#help-33
1 messages · Page 77 of 1
do you have any problem in mind or like a type of problems?
i mean you just apply the theorem
I don't understand it tho
the sum of any 2 interior angles (like <CAB and <ABC in this case) is equal to the exterior angle of the opposite angle (<BCD in this case)
bruh what have u done
this is a new account i just verified the number, idk what discord has
want to try and solve some problems with it?
sure
would it be 49??
yes\
no problem
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can i prove this by mathematical induction?
i find it confusing since i have N and k
@tough abyss Has your question been resolved?
@tough abyss Has your question been resolved?
@tough abyss Has your question been resolved?
YEP
SIMPLEST CASE OF K>N IS N=||1|| & K=||2||
GENERAL CASE TO ASSUME TRUE: N=||R|| & K=||R+1||
IMMEDIATE SUCCESSOR OF GENERAL CASE : ||N=R+1 & K= R+2||
ALTHOUGH POSSIBLE, YOU DONT REALLY NEED MATHEMATICAL INDUCTION FOR THIS. A BUNCH OF STATEMENTS WOULD DO
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what on earth
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hi
hi
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hm
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Quick question, in discrete mathematics, does A\B translate to (not)A(or)B? Or: ¬A∨B?
to prove (or disprove) that two sets are equal you may take an element x from the first set and prove that its in the second set
take any x that belongs to A\B, thus x belongs to A and does not belong to B
consider (not)A(or)B
x should be either in (not)A or B
x is in neither of those, so the two sets are not equal
it should equal A only?
so it's true only when B is false?
and A is true
1 0
yes?
<@&286206848099549185>
as Davit said, if x belongs to A\B, then x belongs to A and does not belong to B
right, so A is true, and B is false
for that to be true
?
yes
if it's 1:1 it's no again? 0:0 too?
we get A and not B
?
what
oh so A∧¬B?
yes
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hi
$\lim_{x\to0}{ (\log(1+x)(\frac{1}{\sin{x}}-\floor{\frac{1}{\sin{x}}}}))}$
JoeTheLazy1
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I've been told that if a limit with is euqal to zero is multiplied by another limit which is += ∞ it's indeterminate form
I guess in this case we can rewrite the whole thing like this
log(x+1) (t-[t]) and t-[t] is between 0 and 1 so this limit is 0
is this correct?
@hard schooner Has your question been resolved?
<@&286206848099549185>
yeah can prove it with squeeze thereom
E. G. Lower bound being 0,upper bound being log(1 + x)
Like 0 <= log(1 +x) (1/sinx - [1/sinx] <= log(1 + x), although now that I think about it you might need a diff bound
, or like calculate the left and right handed limits separately and show they're both 0
Cus the bounds don't work when log(1 + x) is negative
but it would if you just do it separately for right handed limit and also left handed limit
Well would have to do diff bounds for left handed limit but ye
np
I just have a little question
$\lim_{x\to0}{ (x)(\frac{1}{\sin{\frac{1}{x}}}-\floor{\frac{1}{\sin{\frac{1}{x}}}}}))}$
JoeTheLazy1
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it works for this one as well, right?
yeah
I am worried about the 1/x
the "x" makes up for it
Intuitively it makes the amplitude go to 0
Rigorously
U can p much do the same trick as before, where the function inside the parentheses is between 0 and 1
And use squeeze theorem on that
can we solve this buy using mac laurin series as well?
hmmm idk how'd you get that to get out of the floor function tho
cuz the 1/sin(1/x) gives us a beautiful x at the end
but imma do it with squeeze theorem like the other1
thank you so much man
np
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Guys
Help
Me
Is it 12cm and 2.1m?
