#help-0
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What is v sub 0
initial velocity
yh
O meaning ground level ig
i had this question in my exam today and i had a heart attack
Isn't √3Vo as a whole initial vel
i could only get part 1
I'm having a heart attack just reading the equation
I'm in alg 1 so this confuses me a lot
idk what alg 1
Well it's just integration differential with variable accN
Basically basics of algebra
idk if youre in australia
U might wanna put a=vdv/dx or smthg
but this is from the highest level of school math
yeah i did that
for pt 1
but for pt 2 i was frozen
I just got over with hs...we have harder problems in jee advanced
i was just wondering if anybody could help
India
whats hs?
High school
lucky
💀
looooooooool
Fr
Ok
maybe itll make me see a different perspective
So mg down air resis up?
While moving from topmost to down
Starting with hMax
I thought u only wanted help with part2
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can you get log(b) / log(c) = a from log_a(b) = c?
You mean log(b)/log(a) = c?
You get
a^c = b
from log_a(b) = c
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for a set (R/{0} x R) does it have a boundary or boundary point?
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Do you mean R \ {0} like R without 0?
R / {0} makes me think of a quotient space which I don't think is what you mean but I'm not sure
@hybrid meadow Has your question been resolved?
yup
what definition do you know for set boundary?
basically that it includes points from the set and its complement
also not empty set
mmk, we need a universal set then (so we can talk about boundary)
hmm that doesn't seem right, nothing is in a set and its complement that's the definition of complement
should have something to do with limit points maybe?
what do you think the boundary of this set should be?
im not quite sure what you mean by that
there's like three definitions of boundary so I'm not sure which one you're using
i was thinking 0 since every point beside it is in the set while it isnt
clos (R/{0})
well, the points in this set are ordered pairs
yup so basically all points with x as 0
yeah that's what I think as well
can you prove that every other point is not part of the boundary?
like if I gave you (x,y) where x != 0, how can you show that that's not part of the boundary of S
yup because if take because it would be of the form (R,R) meaning that its fully in the set
and all surrounding points are too
what do you mean by "all surrounding points are" exactly?
like this
(I'm assuming this is for topology?)
yeah, not very deep though in terms of coursework
still, you should have a workable definition of what it means for a point to be in the interior of a set

just this really
nothing about an open ball around the point being a subset of S?
that's how we usually define interior
i mean ive visualized it like a disk surrounding any interior points and as long you can move the disk with it still being in the set its an interior point
but similar to that yeah
that works for the real line/plane/space yeah
but if you're in topology you'll soon get some cool counterintuitive results :D
ahh ok, although im not sure how deep we'll get into that. Anyways what would then the boundary be though, just (0,y)?
yep! {(0,y) | y \in \R}
?close
you have to ask nicely
.close
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How to do this?
whats the task
solve it
<@&268886789983436800> troll
uhh 
@vernal arch Has your question been resolved?
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Let's consider the body K = {(x, y, z) ∈ R^3: x^2 + y^2 ≤ z^2, 0 ≤ z ≤ 1}. The density of K is given by the function %(x, y, z) = x^2 + y^2 + z^2.
We need to find the moment of inertia of the body about the z-axis. can someone help pls idk what to do
@wintry kite Has your question been resolved?
@wintry kite Has your question been resolved?
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sin15, x, cos15 are the first three terms of a geometric sequence that has all positive terms x=?
Show your work, and if possible, explain where you are stuck.
i tried something like r²sin15=cos15
r²=cot15
r=√cot15
x=sin15√cot15
x=√cos15sin15=√2/2√2sin15cos15
=√2/2*√sin30=√2/2*√2/2=1/2
It would have been faster if you used the fact that a term of a geometric sequence squared is equal to the product of its neighbouring terms
what..? (the last step)
So, x^2 = sin(15) * cos(15) in this case
2sinacosa=sin2a
Oh
so x=1/2 right?
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If we have an N x N matrix A
and we want to change it's base
we will write it as B^-1 * A * B
why is it written like that?
