#help-39
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We know $Av = \lambdav \implies A^5v = \lambda^5v \implies \lambda^5 = 1$ so we define $p(\lambda) = \lambda^5 - 1$. Thus $p(A)$) = 0. p(A) is not necessarily the minimal polynomial or characteristic polynomial, but if we have some mimial polynomial $m(\lambda)$, then $m(\lambda) | p(\lambda)$?
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absolutely!
does $p(\lambda) = \lambda^5 - 1$ necessarily split into linear factors?
toast
ok thx, and
ah wait, you said linear factors
yeah
idk
oops
$p(\lambda) = (1-\lambda_1)(1-\lambda_2)(1-\lambda_3)(1-\lambda_4)(1-\lambda_5)$ so $m(z)$ is some product subset of $p(\lambda)$ for example $(1-\lambda_3)(1-\lambda_4)$, thus $m(z)$ has distinct linear factors thus it is diagonalizable?
toast
everything there is right except for the claim that m(z) is some strict subset
m(z) has to have the same roots as the characteristic polynomial of A
hm
a couple of the details are a bit fuzzy to me right now 
hahah thats okayy
do we know the size of A as a matrix?
is n >= anything?
hmm, you know what? 
I think you're right
wait sorry, I meant to react to this
hm
here's what I think
here is the theroem
A matrix is diagonalizable if and only if its minimal polynomial has no repeated roots
if n >= 5, then the char poly of A, c(z), needs to have at least five roots and m(z) needs to divide it while having the same roots, right
yes!
then because m(z) divides our p(z), and this p(z) is a product of linear factors, p(z) must be equal to m(z)
ye
so m(z) splits into linear factors and we're done
do we need to consider the size of n?
if n < 5, then m(z) must have less than 5 roots while still dividing our p(z)
ahh
in that case, m(z) is a strict subset as you claimed earlier
so if n >= 5, m(z) = p(z), n < 5, m(z) is a product subset of p(z) bc m(z) | p(z)
mhm!
and the reason it splits into linear factors is simply bc of a standard result with complex numbers?

sorry it took me a while to get the details down
it's been a hot minute since I've had to think about min polys
good luck with your review!! 
yeah no worries hahah
i have one more question i couldnt figure out actually 😭
Let $\sigma$ be the largest singular value of a square matrix $A$. Prove that if $\lambda \in \sigma(A),$ then $|\lambda | \leq \sigma$
toast
what's \sigma(A)?
uhh
the spectrum of A?
yes
ye
iirc, the largest singular value is the operator norm of A, yeah?
in this context, it's just a norm for the matrix A
the precise norm doesn't matter idt, though the common might be the Euclidean norm
that's the one where you compute sqrt(sum of |a_ij|^2)
in any case, the basic inequality involving matrix norms is $\norm{Ax} \leq \norm{A} \norm{x}$ for $x \neq 0$
higher!
if you have access to this inequality, the problem should be very quick
oh hm
if not, then I unfortunately don't know how to do the problem as of yet 
suggestion: fix an eigenvalue lambda and leq v neq 0 be an eigenvector. then ||use the defn of an eigenvector, take norms, and use the above inequality. recall that ||A|| = sigma and conclude||
i see give me on sec
okie
so
let $\lambda \in \sigma(A)$, then by definition, $Ax = \lambda x$ and $|Ax| = |\lambda x| = |\lambda | |x|$
toast
we also know that $|Ax| \leq |A||x|$
toast
so then $|\lambda | |x| \leq |A| |x| \implies $|\lambda | \leq |A|$
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but is $|A| = \sigma?$
toast
yes, by definition
er, not by definition actually
it's a fact that I've forgotten how to prove 
😭 hahaahaha
it seems like you're following Axler
I have no idea if he ever talks about the operator norm
if he doesn't, then this is an invalid proof 
my teacher makes is own set of notes
loll
does your teacher talk about norms of matricies/lin maps?
he talks about the modulus of a matrix
hm, that seems to be a slightly different concept
mhm, that's not quite the same
mhm, it's probably not here then
maybe we can perhaps just use SVD?
