#help-38
1 messages · Page 224 of 1
yeah lol i’m looking at that in my notes right now, i understand
so let's take an arbitrary slice, at height x
also, upsidedown things is weird cos you need to start at 0 then go does x metres then do stuff
but there's nothing stopping us from putting the cone right side up and just flipping a negative sign in the density
if you dont want to do that that's okay as well
i’d like to keep it as is for right now until i get more comfortable and not go through that mental gymnastics LOL
that's okay all good
so now we need to know how big our discs are
given that we go down x meters from 0, what is the radius of the disc?
(use similar triangles)
oh, i see. i remember my prof went through an example like that where he used the pythagorean theorem to find the radius of the disc like that?
i dont think you need pythagoras here
similar triangles use scaling factors
which means you just need fractions
so like, if you go down halfway, ie x = 4.5, then the radius should be halved as well, ie r = 5.5
because the similar triangles created should differ by a scaling factor of 2 here
okay, i understand what you’re saying, im just having a difficult time answering this LOL
So think of it proportionally
If you go down x metres, what proportion of the whole way have you gone?
x/9? because our depth is 9 meters?
i mean it’s just linear variation so just integrate dm
and dm = pdV
p is density btw
dV is a volume element as you go along x
and ig you should take an infitessimally thick disk of thickness dx for that
Uh huh, so proportionally speaking, how much should the radius be?
are they trying to find dV or smt?
hold on the gears are turning
since the raidus increases linearly from 0 to 11 m, shouldn't it be
r(x)=11/9x
You’re not the op
If you have a question ask it in your own channel
I’m trying to help bianca here
i’m a little thrown off by the radius at the top being 11 meters, i’m trying to figure out how this relates in proportion to the x/9 i stated earlier
not here to argue
So if x is 0 what should the radius be
11, because x at 0 is the top ?
i’m really curious if you are trying to find r(x) rn?
We are
hmm
1?
no shit sherlock , you could've just said nicely , I'd understand
Nah it’s 0 because it’s a point
i mean since any triangle formed in the cone will be similar
There’s no radius to disc that’s just a point
x/r is constant and equal to total height/total radius isnt it?
I did say earlier to use similar triangles but they are struggling
damn
Guys you’re not helping
By the way, let’s just try it upright
okay!
If I stand the cone upwards can you find the radius at some height?
actually, can i show you my notes that i took of the example my professor provided? it’s got a cone shape and he used a triangle to determine the radius and im wondering if it would be useful at all. only thing is its the pythagorean thing i mentioned earlier
Sure
Yeah okay so here Pythagoras helps because it’s a hemisphere
We have a cone so we don’t even need to think about the hypotenuse
ohh right i completely forgot that it was a hemisphere, my bad
saw the disc and triangle and immediately assumed cone whoops
Lots of things going on in this picture
But the blue part is the question info
Red part is what we want to find out
Green part are some extra bits of construction to help us find red
Do you see that the green and blue triangles are similar?
yes, i do!
So if I give you 9-x can you find the red ? Length?
wait, so 9-x is the height of our green triangle right?
Yes
i see two separate arrows so i’m a little confused lol
Oh sorry
The arrow in the middle is me saying use this to find the green triangle’s base and subsequently the ? Length
okay, i don’t really remember how to find the length like that. i’m really tempted to use something with 1/2(b*h) but i don’t see a value for area we can use to determine the base’s value and it sounds inefficient to use that formula anyways, so im trying to remember what else i know
A is double the size of a, B is double the size of b?
the green triangle is twice as big than the red triangle
Well I haven’t actually given you that they are exactly double
oh
But proportionally speaking they are the same right
yes
As in, if I multiplied a by some factor k to get A (ie. ak=A)
Then this same factor will also scale b to B (ie. bk = B)
So we can say that k = A/a and k = B/b
In other words, A/a = B/b
Is that right?
okay, yes
so that answers this question
Can you apply the same thinking to this problem? We have the bigger blue triangle and the smaller green triangle
11/? = [(9-x) + x] / (9-x)
So we’ve answered this question
Now we have the radius we can find the volume at each height
it wouldn’t happen to be pi(r)^2 would it?
Yes but replace r with the thing with x
And also we need to multiply by a little height we will call delta x
Δx
Yep!
like so?