B is your change of base matrix
so suppose B is your change of base matrix from D to E
then you would write B_ED
and (B_ED)^(-1) = B_DE
oh
so suppose you have a vector in base D
In picture 
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What is 3×(-4)+2
yes
yeah I mean just that
so if you know the operators
then can't you find the answer?
there is this thing called BODMAS that defines the order of what operators you do first
see the last 4 alphabets
they stand for
division | multiplication | addition | subtraction
so first you'll calculate 3×(-4)
and then add 2 to that
10 right
nope
its not -10?
it is -10
We've all been there 🙂
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Let A and B be two 100×100 real matrices such that A^2 + B^2 + AB = 0. Show that the determinant of AB - BA equals zero
Show work 😄
I don't have it, this is a question of an exam I did yesterday and I didn't keep what I tried
But I basically just tried to multiply the equation of the hypothesis with A and B and tried to add things
Also tried to see if I could do something related to eigenvectors but I had no luck
I've also just done my exams in linear algebra. Did pretty well.
I can't see the answer, but we can try to work the problem together? Or I can let the chat go to an expert if any show up
$$ A^2 + B^2 + AB = 0$$
Should give us:
$$ (A + B)^2 = 0 $$ right? This should be useful
zeimon4
no
AB
this is not even true if A and B commute
The expert came
which we do not know if they do
No, (A+B)^2 = BA
yh mb BA
Cool, worked mostly with eigenvalues / vectors and determinants along with complex numbers. I'll just follow the chat 👀
For example it would be sufficient to prove that A and B have a common eigenvector
But that doesn't look useful
@ivory fern Has your question been resolved?
<@&286206848099549185>
I'm still here lol and will happily admit I'm pretty much stuck
This is a gross question
Yes
I tried it for more than an hour
At this point I believe the question might not be correctly written and perhaps there is a counterexample
u guys solved it?
Nope.
I suspect 100x100 is just to prevent direct computation, although I can't rule out it being relevant entirely. Real doesn't really matter I don't think, could be over C.
i see
The 100 might be inportant at some point, perhaps there are roots of unity or something and you need 100 to be congruent to some number modulo some other number
But maybe not
hmmm seems unlikely but perhaps
I don't see how you could get that kind of information from this setup.
And it might be important that they are real at some point for some reason but maybe not
It is unlikely, but it would not be the first time I see roots of unity appearing in linear algebra
did you remember the identity wrong?
The closest thing I found online was the following olympiad problem: https://math.stackexchange.com/questions/4337421/is-it-necessary-that-detab-ba-0
This problem is even more difficult, in my opinion, since the form $A^2 + B^2 -2AB = 0$ is much more workable.
kimbo7
So it seems possible to me that it was either misremembered or there is a crazy trick.
I should add that the method in the olympiad problem sort of gets you close to something meaningful, perhaps contradicting invertibility does work but in a different way, but I've tapped out for now.
@ivory fern Has your question been resolved?
No, I did not misremember it. I am completely sure the question said A^2 + B^2 + AB = 0
Fair enough! No idea then, this is a tough question.
But again, the exam might have been wrongly written
And can't this be adapted to the case A^2 + B^2 + AB = 0?
Currently on my 26th awake hour. Idk how I could say such thing as the above, yet I did.
By all means try!
@ivory fern Has your question been resolved?
interesting question
another way to write it is
if AB = -(A^2+B^2) then det(AB-BA) = 0
may be useful as you have AB on the right side
you can show that
A(AB-BA) = A^2*B -ABA = ... = B^2*A - AB^2
similary you can show that
(AB-BA)B = BA^2 - AB^2
can we show this in a limited case, i.e. det(A) = 0?
You can separate cases det A = 0 and det A ≠ 0, but at the end both have to be proved
can we do at least det(A) = 0?
it would imply det(A^2 + B^2) = 0
We have to prove it
just trying to see if there's an easier case from which we can learn
alternatively would be interesting to show det(AB-BA) >=0 or <=0
This might be useful too
The fact they specifically want you to show det(AB-BA) = 0 leads me to think we shouldn't just be trying to show they commute
Otherwise why not just ask to show AB = BA
I agree
My only other thoughts are somehow showing AB - BA has 0 as an eigenvalue
indeed
Maybe with some char/min poly shenanigans but nothing looked nice when I tried
anything interesting that can be said about A^2 + B^2?
honestly I wouldn't be surprised if the statement is false either
Neither I
Maybe we could look for counterexamples for A, B with 2, 3 or 4 columns and see if they can be adapted to 100×100
@ivory fern if you don't mind, ping me when you have the solution as I'm curious myself
Ok, I'll tell you if I solve it
@ivory fern Has your question been resolved?