Guys










<@&286206848099549185>
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hello so i've completed this question
however i dont understand this question
its connected to it
think about what changes about the numbers when you round them for the estimate
do they go up, down and are they in the numerator or denominator?
i change the denominator and
i round 8.34 to 8
which is down
and 10.21 to 10 which is also down
so would my expanation be acceptable if i said "the numbers that i change are in the denominator, and i round the numbers down"
@paper fiber
you should explain why that results in a higher value
and explicitly say the numerator stays the same
i dont get it
what don't you get
so rounding the numbers down (for the estimate) would get me a higher answer
yes
take this example
1/4 = 0.25
let's make the denominator smaller
1/2 = 0.5
we get a bigger number
when you round down the numbers
you are getting a smaller denominator
ohh
which means you are dividing 1 into a smaller amount of groups than the exact valueb
since you have less groups then the group size will be bigger
the numerator stays the same, and i'm rounding the numbers to the nearest significent figure, which means im rounding it down, which means the denominator is becoming smaller, which means the estimate is going to be more than the actual answer
would that get me the mark
is this an exam?
okay
would that be correct tho
it might be best to say how you are dividing by a smaller number
the same quantity by a smaller number
that being 1
so since it isn't 'divided as much' the result is larger
the numerator stays the same, and i'm rounding the numbers to the nearest significent figure, which means im rounding it down, which means the denominator is becoming smaller, so im dividing the same number which is 1 by a smaller number which results in a larger answer
is that any better
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is there any way for me to say that if the Trace of a matrix A is 0, then said matrix A has no inverse?
to be more precise, my problem states: Prove that if AB-BA=A, where A and B are square n x n matrices, then A has no inverse
since the whole question is using traces, i suppose that this sub-question will be no different, and ive ended up quite easily at the remark that Tr(A)=0
[1 0]
[0 -1]
Is a matrix with trace 0, but has an inverse
yeah thats right...so i assume that i have to work with determinants, because the only way i know to prove that a matrix has no inverse is to prove that detA=0
you could also talk about its kernel or rank
not sure what those are, havent discussed those in class yet...
Big hint: ||Move BA to the right hand side and take determinants||
is it a linear algebra class? maybe it's a class that's just purely about matrices without going into vector space ideas, dunno
it is but its kinda strange, its linear algebra and analytical geometry but two professors teach us, and one seems to do a loooot more hours than the other
so while we are completely finished with matrices and determinants by now, heading into other stuff, in analytical geometry we've barely done anything
thank you, ill try to work from there and ill let you know how it goes
oh yeah that went easily, if detA is different than 0 then you end up with detB=detB+1
which is clearly false
thank you bean!
and thank you to the rest who enlightened me on the matter, of course
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Do all free falling objects have an initial velocity of 0 m/s ?
No
relative to what?
earth
well if you throw a ball up into the air as far as you can, it has an initial velocity leaving your hand right? but as soon as it leaves your hand, the only force acting on it is gravity (ok say you are doing this experiment in a big vacuum chamber so no air drag) so it's in freefall
or a parachuter jumping out of a plane might have some horizontal velocity simply from jumping and pushing off the plane
or a spaceship that is in orbit (which is also in freefall) has a lot of horizontal velocity, enough that it keeps completely missing the planet over and over as it is falling
does that answer your question or is there something else you're trying to express \ ask with it and i'm missing the point?
I don't see a way to answer this without assuming that its initial velocity is 0.
yeah you can use the idea that its initial downwards velocity was 0 at the beginning of its fall
in this case any horizontal velocity is irrelevant since it doesn't affect how long it takes to fall down (assuming it's small and not planetary scale like a ship 😬 )
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is this the correct inverse?
,w inverse of 4*(5/3)^(2-3x) - 1
@terse dome Has your question been resolved?
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What does it mean to be closed under addition / closed under scalar?
if you add two elements of W, you get an element of W
if you multiply an element of W by some scalar from the field, then that result is also in W
Ohhhhh
So closed meaning it exists in W
and if it exists outside w, it is not a subspace
means doing those operations wont give you something not in W
example: whole numbers Z are closed under addition, if you add 2 whole numbers you also get a whole number
but they are not closed under division, because for example 2/3 is not a whole number
Oh ok that makes sense!
So when it says non empty
does that mean it contains a zero vector?
nonempty is describing a set, i.e. it not the empty set { } that contains no elements
so there is at least one element in that set
why is that confusing?
