#help-19
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I think I might have solved it to be 1.728 ?
@harsh bison Can you elaborate on what you mean by "trying to get the average of the numbers while attaching a value to them?"
no no it's fine
@harsh bison , you need to find the weighted average
Oh, ic
cause there are 4 kinds, perfect, good, avg, and fail.
yep! 3,2,1,0
maybe, perfect can be weighted as 1, fail is obv 0, and blah blah
yeah I did it by hand for 1 but i have 36 players to do that since we combined stat programs and they wont accept data automatically
owhp
well, the sum was 733?
my calculator says no...
that was total number of passes
oh
but you want to find the avverage right?
yes please! it should be below a 1.8
i mean weighted
hold up
alright
i kind of fforgot how to excel tbh, but this is quite simple
can you zoom out so i can see the row and column?
ok
it was also 719 total passe, no idea where i got 733
yes please
kk done
hold up
i need to re load
ok on E2
we type (3 *A2 + 2 *B2 + C2)
then we want to divide by the sum
waitt not 2
we type =(3 *A2 + 2 *B2 + C2) / SUM(A2 , B2 , C2, D2)
@harsh bison it should work
wow awesome thank you!!
yes, now just pull it down
you know right?
so it applies the function to every row
well, you need to put the data first
!done
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I tried the previous suggestion. Can't seem to telescope. Help.
till where does the summation go to?
from 1 to n
The problem is some guys in our group are using formulas like tan(a)/cos(2a) = tan (2a)-tan(a), without any prior discussion or exposure. From where are they pulling these formulas out?
They are so easy in hindsight
But to think that will be used, is hell.
pretty sure it goes on like
cos(2a) = (1 - tan²(a) )/(1 + tan²(a) )
nahh, thats different bro 😭
It isn't used here
I am sure as, that part of the theory is after this question...
nah I was like just sharing a proof to that tan(a)/cos(2a) expression
here I have to do something similar like sin(a)/cos(3a)= a telescope
ohh, I did differently
that question looks kinda difficult 💀
its really not when we discover the cheat code formula
We are in the same boat brother...
ayy bruv I almost solved it
the summation
wait a bit, my chemistry teacher called. Will be back in 10 min
@edgy holly I could do this, hope it helps
merci beaucoup
thx to u too, I got it revised
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Okay all the channels I message on keep getting closed so I’m gonna try to open another one,
I am a grade 8 that can do grade 3 math, I have dyscalculia and dyslexia so it makes math quite difficult, I need continuous help in math as I try to understand, I don’t understand anything further than average addition and subtraction, it’s quite embarrassing.
Hm?
Your question is a how-to-learn question
Unless you're working on a concrete math problem, please ask in #study-discussion
Any homework question you encounter
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do you have 540,000 or the square root of 540,000 in the top right?
i am also confused as to where the 2324m came from
@kindred hazel Has your question been resolved?
I took the square root of 540,000 to get 2324
I always just use my answer in the equation of the next step to save time
ok, so we don't need to take the square root of 540,000
and if we did, that square root is ~ 734.85
can you see why?
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I don't understand this at all, can anybody be willing to help me and explain step by step?
take the coordinates of each point
A , B , C , D , E
and check how the x and y changes
so for example
x of A goes from -4 to 3
so x becomes x+7
also y of A goes from -2 to 1
but since its using reflection
if you can tell by moving the whole shape 7 to the right
-4 + 3?
and reflecting for y axis it becomes the new shape
no 4+3
so if you move the whole shape 7 to the right and 1 up
do we js ignore the negative
then flip it symmetrically to x axis it becomes the new one
no you are not
to find distance of A' to A
its
3 - (-4)
for x going from a to b
the difference is b-a
just happens that a is negative so its addition since the - cancel out
wdym reflecting from y axis
im confused
I get how we got 7, but I have no idea what your talking about atm
ok so
draw the shape
if we move all the points 7 to the right
then move the shape all points up by 1
now from this shape
if you draw it
you can tell that the points of the shape in comparison to the points of the A' ... shape have same x coordinate and opposite y ones
so if one point has -2 the other point on the above has + 2
ooo i see now
so its the first answer
do you know which the x axis is ?
when it says reflexion towards to x axis
it means that all the x coordinates are the same
yeah i do
ohh alright
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A puma runs at a speed of 8 km/h. It travels in a S65°E direction for 1 hour, and then continues in an E20°S direction for half an hour.