Yep
and then the total mass is just the integral of that from 0 to 9?
okay!! let me punch this into desmos and see if the answer is correct
I think wolfram is usually better than Desmos at computing stuff
ooo okay i’ll try that instead
i’ve never used wolfram before, does this input look okay?
oh it didn’t work hm
What do you mean it didn’t work
oh no just the way i punched it in to wolfram was wrong
i went back to desmos LOL here’s what i got
it’s finally right ☹️ thank you i really appreciate your help
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may someone help me with basic grade 9 physics
using the circuit below calculate total current 1T. potential difference for 2nd resistor V2 and total power Pt show all work and use grass method
is what the question says btw
,rccw
first off, what's given to you (all ur voltages and resistor values)
and what are you solving for
theyre at #help-44|stanley-🌲-v2-dans
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The angle between two intersecting planes passing through one of the cylinder's radii is 60°. The areas of these intersecting planes are 360 and 720. If the height of the cylinder is 30, find the radius of its base:
I tried to do it through Pythagorean theorem but there was no answer like that
What else can I do for this one?
@sleek imp Has your question been resolved?
<@&286206848099549185>
Not sure if you have the problem set up right, or if I’m just wrong.
Yeah that’s why I’m thinking you got the problem set up wrong
How else could it be drawn then?
Good question
I just assumed that it would look like this since the angle between is 60° and it's a cylinder
I don’t think you’re simply just finding the radius the the cylinder, but the radius of the plane being intercepted
Yeah but wouldn't those two be equal?
But wouldn't that be an ellipse?
I don't really understand the question
Well, there is another translation for that
The bilateral angle between two sectional planes passing through one of the cylinder makers is equal to 60°. The areas of these sections are equal to 360 and 720. If the height of the cylinder is equal to 30, find the radius of its base:
But I don't think that changes anything
Wouldn't that pass through both radiis (like the heights)?
@sleek imp Has your question been resolved?
@sleek imp Has your question been resolved?
What is bilateral angle?
And where are you from? @sleek imp
Kazakhstan
Its just the angle between two sections/planes/cuts
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Let A be an nxn matrix. Let S be m-dimensional subspace of Rn with m<n.
Does any subspace of Rn have a basis? and if the rows of A are linearly independent the is it true that Rn is a subset of col(A)
i dont see how S is relevant
every vector space has a basis
it was for a follow up but its not relevant here
for finite dimensional spaces, you can prove that with just lin alg
for infinite dimensions you need set theory
did you learn that?
yes, but my lecturer marked my multiple choice answer incorrect when i said it was true
what was the question?
that is absolutely wrong
right?!
i just want to know about (I) now as well. Because would it not be true if it was col(A) subset Rn
do you know any theorems connecting column space to row space?
yup. row(A) = col(A) and if they linearly independent they span the subspace
is that what you mean?
not necessarily row(A)=col(A). you need more conditions
right..
but how is Rn a subset of col(A)
I have to go, but, the hint is
dim row space A = dim col space A is the formula in general
see if you can justify equality here gl
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why is tany plus minus?
even when the tany is positive all the way in the
0 < y < pi/2 and pi/2 < y < pi
im
fucking stupid
thats why
SHAKE MY HEAD
pi/2 < y < pi is another damn strand of tan function
which is negative
i asked about why they got plus minus
then to solve for tan y using that trig identity you need to take square roots on both sides in the second to last line of what I posted
i mean i skipped some algebra to solve for tan y but yeah
yeah but the purpose of plus minus i asked lmao tho i got it as i mentioned above it is because theta angle is between 0 and pi/2 and pi/2 to pi which is negative and positive
so it would chnge signs
so they got both of them
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Please help 😭😭😭
,rccw
@obsidian kraken Has your question been resolved?
Usually in these type of problems its nice to extend some side in order to simplify the problem into proving two lengths are equal instead of the sum
Id suggest extending MB by the length of ND
"upwards"
now we have to prove a triangle is isosceles
this channel is occupied please use the available help channels
oh sorry
@obsidian kraken
I tried it, but I couldn't find anything
like this PD = NB and we have to prove that PM = CM
okay
Ill give you a hint
notice that triangles BCN and DPC are similar
can you see why?>
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i’m trying to solve for c and i got to how many cycles there are in 29 seconds, 5.8, but im not sure what to do with the 0.8 cycles that’s left
i vaguely remember having to that that into the function but i’m not quite sure
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<@&286206848099549185>
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!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
1
okay
so what's your understanding of turning points
and how to find them
idk
so are you familiar with derivatives and what they mean?
alternatively completing the square form
no
oh yeah you don't need them at all here mb
... ok what level of education are you at
$y = a(x-h)^2+k$
have you seen something like this before at all
Ann
yeah i think so
ok that is called vertex form in English usually
can you convert your quadratic into this form?