@ivory fern Has your question been resolved?
I proved that A^3 = B^3, perhaps that is useful
AB = -A² - B²
A²B = -A³ - AB²
A²B = -A³ + (A² + B²)B
A²B = -A³ + A²B + B³
0 = -A³ + B³
the factorization in your third line is incorrect
Why?
I just substituted -AB with A² + B², which is the first line
got it didn't realize that
usually for these kinds of problems i like to pretend that the matrices are all like, real numbers, or indeterminates, or whatever. so i would factor A^2 + B^2 + AB to get (A - zB)(A - (1/z)B) for z = -1/2 + i sqrt(3)/2
so looking at those factors might be helpful
(obviously this doesn't apply word for word. A^2 + B^2 + AB isn't actually that. but hey)
like my favorite example of how i think about matrix problems is the following classic
if A is nilpotent then I - A is invertible
well okay so like, you want basically 1/(1 - x) with A in place of x
we know that that's equal to 1 + x + x^2 + ...
if A is put in for x then nilpotency kills all but finitely many terms. so this works
i try to throw this at literally everything
maybe mark spoilers 
it has to do with 3 not dividing into 100 (!)
unsurprising
that's slick as hell, imagine having to come up with this in an exam though
what level class is this?? like intro linear alg?
this feels more like a contest kinda problem than a class kinda problem
the observation you need to make to solve it isn't really linear algebra
@ivory fern Has your question been resolved?
Yes that solves the problem
But ||we have to use a sixth root of unity instead||
Yes, it was a math contest
However this problem was dramatically harder than the other three
^
ah thanks
@ivory fern reading on the solution I see they somehow use 1+w^2 = -w ?
ah okay that's true bc
1+w+w^2 = w(1+w+w^2)
and w!=0,1
Yes
Anyway that is not needed in the case of our problem
Because the proof changes at that point
it's needed for the first argument
= w(BA-AB) thanks to the above
But instead of (A+ωB)(A+ω²B) we use (A+ωB)(A+ω⁵B)
With ω a sixth root of unity
why so? the proof as it's given solves the problem
No, because in our problem we have a slightly different hypothesis
Suppose A and B are real n×n matrices with A^2+B^2=AB. If AB−BA is invertible, prove n is a multiple of 3.
and since n is not multiple of 3, it implies that AB-BA is not invertible, that is det(AB-BA)= 0
We have A^2+B^2+AB=0
ah right
honestly that's an extremely clever solution
I bet it arises through some more heavy math I'm not familiar with
Perhaps from something related to the second solution
Or maybe there is a more elementary solution
why do they bring in w^n in the solution?
" det(A+ωB)det(A+ωB) is a real number, that is, ω^n * det(BA−AB) is a real number"
Because det(kA) = k^n det A
ohhh right
I don't think it can get more elementary than this, then again it's really hard to come up with
But maybe something easier to come up with
possibly with high level math which is beyond me lol
It would not make sense that we were supposed to find this solution in the time we were given
I think we weren't supposed to use too advanced math
Just the most basic things that are studied at the university
it might be just someone "showing off" and going "look how simple the solution is" even though it's not
I think there might be an easier solution using A^3 = B^3 and something like Jordan normal form. Or maybe not easier but at least easier to come up with
I feel completely vindicated reading this.
Beat myself up for like 2 hrs not being able to do this yesterday lol.
how would you know that A^3 = B^3
They proved it earlier in here.
Scroll up.
huh cool
this means that
det(A^3) = det(B^3)
det(A)^3 = det(B)^3
and since A,B are over R
det(A) = det(B)
you can replace A with -A
i agree that jordan normal form also looks promising
ah true
@ivory fern Has your question been resolved?
Help!!!!!!!!!!!!😭 😭
I can help you further if you want
Let me make a picture
wow thx
@ivory fern Has your question been resolved?