From its final position, it is seen by a control tower located 1 km away in a straight line.
Calculate the straight-line distance from the control tower to the refuge.
@teal marsh Has your question been resolved?
what do you need help with in the question?
I only need the distance from the tower to the first point from where it came out
im not allowed to do the question for you but I can walk you through it
Np
Uhmmm kind of
so you just take a compass like this
im drawing on ms paint with a mouse it may be a littl emessy
you start at the first letter, in this case it's S
then you go 65° towards the second letter, in this case it's E
so it looks like this
Kay
so with that we can make this diagram for the puma
can you explain what it means by a control tower 1km away in a straight line?
is that what the question says?
Oh srry
1 sec
A puma escaped from a wildlife refuge, running at 8 km/h for one hour in a S65°E direction, then E20°S for half an hour at the same speed.
At that point, it was spotted by a control tower located 1 kilometer from the puma's location, so the animal was located exactly on the same straight line that connected the refuge to the control tower. Determine the straight-line distance from the control tower to the refuge.
That's the whole question
wait this question is weird
YUP
so if i draw a sraight line through point A (where the puma started) and point C (where the puma is right now) the control tower is on that line?
No, the pont C is within the line that joins the tower with the point A.
here's an updated image that makes the 0.5 line shorter
could you copy it and draw where you think the control tower is?
is it like this?
Yup
okay okay that makes send
sense*
so we're trying to find the distance from T to A
aka the red line
Yes
the first thing to do is turn the lines that are measured in hours into distance
the puma runs at 8 km/h
so with logic you can assume in 1 hour it will run 8km
and in half of that time, it will run half the distance, so in 0.5 hours it will run 4km
Yup
ok I'll show you
if we have a line passing through two parralel lines, you can follow a Z pattern like this
the angles on the left are the same as the angles on the right but they are flipped
the red line is the z pttern
so if i have an angle like this
i know this angle is also 50 degrees
going back to the diagram of th epuma, do you notice a Z pattern with the 65 degrees?
I think so
can you explain where
From point B to A the angle would be 20?
Haha okey
the 65 degree angle is on Z pattern i marcked with red
this means that this angle is also 65 degrees
now we need to find the other side of the angle on point B
I'll make this part of the diagram bigger
we're looking for x
70?
Yes
Kay
it's not very useful to have 65 and 70 degrees apart, so we can add them together to have one big angle there
just like this
so if we're trying to find the red line, that means we need to find this blue line
do you know what equation will give us this blue line?
Pythagoras?
pythagoras' theorem only works with a right angled triangle. The angle we have is 135 degrees
The cosine theorem?
yes thats right
so $c^2 = a^2 + b^2 - 2ab . cosC
so $c^2 = a^2 + b^2 - 2ab . cosC$
so $c^2 = a^2 + b^2 - 2abcosC$
CristianThe12
Yup
ok so because the line we're trying to find is the longest of the lines (you can tell because the angle opposite to it is over 90) we're going to give it the variable c
the two other side lengths are a and b, it doesnt matter which one is which
Kay
and the capital C is the angle opposite to the line we're trying to find, so it's 135
can you try to do that
CristianThe12
what is that r
igrnor that
simplifying a little we get $c^2 = 16 + 64 - (64)cos(135)$
CristianThe12
$c^2 = 80 - 64cos(135)$
CristianThe12
ok now we're going to find cos(135) and approximate it in the equation
it's approximately -0.7071
so $c^2 = 80 - 64(-0.7071)$
CristianThe12
$c^2 = 131.65$
CristianThe12
$c = 11.47$
CristianThe12
you got 11.9?
its very close but can you look at what I did and see what you did wrong
maybe i did something wrong
but just see what we did differently
lol
its pretty common to get those mixed up
cool that our numbers were so similar
lets hope my c = 11.47 is right
can we find out what the red line is now? (the distance from the tower tot he original point)
thats exactly right
that means the answer to the question is 12.47km
does everything make sense?