I'm genuinely not sure how to do this problem then, I apologize
maybe? I'm not sure where you'd go with that approach, but I guess it can't hurt to try smth 
no worries ahahaha
i wish he put solutions to thes eproblems
but i think he makes his finals directly out of these questions
with maybe slight modifications
icic
let me know if you find a solution to this problem
I'm curious to know how it's done now, but too tired to continue thinking about it 
ahahaha no worries
@warm elbow Has your question been resolved?
actually @prime bramble
could we just do soething liek this
$|Ax| = |\lambda| |x| \leq \sigma |x|$
toast
bc like
$\lambda \in \sigma(A)$ and $\sigma \in \sigma(A)$ and $|\lambda| \leq \sigma$
toast
aren't we trying to prove that |lambda| <= sigma?
you can't just use it in the proof
Over C this statement is true for any n
hello
Hi
hi
hiiii
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So for some reason the pattern I get is 0,1,2,3,5
I assume it can be viewed as finding maximal overlap. Like triangle A and its reverse B
If you manage to move A and B such that their intersection C has the most many dots, then |A|-|C| will be the answer?
you mean B and C?
And I also guess there might be two sets of answers, one for odd, one for even
Then yea, that could be one way to go about it
Ye, thats what I was thinking
So you're suggesting I go further?
Yeah. My hypothesis is the patten might be recursive, P(n) has something to do with P(n-2)
I see, I'll try that.
Let’s explore few more terms together. And verify them first
Mine: p_6=||7||, p_7=||9||
Yea, got the same
My hypothesis is p_2n=n(n-1)+1, and I am coming up with a hypothesis for odd too
<@&268886789983436800> troll
Or maybe the answer is mod 3 recursive. Maybe it’s time to consider whether there is any recurrence
Like I also believe p_(3n-2)=(3/2)n(n-1). so not sure I should proceed mod 2 or mod 3
@thin eagle Has your question been resolved?
I see, unfortunately I'll get busy with something else so I'll close the channel for now.
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To construct pull back of f:A->C and g:B->C Consider how you can construct morphisms A prod B->C
🙌
What does you reply mean
Anyway, there are two morphisms A prod B -> A, A prod B ->B, use them, what are the two morphisms A prod B->C enter your mind?
You are overthinking
^
the two projections π1 π2
To C
oh those are from c
Those are from A prod B to A and to B respectively, i need two from A prod B to C
You have f and g here
Really? Can’t see any?
A×B---pₐ-->A
| |
pᵦ f
| |
v v
B-----g--->C
f and g
<f,g>
No
Oh you mean to C--->(A×B) from A and B?
No
I can’t continue, f•p_a and g•p_b. Now prove by definition the equalizer of these two is a pull back of f and g
I don’t understand why you shift your attention and focus on something else, so I had to tell you what those two morphisms are
( any p: D->A, q: D->B such that fp=gq, <p,q> factors uniquely through this equalizer)
Have to go running
Thanks for your help @naive zinc
f:A→C, g:B→C
p_A,p_B: A×B→A,B
eq:
E→A×B
equalizes f∘p_A, g∘p_B
∀p:D→A, q:D→B,
f∘p = g∘q
→ ⟨p,q⟩:D→A×B
factors uniquely through eq
∴ E is pullback of f,g
This is what I said, which is a sketch not the whole proof
You need to prove it, in full
I have a 15 min walk to bus station
@void grail Has your question been resolved?
Arrived. e:E->A prod B being the equalizer, <p,q>=er for some r: D->E, as you desired. Showing uniqueness I left to your own
This has a more general result:
small (co)products + (co)equalizers -> small (co)limits. Left to your own, similar idea
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Do i just apply mod term formula here
Mid term
whats mid term formula
add a new name to the diamond list
?
is the midterm formula the one with the X?