So if there was no zero vector, it would mean it is a empty set?
the set W contains some element, therefore it is non empty
empty set is just a bag that has nothing in it
if there is literally anything in the bag, it is non empty
💀 wow i kept thinking it had smt to do with zero vectors
that anything could be either the 0 vector or any element
we do that a lot in math lol
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does anyone have experience when it comes to N-bit shift registers (bi-directional), its not really math related but logic related
the question is to Design a 4 bit bi-directional shift register
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In math currently (sorry its in french) we need to learn how to graph functions by transforming the default function into the given equation using a transformation table known as BDX AMY HAX KAY(B divides x, H adds to y, a multiplies y, k adds to y) I dont exactly know how to use this table and we HAVE to use the table in order to complete the test
(sorry for the bad handwriting)
<@&286206848099549185>
Other option is to write a full paragraph on why this is studpid and I shouldnt use that. Could someone give me some solid reasons on why not to do it?
@dry tulip Has your question been resolved?
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HELP
You have to say what you want 
Does this look like a help channel to you?? 
@limpid kindle Has your question been resolved?
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how can i find the antiderivative of f(x)=(5sin(t))/cos^2(t)?
take u = cos(t)
consider
sin(x)/(cos^2(x)) = sec(x)tan(x)
Rewrite it as 5 tan(t )sec(t)
And it’s a common derivative
wait, why is there x and t ?
f(x or t)?
@vestal mist Has your question been resolved?
Oh yeah that makes sense
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Can someone explain this (I just saw on TikTok so maybe it’s not true.)?
Why is it 2-
And I thought you could only bring the limit inside if the function is continuous
it's 2^- because it's approaching 2 from the left hand side
I’m not seeing how it’s approaching from the left hand side
from below (values less than 2)
like if you turned it 90 degrees you can see that as x approaches 1 it goes towards the left
i misspoke but that's what i meant
how's the limit of h(x) as x->1 equal to 2 from the left hand side
Oh so like as x goes to one h(x) goes to 2 from below?
follow the curve
Like it’s slightly less than 2
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@gilded peak Has your question been resolved?
<@&286206848099549185>
!show
Show your work, and if possible, explain where you are stuck.
im not sure where to start because theres no standard deviation or mean given, and i dont know how to use the probability given to calculate it
@wary condor do u have any ideas?
Yeah, you should start by relating that probabilty to the CDF for a normal r.v. variable
For 2009, we are given that $P(6 < x_{2009} < 12) = 0.8$
Xenophon
right?
yeah
Can you write that probability using the CDF of a normal r.v.?
like Fx (x) = 0.8?
It won't look exactly like that
ok let me see how use it
no i havnt
yes i have seen that one
yes i have
Okay
i know how to use the zscore, but i dont know how to find it here
I'm going to make the assumption that the mean for each event is at the center of the given range
I think that's reasonable given the context
yeah
now, using that assumption, write this in terms of the standard normal distribution
And you will be able to solve for the standard deviation
so it would mean the area between the mean and 12 and the area between 6 and the mean is 0.4 each?
yes
how would i use the cdf formula here or is looking up the z scores all i need to do?
Z scores are related to the CDF of the standard normal dist.
oh okay
thanks
for this , would it be able to assume the mean is 9 because its in the middle of 6 and 12?
or thats only determined after i find sd
yes
I don't think the problem can be solved if you try to assume that any mean is possible
oh okay
the thing is if i assume the mean is 9 therefore a sd of 3 , then what relevance is the given probability?
The sd. need not be 3 just because the mean is 9
The given probability gives you the width of the distribution
ohh right
i.e. what z-score gives you an area of 0.4?
1.29
this is the standard deviation?
i mean 1.28
actually my mistake thats just the z score of 9
You want the z-scores of the boundaries
would the area of the zscore of 12 be 0.9? i really dont know what to find
No
You want $\phi(z_{u}) - \phi(z_l) = 0.8$
Xenophon
Xenophon
$z_u$ is the z score you get when x=12
Xenophon
oh okay
u for upper
Since the normal is symmetric, this is equivalent to $2\phi(z_u)=0.8$
Xenophon
And since mean is in the middle of the range
i found the zscore of 0.4 its 0.25 right? how do i use that
show your work
i just looked up 0.4 on the zscore table
oh okay 1.28
https://gyazo.com/e77c4c6319fb73013372c229e715a0c4 why wouldnt this one work?
I don't have context for what that table is talking about
oh alright
(x - u )/ sd
yep
i thought to plug those values but the 1.28 isnt the real z score of 12 so is it possible to do it?
Xenophon
here
okay thanks, this works even though 1.28 is not the real zscore of 12 but the area between 12 and 9?