Ty
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why couldnt i cancel out the 1-x
You also have to cancel out 1-x in cos(1/1-x)) since we can't define cos(x) with x go to infinity
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hi, can anyone help me get an intuition for the functor-less def. of universal property (that is, a thing satisfies a universal property if it is a terminal [in this sense meaning initial or final] object of some category)
@robust mortar Has your question been resolved?
@robust mortar Has your question been resolved?
you will have more luck in the advanced channels
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@robust mortar
Let's say X is a terminal object.
X has a "universal property" in the sense that, for any object A, A has exactly one arrow into X.
The "for any object" and "exists exactly one arrow" are the important bits. While constructions may get more complicated, you still need those two facts
i think i understand the definition but i have trouble understanding what this "really means" for whatever property the category is based on
It's exactly the right information to set up this:
Let's say X and Y are both terminal objects. They're isomorphic.
This is always true of universal properties. Any two objects that have the same universal property are isomorphic objects
Oh okay wow that's significant
Trying to think up a nontrivial example haha. Maybe I'll grab one from a book
is something said to have a universal property only if each object has exactly one arrow going to it or does it include objects which have exactly one arrow going from it to each object
A more complicated example of a universal property is a product.
Let's say there's two objects X and Y, and we can find a "product object" X*Y, defined by this universal property:
For any object A, and any two arrows from A to X and A to Y, there exists exactly one arrow from A to X*Y
So in this case, there's a condition that the object A needs to follow. But if it does, then the "exactly one arrow" bit kicks in
As previously mentioned, if there's two objects that are a product of X and Y, then those two products are isomorphic
right okay
The neat thing here is we are making statements about the objects without needing any information about the objects. We are only using the arrows coming from the objects
I think i see
Like, a terminal object in Group is the group {e}.
We don't actually need to know what's in this group, we just need to know how other groups map to it
If there's another terminal object in Grp, it's isomorphic to {e}. In the language of group theory, there's exactly one group with one element
im not very familiar with groups yet b ut i think i get that
Haha I kind of ranted there, I guess I felt like talking about category theory atm. Feel free to ask if you have any questions
Might just have to take you up on that at some point
Thanks for explaining and giving examples, really did help
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Sup
Ok, I want help with geometry.
I'm designing a bellows for a custom accordion.
I want to design it with a shape other than a rectangle or hexagon.
I don't know if this can be achieved. But it's an interesting puzzle to think about.
Best case scenario is that we're able to generalize a technique, that can maybe even be implemented into code, where we input a 2d shape and we get the 2d shapes necessary to cut the cardboard with to assemble the bellows.
hmm, what's the math problem?
Do you think this is more of a physics thing?
by the way, if you know about the flexible polyhedra, you should be aware of the bellows conjecture
https://en.wikipedia.org/wiki/Flexible_polyhedron#Bellows_conjecture
In geometry, a flexible polyhedron is a polyhedral surface without any boundary edges, whose shape can be continuously changed while keeping the shapes of all of its faces unchanged. The Cauchy rigidity theorem shows that in dimension 3 such a polyhedron cannot be convex (this is also true in higher dimensions).
I'm not, I'll give it a read
basically, if the faces are rigid, you cannot change the volume
Hmm...
I don't get it...
What I mean is like
Consider you want to make a bellows with a square cross section (with tapered corners)
The shape you need to cut the cardboard is the one in the image. 4 times, and then assemble.