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Can someone explain b
what part don't you understand
Idk what do they want exactly
1.03^12 means 1.03 times itself 12 times
Yeah ik but like how are they related to each other at all
1.03 * 1.03 * ... * 1.03 = 1.03 ^ 12
the first one is (1+3x) times itself 12 times
(1+3x) * (1+3x) * ... * (1+3x) = (1+3x) ^ 12
taylor expansions give approximiations
Taylor expansions?
oops, binomial
Approximations of what
values like these
instead of multiplying by itself 12 times, you can just add a few terms
Am so lost man😭
to get an approximation
if you didn't learn taylor expansions, you don't need to learn it now
What’s a Taylor 😭💀
Nvmmm all of this back to the question
What’s the relation between the 2
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@alpine sable , I still don't understand
draw a diagram
Can i get help here?
@outer steppe Has your question been resolved?
Yes, in a channel under ✅MATH HELP (AVAILABLE)
yeah
So how does it prove that the area of the picture is the area of the border?
I wrote this before
But it says the area of the border = area of the frame
- An 11x16 picture is to be framed. Find the width of the border if the area of the border is equal to the area of the frame. Include a diagram *
how do you define border and frame
I would have said that the inside = area of frame
but idk
Isn't frame the outer edge of the blue part, and border is the blue area?
so are you saying that the border is the same thing as the frame?
like this?
No the border is shaded
And the frame's area is thr total area?
if those two things had the same area, then the inside picture part has area 0
so I dont think that interpretation is correct
it might be better to ask your teacher for clarification
Okay, thanks for trying
.close
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Hi everyone,
I hope you're all doing well. I'm currently working on a problem and could really use your help in finding a solution. Here's the equation I'm trying to solve:
1380: A fuel mixture for a certain engine should contain 19 parts gasoline and 1 part oil. Lena needs 25 liters of fuel. She has pure gasoline and a gasoline-oil mixture containing 85% gasoline. How should she proceed?
To tackle this problem, I've come up with a plan. Let's assume Lena uses x liters of the gasoline-oil mixture. In practice, this means she would use 0.85x liters of gasoline and 0.15x liters of oil. Now, Lena needs to mix in y liters of pure gasoline to achieve the right proportions.
By doing so, she will have:
- Used x + y liters of the liquid.
- Used 0.85x + y liters of gasoline and 0.15x liters of oil.
I would greatly appreciate it if someone could guide me on how to proceed from here. Any insights, suggestions, or explanations would be extremely helpful. Thank you all in advance for your assistance!
Good solving.
You just have to imput the numbers to get the system of equations.
x+y = (total fuel)
0.85x+y = (total gasoline)
0.15x = (total oil)
Well, there is also the fuel solution ratio that you can write an equation of.
@primal galleon Has your question been resolved?
@proud fjord x + y = 25 (total fuel needed is 25 liters)
0.85x + y = (total gasoline in the mixture)
0.15x = (total oil in the mixture)
Additionally, we can express the fuel solution ratio equation:
x : y = 19 : 1 (fuel solution ratio of 19 parts gasoline to 1 part oil)
Like that?
The fuel ration does not look right. x and y is the liters of mixed and pure gasoline respectively.
You're right, x represents the liters of the gasoline-oil mixture, and y represents the liters of pure gasoline. Let's correct the fuel solution ratio equation:
(0.85x + y) : y = 19 : 1 (ratio of total gasoline in the mixture to pure gasoline)
Yep, now if you write the ratio as fractions youll have 2 equations and 2 variables, making it a solvable system
ratio equation and totals equation
Ratio Equation:
(0.85x + y) / y = 19/1
Totals Equation:
x + y = 25
,w (0.85x + y) / y = 19/1; x+y = 25
@proud fjord
oops, there is a mistake on the ratio equation
A fuel mixture for a certain engine should contain 19 parts gasoline and 1 part oil
Ratio Equation:
(0.85x + y) / x = 19/1
Totals Equation:
x + y = 25
So like this instead?
,w (0.85x + y) / x = 19/1;
x + y = 25
well, x is the ammount of mixed fuel, not the total oil
and the question asks for 19 pure gasoline to 1 pure oil[
Ratio Equation:
y / (0.15x) = 19/1
Totals Equation:
x + y = 25
,w
y / (0.15x) = 19/1;
x + y = 25
@proud fjord
Still, you have to consider that there is gasoline in the mixed fuel too
Refer to the equations of total gasoline and total oil you wrote previously
Total Gasoline Equation:
0.85x + y = (total gasoline)
Total Oil Equation:
0.15x = (total oil)
Would this be more accurate?