You're confusing a few different things
The area between 12 and 9 is 0.4
The "z-score" is the argument of the standard normal cdf
So P(-1.28<z<1.28)=0.8
oh okay that makes sense
This implies that $P(-1.28< (x-\mu)/\sigma^2 < 1.28 ) =0.8$
Xenophon
As required by the problem
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would this not be -u(t-2pi)sin(t-2pi) or am i missing something?
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Let a∈R and f be a function defined on all real numbers. If there exists a function g, defined on all real numbers, such that f(x) - f(a) = g(x)(x-a), then f(x) is differentiable at x = a.
Is this true or false?
think about what (f(x)-f(a))/(x-a) means in the context of derivatives
well its the definition of the derivative if lim x--> a of that exists
yeah
and if g(x) is defined on all real numbers
what is it saying about that limit
because that also means g(x) is defined at a
erm
whats the last word here
exists...
yeah
er i guess the issue i had here
is this "counterexample" (or so i hope)
f(x) = 1, x ≠ 0
f(x) = 0, x = 0
g(x) = 0
if i say f(x) - f(0) = g(x)(x-0)
then i get f(x) = g(x)(x)
the right would be 0 but the left would be...?
i dont know if f(x) is 0 or 1 here
it is
because f has to be continuous at least
cuz dont think about g for a second
its impossible for f to be discontinuous and differentiable at the same place
well you know that any discontuous function is a counter example
so i think generally the statement is false
but i need it to satisfy both conditions for it to be a valid counterexample no?
it needs to satisfy f(x) - f(a) = g(x)(x-a) as well as being not differentiable at x = a
ah i just realized i didnt write it as an if-then statement in my original question, my apologies
wait
i think its true then
mb
if its not differentiable at a
i originally thought it was true too- but then i dont know what to make of the "counterexample" i wrote above
then lim x->a (f(x)-f(a))/(x-a) doesnt exist
so g(x) doesnt exist
so its impossible for both requirements to be true
the thing with your counter example
is that like
ok so you have (f(x)-f(0))/(x-0)=g(x)
yes
yeah..?
but because its not continuous at 0
f'(0) doesnt exist
and g(x) has to have a value for all reals
and zero is a real
ah wait i just realized you're doing the contrapositive right
yeah basically
wait so if f'(a) doesnt exist
then g(a) doesnt exist
which is a true contrapositive
so we know the original statement is correct
wait im sorry how did you reach that conclusion
we have if g(x) exists on all reals st g(x)=(f(x)-f(a))/(x-a) -> f is diff at x=a (same as f'(a) exists)
with constrapositive we have
if f'(a) DNE -> there doesnt exist a function g(x) defined on all reals st g(x)=(f(x)-f(a))/(x-a)
we know g(a) is equivalent to f'(a)
yes
If g(a) DNE -> there doesnt exist a function g(x) defined on all reals
which is a true statement
cuz a is real
for this line i just substituted g(a) in for f'(a)
substitution property of equality
isnt f'(a) defined as the limit
we know g(a) = f'(a)
whereas g(a) isnt a limit
g(a) is just the value of the limit
is f'(a) Does not exist then theres no value to the limit
so theres nothing for g(a) to be
yes
okay
then one more question i guess
why is the contrapositive f'(a) DNE --> there doesnt exist a function g(x)
ok
shouldnt it be f'(a) DNE --> every function g(x)?
wdym
the opposite of there existing is there not existing
because the negation of "there exists a function g(x)" would be "for all functions g(x)"...?
is that wrong
yes
The opposite of g(x) exists is g(x) does not exist
or i mean
yes that is wrong
i was taught that the negation of "there exists" should be "for every" though, why is that incorrect here
ok think about a different example
If an animal is a dog then theres a person that exists that has petted it
The contrapositive according to you would be
For every person that has petted an animal it was not a dog
That doesnt make sense
wouldnt it be "if every person did not pet an animal, then the animal was not a dog"?
like a statement such as "if there is a math class being held, then there exists a student that will not fail". Then the contrapositive would be "If every student will fail, then there is not a math class being held".