That would result in a bellows like this
don't worry too much, just be aware the faces shouldn't be rigid
Would it be possible to generalize a method to translate the cross section of the bellows to that zig zaggy pattern
lemme see if i understand, you want to figure out what shapes to cut to make any arbitrary polygon
maybe you can try relating the shape you cut to the length of a side and the adjacent angles
but there might be an issue with changing sides and changing angles that we might need to calculate
Is there a timer on these question channels?
I think have a good way to do it
But I'll have to do it tomorrow because it's late now
The horizontal lines in the zigzag pattern are from the sides of the outer and inner polygons.
You add them in alternating patterns and that's half of it.
Now the vertical distance between these lines will result in the angle of the zigzag lines
There must be constraints on these angles
I believe there should be a relation between outer to inner area ratio and those angles
well, you can use the discord search feature to look for your own messages, or keep this on unread and search for something that pinged you
@rustic tartan Has your question been resolved?
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5 In p = root 6 In q
Any context?
Express p in terms of q or euler
Is this option 1 : $5\ln(p) = \sqrt{6}\ln(q)$ or option 2 : $5\ln(p) = \sqrt{6\ln(q)}$?
And what have you tried?
Azyrashacorki
Option 1
well probably find some way to isolate p
They are equivalent
Theyre the same?
One sec just doing something I think they are but might be wrong
Yeah nvm I don't think they are I'll come back to it shortly
@shadow halo Has your question been resolved?
Yeah well what you did is correct regardless
It might depend on the format of the answer as the way you've typed is a bit ambiguous, but you did it right, so either they are equivalent, or the key is wrong, or you typed the problem wrong to begin with.
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Give that abc = 60
And
1/a + 2/b + 3/c is 22/15
Find the value of a+b+c
I tried asking chatGPT but it use the substitution method instead of the algebraic ways to approach
Have you tried rewriting 1/a + 2/b + 3/c as a single fraction with denominator abc? What would the numerator look like?
yeah chatgpt is known for not being very elegant
bc+2ac+3ab over abc
Now, since you know
abc=60, what does that tell you about the numerator bc + 2ac 3ab when you multiply both sides by abc?
try setting up that equation and seeing what it simplifies to
Maybe try expressing one variable in terms of the others from the product
and substitute into the sum bc + 2ac...
U mean try to write every factor in terms of a right?
Yes
oof that's no good for substitutions
@fallen sparrow Has your question been resolved?
@fallen sparrow got an idea
since abc=60
one of those 3 numbers must be divisible by 3
and you'll easily see that c can't be divisible by 3
so one of a or b must be 3 or 6
It seems to me that you cannot find the independent values of a, b and c; because you only have 2 equations, you would need a third one, you will have to perform tricks to find a + b + c
a,b and c are integers so is that enough restrictions?
If you were given the restriction that they are integers then yes, but the guy in the problem didn't say they were positive integers.
^
but if we do include negatives
I am blind
either none or two numbers are negative
If we include negatives, two of the numbers must necessarily be negative, so that the product of the three equals 60.
so it's easy to show that c must be positive and not equal to 1 (too big)
so c = 2 and 1/a + 2/b = -1/30 and ab = 30
2a + b = -1 but both a and b are negative
so impossible
all 3 numbers must be positive
did you blind guess or?
Yea
the only thing I know rn is this ^
trial and error isnt that bad since you can just factorize 60 🤷
To find the values formally, it would be necessary to restrict values and use modules.
Okay, I think we're going to have to prove at least one value.
If a=2 then bc=30; c=30/b and replacing in the 2nd equations we can operate a quadratic equation to find b and thus also find c
my idea is to use AM-GM on 1/a + 2/b
we get 2√(c/30)+3/c<22/15
since c is not divisible by 3 then we can limit our options for c that way
Do you mean arithmetic mean and geometric mean?
I felt like grabbing a pencil and paper and trying it.
but it's 1 in the morning in my country
😨
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I've seen people (usually on Math Stack Exchange) come up with insane AM-GM solutions with a bunch of numbers like this. Those solutions are neat and easily confirmed to be true. However, how does one come up with it?