Yes, so you have the equations. The question says that total gasoline to total oil is 19 to 1
Total Gasoline Equation:
0.85x + y = 19/20 * (x + y)
Total Oil Equation:
0.15x = 1/20 * (x + y)
Yes, that also works
Or the correct writing of the rations.
(total gas) : (total oil) = 0.85x + y : 0.15x = 19 : 1
But this is good too
,w 0.85x + y = 19/20 * (x + y); 0.15x = 1/20 * (x + y)
@proud fjord
In the system you just wrote you can sub (x+y) for 25liters to get a numerical answer
The solution you got here is y~~2x
So to get 19 to 1 proportion you put:
2x to 1y
2mixed to 1nonmixed
,w 0.85x + y = 19/20 * (25); 0.15x = 1/20 * (25)
and here is the numerical value for 25 liters
I see, thanks for the help
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Alright so, I've got a trig problem, I
hit enter too early
retyping
Alright so, I've got a trig problem, I don't know which formula to use/how to solve it, but I have the word problem:
Angular and Linear Speeds
The circular blade on a saw rotates at 5000 revolutions per minute.
(a) Find the angular speed of the blade in radians per minute.
(b) The blade has a diameter of 7 1/4 inches. Find the linear speed of a blade tip.
For A, I was trying to use the angular speed formula (w = (theta/time) ) but I realised I have no idea what to do with the formula after plugging it in. For B, I'm not totally sure how to proceed yet.
do you know how many radians are in one revolution?
so i should plug that into the numerator and put 60 in the denominator right?
or am i on the wrong track
so we have 5000 rev / min and if 2pi radians are one revolution, multiply by 2pi radians / 1 revolution
why 60?
we aren’t worried abt changing the time
they want to keep it in minutes
so the answer is just flat out 2pi per minute?
uh no
maybe read this back
2pi / 5000?
actually, I should probably ask what kind of answer I would get from doing this equation
$\frac{5000 revolutions}{minute}\cdot \frac{2\pi radians}{1 revolution}$
kihei
this may help to see it
sorry for no spaces lol
but essentially we are “cancelling out” the revolutions unit to end up with radians / minute
okay that makes more sense but how does it become 2 fractions instead of one, my notes from the class today only show up with having one fraction somehow
well yeah I didn’t solve it
I’m multiplying those fractions
that’s what the dot is
i just multiply those and thats that
damn thats easy
yeah haha I just like to use these sort of fractions as it makes it easier when converting many units
so from doing the multiplication I got 31415.9265, this doesn't feel like the final answer
is it the final answer?
oh it is
okay im still stumped with B
wait one sec
i think ive had a break through
so linear speed is just angular speed times radius
I need help
wrong channel?
bro its the diameter
i was plugging diameter instead of radius
alrighty
thank you kind math man
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✅
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.you got it or nah?
oh lmao it takes a bit
so if i need math help where dos one gO?
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ask
why -24?
can you use parentheses
Thank you
ups
no
no
under what
I'm sorry i haven't slept in a while i'm a bit confused
I tought it is 8-32 = -24x^3
I'm sure you can do this now
so you end up with 2^-2 . x^3
and what's 2^(-2)?
yes ofcourse
a^(-b) = 1/(a^b)
what
1/4?
done
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your painting skills are worse than mine, but ok xD
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i do not understand this second step
Expand by the first column
Doesn't look triangular to me
?
You have the extra 1 above the diagonal
oh
it isnt
but not on the first terms
just on some
anyway, how is that the same as A_n?
tbf their latexing sucks a lot, they're missing 1's all over the place
yeah i just noticed
but yeah it's expanding on the first col again
your matrix in green should be this
(empty cells being 0s)
if you expand on the first col
yeah so we have the same thing ok
now expand on first column again for the second
yes
well then we won
well, but thats not the same as here
and there they have (1+a)det(A_n-1)) - a det (A_n)
oh true
i have the same
i just forgot they were starting at A_n+2
so my n-2 is their n
srry 😄
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aaa
I keep getting1792pi/15 as my answer when it should be 2048pi/15
My denominator is right but my numerator is wrong
which means that I t hink my limits/boundaries are wrong
or interval sorry
Useful to post that in future!