yes\
Turn 9x into 5x x 4x
5x + 4x instead
Alr
yes
later on youll learn a method that goes by a lot of names
that method has you draw a big X
you put 9 at the top and 20 on the bottom
then on the left and right is where youd think and then figure out 5 and 4
Wb thus
for this one, remember that $a^2b^2=(ab)^2$
mtt
ab=x
yoda is then saying you can replace ab with x to make it easier to process
since all youre seeing is just ab
see if you can recognize or factor x^2 - 10x + 25
Yes
that took a while but now that its in your head,
Im gonna replace y with the the letter c
and you read it as standing in place for a number
(x + c)^2 = x^2 + 2cx + c^2
and you have x^2 + -10x + 25
Oh
lol
Then js use midterm
this is a special formula if the terms you split apart into are the same
lot more symmetry so its easier to recognize the pattern instead of noticing you have to split it in half
this is useful for example for x^2 + x + 1/4
thats (x + 1/2)^2 which is hard to see
hey im a high school student very interested in maths and new to this server
hi there, go chat in #discussion
can i tell smthng i have completed grade 12th maths and also learned calculus
thats why im here
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im in grade 9 and imbored so imhere to help others
where should i go to help others wiuth hard problems
can someone pls tell
CAN YOU READ THIS, PLEASE? @worthy urchin
sorry
wlcm then
ok this one took me a while
idk how theyre showing you this if you dont even know the X method (otherwise known as the diamond method) yet
for this one, go look at xy - 3x - 3y
do you think you can factor xy - 3x - 3y or nah
if you write it as (x^2 + xy) - (3y + 3x) you should be able to continue factoring this
yea thats easier than what I was gonna go with
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I Wrote my answer to this Question as 3,8
Am I correct?
Its making an estimate
Can someone tell me if I got this correct
you need to be more precise than that
say, the biggest root looks to be around halfway between 9 and 10
Would I get the marks for 3,8?
no
Its 2 marks
you'd get 0/2
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does anyone know how tho solve this? I dont know know any formula that can help
maybe this could help
i was about to suggest that you mark the centers of each circle and also connect them all
how can that help ?
Area of shaded = area of triangle - area of 3 sectors
area of sector is about 32π/3 I think. the area of triangle is just √3/4*a squared right?
area of sector is about 32π/3 I think
area of each sector would be exactly that
are you using calculator mid-problem again?
yes, and a is what?
lenght but i am kinda stuck tere currently watching a youtube totorial on how to solve
think about how the length could relate to radius
radius is distance from center to any point on the circle
*circle, not triangle, sorry
yeah but the height is still gona be longer tho
what height? You dont need height, you only need side of the triangle
try splitting the sides in the middle
wait isnt it heigh 8 base?
height * base / 2? Yes, thats one formula for triangles area
area of triangle is just √3/4*a squared
This formula works fine for equilateral triangle tho
so why not use it
i was doing that but got no iea what to do with the root
i never did that type until now
sqrt(3) = sqrt(3) is just a number
leave it as such
work with it same way as you would pi
keep values exact
are you using calculator mid-problem again?
root3 is root3
leave sqrt(3) as sqrt(3)
sqrt(3) is irrational and can't be represented with a finite number of digits
u dont need to plug decimal for everything right away
ok
and the question implies that you want your end result to have a radical and pi
so just leave the area at root 3 * 16?
that's not the correct area,
be careful of the value you use for a
value of a=8
no
8 is the radius of the circles
however the side length of the triangle isn't just the radius
as indicated by the pic above
I am at the last part wheree its just sqrt 3 * 64-32=a sqrt b-c. I am stuckk how to remove the roots
@bold lynx Has your question been resolved?
do you know how to do that part
32pi?
Uve to compare
nah i removed pi from both sides
U cant do thtTT
you cant?
64 rt3 - 32 pi = a rtb - c pi
How would u do tht?
idk divide both sides by pi
Here we compare. LHS the coefficient of pi is 32 and RHS it is c so c=32
Tht would give 64rt3/pi -32 = a rtb/pi -c
ohh i see
Now whay can u say for a and b?
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Can someone check and lmk if this is correct
,rccw
you missed half the problem in i)
You only calculated g(1)
oh, i just saw the right part, i guess thats a -3
Oh yeah i juat realised
in ii) you plugged f(x) wrong, its 5x + 7, not 5x - 7
for iii) you can simplify it further too
and iv) is actually just a theory question
you dont have to do anything fancy
it is not really a simplification
Do you recall the definition of an inverse function?