For example here, I would never consider to use AM-GM for 54 numbers
For more context, the original problem was:
Suppose that x,y,z
are positive real numbers and x^5+y^5+z^5=3
Prove that {x^4\over y^3}+{y^4\over z^3}+{z^4\over x^3} \ge 3
he's old school
Please elaborate
do you know what weighted AM-GM is in general
I just copied it from Math Stack Exchange, don't put the blame on me 
Probably not
ok in that case let me enlighten you
Please do
I mean it's just the regular AM-GM but there are multiple copies of the same term
so there's a "weight" or a "frequency"
let $w_1, \dots, w_n$ be positive numbers (``weights'') adding up to 1, and let $x_1, \dots, x_n$ be positive numbers whose mean(s) we're interested in. then $$\sum_{k=1}^n w_k x_k \geq \prod_{k=1}^n x_k^{w_k}.$$
Ann
a variant of this is that if the weights don't sum to 1 but to some other total weight $W$ is $$\frac{1}{W} \sum_{k=1}^n w_kx_k \geq \paren{\prod_{k=1}^n x_k^{w_k}}^{1/W}$$
Ann
regular AM-GM can then be recovered as a special case by setting each w_i to 1 (and thus W = n) @tardy knot
if say $n=3$ then $\frac{w_1x_1+w_2x_2+w_3x_3}{w_1+w_2+w_3}\geq \sqrt[w_1+w_2+w_3]{x_1^{w_1}\cdot x_2^{w_2}\cdot x_3^{w_3}}$
skissue.in.a.teacup
this is basically the same as making like 2x+y=x+x+y>=3cbrt(x^2y)
I think i get the weighted AM-GM part, but i don't get how that yields those
How do you find the "coefficients" here
Like how many numbers to use
w_1 is 30, w_2 is 7, w_3 is 1, w_4 is 16
the numerical coefficients on the left are the weights they use
the 30, 7, 1 and 16
But how does one find such values so that the right hand side end up with the ...x⁵ they need?
wait are you sure this is the right original problem
i think we're missing some context here
Am I allowed to link the mathstackexchange solution?
this convenienyly works, but sometimes when it doesent you have to manipulate the weights abit, you can make a system of equations using the powers
Yes?
you're not just allowed i'd really like to see it
wow that is some fucked up ex-recto AM-GM
And are there tools for this?
If people are simply coming up with those by hand, I don't think inequalities are for me 
i actually do t see what happend here lmao how??

Well they repeated this for y and z, then summed the 3 similar inequalities up
im not convinced thats the easiest method
I think someone else found smaller weights that worked but it was still kinda ridiculous
I guess I just need to get good, my skill issue
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How to solve relations such as R is defined by aRb a>=b
Can you send a screenshot?
Do you the definitions for each type of relation
B
@celest osprey
Let there be 3 values a,b,c
(a,a)-reflexivw
(a,b)(b,c)Then (a,c) also-transitive
(a,b) Then (b,a) - symmetric
@desert jolt
No offense but i didn't ask you
Definition is R ={ aRb : a>=b}
No i mean reflexive, transitive and symmetric and equivalence
We use the definition to check for reflexivity, symmetricity and transitivity

Rudy was asking "what is transitivity, symmetricity, and transitivity? "
He wants you to type it out
It has already been typed out by Universe
Then what is the problem here
R is a set of real numbers
What exactly is the expression aRb
Is it a multiplied by Rb?
Its just notation
Of?
a is given as greater than and equals to b
Yes
But what are a and b, real numbers?
Yes!
R is a relation in Real numbers
a and b have to be real so that they can be related via R
2>=1
1 is not >= 2 so it can't be symmetric
Their notation for relation R and set of real numbers R seems to be the same but its not
Correct
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Hi, math question wrapped in a coding problem. I have a position and rotation transform that is changing over time. As an attempt to estimate the trajectory of the transform I take the positional and rotational velocity of the transform and get a dX and dW using the velocity as a linear approximation over some timespan dT.