every student failing is equivalent to there not existing a student that will not fail
so yeah ig you could think about it like that
idk for me it just makes more sense to go from there exists -> there does not exist
okay okay thats fine
but what does it even mean that every function g(x) satisfies those conditions
nvm
i got it
i need to negate the conditon too
my bad
every function g(x) that is defined on all reals such that f(x) - f(a) ≠ g(x)(x-a)
ok im sorry for taking up your time
i am good now
thank you very much
np
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Hello
$\int_{0}^{\pi}\cos\left(x\right)dx$
LE SSERAFIM
How do I represent this as Riemann's sum?
wdym?
for example does it tell you to make a reimanns sum of pi/2 or pi/4?
or 3 sub intervals
or 4 sub intervals
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Yeah it is
the riemann's sum can be approximated by evaluating it for a finite number of subintervals. for example the following is a left riemann sum approximation for the definite integral above using 4 subintervals
1^2 Δx + (1 + Δx)^2 Δx + (1 + 2Δx)^2 Δx + (1 + 3Δx)^2 Δx
divide the interval of integration [1, 2] into 4 subintervals of equal width Δx
do you know how to do that?
sorry i dont know what i talking about
goodbye
i tried
$\frac{\pi-0}{n}$
LE SSERAFIM
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Don’t understand why the transpose part is there
$||x||^2 = x^Tx$
ΣΑCu
replace x with lambda*a + mu*b and expand
@azure trench Has your question been resolved?
important to note that ab^t is not the same as b^t a
you're probably getting b^t a + a^t b
if you're using this equation
Yh did it again and got this
Oh and a^T * b = b^T*a?
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I need help
Do you remember what tangent means?
Find theta and then use tangent:)
no i don't
How do i do that>?
are you familiar with what tan does in a right triangle / sohcahtoa?
no
adj, not alt
yes my brain is funky rn
applying that, focussing on just the triangle,
what is tan(theta)?
4
focussing on just the triangle,
yes
tan θ = 20/x
and that has the numerical value of 4
ok
so to find x,
solve
20/x = 4
yes
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Stuck
If A is n×n orthogonal matrix,then A(A^T)=n×n identity matrix
(A^T is the transpose of A)
Use this characteristic to prove
What just pick an example and do that
I like method but they’ve done it some other way
I don’t really see how they get to the conclusion just from that
It's the same with what I mentioned above
A(A^T)=I→A and A^T are the inverse to each other
i.e. A^T=A^(-1)
Then you can prove it like the answer
orthogonal matrix is invertible so you can prove by this way
If use this to prove
det(AA^T)=det(I)
→det(A)det(A^T)=1
Because det(A)=det(A^T) for any square matrix
We can rewrite
[det(A)]²=1→det(A)=±1
Oh i think i kind of get it
Oh shit
So ur saying that determinant of identity matrix is where the 1 comes from
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Hii guys
I have a question in my real analysis homework , ( English is not my main languague so i used chat gpt to translate the question )
one of the first azo supported uses of gpt on here
I have this question and i already showed the Lagrange Theorem
But i dont understand the next part of the question
Cause if f has a non-finite derivative at some point lets say a point c ( that is between a and b) , it means that the function is not differenciable there so you cant apply the Lagrange Theorem right?
And the same thing with the second condition , if you dont have a point (c) in the intervel a b , it means that you cant apply the theorem so you cant conclude nothing
Thank you for your attention, but still i am not 100% sure , cause did I really answer the question? Perhaps this is more a matter of interpretation, but the question asks for the conclusions that I can draw from the theorem considering these conditions, and I merely stated that it is not applicable under these conditions.
So i didnt conclude nothing
But i dont know , cause for me the question doesent even make sense in the first place
cause like we discuss the theorem cant be applied
thats pretty much it, the conditions arent fulfilled so you cant really accept the outcome of the theorem
ig its not impossible that such a derivative exists in that region, but the theorem also cant be used for it
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Soosh
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give an example of an integral with such a u-sub if possible
$\int\frac{dx}{x^3\sqrt{x^2-9}}$
Soosh
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and here you propose u = 3tan(theta), right
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Not sure what to do after this
You know the integration of 1/x²+a²?
is it x^-1/-1 + a^-1/-1
sorry
tan^-1(x)?