Could you solve it? Im stuck
Thats how you algebraically find them
i want to believe that at some point you saw the definition of a function as something like this:
$f: A \to B$
Where A is the domain, and B is the codomain
And from here, you also saw what injective and surjective functions are
and why bijection is important
\log_2(x - 1) + \log_2(x + 3) = \log_2(4x)
Can someone help me please
@viscid shale can u
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@teal rose
actually, 0580 is igcse and they don't cover that
it's okay thoguh
Yes
right
you rearranged to get it in terms of this other value
so what would happen if you rearranged it for the other value again
Can someone solve it and send me the working if possible?
it's ok lets go through this
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Ik how to do f inverse (x)
actually wrong factoid
forget finding the inverse for now
focus on this
Uh i dont really get what u mean tbh
okay, let me reword it
to find the inverse of y = f(x), you essentially set x = f(y) and rearranged back for y, right
what if you wanted to find the inverse of the inverse
what would happen
Inverse of the inverse?
yes
Huh
what would happen
Is there a board where u can show me or smth
I rem this server had some white board u can plug fractions into
hmmm
Ill give a really basic problem related to this idea.
Try to find the inverse of f(x) = 2x + 1
Y : 2x+1
Y-1 divided by 2 = x
So whats the resulting function in terms of x?
Y-1/2
- parenthesis are important
- thats in terms of y.
remember you "switch around" x and y at the end
Whats a parenthesis-
brackets
( )
Yeah
Oh
Idk bro im stuck
X-1/2
So f(2) -1/2
(x-1)/2 is good
Try to find both fg(x) and gf(x)
if you get the correct result, both should look the same, and also show a really important fact about inverse functions.
Can u check if this is accurate
youre missing the point in this, you dont even have to do any math to solve the problem in your paper.
Is what i dis there accurate though?
Yes
Also do i need to solve it further
F(2)
In which i add the values and further solve it?
Youre doing work just for nothing, but yeah, ig.
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seeing by your previous channel, have you been attempting your questions before posting? if not, can you please try to do so?
if you did, please go ahead and say what you tried and/or why you got stuck
right, so what do you know about theta/2 ?
yeah, what about it? particularly its sign?
its negative
and since its tan, what does that tell you about its quadrant placement?
also, isn't 1/root 3 familiar? do you have something you can reference it to?
yeah my bad, I meant to add tan but it skipped my mind lol
No need to apologize. We all make mistakes 🙂
So
i dont know what the 1/root3 means
but i know that its in the 2nd or 4th quadrant
do you know how to find a reference angle, especially now since you know what quadrant(s) youre working with?
im familiar with it
but i dont think im confident
in this case
and am i not meant to take hte absolute value menaing that it would be in the 3rd or 1st quadrant
or is that something else
oh, I see where you're confused, just to remind you then, you should know that tan(30) or tan(pi/6) = 1/sqrt of 3. this is what I was hinting at earlier, but you might've forgot. can you move forward knowing this?
i wouldnt have known that
it was part of foundational trig if you aren't familiar with that, if you'd like I can explain it to you pretty quick, although they are just values to remember/memorise
its ok
^ I know you are concerned about the 1st and 3rd quadrant, but lets focus on the 2nd and 4th now, because it has already defined to you that tan is negative and where its two solutions lie
ok
wanna go ahead and try and tell me where you get?
feel free to post pictures of your work, it's easier for me that way too
so you're on the right path, but heres the first thing - your question was given is radians, not degrees. and so was your range. I get why you used arctan here, but its application is redunant, as we have already defined what tan(1/sqrt3) is (pi/6). wanna give it another go with radians?