Over several iterations, I need to apply dX and dW at each step of the trajectory (this is assuming that the rotational velocity and positional velocity (relative to the transform orientation) stay the same.
My question is this: I have 3 applications of these dX and dW that each produce convincing trajectories but are intuitively different in their intepretations.
The first is in the screenshot: apply the dW first and then the translation relative to the new rotation.
The second is to do a conventional transformation: i.e. future = future * delta where delta.position = dX and delta.rotation = dW.
(This would be applying the positional transformation first and then the rotational)
The third is to do a conventional transformation but flipped: future = delta * future.
As I said, all 3 produce similar and convincing results but only one of them can be 'physically correct'.
Ive also attached the transform multiplication method which is what i refer to when i say future * delta. Transforms store a position as a 3d vector and rotations as a quaternion.
It's an artifact of finite time step. If you were to diminish it to infinitesimally small, that's when you'd get the 'real' trajectory. That said, that's not exactly practical.
If you want something that converges faster, I'd recommend you look at higher derivative methods like Runge-Kutta.
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i am not understanding constraints in a continuity question, especially the equal signs
are you not allowed to say |x| is continuous everywhere
continuous at a point
continuous at every single point in R
f(x) = |x| at x=1 is not continuous
the question is: f(x) = |x| + |x-1| is continuous at x=0 and x=1 or not
i understand the graph but the constraints are not the same
please tell me why we're taking the equal sign
modulus functions are continuous everywhere, but not differentiable at x=1, and 0
it is continuous since there is no break in the graph of the function
the answer is continuous but i am not understanding the constraints shown in the above picture
without the process, there will be less marks
how are we taking the constraints in the piecewise function?
f(x) = |x| is not continuous at x=1?
what type of discontinuity is it?
removable, jump, asymptote?
does the limit of |x| as x->1 fail to exist? does it exist, but without being equal to |1|? why is it discontinuous?
the constraints are simply there to define the function
using those constraints, you have to find the value of the function and its limiting value to find out whether it is continuous at the given points or not
half of your x's do not look like x's and also your LHL value is wrong
LHL=RHL so it is continuous at x=1
lol that was rude
at x=1 whether you approach from the left or from the right you're still governed by the condition x>=0 in BOTH cases @uncut seal
rude how?
how do you think i should have said that?
nvm
i mean, you're not wrong
@uncut seal did you get where you went wrong?
damn bro ghosted us
is it -(-x)
no, it's just x since the constraint applies at x=0 not at x=1
understood
and the last thing, how are we taking constraints from this graph
plot the graph as per the original function and expand the function as it changes for different values
the values at which it changes are basically the constraints
|x| is continuous everywhere. But it's not conductive at x=0
conductive?
did you mean differentiable?
we're not talking about differentiability here
continuous function at x=x_0 plus continuous function at x=x_0, result is also continuous at x=x_0
that graph is an overcomplication and you dont need it. the answer is simple: YOUR FUNCTION IS CONTINUOUS EVERYWHERE.
is this graph ok?
we are taking inequalities
but i dont understand the two different equal signs
If the value of the left function is equal to the value of the right, the two different signs are allowed.
Take x=0 as an example. The value of -2x+1 at x=0 is 1, and it is also 1 on the right, so both signs can be allowed.
No need to ref. Function is actually a correspondence. As long as two functions yield the same value for the same input, they can be considered the same function.
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Am gm inequality
hmm
how would it even work here
.
no you have to express a+b+c in terms of x,y and z
Cosider x+y+z
I think to make it more rigorous you have to show that at most one of 3 numbers x, y and z are negative
Then you can apply am-gm
$$\mathrm{G}\leqslant \mathrm{A}\Longrightarrow \sqrt[3]{xyz}\leqslant \frac{x+\mathrm{y}+\mathrm{z}}{3}
\
\Longleftrightarrow xyz\leqslant \left( \frac{x+\mathrm{y}+\mathrm{z}}{3} \right) ^3=\frac{\left( a+b+c \right) ^3}{3^3},,\Box $$
AndyM
yeah
These are probably sides of a triangle
yes
yes
I find that it also works even if they arent 3 valid sides of a triangle
that'd make for a more interesting problem ig
Would it? Atmost one of x,y,z can be negative(not hard to prove), and in that case the inequality is trivially true.