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I dont know what exactly this is asking, no one on chegg has been able to do it. No radian value appears to work
i think they want the angle of the line to the horizontal line
so the tangent and inverse tangent?
this angle i think
oh wait
is it asking how many of the "red" circle can fit in "blue" circle
i dont know exactly, it wants me to use inverses though
<@&286206848099549185>
But here do we agree that teta = Pi/3 and 2pi/3 in order to get h=0.5 ?
@leaden spade
I think? it might if were measuring by the unit circle
@leaden spade Has your question been resolved?
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@still temple Has your question been resolved?
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if you have a matrix A and you multiply it by its eigen vector, why do you get the eigenvector back
okay this is bad
i dont think my intuition of eigenvectors is good
i know how to get the stuff
but like
does it just scale a vector
A just scales its eigenvectors yes
scaling != "getting the vector back" in my book
you can scale with factors which are not 1
also i want to use my intuition to understand why an inverse matrix shares the same eigen vectors but reciprocal eigenvalues
I also want to understand why you can just raise the eigenvalues to powers if you raise some matrix to the power
i am finding eigenvaleus difficult to measure
visualize
idk
well the inverse matrix reverses the action that was done by the original matrix
so if A scales the vector x by a factor lambda, then A^-1 will scale back that vector by a factor 1/lambda
well A^k x amounts to scaling by lambda, scaling by lambda .... k times, so in total x would be scaled by lambda * lambda .... k times : the total scaling factor becomes lambda^k
yea
honestly just computing the result is easier to remember in this case
also can you explain what the point of SVD is
one way to understand SVD is that it's a way to generalize diagonalization to rectangular matrices
with singular values playing the role of the eigenvalues
it allows you to see which directions are the most important in a transformation : the greater the singular value associated to a singular vector, the more the singular vector contributes to the final result
also whats the importance of similar matricies
you can create approximations of matrices (by only keeping the most important directions), which are in some way the best you can do
I do know it's very useful in image compression, since the diagonal matrix is from largest to smallest values so you can ignore the smaller ones
A and C represent the same transformation in different bases
B C B^-1 is just a change of basis
thats another thing i dont get
a change of basis
i watched a video of it
by 3blue1brown
but i still didnt get it
you want to do all linear algebra lord
like why are you translating the basis
idk my class doesnt really teach why, they just show the formula
gotta find a good book/video if your class sucks then
we can help to some degree
but a full class is too high of a bar
basis are kinda cool
its like finding all the possible lines in some dimension, but like without the fact that you can duplicate other vectors
so its like all the unique vectors that exist
one book I like is "linear algebra and learning from data" by gilbert strang
and since you want to do ML at some point it's prolly a good mix
aight
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what do i do to prove this
do i just use how its defined
like
it seems so obvious but idk how to properly prove it
Are you using ε-N definition of a limit?
Yeah so unpack that definition for sn and tn
And then try and find the right N to prove it for rn
yeah i did that but idk how to find the right N
Have a think about what you need N to be bigger than to get what you want
Write out in detail what you need to be true and what you know
@timber hull Has your question been resolved?
ima be honest i have no idea how to go about this
<@&286206848099549185> someone else or something more useful pls
you have an N for s_n, and another N for t_n, so wihich one of this two N could you use for r_n?
i dont know what your question is. if you think it makes no difference, then you can choose any.
then how does it make a difference
ok. lets go back. you asked "but idk how to find the right N", so when is an N the right N and when it is the false N?
the N is > epsilon?
well, then you have the answer for "how does it make a difference".
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what is the equation of the following function in the form y = ab^x +k where the coordinates are (-2,8),(0,24),(2,72),(4,216).
a and k both need to be determined though
Is that -6 asymptote a different question
yeah, but same format though
you could just notice the pattern that every time x changes by 2, you multiply by 3
ik. that would probably be truee, but im not sure if my teacher would dock marks for not showing work
you can subtract your 2nd equation from your 3rd and the first from the second to cancel out the k
they you just have a system of 2 euations
k, let me try that outt
doing so gives, -16 = ab^-2 - a and -48=a-ab^2
not to sure where to go from here
@mental phoenix Has your question been resolved?
@mental phoenix Has your question been resolved?
