be only one solution (x,y)
Because
(4 10
8 7)
is invertible
But yeah.,, still so much work😂
So 4 solutions
i solved it, you get 8 systems of equations but since its a diophantine equation only 2 valid solutions, rest arent integers
i wrote it in paint
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You know sum of C(n,k) k from 0 to n is 2^n right?
The first equation, the left hand side, is half of the total sum
- is trivially just solve it
No
2^26
(1+x)^n=ΣC(n,k)x^k we just let x=1
Yeah
Just by definition I think, it holds for any c actually
d>=x^2+42-c right
You can always find such d, no matter what x and c are
Make d larger than the right hand side
Yeah
👍
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Just wanted to check my method and answer
I've calculated the perpendicular distance to be 4sin(3) x 80N
and the other force should just be x100N
and equating the two together
I have x = 1.6
am I missing something?, and also which distance have I just calculated?, the distance from wall to x or from x to the point at the end of the rod
seems to simple to be true 🚟
Perpendicular distance? Perpendicular to what?
There's an N in your distance
You are confused about whether your equation represents a force, or a distance. 4sin(30) is the height of the wall section, why are we multiplying that by 80N?
Wait, no it isn't even that. What is 4sin(30) here?
Make sure to draw an FBD and split it into components
@coarse tapir Has your question been resolved?
Sorry should have clarified
The moment of the tension force is perpendicular distance x force
Distance is 4sin(30) and force is 80N
The 4sin(30) is also the perpendicular distance if you make another triangle
Sorry im on phone but I'll try to draw it
That blue line is 4sin(30) indeed
Why is that important?
Seeing as gravity acts directly downward, I don't see what you gain from picking a weird frame of reference
Its about the tension... When I'm resolving forces tension acts anti clockwise while gravity acts clockwise
And it says they are in equilibrium
How would you solve it?
There's forces holding up the left and right side of the rod. Having the tension of the cable is enough to get the force on the right using an FBD. Then check the moment at the left side.
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suppose you have n dice. every time you roll all of them, you remove every die that shows a 6. for example, if 2 show up as 6s, you remove them and then roll n-2 dice, etc. (the original problem was with 25 dice)
what is the probability that it will take N rolls to eliminate all the dice?
i started by just looking at n=2 but i wasnt able to figure out a pattern
well maybe the first step to solving this problem could be observing each individual probability in the first trial/roll.
let's say you roll all N dice, with an even 1/6 chance of rolling a six for each individual die. Then the probability of rolling x sixes is equal to the binomial pdf of x, given that p=1/6 and n=N
in the second trial, the probability of rolling x sixes is equal to the binomial pdf of x, given that p=1/6 and n= the amount of dice remaining from the first trial
i can't think of where to go from here though; my method might lead to nowhere. i'm thinking about it
@glossy wharf Has your question been resolved?
it's that thing where you go in circles
?
what if n = 1
then P=1-(5/6)^N), where N is the amount of trials/rolls
yea sorry for the confusing variables im tired
it's 5/6 × [same problem with N = 9]
probability is equal to 1-(5/6)^N, N rolls for n=1 die
we're probably not seeing the same problem
how so
are you saying i'm thinking about a cumulative probability?
not really
i don't know
1-(5/6)^N is not(die lives for N rolls)
so N or less
For one die, P(rolling a six in N rolls) = 1-(5/6)^N, correct?
yes
it's a branching process except no branching
that's N or less
gimme a sec, this is semi-advanced probability theory
yeah
it is a difficult problem but i believe it can probably be solved with simple probability math
nope
hopes=crushed
it's a branching process, you want to bring in the heavyweight stuff, gimme a sec
you;re answering a different question
it asks not more and not less than N
and you're only doing not more
you're right, i'm doing it cumulatively when it should probably be considered individually
wait i'm a fool
yeah it's simple enough that you can do it with basic prob
ok so
oh?