Oh i guess its more interesting than this
Ofcourse
When a,b,c are the sides of a triangle x,y,z are all positive, right?
cannot be maximal because it can be adjusted (increased
by equalizing its sides. We assume the theorem that says that equalizing two sides in a non-isosceles triangle increases its area.).
So the equilateral one E is the maximal because all its
sides are equalized.```
This is (in my own words) the proof for the maximality of the area of the equilateral triangle, presented here https://sci-hub.se/10.2307/30037526
I find it incomplete.
cannot be maximal because it can be adjusted (increased
by equalizing its sides).
So MAYBE the equilateral one E is the maximal.
It indeed IS because any adjustment we'd do to it
it will become T which cannot be maximal.
So E either is maximal
or it is not (there exists no maximal triangle): impossible
because T either
1) has a base m=(a+b+c)/3 case in which it is obvious that it is smaller than E.
2) it has all three sides different than m. We still have to prove that in this case T is smaller than E.```
So to make this proof complete I used heron:
ah nice
Of course I'd love to hear that in fact this proof is complete in itself
Or to hear of alternative shorter proofs
the 1st half was typed some months back, the 2nd half was typed today in another software (AxMath)
I think another way to prove it is to show that the absolute difference between mₙ and mₙ₋₁ is strictly decreasing
d(m₁,m₀)>d(m₂,m₁)>d(m₃,m₂)>...>d(mₙ,mₙ₋₁)
This implies that mₙ approaches m=(a+b+c)/3
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hi i’m doing hw can someone explain to me why for question 4 b is a local max i assumed it was just r
see the y position of point b
values to the right of it are smaller
values to the left of it are smaller
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How do I solve this without a calculator? I don’t get why the person did 1/a.. is there another way to solve this question?
ping me pls
The idea is that $\frac{\sin \theta}{\cos \theta}=\frac{-1}{1}$ does not tell you $\sin \theta=-1$ and $\cos \theta=1$ (aka you can't just directly compare the numerators and denominators). \ \ However, it does tell you that $\sin \theta$ and $\cos \theta$ are in a ratio of $-1:1$. They're letting $a$ be the value you need to divide $-1$ and $1$ by so that you can directly \text{"match"} the values in the numerator and denominator with the values of $\sin \theta$ and $\cos \theta$.
Civil Service Pigeon
As a more concrete example, $$\frac{5}{7}=\frac{10}{14}$$ does not mean $5=10$ and $7=14$. However, if you divide the numerator and denominator of the right hand side's fraction by $2$, then you get $$\frac{5}{7}=\frac{5}{7}$$ at which point you can directly "compare" them since they're equal.
Civil Service Pigeon
Except here, we don't know what we need to divide by, so we just call it a variable (in this case a)
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How do i find the coordinate of A
Equilateral
welcome to mathcord
I tried finding length of one side
Ohh ryt as in median
a suggestion: try finding the coordinate of the red dot
that'll give you the x coordinate of A (and then hopefully you can see what to do from there)
Yeahh got it ,thanks
Yea
I found 2 values of y,while x is 0
How do i know which one belongs to the triangle
Okay no i figured it out
Thanks yall
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hello
hello the country of russia
Hi, welcome to the server! 
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How do i continue
Differentiate
take derivative of both sides
Use product rule for lhs and chain rule+quotient rule for rhs
you could also first apply sine to both sides to get y/x = sin(y(x+1))
might be a tad easier to deal with
I dun think i k them
Yeah lemme try
,tex.diff rules
product, quotient, chain ^^
Didnt know abt chain
wait what
u cant do this w/o chain
how did you get to implicit differentiation without the chain rule 

I meam i didnt know it was callee chain rule
Idk😃
U can use a shortcut for these
Yeah i would like to know that
u can use partial derivative
Yeah for that wont i need to separate y and x terms?