Sorry!!!
wait a minute
(4x)^2 means everything in that bracket squared
wait omg is that constant not a function ofo that x???
why are we integrating from -4 to 0? the intersection points are at x=0,4 right?
I JUST REALIZED THIS TOO
So
my mistake was instead of setting the two equatiosn EQUAL to each other, I just added them together and made it equal 0
which is not how things go
yeah that's not quite it haha
2nd mistake was that I forgot to square the 4
Okay I'm gonna erase eveyrthing and try again
It would be subtracting one from the other that achieves what you want
Hence the sign error there
yess
@winter seal Has your question been resolved?
@winter seal Has your question been resolved?
<@&286206848099549185>
if you do a substitution you need to change ur bounds as well
wait is this from the stewarts textbook lol
ohh
yeeh
also for the problem
i would suggest graphing it on desmos
and then seeing if disk or washer would fit it
and then plugging in the values
oh and shell too
but wouldn't u determine that by seeing which axis its rotating by?
hmm from what ive been taught
idk how to explain this lol
uhh lemme try graphing it and seeing waht we use
oke
oke i graphed it
the blue shaded region is wat we are reflecting across the x axis
alright for this one i believe we use a disk
Oh is this about rotation along the marked axis?
this shaded region is rotated about the x axis
Yee gotchu
so it forms kinda like a cone pointing to the right i believe
i think we use dy? correct me if im wrong
Either pointy or smooth one of those
mhm but i dont think it would matter too much
not sure what a is for the integral but** b** is 1.099
oh yeah cuz we will be sliding the disk from left to right
so change in x meaning we use dx
See, the solid is made up of infinitesimal disks, if you recall how you integrate sphere's volume thing
You just keep imagining radius that changes with respect to x, then the formula makes sense
radius would be e^x i believe
Wait is your y, e^x?
Then I think there is no problem in using -infty for a
It really does go until that after all
this is all the equation of lines @winter seal 's picture had
This improper integral should exist
this volume problem doesnt seem like it has a nice solution lol
$V = \pi \int_{-\infty}^{1} e^{2x} dx$
Riku
wait how on earth would u solve this
the solution is
I think it should have one of the nicest solutions
:)
!nosols
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
oh.
LMAO

ohh nicee
yeah i think it is
Do you know how to integrate e^2x?
ik that part but i meant the part where we plug in infinity lol
You actually usually don't plug in infinity but rather find a limit
This is called improper integral
Riku
REMEMBER ALL THE RULES FOR INTEGRALS AND DERIVATIVES
AND THE TRIG IDENTITIES
that's my biggest struggle rn
I feel you I really hate calculus
Did you get this? @visual girder
😭
nope
oh ;-;
ig ill udnerstand when i take calc 2
idk why i as a calc 1 person was helping someone taking calc 2 😭
What I mean is, you plug in L like your normally solve
And then find the limit when L goes to negative infinity
Like you do for infinite limits, I think that should be covered in calc 1
If you want to know more, you can read about Improper Integrals
But tbh the core definition you'll only see in a Real Analysis course rather than any calc course but they might still teach you this
(yes integration has a lot of theory
)
ill go through this pain later 
rn im redoing the ap calc bc course on khan academy
so i can like remember calc 1 stuff for calc 2
when r u taking calc 2?
august!
when school reopens
im in highschool but im taking math at the local community college
damn you guys still in high scho- oh right I did this in my last year of high school also 
but jokes on you im doing this as a sophmore/junior 
and senior too i guess
Nothing wrong with that I didn't know m about math in high school
Despite doing everything and getting somewhat good grades
I just graduated fcuk you


I didn't do any proper course on calc 
Honestly I was spared i hate most computations there
Though Several Variables would be interesting to do
calc 3 has a lot of really annoying computation
mostly around velocity/curvature/torsion
calc 3 is multivariable right?
yeah
ew
I just learned how to do the Gaussian actually 
Guess who has it this starting sem on august alongside Rings and Modules and Number Theory and Differential Equations

I really hope it's mostly theory and not computation
the ideas of multivarable made a lot more sense to me in college
I am absolutely trash at Computation
Because you already did some intro analysis amirite
yeah true
The guy who would teach us that this sem doesn't care about computations at all so I'm probably saved
but i also, like, cared about the theory instead of just the procedures
I only care about the theory 😭
Because I can just look up procedures if I need it 
Never had to deal with torsion :)))
aint no way this turned from a help session to a flexing session
It says that τ = -N • B' which makes sense
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Hello, could someone tell me what's the meaning of those n 1, n 2,... n n vertical perantesces?