(x-4)^2+3
why (x-4)^2 tho
that gives you a -8x term upon expanding back and not +8x like you had
sign error?
Idk
could you show your work as to how you got to this answer
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Hey, I'm trying to prove a greedy algorithm is always optimal for this merge operation on an array: repeatedly merge adjacent $x$ and $y$ into $\max(x,y)+1$, goal is to minimize final value. At each step, pick the merge with smallest $\max(x,y)+1$.
I tried formulating an exchange argument but got stuck. Wrote this up cleanly here: https://math.stackexchange.com/questions/5063365/optimality-of-the-merge-the-smallest-greedy-algorithm
If anyone has ideas or sees a clean proof, would love to hear it.
Avighna
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<@&286206848099549185>
@waxen cloak Has your question been resolved?
Hi
@waxen cloak seems not optimal
For instance take $1, 1 - \varepsilon, 1 - \varepsilon, 1$
the greedy will begin with the middle 2
Cain
instead of merging (1,1-eps) and (1,1-eps) and then merge (2,2) to get 3
the greedy will merge (1-eps,1-eps) and then (1,2-eps) and then (3-eps,1) and get 4-eps
@waxen cloak Has your question been resolved?
okay im really sorry but i shouldve mentioned that all values are non-negative integers
in particular, 0 ≤ a_i and a_i is an integer
i'll edit this into the post
Avighna
under this constraint, $\varepsilon$ would have to be $1$ so the final answer would be $3$
```Compilation error:```Image processing timed out!```
@waxen cloak it doesn't matter
still 1,1,1,1 would do the same
as greedy might choose the middle two first.
Ok yeah, you're right. The version I was imagining always picks the leftmost pair in case of ties, which I now realize might matter.
This problem is from the Baltic Olympiad in Informatics, 2025 (Day 2, Problem 2), and- spoiler alert- my friend coded this greedy solution that worked for $n \le 2000$. I’m guessing his implementation broke ties by picking the leftmost option, which might be why.
It might seem like I’m just patching the algorithm to make it work (which I know can feel a bit annoying), but I’m genuinely curious whether this tie-breaking tweak is enough to make the greedy strategy provably correct. Or is there a counterexample even then?
Avighna
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can smn help with this
I do not think there is enough information.
You could rotate point E about point C, and none of the given information would be contradicted.
And, looking at your work, it doesn't look like you added in any extra information. This problem is likely impossible.
@opal snow
Is FCA a straight line
thats what am saying its weird
It has happened more times than you likely think.
It looks to me like the lines were drawn on a computer, after which the labels were hand-drawn. I doubt they meant to make FCA a straight line.
Thoughts? @grim saffron
Are you assuming angle FCB measures 90 degrees?
mm perhaps
I think it's more likely that the diagram is drawn by hand, since the line FCA is almost a straight line. You'd think that if the angle is intentional, it would be exaggerated.
just noticed AF may not be a single line
Yeah, that seems to be the deciding factor.
@opal snow for now, I think it's best if you assume FCA is a straight line.
You certainly can.
how
Angles ACB and FCB are supplementary. In other words, they form a linear pair.
alr ty
This seems like an unnecessary overcomplication. Can I DM you a potentially faster way?
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My book legit just didnt provide a proof for this proposition
is there a reason this holds?
i hope so
in math, things usually are true for reasons
even not in math actually
what's the definition of lin dep and lin ind?
a linear combination is linearly independent if when the linear combination equals $0 \implies$ the coefficients must also be zero.
BOSS
or if a vector cannot be written as a lienar combination of the other vectors
oh
wait
i get it lmfao
@thorn bay
if its a basis by definition
anything else will have to be generated by a linear combination of those elements
so it wont be linearly independent

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right because you could v - (linear combination of the other elements chosen to equal v) = v-v=0 even if coefficients are not 0, exactly what you said but im.spelling out the details
✅
@thorn bay do you know how to define maps between vector spaces?
sorta like homomorphisms preserving verctor addition and scaler multiplication?
this is from my lecture notes and i kinda just
this is a standard proof in linear algebra texts. this textbook has a free pdf online: https://linear.axler.net/
yes that's called a linear function, in general
if the domain and dcodomain are the same it's called a linear transformtaion
if the domain is V over F and the codomain is F it's called a linear functional
and if the domain is a set of functions it's called a linear operator
linear transformations = linear functions, theyre cinnamonous
how much of this is needed to understand extention fields?
honestly, i'm bad at algebra
I like analysis and topology
so, I dont even know what extension fields are lol
ah nw
im learning lin alg to understand them so i was curious how deep i need to go
tysm for the proof help!