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✅
Why
Cuz it's kinda tough to separate x and y terms maybe
leeave it exes are clutter
Did u treat it as F(x,y)=0
ah
interesting
is it ok to assume it as a relation tho? @wanton bison
I’m saying this cause if u use it the expression might not match the result alot of the times
So it’s just better to use the core methods
You can always bring it back in terms of the ans

Never worked for me
Cause the terms get clunky
When u take partial derivative
Also have to take it twice
And then divide

$\dv{y}{x}= -\frac{\pdv{F}{x}}{\pdv{F}{y}}$ ?
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Yes
alr
Very useful
implicit definitely easier tho here
For some questions
perhaps
Where they just ask u to find the value
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Yes, you do that.
.solved
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Hello! I've been trying to figure out why and how formula above in the picture works but I can't figure it out. Can someone help me please.
You can see it if you click on the picture
This is the dot product or scalar product
Dot product
A and b r two vector and the angle between them is the angle fi
It is known as both dot and scalar
O ok
What r u not understanding abt it?
Can u share the full picture
It' in dutch
I can translate
do u know what dot product means geometrically?
As I understand, it's the length of a vector?
length of what vector?
I don't know
I will have to google that, projection has been a while
right?
Do u know how to derive it?how to derive the abcostheta
if you understand what a dot product is geometrically, it will be very easy to understand this
What do you mean
So it's the length of the projection of b on a, which is b.cos(fi), but why do you have to do .a too?
wait, i will send a picture
Oh yes I understand that, I can do that
In this sense dot product can be called the product of magnitude of a vector and it's projection on another vector
Am i wrong
the diagram in your picture is not actually a dot product, the dot product is scaled by length of B too basically
i couldnt find a good picture 
i recommend you to watch 3 blue 1 brown's video on it
Can u verify what i said?
Can you send me a link
wdym
just search "dot product 3b1b"
on youtube
it will probably pop up
The pic and description
Thx
this is correct
this is not very accurate
On the basis of angle?
wdym
Like specifying angle will make it accurate?
First 2 min and I get it
uh, i meant ur definition is wrong
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Oh ok
your definition = |a|^2 * cos(theta)
Yeah i made a mistake
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Find the volume of the solid formed when the area of the region bounded by the curves x^(2)-3y = 3 and x^(2)+ 4y = 0 is rotated about y-7=0
what should be my upperlimit and lowerlimit, the x or the y?
I am really not sure, since I tried the X up and X down and got 82.1095 cubic units as the answer which I don't know if that is the correct answer.
I used washer method
if y-7=0, am i to use the X1 and X2?
but if its x+7=0, am i to use the Y1 and Y2?
Wdym "upper limit or lower limit"?
Which variable u want to integrate with respect to?
When using washer method :
If rotated about the x axis integrate with respect to x
Vice versa
the integral
yea
Yeah
Do u understand what i mean?
so if x+7=0, i use the X?
and if y-7=0, i use the Y?
Think about it. X + 7 = 0 is a vertical line right?
Basically the same as the y axis
Get it?
yes, integrate with respect to y
Thank you, I have like trust issues with how I am solving with my maths
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What do we substitute here
yep
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help me pls
what do think
this means
this is interpretation problem
daddy chill
its sat. it aint that serious
its the equation
it saying it find the price of the small containers
i dont understand
ow i thought of diophantine sorry lol
4.51
Yea
Yea could be
wonderful
bro wat
where did u get 500 from
cuz 500 is in the question lol
😭
🥀
think abt
f(t) models no. of particles t mm under the surface
if we want the value at the surface
what should t be
like sorta
yeah
so
what should we input here
so that f(t) spits out the no. of particles at the surface
think abt it
t represents our position some milimeter under the surface
and we want the thing exactly on the surface
what should t be
idkkkk 😭
ok
if i say that h represents my height above sea level
if im at sea level
what should h be
yeah
t = 0
ye