probability that it lives through 24 rolls is (5/6)^24
probability that it dies on the 25th roll is 1/6
so probability that it survives 24 rolls but dies on the 25th is just gonna be (1/6) * (5/6)^24
we know that at least one is like this
tru
the rest can be anything, they can live to 25 or less
ok so really we want the probability that none live to 26
minus the probability that none live to 25
no i'm erratic
i'm changing it up
this is not what i was originally saying
i'm starting over
probability that none live to 26 is (1 - P)^n
where n is the number of dice, P is the probability that any single one makes it to 26
P is (5/6)^26
so it's (1 - (5/6)^26)^n
then the probability that none live to 25 is just
(1 - (5/6)^25)^n
so the probability that at least one lives to 25 is 1 - (1 - (5/6)^25)^n
wait, bugger
conditionals
end me
this is killing me
so the probability that it ends after N trials is equal to (1-(5/6)^N)-(1-(5/6)^(N-1)) or is that not true
ok it's fine
have you solved the problem o great statistical problabilical genius
the probability that none make it to 26 is (1 - (5/6)^26)^n
the probability that at least one lives to 25 is 1 - (1 - (5/6)^25)^n
and you can do it for every number
so the probability that at least one makes it to 25 but none make it to 26 is the second minus the first
substitute 26 for N and 25 for N-1 so that we can get a true representation of the variables initially presented in the problem
and kill them off at the last moment
it rings tru
no
maybe
it's gibberish
yea
i put it in desmos
it's too complicated
(1 - (5/6)^26)^n − (1 - (5/6)^25)^n
just an extra 1 -
all die minus all die too early
P(A) = P(a single one reaches 25) = (5/6)^25
P(B) = P(a single one reaches 26) = (5/6)^26
P(C) = P(none of the n dice reach 25) = (1 - P(A))^n
P(D) = P(none of the n dice reach 26) = (1 - P(B))^n
||P(C' and D) = P(at least one die reaches 25 but none reach 26) = P(D) - P(C and D) = P(D) - P(C) = (1 - P(B))^n - (1 - P(A))^n = (1 - (5/6)^26)^n - (1 - (5/6)^25)^n
ok done
that looks more reasonable now
but 26 should be before
oh
i goofed it
other than that, though, would it be correct
ok fixed
wait
ok so 26 > 25
so (5/6)^26 < (5/6)^25
so 1 - (5/6)^26 > 1 - (5/6)^25
no, that's larger
fixed already
so (1 - (5/6)^26)^n > (1 - (5/6)^25)^n
so (1 - (5/6)^26)^n - (1 - (5/6)^25)^n > 0
which is what we want to see
done
yea i believe that would be the correct solution
considering the integral of f(n) on the interval zero to infinity would obviously be equal to one i don't see anything wrong with these numbers
awesome
finally i can rest in peace knowing the answer to a silly little probability problem
does this satisfy the answer you needed?
still trying to understand what was done
so it sort of looks like instead of viewing it as one big system, we look at each die individually since each roll is independent.
im a bit confused here though. the original problem was starting with 25 dice (a particular case of n=25 dice), and seeing if it takes N rolls to eliminate all of them, but it looks like this is solving for n dice and 25 rolls.
am i the biggest fool in existence
sorry
i'm sleep deprived
P(A) = P(a single one reaches n) = (5/6)^n
P(B) = P(a single one reaches n+1) = (5/6)^(n+1)
P(C) = P(none of the 25 dice reach n) = (1 - P(A))^25
P(D) = P(none of the 25 dice reach n+1) = (1 - P(B))^25
P(C' and D) = P(at least one die reaches 25 but none reach 26) = P(D) - P(C and D) = P(D) - P(C) = (1 - P(B))^25 - (1 - P(A))^25 = (1 - (5/6)^(n+1))^25 - (1 - (5/6)^n)^25
swapped everything around
im guessing it should be N instead of n here?
arent we all
sure whatever
yea in place of n, they use 25 and 26 to represent the probability at n=26
yeah
P(A) = P(a single one reaches N) = (5/6)^N
P(B) = P(a single one reaches N+1) = (5/6)^(N+1)
P(C) = P(none of the 25 dice reach N) = (1 - P(A))^25
P(D) = P(none of the 25 dice reach N+1) = (1 - P(B))^25
P(C' and D) = P(at least one die reaches N but none reach N+1) = P(D) - P(C and D) = P(D) - P(C) = (1 - P(B))^25 - (1 - P(A))^25 = (1 - (5/6)^(N+1))^25 - (1 - (5/6)^N)^25
same difference
just making sure
also wouldnt you want to use (n-1) and (n) instead of (n) and (n+1), respectively?
