#help-13
1 messages · Page 321 of 1
can the unit cube be from , say, -0.4 to 0.6?
(in all axes)
i see some definitions defining it as always [-0.5, -0.5, -0.5] to [0.5, 0.5, 0.5]
in other words, does it matter if the center of the unit cube is precisely in the origin?
<@&286206848099549185>
I mean it’s kind of a semantic question I guess I would say that typically the unit cube would refer to the unit cube centered at the origin
But you can totally apply a translation to it
It’s changes the equation of the shape though of course
hmm i see
yeah, i guess i will have to ask my professor about this. He specifically says that we should ensure the barycenter of the shape coincides with the origin, but i am not sure if then further scaling changes that property
as in, after the translation it should coincide, but after scaling he doesnt explicitly say so
Yeah I would definitely ask them because the cube with side lengths 1 centred at (.1,.1,.1) could be considered a unit cube but it probably isn’t “the” unit cube
Barycentre is the spatial average correct?
Or I guess the “center of mass”
yeah
but even barycenter seems a bit ambigous to me
because depending on the structure of the shape it can be different
Well if the scaling is done uniformly in all directions it would be barycentre preserving
we learned about a weighted area barycenter
Do you solve for the barycenter computationally or algebraically?
Algebraically I guess you would need some triple integral of some kind
thankfully cmoputationally ;p
it's kind of shitty my partner did it and he obv used chatgpt. I had to revise the code and then i asked chatgpt different ways to get the barycenter and it gave me literally the exact same code as he wrote
but if you're interested i can show u
Well the code will most likely just be using numerical methods to compute an integral I guess
so i am actualy using a scale operation from a library called Open3d
and this takes a scaling-factor as well as a center
So it scales it about a particular centre then and the centre you input should most likely be preserved by the scaling
i am giving it the barycenter as the center and then the scaling-factor is computed as the max-extent of the bounding-box of the shape
the issue might honestly be related to floating point precision
Max extent I assume is the longest distance from the centre to the perimeter
because its always about 0.1 or max 0.2 off
nope, max extent is, if you imagine a box surrounding an object, the max length of any axis
The orientation of the object must be important too then
You could rotate it in such a way that the scaling factor could be increased and the object would still sit in the cube
hmm, not sure what u mean
anyhow, i just verified that the barycenter in fact does not change with my scaling
so somehow, i scale with respect to the barycenter with a certain scaling-factor, yet it very frequently goes , say, -0.4 in neg. X and 0.6 in pos. X
i think it's just because the actual barycenter is never exactly [0,0,0]
but i didn't think it would be off enough for it to be even noticeable
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I’m trying to figure out 26, the second photo is an example of what we’re supposed to do. The third photo is an equation someone gave me when they were trying to help. It looks correct, but I asked my friend who’s rlly good at math and he got a completely different answer.
The equation I provided is correct
Solving for k from it should be straightforward
yes but my friend got a different answer when I solved it
I got -1.75 and he got -5.75
Oh sorry I meant to put plus
Why did this become minus?
I made an error
Show the work
You weren't suppose to change both minus signs to plus
She gets that
I got -5.75!!!!

lemme try the next one and then I’ll close if I get the right answer
Good job
ok I got 2
and ty!
What's the problem?
Yes it is 2
Fyi, you can plug in your answer back in to check your work, because it's an equation, the left would equal the right side
ooh yes I forgot about that
I hope my teacher doesn’t make me redo it since I didn’t do it her way
tysm for the help tho!! I rlly appreciate it
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how is this possible? the inner radius and outter radius ave the same equation.. won't that cancel out the volume?
probbly
im trolling
for the shell method?
well you want to find r(x) and h(x) for the cylinder
radius and height
the radius will just be x-1 if you can see
yea
since you rotate around x = 1
for the outter is 1 - (4x - x^2)
and then the height will be ((4x-x^2)-3)
what why?
imagine taking cylinders throughout the requested area
the height of those cylinders will be the higher-lower function
so the outer is like 3 away from it
so it's actualy 3 - (4x - x^2)
and the inner starts at 1 tho so does it even need anything
some kind of shell like this
you can see that h(x) will be upper-lower function
radius will be x-1
why do you keep saying x - 1 it's 1 - x
wdym
you're rotating around x = 1 no?