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how do you prove this?
b=ka for integer k
I want to show b=t(-a) right?
for integer k
so pick k= -t
does this work?
thats all
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omg
no way
holy shit
calculate $w'(t)$, and then apply the formula $v'(t) * w(t) + w'(t) * v(t)$
nosqldb
and then take a nap ig
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what topic is this?
i have no clue lmao
i think descriptive geometry?
I mean i don't see any symmetry
these are supposed to be cases where mean = median btw
if that gives any insights but idk anything beyond that
<@&286206848099549185> , does anyone have any clue?
maybe has to do with frequency. there are two modes (repeating values), 1 and 13, both on either side of 9 and are max min values
@severe island Has your question been resolved?
could you elaborate
honestly just based on intuition this doesn't even look symmetric to me lol
this makes sense yeah but idk the whole idea of having 4 on one side and 3 doesn't make it symmetric?
mode is 1 and 13 on the on the let and right
but then you have 2 and 5 on the left but only 12 on the right
if there are multiple types of symmetric properties then the symmetry you mention, the count to left and the right of center, is not the only type of symmetry that can describe the set
okay then what type of symmetry is this
and where do i even read about this
also the medians of the modes and the median are the same 1+13/2=7 and sum of the set/count of the set =7
no reference to give you, just reasoning and definition of symmetrical distribution
lol
so do i just
okay i kinda can see
is an evenly spaced set a type of symmetry?
all of my responses should be prefaced by a big maybe because i am not certain about this question but am tryiing to think it through
is there a part to the question above the text "Two possible cases..."
nothing
it's a "flashcard" lol
WHen i click "when mean = median"
i think this is a typo
did you calculate the mean and the median of the set and then check that they equal?
because they don't
you're right
,w mean {1,1,2,5,9,12,13,13}
Weird right lol
well that is the within the definition of a symmetric distribution
mean=median and sometime mean=median=mode as well
So they just constructed one?
And technically i wouldn't be able to spot just on cursory glance right?
Cuz they look like random numbers to me
they are giving you an example
Yeah but they're giving me two cases, evenly spaced and symmetric
it's trivial to spot an evenly spaced case
can i spot a symmetric though?
I could if it was continuous cuz it'd resemble something of a symmetric gaussian curve
If i don't require to be able to spot a set = symmetric then ig i won't worry about it too much
the fact that they mentioned "spot symmetry around 9" kinda feels like they're suggesting that a pattern exists for me to instantly spot a symmetric set (had another one popped up)
well with an evenly spaced set the mean=median always
Yes but i can spot ane venly spaced set right
{-2,0,2,4} okay boom evenly spaced set
now i can leverage mean = median
oh yeah for that question it wouldn't, but what if they give me a huge set?
excel!
per question
i see
it's still easy for evenly spaced
but symmetric is not so easy cuz where's the pattern
even without knowing mean = median
that's why i was curious
calculator allowed?
basic calculator?
basic yes
my guess is the test takers would not give you an impossible task
so it would be a set of reasonable size
no my issue is, they could give me the mean of a set (let's say one that's "symmetric") and ask me to find the median, but if i can't even identify it's symmetric then i wouldn't be able to give the set's median right?
hmmm
they're not going to ask computation heavy stuffs yeah
that's right
yeah but that'll take forever?
its the mid-value
like if they give me a set of even numbers between 101 and 901 i can solve for the mean
Imagine an analogous version but it's "symmetric"
{1,1,2,5,9,12,13,13,...} like 400 elements of this 😭
they wouldn't do that because its not reasonable to count up to 200 and 201
why do you think the set would be that large
Okay so your proposal is that the symmetric thing isn’t a big deal and it’s just giving an example and I shouldn’t worry too much about it right?
idk how they can construct the set
but i can see them being able to construct one
definitely a mathematician can ig
And then I’d be expected to realize it’s symmetric but I don’t see any symmetry lmao then I’m doomed
If it’s supposed to be something I shouldn’t be able to spot instantly then okay, just making sure I’m not missing anything
okay, i see like if they give a set that is constructed from a sequence
anything that'll give something like this ig
all the values are not explicitly listed, but you could find the center value of the set by the index of the sequence
wha tabout mean?
thinking you'd need every value of the set to calculate the mean if it was not given
okay i'll just assume this is something on the dark side and not venture more into this
the symmetric thing
or you could do sum of a series and divide by index amount would give you mean