oh never mind we have a different interpretation of what n means
wait is that last line actually correct?
no i think you're right
wouldn't you do minus 1?
oh i copypasted something without changing it
n is the amount of rolls where there are no more dice
ok lemme rego
P(A) = P(a single one reaches n-1) = (5/6)^(n-1)
P(B) = P(a single one reaches n) = (5/6)^n
P(C) = P(none of the 25 dice reach n-1) = (1 - P(A))^25
P(D) = P(none of the 25 dice reach n) = (1 - P(B))^25
P(C' and D) = P(at least one die reaches n-1 but none reach n) = P(D) - P(C and D) = P(D) - P(C) = (1 - P(B))^25 - (1 - P(A))^25 = (1 - (5/6)^n)^25 - (1 - (5/6)^(n-1))^25
_ _
third time lucky
(5/6)^N → a die lives for N rolls
1 - (5/6)^N → a die dies at some point before N+1
(1 - (5/6)^N)^25 → they all die before N+1
(1 - (5/6)^(N-1))^25 → they all die before N
you want them all to die before N+1 but not too early
okay that makes a lot of sense actually
yea im pretty sure this is correct. like 95% sure
the amount of time it took me to do that
i am unfit for any task beyond making simple gruel
well look on the positive side. you can feel satisfied now that you've synthesized a coherent and logical answer to the problem you've been analyzing for about half an hour at least
is this a geometric distribution?
surely not
close to at least
it's the difference between geometric distributions
the difference between n and n-1
i was kinda of thinking a geometric distribution might come up here since it deals with how many failures before a success
for each individual die it's clearly geometric
overall, no
more complicated
yeah
thats what i meant
alrighty neat
thank you guys so much for the help. that was a doozy to be sure.
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How did you get to 4(13-x)=5(11-x)?
U crossed multiply
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Can anyone help me to show this?
I checked in the Wikipedia, they used the young’s inequality
But I didn’t learn that in my courses
Is there any ways to start the proof?
Originally I want to try the mathematical induction
But since it is not proving for integers only, so I am not sure about that
Can I just use basic knowledge of vectors and Cauchy Schwartz inequality to prove it?
Can be done with Jensen’s also
Umm sorry I didn’t learnt that as well
Can I develop the inequality only by Cauchy?
I know it is quite impossible since Cauchy is the special case of holder
Uh
Sounds weird you are asked to prove it then to me
Claims to only use CS (haven’t checked its valid)
Umm sorry for the confusion, but when I search in the web, I always find the integration version of the Holder’s inequality
And idk how to proceed
Sums are just integrals
Oh
So they use the integral sign to replace the sigma
Seems we have to use Jensen’s anyway
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partial decompisition
what
my friends been stuck on this question for awhile
tell your friend to google partial fraction decomposition
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would i substitute x = au, y=bv, z=cw. Get boundaries for z between -1 and 1. Get the first jacobian to be abc
then substitute further into polar
and get another boundary
0 to sqrt(1+w^2) for w
and 0 to 2pi for theta
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anyone help? how to find Θ
idk why i find the slant height but my goal is to find Θ
angle formula
which one?
can we like determine the Θ at the 3d cone? not the one that's been deform
maybe that'll help
@gloomy tusk Has your question been resolved?
<@&286206848099549185>
@gloomy tusk Has your question been resolved?
theta is defined to be the angle of the sector of the unfolded cone, dunno why you're trying to get it from the 3d form
consider the which parts of the 3d cone correspond to the unfolded cone
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How do I show $X_{n} \overset{L^{r}}{\longrightarrow} X$ and $Y_{n} \overset{L^{r}}{\longrightarrow} Y$ implies $X_{n} + Y_{n} \overset{L^{r}}{\longrightarrow} X + Y$? I am confused when $0 < r < 1$. For $r\geq 1$, Minkowski inequality works
pepper
Doesn't seem to be qualified in my homework
might at least be worthwhile to consider convergence towards zero to have less moving parts
@desert sparrow Has your question been resolved?