you can see that the radius from that line to the curve will be the x position of that curve - 1
or x-1
no it's 1 - x
assuming the intercepts I was thinking this
are we using the same method
and why are you squaring 4x
do you write it that way when it's a x rotation then?
i recall putting it beofre the function
maybe it was because it was rotated on y = 3
so i put it as 3 - f(x)
rotating around x = 1 is rotating in the Y axis no?
yes i am asking about rotating on X axis
is that why is it confusing me
please confirm my question
for an X rotation you would use the disk method instead
or invert the function
just simple question
if it is rotating on X - axis
do you subtract it like 3 - (x+5)
well to use shell method for x you would need to invert the functions
you don't seem to understand
i am specifically asking about how to set up
NO U DONT
when it is rotating on x - axis
vs y - axis
yes
do you need to set it up a differnt wayu
go on
that is the question
I AM JUST TALKING ABOUT THE AXIS OF ROTATION WITH RESPECT TO THE VALUE WHER IT IS ROTATING
FOR EX
if blah blah blah rotates about y = 3 vs x = 3
our disagreement is laying on this
you say it is x - 1
rotating around x = 3 would be rotating around the Y-axis over that line
i say it is 1 - x
I am asking
if
it
changes
1 - x
x - 1
does that form change
based on whether it is rotating on the x or y axis
nothing else
not asking abt dy or dx here
just pretend everything else is perfectly setup for the equation
because we have a disagreement about how to set up the rotation part
back into the equation
you say x - 1
i say 1 - x
ok I kind of understand what you are trying to say but it doesn't make sense
so all i am asking is
because if you were rotating around the x-axis you can't rotate around the line x = smth
you would be rotating around y = 1 or y = 3
it would work with a different equation
I can't pretend if it doesn't make sense
you have no imagination that is why
because you wouldn't have to worry about 1-x or x-1
why don't you give an example question
1-x and x-1 are different
you are just stuck
because the line x = 1 shifts the graph one to the right? So to find the correct radius
you have to use (x-1) as the radius
alright
so you have a quesion rotaing on the X - AXIS
at y = 3
now
when you go back to put it into the equation
how are you going to do that
would it be x - 3 or 3 - x?
since it is the X - AXIS
not the Y
You rotate on the Y axis
how can you rotate the line x = 3 around the x-axis??????
look at this line
do you understand what i am syaying tho
Imagine spinning your hand on each axis and filling the shape
you guys are totally missing the point
^
all i am asking
is
if you rotate on x - axis lets say y = 3
ok Y = 3!
get it:
would you insert it back in
as 3 - x or x -3 to f(x)
if you are using washer method or disk or whatever doesnt matter
do you get it?
Integrated with respect to x will be a lot more difficult.
wow
u are stuck
ok
we have to move on from this
u just are not folowing
its very simple
I think you are either not explaining what you mean well enough or you're misunderstanding something
you guys are just not understanding
you cannot think outside of this equation
it has nothign to do with this equation
ok
first of all
you're asking for help right
just forget about this equation right now
how do you expect to get help
then you can think about waht i am asking you
If you integrate from x=1 to x=3, you’ll have an unnecessary area included in the final shape
we are trying to think about what you mean but how you are explaining it atm doesn't make sense.
well it wont make sense at all because like i just said 4 times
x-3
it is not related to this equation
Aka the box “sliver” under the shape you’re trying to find the area of.
so if u want to keep referring to this equation you will never be able to answer the question
this is why you would use x-3
you can see that the line x=3 is transformed to the central axis in this case
This is not trolling. I understand this can frustrating.
Choosing the right method is important
y would be the same
If you don’t choose the correct method, you make it much harder for yourself.
ok
you transform y-3
yes good it is
well
i did hw the other day and we did 3 - yh
3 - y
and it was correct
so why are you saying it is y - 3?
it is question dependent
how
on whether the function is above or below the axis of rotation
no that would just make it addition or subtraction
if the axis of rotation is above the function you would use 3-y
and for the counterexample you would use y-3
you're trying to find the radius from the axis of rotation
it's not that simple
if y = +3 you subtract it
ok this is my question you are finally understand what i am asking then
so please explain, what it is
you are doing a good job so fart
far*
ok but you are missing something
because
wait maybe
so if we rotate at y = 3 vs y = 4
you are saying what exactly
since one is above and one below
you would have to invert the function first if the function is y = f(x) but yes
let me draw out the cylinders for you to show
nonono
u dont need to
i am just asking about this
plz trust me u dont need to
i am just asking
look
if you rotate at y = 4 then are you saying you make it y +4 ? 4 -y? or y - 4 ?