unfortunately the error from your previous work compounded here, giving you an incorrect final answer, but you are headed in the right path at the end (angle doubling, quadrants, etc)
you're really close, that arctan bit and turning it into degrees is what got these errors, so just fix 'em and we'll be back on track
(and PS, 360-18 isn't 362, keep an eye out for that)
are you familiar with this chart? (knowing that 30 degrees is equal to pi/6)
yes
is this a time sensitive problem? if not, you are free to go rest and come back another time. math is hard to grasp when you're tired
not off the top of my head but we have a formula table for it
na i just need to get study done exam tmrw
its only 8pm im good
i dont understand how this helps
its the key to understanding the problem, its the reference angle we were talking about at first
its the reference angle, not the solution, and also keep in mind we're solving in radians please
its better to do all your work in radians especially if you're doing it in reference to the unit circle as not to cause confusion or calculation errors
do you have any issue with radians? if you'd like, I can clear them up for you
(if anything, doing it all in radians makes this way easier to solve, btw)
i prefer to do it at the end
ill try work in radians tho
ok so 30 degrees is the reference angle
you know what, sure, lets solve it in degrees, but lets be extra careful on that convertion at the end
yeah perfect
yes exactly 😭 you did it
give me those two numbers and we can move on to the last 2 steps
why'd you add the 4pi?
because u add 360degrees n
for the general soluti
no
?
or because its not asking for the general solution i just leave it as 5pi/3 and 11pi/3
the question said "within the range" you dont have to add it
yeah exactly
its just that
ok thx
I hope you got everything, I'm sorry if I confused you at all. if you need any part cleared up better for you just ask
and if you're done go ahead and close the channel :)
go ahead, I might need to go soon though
yes, that'd be correct
show me anything youve attempted if youd like
21cm is not the area of the full sector though, hence why this doesnt work
and by the way, we know theta, as it is (I think?) 1.2rad
its okay, since you know the formula, we can just do this together,
area = 1/2 r^2 theta
so we just plug it in
1/2 x (7)^2 x 1.2
can you give me the value?
29.4
yes great, so now we know the area of the entire sector AOB, we also know the shaded area as 21, can you find the area of the unshaded triangle?
okay yay! now we have a triangle, wanna have a go at trying to find |OC|?
yes
idk what a or h is tho
half the base times the height
we cant use this, because this is not a right angle triangle
theres also no way to figure out the h anyway
yes!
where |OA| is a, which we know is 7,
|OC| is what we're getting at,
and C is the angle AOC or 1.2 rad
(if you're using a calculator, make sure its in radian)
can you show me your work? I wanna see what went wrong
if you can just show me what you plugged into the calculator
ah I see where the problem is, this is correct, but
minusing it from 8.4 is the issue
you need to divide them instead, not subtract
yeah great job :) thats all there is to it
dont forget ur unit lol
cm
I gtg now I'm sorry, hope I was of help to you, have a good rest of the night
Thank you Bubsy u too
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i dont understand what they gave the function for
because they are not using it in the limit asked
also how to find the limit? i thought write arctan(1/a) as 1/a
tried expanding tan^(-1) = 1/a ?
theres a typo in this question, wheres the f in the limit?
thats what i said
but is it a typo?
that limit -> infinity
they must have scraped the question
that must be why these all look identical
make it digital without looking twice
so a typo in the question -> typo in the digital version
i still wouldnt know how to solve it 💀
you need an arctan to get the pi/whatever
and even then the limit would still -> infinity
yea
lol that was quick, now you can
alr then i wont waste more time
you know it -> infinity now
wait what
look at what you said
this means you agree that the limit would be -> infinity if we replace the arctan with f
oh i was saying yea to this
I dont see a way to fix this question
youll notice they add a lot
then only subtract 2 ln a
with the + a^2 there there isnt really a way to get this to -> a finite number
either way its like degree 2 vs degree 0
np
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I have the answer key to this but I watched videos and everything i still dont understnad.
if 7 = 40, then 1 + 7 = 90deg. if 9 is 100. then its 190 and thats not 180 so im not sure.
I originally thought it was 50 for 7 instead of 40. and 2, I dont know how to find or how they found that.
im not sure its the district they kinda suck
Is PRST given to be a rectangle?
yes
Then you're right, angle 7 is 50º
9 cannot be 100
just look at it
(if those are degrees)
so then 9 should be 90 deg?
No
how would i get 9?