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After reducing the matrix to row ech form and doing the diagonal product, why isnt the determinant -2?
I dont understand the last step of (-1)^1 * -2 = 2
Why interchange rows? Which rows are being interchanged? and why does it negate the determinant
@autumn patrol Has your question been resolved?
it doesn't matter which rows are interchanged
you can find out why it negates by doing a trivial example
@autumn patrol Has your question been resolved?
im not following
take a trivial 2x2 matrix
solve its determinant
then change the rows
what do u get
1 2
3 4
4-6
6-4
hmm ok makes sense now
but why interchange rows anyways? what does it achieve?
I think when making the matrix into diagonal form and taking its det
u have to swap 2 rows then, to get the det of the 'actual' matrix
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Hi, how to find the cumulative frequency for Q2 and Q1?
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<@&286206848099549185>
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Prove that the diagonal of the 3D parelelogram ( not a native english speaker ) ABCDA1B1C1D1 cuts through the center of the triangle BDA1
Hm
Let's see 
we are working with vectors btw!
The triangle inscribed inside is an isosceles triangle
As far as I can tell because all 3 sides r equal
i just drew the sketch to make it easier for people to visualize
The center of the tringle is also the midpoint
What grade math is this
college math
the incenter
analytical geometry
im in middle school
thats way but i'll try to help
i need to prove it tho 
yes
u learn this stuff in middle school?
no
i think you should start by proving its an isosceles triangle
yes at least i think
uh
hm
because
if u slice the thing in half
u would have like a trianglular thing
2
no not like that
go for it
but i need to write it on the paper
i-my brain's stuck with colege math
yeah yeah ahahahaha
yeah you probably should avoid doing that
mk doing these
i want challenges cus middle school stuff easy for me
i wish i was thinking like that during my highschool days
i went to the easiest highschool i could find cause why not
and then i went on to go to the hardest university in serbia lmao
Prove that the diagonal of the 3D parelelogram ( not a native english speaker ) ABCDA1B1C1D1 cuts through the center of the triangle BDA1
@toxic canopy Has your question been resolved?
<@&286206848099549185>
You let A=0
You have three vectors
a=AB
b=AD
c=AA_1
So AC_1=a+b+c
On the other hand
The center is P, AP=(1/3)(a+b+c)
So P is on the line AC_1
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thanks!!!
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You randomly take a card from a well-shuffled deck of cards and then put them back.
- What is the probability that after 100 times you have not drawn an ace of hearts.
- What is the probability that after 20 times you drew an ace at least once.
I don’t really have any work bc I don’t know how to start and we use this formula called la place or whatever
Well in theory if you got 1/54 chance to draw ace of hearts you should draw at least 1 in 100 drawns. But thats not true
Well yeah obviously, but that’s the whole point of this exercise it’s to go beyond that logic
@runic arrow ok after a bit of search
I found out the formula
$$(1 - p)^n$$ to be true
Pluton
p being probability n being tries
Yea
Well a deck has 54 cards
And 4 aces
Probability it wont happen
$$(1 - p)^n$$
Probability it will happen
$$1 - (1-p)^n$$
Pluton
Just plug in second formula
But then I get one as the answer
oh wait I got it
But the n is supposed to be only for p
Not one
,w 1 - (1 - 4/54)^20
Seems correct to me
Not if u do the first one lol
What do you mean
Basically 0
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Hey i am in 8th grade and I tried everything i just don’t get the question
solve for x and y first
do you know how to solve?
no sorry
have you learnt solving simultaneous linear equations?
yes but we got a really bad teacher so I asked about it be she couldn't really help me so i thought I would aks here
I think you should trace
For the equation 3y - 2x = 12, express y as the subject in terms of x
i hope you know how to do this
yeah i think so
try it now, and let's see what you get
i will
hey i am back
i dont have the answer yet
I tried but I just get stuck
<@&286206848099549185> can you help me i don't understand the question
I dont think thats how its supposed to be solved
oh
Normally when i see this type of questions you need to manipulate somehow both equations
I think for an 8th grader, the most straightforward solution would be to solve for x and y
I agree with you
@gritty dragon do you know quadratic formula
yeah I think so but i am not relly good at math
have you tried this?