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I need help on radicals
No need to ask “Can I ask…?” or “Does anyone know about…?”—it’s faster for everyone if you just ask your question! See https://dontasktoask.com/
Does anyone know about radicals
you should just send your question
not ask "does anyone know about <topic>"
just send your question
Ok I’m sorry
I need help with both of them this was my check in and my teacher is learning the material with us so it’s tuff
I copied the work off what she was showing for review but I got no idea how to do this
ok right
so first off do you know what a square root is?
like just to ensure we got the basics of the basics down for this whole topic
Yes
ok
Like I know what a square root is but it’s just the showing of the work part
ok so do you know any properties of square roots
What do you mean
we're gonna need some of those for the work
sqrt(ab) = sqrt(a) * sqrt(b) for example
that ring a bell?
I think you separate the two doing square root of 9 and 5 multiply them with each other then because square root of 9 is 3 and 5 doesn’t the answer is 3 square root of 5
Is that correct?
when typing roots in plain text you can and should abbreviate them as sqrt(), so instead of "the square root of 5" you write sqrt(5)
My bad
this is more or less correct otherwise. not how i would have worded it but otherwise okay.
How would u have worded it
now looking back at question 7 here, you've got a sqrt(50) and a sqrt(8). these are both simplified following the same logic as in the concept example: 50 is broken up as 25*2, and 8 is broken up as 4*2
from which you get $-5\sqrt{50} = -5\cdot 5\sqrt{2}$ and $3\sqrt{8}=3\cdot 2\sqrt{2}$
Ann
Ok I’m getting it more
the general strategy when faced with a root of a big number is to factor out as big of a perfect square as you can from it
as far as simplification goes
Yea I understand that concept
ok so we good on question 7 then yeah?
Ohh I’m starting to understand it now
Yep question 7 is all good
Is it ok if we move on to question 5
Yes
ok yeah that's what is happening there
multiplying the top and bottom of the expression by the conjugate of the denominator
an equation is something that has an equals sign
Ohh so it would be multiplied by 2+sqrt(8) top and bottom correct
yes
the idea behind this move is to set up a difference of squares identity on the denominator so that the square root in there simplifies away
Ok
idk what went on with this three or the 2 just randomly hanging there
No the -2 was because originally in pencil I got the problem wrong
Pen is corrections
And idk abt the three I probably accidentally wrote wrong number in there
It should be a 2
it should be an 8 actually
let me rewrite the entire thing in a less messy manner
idk if this handwriting is yours or the teacher's but it is a bit sloppy
It’s mine 😂😂 I Know my handwriting isn’t good
Can you explain what you did here?
@twilit lion Has your question been resolved?
Rationalize
I still need help with this one
I don’t understand how they got -2-2 sqrt(2)
<@&286206848099549185>
which part didn't you understand?
I guess after staring at it for 15 minutes I kind of understand the last part
The 8 simplifies to -2 and 4 simplies to -1 multiplying with 2 to get -2
you have pretty handwriting
So it will be -2-2 sqrt(2)
But I do need help with a couple more problems
If anyone can help with that
which line
I got a test so I’m cooked
sorry i had to disappear for a while
All good
I figured out the last one kinda
^
It was the last part
ah so yeah it's the distributive law
$\frac{8}{-4} + \frac{4 \cdot 2 \cdot \sqrt{2}}{-4}$ first
all good
south
2 and 4 are right and are roughly how I'd do them
for 8, start by factoring the stuff under the radical
like 24 = 2.2.2.3
which is 2³.3, so if you take the cube root you get 2.³√3
Alright thanks
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okay so i know how to do most of this question
im issue is i get the pi/3
but idk how to figure out that the next one would be at 5pi/3
(ik that if it was like 1 that hapepns every 2 pi, or 0 hapepns ever pi..