180º - angle 1 - angle 7
80º
That would imply PRST is a square
If your answer key is saying angle 7 is 40º and angle 2 is 50º, they might be swapped in the picture
If I were you, I'd first re-label the 9 angles labeled 1 through 9 to nine of the 24 Greek letters.
And work from there
In a subject where clarity and understanding are supposed to be profound, this seems rather counterproductive.
Yea, thats what i was kinda thinking too since it mixes up sometimes as well. it seems like it did swap it. i got angle 7 as 50, angle 9 as 50, and angle 2 as 40. the picture is pretty confusing to me
Yes exactly
And then stuff like 7 = 40 follows
I know it's 'angle' 7, but nobody is going to be writing the symbol 500 times here
And then we get 1 + 7 = 90°
Which not only is already confusing right now, think about a month from now when you get back to it while studying
yea, id rather label them with letters
Simply defining $\alpha = \angle 1$ and $\eta= \angle 7$ makes reading $$\alpha + \eta = 90^{\circ}$$ much more sensible
USS-Enterprise
@sinful tusk Has your question been resolved?
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A small archipelago is located at the junction of two moving tectonic plates.
The tectonic plate located to the southwest of the archipelago and represented by vector u
moves at a speed of 2.17 cm per year in the direction shown.
The tectonic plate located to the southeast of the archipelago and represented by v
moves at a speed of 2.23 cm per year.
What are the magnitude and direction of the annual displacement of the archipelago if it
corresponds to the sum of the displacements caused by the tectonic plates?
how do i find the orientation of the vector u and v?
how do i do that without an orientation
orientation is counter clock-wise no?
alrigt
we only want the horizontal components?
alright
wait v doesnt have an angle
39
not sure how i can use it
if it said like it was perfectly between 2 vectors not one being more obtuse then i would do 180-80
100/2
but it says nothing about it
ohh
that doesnt help though
40
how?
oh
what about the other side
with the blue vector
the 41?
like this
not sure if i understand but thats not the angle for the blue or am i missing something
oh wait
you moved blue vector
?
oh ok
yup
(1,67;1,46)
yeah
found it
the norm is 4,38 and the orientation is 40,09
yeah
its that
i double checked
nope
why
oh cause its going to the left
but when i did the thing to find the x component
it gave me a positive number
gotcha
so its 0
wait
let me redo
yeah same
(0,0034;2,82)
what how
wait how can it be -2,23 tho
a vector cant be negatif
ive never done a number like this
like this problem
its very different
i see
i got (3,36;-0,1)
alright
norm is 3,36
what how
how can the x be at the y spot
oh yeah
because vertical is x
this number is filled with traps
i meant horizontal mb
the orientation os
-33,6
but wait
u have to do +90
i got 1,54 after adding 90
what idd u get
why subtract by 180
but u subtract when its in the 3rd quadrant by 180
2nd quadrant by 90
or add depends o nthe context
yeah
i see now
alright tysm for helping
have a good day
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use generating functions if possible
i just dk how to deal with the modulus and complex values i can solve if its real numbers
!show
Show your work, and if possible, explain where you are stuck.
@signal sparrow Has your question been resolved?
Make the unit-modulus terms point almost in the same direction so their sum is large, while the smaller-modulus terms die out.
Actually, if number theory approach is valid, Kronecker’s theorem makes this rather trivial.
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Hey, I'm trying to graph a line of best fit and I get an equation around y=1/3x + 58 but it doesn't work when you plug in the slope in c.
Am I messing up somewhere?
When I try to check with AI, not the best solution, but when I do, it says things like y=7x+40, but that's not even near the line but it checks out for c. I don't get it, doesn't the line have to have most of the points equal on each side?
When you plugged in for part c did you make sure you plugged the value in for y and not x?
pretty sure its b
yea
90=1/3x+58
32=1/3x
96=x
it wont take 96 hours to get 90%....