No I'm sorry, could you give a simple example?
So basically in combinations
The top number tells you the total number of things you have
And the bottom number tells you how many things you must chose .
Then the answer to that gives how many possible sets of things you could choose
Cool, thanks for explanation. So (n 0) means we have n of something which we cannot take anyone? and (n 1) means only one from n?
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Can anyone help me with this question
are you asking me?
Yes
they can become increasingly large?
@still wadi Has your question been resolved?
what do you think? Can you give an example?
the question doesn't make much sense - the numerator is a number and yet we're supposed to consider the x values where the numerator is zero?
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can anyone help
what do you need help with, you already selected the correct answer
ok thank you just making sure
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how to start
probably look for a trig sub? I think?
Some form of u sub? Also a^2 is a constant since we r integrating with respect to x
my guess is to take x = a sint
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,rotate
which one is A?
The lil one
no clue
I have no idea is well
Querter of the area of a circle with area x = pi x² /4 = 2Pi x
X = 0 is a solution or
x/4 = 2
X = 8 ?
Are you sure its the little one ?
Ok now assuming its the larger one
Pi (x+1)² /4 = 2pi X
X² + 2x + 1 = 8x
X² -6x +1 = 0
1/6 isn't a solution tho
Maybe its the narrow strip
Hmmmm
Pi [(x+1)² - x²] / 4 = 2pi X
2x + 1 = 8x
Yes this gives 1/6
A is the small strip between the 2 arcs
Wowwwwwww
SHIIIIIIIIIIIII
OKAY
ALRALR
THANKS 2 3 5 7
🐐
How did you form the equation though
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What will be the HCF and LCM of 0 and 2
HCF is same as GCD
do you know in general what gcd(0,x) and lcm(0,x) are
@regal shore Has your question been resolved?
right
yeah so these present a nuance in the definitions of gcd and lcm that basically only comes up when 0 is involved
tho i guess for lcm specifically its a bit easier
since the only multiple of 0 is 0 itself
so theres not much else that lcm(0, x) could be
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Company A has a turnover of 1.5m, and costs of 1.5m.
Company B has a turnover of 0.5m, and costs of 0.1m.
Company A provides goods to Company B, so that the cost of these goods increases Company A's turnover, and Company B's costs.
What would Company A charge Company B for these goods so that both companies have the same percentage profit?
Effectively working out what the green value is when the blue values are equal
@alpine sable 👋
Ah amazing man, thank you
Yeah please
% profit for compA after the transaction
$$
Profit%_{A} = \frac{T_A' - C_A}{T_A'} \times 100% = \frac{(T_A + x) - C_A}{T_A + x} \times 100%
$$
weig
and for compB its
$$
Profit%_{B} = \frac{T_B' - C_B'}{T_B'} \times 100% = \frac{T_B - (C_B + x)}{T_B} \times 100%
$$
weig
since new cost ( C_B' ) is ( C_B + x ) and the turnover ( T_B' ) remains the same as ( T_B )
weig
and we want the two profits to be equal
so we gotta solve for x
$$
\frac{(T_A + x) - C_A}{T_A + x} = \frac{T_B - (C_B + x)}{T_B}
$$
weig
for the calculation
let me just scan my tablet i didnt write this on ltx
oh nvm i can transfer
$$
\frac{(T_A + x) - C_A}{T_A + x} = \frac{T_B - (C_B + x)}{T_B}
$$
weig
wait no
ah yes
$$
\frac{(1.5m + x) - 1.5m}{1.5m + x} = \frac{0.5m - (0.1m + x)}{0.5m}
$$
weig
weig
to clear the fraction by cross multiplying you get
$$
x \times 0.5m = (0.4m - x) \times (1.5m + x)
$$
weig
and from here you want to expand the right side of the eq
$$
0.5m \times x = 0.4m \times 1.5m + 0.4m \times x - x^2 - 1.5m \times x
$$
weig
weig
weig
$$
x = \frac{0.6m^2}{1.1m = ?
$$
weig
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weig
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what