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do u know the unit circle
u only need to remember the first quadrant
the other quadrants are just reflections
like i said for hteo ther one since it = 0 i just knew the oher one would be within pi
is there any similar trick without remeebring it
i dont have time to remeber it before my test
any other way i couold do anything at all
can u bring a cheatsheet?
nope :(
This is the thing that has kept you up at night all week! That darn unit circle! So many roots and fractions and pies, how will you get it all in your head? Actually it's super easy to memorize the unit circle if you know a few tricks, so check this out and rest easy tonight!
Watch the whole Mathematics playlist: http://bit.ly/ProfDaveMath
Cla...
i dont have time
one way or the other, u at least need to know the first quadrant
i need something else sorry
then no
what do you want to remember? like the values of sin, cos, and tan? As in sin 90 = 1, etc
those two triangles give you most of the 1st quad
you also need to remember the trig values at 0 and 90°, which for sin and cos are just 0 and 1 (but dont mix up which is which)
is there a way to fiure out how long untill the next solution, like i said eerlier when cos=0 i knew that the next one would be A total pi after. any way to do a similar thing for 1/2
can somone help me through this simple polynomial factoring " x^3-6x^2+11x-6 "
i think "how long until the next solution" is not a good phrasing
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sorry im just saying it the best i can
when solving cos(x)=a the two fundamental solutions are horizontal reflections of each other
for sin(x)=a they're instead vertical reflections of each other
I have a trick for you
yea i'm not sure what you're looking for here. I'll drop this just in case.
https://www.youtube.com/watch?v=PF2nmCVSUEs
Exact Trig Values - Hand Trick | Trigonometry | Maths | FuseSchool
There are some key angles that have exact values in trigonometry. The ones we need to know are 0, 30, 45, 60 and 90.
In this video, we will discover one method to remember what these values are: by counting fingers on our hand!
In the first part we explored a different metho...
oh yeah the trigonometric hand thing
good luck
what
Suppose they ask you what is sine 60
that one ik off the top of my head
Or what is inverse sine of whatever
This is what you do
They ask you a fraction
Arcsin(a/b)
If the argument is positive then there’s 2 options, the top is positive and the bottom is positive
Or they are both negative and cancel each other out
If the argument is negative then either the top or bottom (but not both) are negative
So let’s try -1/sqrt 2
Sine is opp/hyp so the triangles look like this
also say there was no like domain or whatever
and i had to answer in general form, then id need to know how far between each one
so how do you do that?
Then you can use Pythagoras to figure out which angle is 30 and which is 60
Or in this case they are 45 degree angles
For example these are 4 of the 8 ways these 2 numbers can be arranged
And of course the hypotenuse here is 1
Red are the other 4
If you need cos or tan then maybe you need to flip the triangles
Arcsin(1/2)?
i know that its cos = 1/2 and i know that means that its 60deg, or pi/3
but then idk what how to find how long untill the next one for gneral form
Look at the red triangle
The angle is pi/3 as you said
But the blue one is the other way of drawing the triangle
It still has +1/2 as the adjacent side and the hypotenuse is always +1
The angle for the blue one is clearly 2pi - pi/3
So the general solution will be 2kpi + this
And 2kpi + this
You need to recognise that there are 2 distinct solutions that aren’t really related to each other (their relationship depends on the trig function)
So I use the triangles to find both solutions for me
Then I use that to then add on 2kpi onto each of the 2 solutions to get all my solutions
This corresponds to the 2 different ways you can draw each triangle
okay i think i mnaged to remeber the unit circle
so
how do i use it exactly
I just explained it…
sorry im just overwlemed
also if i had sin= sqr 2
sorry
sin = sqr2/2
since sin is y/r
i look at when y ris sqr2/2 on the uniti circle?
so pi/4 3pi/4
this crrect tho
if i have the unit circle cheat sheet if im allowed i just look fro the y
i dont think im allowed but i thinkim close to remebering it good enough
Well it’s just this without the minus signs
So it’s the ones up above
Or as you said, pi/4 and 3pi/4
okay
im cooked for my exam tmr
tty for the help to make me do a little bit better
if im not allowed a cheat sheet i lowkey might need ot load the image onto my calc 😭
idk if i will do that tho since i hate cheataing even tho its easy to get good grades
doestn feel right to cheat for my self (unless everyone is)
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!work
huh
the factoid didn't work 😢
just show your work
or
!status
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1. I don't know where to begin.