if you rotate at y = 3 then are you saying you make it y + 3 ? 3 - y? or y - 3?
cause you said it depends whether it is above or below
so i want to know which is which that is ALL Ii want to know right now
that is my simple only question here
the height for cylinder at y = 4 will be 4-y and at y = 3 y-3
what did u draw ?
the red squares
...
r u being serious
what does that represent
i know u drew red squares
i just sent that picture without the square i mean what are those supposed to be
representing
lol r u trolling me
those represent the cylinders you would be finding the area for in the shell method-
i dont think that's right
why is one on the outside
it looks like an inner radius
on top
and the other one looks fine
but u drew them for 2 different equastions no?
because you're rotating around a line above and below. There's two separate different rotations
i am literally just asking u
yes or no
y would u only draw the top one inner radius then
yes. They are drawn for two different lines.
that is not even in the area of the curves
I don't understand why you keep mentioning inner and outer radius, can you explain your methodology to me?
you made the lines-
you drew the cylindar outside of the area
the top one
that is your rotation? it is not even making sense
how do i draw on the picture
you rotate the cylinder I highlighted around y = 4
I used screenshot
ok hold on
this is the rotation I was talking about
that also works ig
that doesn't make my region incorrect
it really depends on which region the question asks for
im saying it is the inner radius
but also the rotation around y = 4 would be an infinite rotation
unless you set a bounds
I would argue my rotation drawn makes more sense since it is an enclosed area but regardless both are correct and dependent on what the question asks
ok but my question was only just how do you know when to wirte it back as 1 - y vs y - 1
so if the rotation is above then you write it as 1 - y
and if it is below you just do y - 1..
?
did i get that right
I don't have a mouse but here
the radius is x-1
how are u even drawing then
well it depends what direction are you going
the height is (4x-x^2)-3
sigh
or left to right
the line is to the left of the area
so you rotate the area around the line to the left...
I'll just leave my working there
see if you can figure out what I'm doing at least.
if it doesn't make sense I would encourage you to go look over the method
you are just drawing weird stuff
it is not correct
not totally incorrect but not correct either
so not helpful
but thank you for trying
if you knew how to drawe it better it would prob make more sense you know what you are tlaking abt i can tell
ya just your drawing is confusing
and i am saying the wrong thing
cause in shell you have radius and height
so i keep saying outer radius and inner radius
but you should be able to understand what i am talkikng abt tbh
maybe you are afraid to be wrong it's ok
when i kept saying outer radius i mean height f(x) my bad
I'm not afraid to be wrong
anyways you seem to know your stuff
the height is outer-inner radius
but you should get better at helping people
or (4x-x^2)-3
try to understand what they are saying better
and the radius is x-1
sure. But I want you to also consider the converse
i hav to go to sleep
and try to understand how to explain better
i can tell maybe you are using chat gpt or something
it is a new trend in this server
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if 3x+5-7 as swaped is 3x-5x+7x and then 2-12 is equal to 10?
That's a lot of attitude for someone needing help with highschool math
It is cute though, attitude matches the level
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I wish my highschool taught Calc II.
you've opened this channel, but haven't asked a question 
do you have a question to ask?
it was by accident sry
no worries
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My professor in his lecture notes would like me to recall a fact from a previous class, I hardly remember it. Could someone explain to me why a line can be parameterized in the way described by the first paragraph please?
Thank you!
It doesn't even feel like a line to me, since x(t) seems to take the form of an x and y coordinate
The intuition is that t ∈ [0, 1] is a 'weight' between the points P and Q, where at t = 0 we have that x(t) = (1 - 0)P + 0Q = P and then it increases in the horizontal coordinate and the vertical coordinate at the same speed towards Q (and therefore in a straight line) as t goes from 0 to 1, where we at t = 1 then have x(t) = (1 - 1)P + 1Q = Q.
Hm, but t could also be 0.5, uneven weights, what would happen in that case?
Then you would be at the midpoint of the line between P and Q.

Wait that makes so much sense.
Tysm!
I have another question further down my lecture notes, I'm not sure if I should start a new chat or not, but it is somewhat (not really) related.