I meant for the equation, and anyway if you did graph that it would just go up and away from the points
Yeah looking at it 1/3 appears to be a little low for the slope but let me run it with my calculator and see what I get for the line of best fit
I get approximately y=6.3253x+57.37308 as my line of best fit
i think i get it
Kind of similar to the AI now that I look but with a closer intercept to yours
i need a calculator lol
should you not use fractions when finding lines of best fit>
Yeah but using a calculator I can only put in decimals
It's approximately 70/11
Although that number doesn't mean much
Using the decimal tells us for every extra hour of study the grade increases by about 6, like you wrote here
alright
whats the math behind the calculation? did you just pick two points and do y2-y1/x2-x1?
I used the linear regression tool in my calculator but that would be how to do it by hand (without the tedious calculations)
Draw a line yourself that looks like it fits the data, and then choose two points on it, and do y2-y1/x2-x1
Fancy word for line of best fit
Also do you have any suggestions for learning Geometry?
No problem! I'll just add in an example with my line so you can see
alright
It kind of looks like it passes through these two points
So the slope is about 25/4 which is 6.25
Very close to the actual answer
Which is how I'd eyeball it on paper
Mmmm personally not sure since I never took it 😅 I would have just used Khan Academy since they do technically have written guides for each topic
And then anything I didn't understand based on that I'd look more into
That's what I do with my SAT students
Have them read it, do the practice, and then bring any questions to me
Since I consider application the most important
that could work
are the guides like extensive or explanatory
If you really want to learn about the meaning though a textbook is a good way to go, although I can't direct you to one
Explanatory yes (on how to do the operations), not necessarily extensive but the videos should help with that
yeah
If I do want to get into a higher class next year, I would have to test out of Geometry which would probably require a good understanding or better
can't hurt to always learn mroe
more* lol
Very true 😆 well except for time
I'm sure someone on here knows of a good way, hopefully they'll find your question
Well see! :D
Thank you for your help by the way!
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Question (c)
Now here's my issue
if this were of the form (1-t) I'm done
which can be obtained by a simple substution, I'm aware.
But is there a way around that
Consider Σ(-x)^k for k>=0. It will be a well defined sum since it will have finitely many terms
Sure
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Let $(A,\tau_A)$ and $(B,\tau_B)$ be the subspace topologies, then we get the subspace topology of $C=A\cup B$ is $\tau_C={(A\cup B)\cap O=(A\cap O)\cup (B\cap O)|O\in \tau}=\tau_A\cup\tau_B$. So, $\tau_A,\tau_B\subseteq\tau_C$, so open sets in $\tau_A$ and $\tau_B$ are also open in $\tau_C$. To show that $\tau_C$ is connected, I suppose $U\in\tau_C$ is a non-empty proper clopen set of $A\cup B$ such that $(A\cup B)\backslash U=(A\backslash U)\cup(B\backslash U)$ is open. From here I don't really know what to do. I attempted to let $U=O_A\cup O_B$ for open sets $O_A\in\tau_A$ and $O_B\in\tau_B$, but expanding $(A\cup B)\backslash(O_A\cup O_B)$ became unwieldy very quickly.
King of Ponies
$A \cup B=U \coprod V$ then consider $A=(A \cap U) \coprod (A \cap V)$ and $B=(B \cap U) \coprod (B \cap V)$
Cogwheels of the mind
U, V open subsets of A cup B and \coprod means disjoint union
(Among four cases only two will be possible)
I don't think I quite understand, I haven't worked with the disjoint union before.
A space X having a clopen subset Y is equivalent to X being disjoint union of two open subsets Y and X-Y
(And X1 subset of X2 subset of X3, the induced topology on X1 from X3 is the same as (the induced topology on X1 from (the induced topology on X2 from X3)))
Like for example, A in U and B in V is impossible, A,B both in U gives you A \cup B in U
Now I am really confused. So if I understand, a clopen set Y of a topological space X defines an equivalence relation by X disjoint union X-Y = {(x,0) u (y,1) | x in X and y in X-Y}?
I said nothing like that
I said literally what I said
Y being a subset of a space X is equivalent to X being disjoint union of Y and X-Y
Then Y being clopen is equivalent to Y, X-Y being open
Then Y being proper is equivalent to Y, X-Y being proper
I said nothing about equivalence relation
Sorry, I over inferred what you were saying.