2. I have begun but got stuck midway.
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7. None of the above
@woven python
@lunar stirrup Has your question been resolved?
yeah
sorry
So we know that this is the expression for electric flux through a surface
But we also know from the divergence theorem:
So how do you think we can use these for this problem?
Greedy gets 4
Both 2,2 and 2,1 give 3, so greedy will pick leftmost and will merge 2,2
It isn’t a counter example
It seems like someone else has claimed this help thread
Since my question got auto closed, i had gone to sleep
what can i do 😔
youd have to post it again in a free chat
uhh
i dont know this one
only this
Thats ok
all it's saying is that integrating F.dA over a closed surface is the same as integrating div(F) over the volume the surface encloses
for this problem you actually dont have to do any integration
Have you seen divergence of a vector field before?
oh ok
never
our teacher told us that the line causing this flux is the z axis
but im not able to explain how
ah i see the approach they're going for
yeah so they probably want you to think about the symmetry of this situation
So since z doesn't appear in the electric field equation
if you fix x and y and move along z the electric field will be the same
then the field would change as we change z
but we can use this symmetry to give us a clue to solving that first integral
do you think integrating using (x,y,z) would be the best approach here?
for this one
its z axis right
which is an infinite line charge
so we can use gauss law right
yeah exactly
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hi, i'm having some problems solving an exercise. I've asked in stack exchange but I don't understand the solution they suggest me and I don't know how to prove it, as it says minimum/maximum is reached when x = 0 with a geometric interpretation.
the exercise is Given an ellipsoid
$$\frac{x^2}{a^2} + \frac{y^2 + z^2}{b^2} = 1$$
and a plane
$$Ax + By + Cz = 0$$
let $S$ be the set of points of the intersection. Find the farthest and nearest points to $(0,0,0)$ that belong to $S$.
diiegorgueez
and here's the stackexchange link: https://math.stackexchange.com/questions/5063457/minimal-and-maximal-distance-to-the-intersection-of-an-ellipsoid-with-a-plane
also the solution I've been able to get is this one, but that is assuming none of A, B and C are zero.
should I divide into cases A = 0, B = 0, C = 0, A=B=0, B=C=0, A=C=0 or something like that?
and also 1-\lambda/a^2 and 1-\lambda/b^2 have to be non zero here as well smh
<@&286206848099549185>
@sudden violet Has your question been resolved?
@sudden violet Has your question been resolved?
@sudden violet Has your question been resolved?
Your big solution seems to work in Desmos empirically, but it only produce a pair of maximal or minimal distance. The solution proposed on stack overflow utilize more geometric understanding to get the other pair of solution on the green circle
@sudden violet Has your question been resolved?
yeah, I understand it must be that solution but I'd like to know how to prove it non-geometrically and if I have to divide into cases or something.
in theory lagrange multipliers should get you the four solutions, but the computations and case checking seems to be horrendous tbh
this works unless B = 0 and C = 0 imo, but in that case Ax=0 implies x=0 and it’s much simpler to solve
you can check this with the desmos demo
also if a = b it becomes a sphere but outside of that imo that's it
alright, thank you :)
also, is this enough to prove that ellipsoid \frac{x^2}{a^2} + \frac{y^2}{b^2} + \frac{z^2}{c^2} = 1 is bounded?
if your definition of bounded is that the distance from the origin of any (x,y,z) in the ellipsoïd is less than some positive constant, yeah this seems ok even if it's a bit hard to read.
alternatively you could put the ellipsoïd inside a closed ball of radius max{|a|,|b|,|c|}
yeah i'm sorry my handwriting is too bad 🥲
nice then, thanks
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basically i need to use desmos to make a map of sorts and im stuck
the brief says "outline of the island. Gradient of curve at a particular point: Hint: Functions will join together more smoothly if they have the same gradient at their intersection point
im not sure how to do this
like if i have a quadratic and a sin function even if i make both the same gradient at the point i cannot further manipulate the graphs
like if i wanted the top part to be flatter i cant change that
idk what to do
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؟
You have to think about the 4 ways this equation might be true
im listening
abs is a function that takes an input and makes it positive, right?
100%
So either you have (x+4) is positive, in which case abs gives you back (x+4) directly
Or (x+4) is negative, and abs gives you back -(x+4)
i will try bro give me sec
You should have 4 cases
||One doesn't make sense, two give you no result.||
||And the final case gives you the solution.||
and i will make them equal how ?
i mean every equation equal to 2 cases of the other
like x+3 = y+4
x+3 = y-4
Let's say you're handling the case where (x+4) is positive and (x+5) is negative. You just set them equal to each other. (x+4) = -(x+5)
Yup
i will try again
so it will be -4.5 after we eliminated the ones who are illogical
correct ?