I don't get the second to last line, when it says ccw pi/3 radian becomes cos(5pi/6), sin(5pi/6)
That doesn't really make that much sense to me. P is the shape we're rotating and it's composed of line segments.
And I guess we are trying to contruct the new rotated basis vectors by rotating the standard bases.
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Hii
Ok so not really a question abt an specific problem
But I'm struggling with math well not really struggling but I keep getting bs in my tests
Might be lack of studying but idk how to study math
practice
Cause js practicing what they give me won't help me that much
how r u practicing exactly...
I must research the logical things really deep to even dare go say I grasp this math subject I'm in algebra 2
Well I do problems from the class
I watch random yt vids:3
are there more problems in your book?
then look online for more problems
I got this one book that is more complex although it has an specific style of solving problems it's not like just do whatever u find best
It has some sort of structured pattern haven't really looked at that one but I will if it will make it better
Well I've never truly had to study for survival like I am now
Because K to 8th it was extremely easy
9th I had a course in which I could rely to learn stuff
do the pset and if u dont understand something about a question write down what u dont understand/what u need
9th for geometry I had to learn from a course aswell
then finish the pset as best as u can then lookup what u dont know
But now I don't have a course to rely on so it's only me and the books
May I ask how u study or used to for math
thats still how i study for it
go to lecture and write down stuff i dont get to ask or google myself later
then do the pset using this ^
Ok we only get 1 day of full review
Our teacher usually just let's us study or follow her with some problems
But I work better independently
Any tips on being accurate while being fast?
1 day of full review as in 1 full day ur not learning anything new?
Yerp
oh well thats fine
ur supposed to do extra practice after class on what u learned everyday too
every week i do some practice problems from the week prior to keep the knowledge fresh
Ah I see
if u leave it all on last day u will be cramming
Yeah ion like that
I've only had to do that once I got full score but ik it ain't the way
That one time was because my bio grade mattered more than my math grade
its pretty common to have the last lecture be on a friday here and midterm exams testing that same material on the monday after
so yea its even more important to chew a little bit at a time
I feel overwhelmed with the hw assignments
Cause it's like 1 daily and It doesn't really tell me much on how to solve each thing haha
can u show them?
Uh currently no cause I'm out but later yes
Or maybe I'm just not viewing them from the right perspective like I can get them correctly but they don't tell me much in my perspective
hm well cant help u too much w/o a concrete example
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A preorder relation p on the class of all funcitons with domain list X1, ..., Xn is defined as. p(f, g) =
The exercise is: Demonstrate that if there is at least one smallest function, then a smallest function exists that is both injective and surjective.
what I dont get is isnt the funciton f: X1, ..., Xn -> (X1, ..., Xn) where f(x_1, ..., x_n) =(x_1, ..., x_n) a smallest funciton
that is both injective and surjective
so why "if there is at least one smallest function"
yeah, the notes arent very clear
is my solution correct or am i missing something, I dont understand why there has to be the "if there is..."
I guess because there’s probably some weirdness that could happen if you had trivial domains or something
I’m not super sure about this without some more clarification
Like I’m not sure how the function class is actually defined
When you say domain list like do the functions all have a domain being the Cartesian product?
from what i understand, the notes are really bad, the class of functions is just any function f: X1, X2, ..., Xn -> Y
where Y is any set
but the domain is not cartesian product, just many inputs
That is Cartesian product
wdym
i mean yeah, but it is defined to take inputs like that, not their cartesian product
Like the input to f is the the tuple (x1, x2, …, xn) where the xis are in Xi
but either way the function f: X1, ..., Xn -> (X1, ..., Xn) where f(x_1, ..., x_n) =(x_1, ..., x_n) clearly satisfies p(f, g) for any function g
so...
And Y and Z are arbitrary?
yeah
A function would be smallest if it is related to all other functions right?
yes
i can also send u the full notes if u would like, they are like one page in total
and pretty poorly written
I’m pretty sure that your function just the identity function
So surely for any function there’s is a phi, namely g itself
So yeah it should be the smallest
I think the reason you have the premise with the if is in case all the Xs were empty or some weirdness like that
Or maybe the class could be empty
oh
Something like that i think is probably what’s going on
But yeah that identity function should be all you need to prove the existential quantifier
Looks good to me
i mean if the Xs are all empty wouldnt like the function f: empty set -> empty set be smallest
its also bijective
I mean i guess the empty function does exist so technically that’s true
I have no clue then why the premise is there maybe it’s redundant or maybe we’re missing something
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for this kind of limit proof a trick is to instead give a sort of minimum for what delta can be, so your delta would be of the form
$\delta=\min{\text{constant}, \text{thing dependent on }\epsilon}$
or wiat is it minimum
I think it’s minimum
well something along those lines. Knowing something delta is at most some constant helps you bound one of the factors
WHAT?