I think I slowly understanding, so you chose two opens sets that cover the union AuB and then defined A and B in terms of how they are covered by these two sets. But what are the cases you are talking about? Do you mean if either one of U or V are completely contained in either A or B, or if they overlap at some point in A or B? But then why is the disjoint union necessary here?
$A=(A \cap U) \coprod (A \cap V)$, then since A is connected, $A= A \cap U$ or $A=A \cap V$
Cogwheels of the mind
(M=M cap N is equivalent to M being contained in N)
@hot bramble Has your question been resolved?
Oh, I think I see now. Since we choose $U\cup V=A\cup B$, then intersect this with $A$ gives $(A\cap U)\cup(A\cap V)=A$. Then since $A$ is connected, then $U$ and $V$ must overlap inside else $A\cap U$ and $A\cap V$ are clopen in $A$.
King of Ponies
U and V being disjoint is given in the beginning
The conclusion is not what you wrote, it is A cap U=A or A cap V=A
Literally what I said
I don’t have more time on this, have to go running
Ah, thank you for trying, and apologies for not getting it.
Your issue is you shift attention from what I literally said to something unrelated
I think a part of the reason is why is that I am not fully understanding the things you stated. Like you defined A as the disjoint union of intersections, and I am still trying to figure out how this disjoint unions works to define A compared to just using the regular set operations.
So I am trying to rephrase what you stated in terms of the regular operations I understand, and I think my rephrasings are then either incorrect or besides what you initially stated.
I didn’t define anything. a space X being connected if and only if for any open U, V such that X is the disjoint union of U,V, we have X=U or X=V. I was proving X satisfies this, when X is your A cup B
Anyway, really got to go. Said all you need, everything at hand, just go through them again
Okay, I'll do my best.
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,w iqr of {1, 4, 5, 1, 2, 4, 5, 5, 11}
,w iqr of {1, 2, 1, 3, 2, 3, 4, 1, 8}
How did you get the IQR of B?
What was your Q1 and Q3?
orz u 
Hmm wolfram lied to me
It said the IQR was 2.25
But it is actuallt 2.5
Must have been using a different method, but anyway
Anyways, I don't think interquartile range is the best measure of consistency, though it is one measure.
Try looking at the standard deviations.
Try looking at the standard deviations.
Looking at the standard deviations though, ||yes D is the correct answer.||
Hmm what did you get for the standard deviation?
o
No problem 👍
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if its a practice exam you should just submit it
and itll tell you
👍
don't know how anyone is falling for this shit
😭
its a practice exam though bro
shouldnt count
and?
yea you want a good grade on your final
we get it

knief you gained a lot of hubris during my year off
opens a channel for every question "aM i RiGhT wITh A HerRE"
i was calling out cheaters just as much last year?
i used to mod ping like crazy over it
no
im just laughing at you
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hello is there a french speaker who can explain to me how to do question 5)c please. I struggled with it so much that I gave up 😔
Can you perhaps try to give an English translation?
Would open the question up to many more helpers here
5c says use the mean value theorem to demonstrate that...
yeah sure just give me a minute to write it down in English
I tried and I can't figure it out
je suis la
oh salut
tu peux m'aider stp j'arrive pas à trouver la solution
je vais chercher
azy merci ❤️🩹
je pense que deja tu dois voir un accroissement avec le $\frac {f(x) - 1} {x} = \frac {f(x) - f(0)} {x-0}$
robins
oui mais qu'est ce qu'on doit faire après
je sais pas c'est chaud en vrai
ok je crosi que je l'ai
enft non
mais tu dois surement utiliser l'hypothese de stricte décroissance de h'
comme ça tu peux minorer un h'(c_x) par h'(0) ou majorer par h'(x)
@royal harness Has your question been resolved?
ouais personne ne l'a résolu
on avait 1h30 pour passer cet examen
le prof est taré
t'es en quoi ?
remplacer l'expression de f(x)-1/x par h(x)/... ne pourrait pas marcher ?
terminale
pas en france si ?
non au maroc
ah ouais c'est cque je me disais
mais quand même notre prof il est pas normal 😭😭
deja il fait des trucs comme ca et il fait pas un beau sujet en latex il abuse