That is correct
how to close the ticket tho ?
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but i have another question what if we have a quadratic. ?
what we doin here
.reopen
✅
I tried to use mode 5 3 to solve it by calc
but what if I did it ;what I will do after that ?.
is the factorized form equals = (abs(x)-5) (abs(x)+2) ?
if we using calc i can just product the root and ignore the absolute X
so it gonna be -10
right ?
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What's your definition of a tree?
a graph connected in the least number of edges possible
Proving by contrapositive is straght-forward from the definition you gave.
wouldnt the question be saying that something like this is a tree though?
There are two paths from upper left to lower right, for example.
oh
so is the contrapositive if graph G is not a tree, then there is not only one path between any two verticies
Yes, i.e., if G is not a tree, then there exists two vertices u,v such that there exists more than one path between them.
Start from the definition of a tree. If G is not a tree, then there exists an edge ${u,v} \in E$ such that $G \setminus {{u,v}}$ is still connected.
ucheo
We can use the same argument. For a contradiction, the hypothesis could be that there is only one path between any two vertices in G but G is not a tree.
Then you apply the argument I hinted at.
contradiction because there is only one path between {u,v} and hence graph G would be disconnected?
Yes, since $G \setminus {{u,v}}$ is connected, then we can find a path between $u$ and $v$. But this path will not include the edge ${u,v}$ since it was removed.
ucheo
So we found two paths between u and v, a contradiction.
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guys
how to solve for x and y
when we have 2 expressions
not equations?
3x+5y-3 and 8x-3y+6
x=?
y=?
3x+5y=3 , 8x-3y=-6
are they equal to zero?
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anyone know how to do b
Take any three numbers say a, b, c
Since they are in an AP, therefore b = (a + c)/2.
Can you continue from here
uh im not sure what to do after that
yes
yes
So now take cases
C1: both a and c chosen are even
C2: both a and c chosen are odd
a and c cannot be even and odd or odd and even respectively
yes
yes
From 1 to 10001 there are 5000 even numbers and 5001 odd numbers
So C1 + C2 gives 5000C2 + 5001C2
Divide that with sample space
I.e 10001C3
C1 and C2 mean cases and 5000C2 means combinatorial C
wdym by combinatorial C
oh yeah
And voila
You still have a problem?
what does it mean by answer in the form of l/k where l and k are coprime integers
Co prime means that the gcd of the 2 integers must be 1
For example 3 and 4
So you gotta simplify the answer into an irreducible fraction
ohhh
Yes
Because it's an 'or' situation that's why
A and C can be either both odd, or both even
Yes which is the sample space
or just 3 from 10001
Yes 3 from 10001
why not like cosequtive
consecutive
or is that already like included in the 5000c2 and stuff
As in?
because u could select any two random even numbers
Yes
Even numbers can never be consectuvie
what artihemtic progression means again
Lol
Np
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any suggestion to calculate the sum of products between two numbers that draw from 1 to 10 and are different from one another.
can you write it down in sigma notation?
I think so?
no
It is not viable
wdym viable
there is a way to do it without sigma notation if you'd like to try that
can you find a way to connect your question to the pic i sent above?
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I know that self inverse is property of klien group four
So I checked and I got answer D
But i didn't understand the upperline means in options A and B
SO if I multiply 1×1 i will always get 1 which is correct
Nanigov
yeah
well it should also include the respective negative integers but ygwim
7×7=49 and divided by 8 yes correct
Option B seems wrong
Residue class 5×5 =25 mod 40
Not getting Identity element
nope! klein 4 group lacks an element of order four, but {1,-1,i,-i} has them.
@lean kraken Has your question been resolved?
How D is in order?@trim lichen
I am saying it is not klien group four
when i said "in order" i didn't mean order like in group theory
i meant like everything is OK
What you mean everything is OK@trim lichen
I am straightforward saying D is incorrect and ABC are correct in simple words not in hypothyroidism
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How should I write out the midpoint sum? I forgot a lot about this stuff
Would it be pi/4 * f(pi/8) for the first interval?
yes
- pi/4 * f(3pi/8)?
yes that works
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anyone explain this? how did he get so many 99s
@near leaf Has your question been resolved?
@tawny escarp