Limit proofs is kind of confusing to me, sorry, but I have (x-2)(x-1) < epsilon. Should I be getting the minimum of those? So x=1?
I got to the point where I’m dividing epsilon by (x-1), so that I have (x-2) alone
so now the idea is to choose a constant that delta can't exceed so that you can put an upperbound on 1/|x-1|. Does that make sense? Then your delta would look like min(constant, epsilon/upperbound)
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flip?
like how 1/x is x^-1
yeah
so (x - 2)/x is (x - 2) * x^-1
yep
thank you
[\frac{\mathrm{stuff}}{\mathrm{other\ stuff}} = (\mathrm{stuff}) \cdot (\mathrm{other\ stuff})^{-1}]
Invariance
lol
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Hi, I have a linear-algebra problem. How was the red-underlined part formed?
Can you provide the full image?
I believe it's a full image, you may please clock to see it expanded please
if you foil then you get uv^tuv^t(...)
in the middle the v^tu is a number
so you can move it to the front
That underlined part is formed as a result of factoring out v^tu from the terms inside the expansion of second term.
Yes, a little confusing. I suppose the 1 was due to typo, or scan issue. I still don't understand why v^tu should be number?!?! if v, and u are 3x3 matrices, how could v^tu become a number?
DANG!
Ouch, so now it make sense, so in case the yare matrices, then that v^tu would be a mistake I suppose?
well the whole thing doesnt work if they are matrices
although iirc there is at least a similar result
Thank you, much appreciate your time sir. Thank you @steep lark too.
Math bless us all. 
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yo i got a question
so if i wannt write this inequality using interval notation
x < 3
would it be this
(-inf , 3)
yes
and can you also write it like this
(-inf, 2]
no
isnt it ]-inf,3[ ?
maybe we dont have the same notations in differents country
im sure this bracket notation would be the same everywhere
why parenthesis then ?
]-inf, 3[ and (-inf, 3) mean the same thing
ah okay
different notations
whatever the notation convention, you'll find that closed brackets [a,b] are common in both
so parentheses, as well as brackets facing outwards, are the same
yes
so here the problem is that you're reasoning in terms of integers
you're thinking that x < 3 is the same as x <= 2
but that's only true for integers
so therr is no stuff with )3,2) ?
oh shit yea
there are real numbers between 2 and 3
for example
yea
parentheses facing outwards don't exist in any convention
i mean u dont write like this ?
it's either parentheses, or brackets facing outwards
ive been working with these inequalities so much in stats so i was only focusing on discrete valuies
ok👍
forgot about continuous ones
[a,b] <-> [a,b]
[a,b) <-> [a,b[
(a,b] <-> ]a,b]
(a,b) <-> ]a,b[
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let I be the centeroid of triangle ABC, prove that AIB=90+C/2
anybody have any idea how to solve this? I'm stuck and it will be greatly appreciated
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if it matters, there is (incenter lemma) next to it but i dont see anything on google thats not incircle excircle lemma
pretty sure I has to be the incenter and not centroid
ok wierd then
its easy to prove AIB = 90 + C/2 for I being the incenter
yea ik its "incenter lemma" but still google says its the centeroid
how fo you prove it then
prove what? AIB when I is incenter?
yea
Just measure the angles of the triangle AIB
I being incenter means AI, BI and CI are angle bisectors
it also wants to prove EA=EB=EI
but this looks so wrong
what lmao im pretty sure thsts dtraught up not true??
what is E?
i mean F, in the image its a continuation of AI
translate doesent make sense, google shows you centeroid
i asked my friend and they said its also centeroid so :shrug:
Nahh, I just wanted to verify, coz translate got that wrong
so if the rest of the problem is correct
it also asks D is center point of BIC, so it makes sense if it means angle bisector
so what is D lmao
AI and BC intersection
in a single sentence it contradicts itself 3 times
Is it part of some bigger problem? Coz this makes no sense
no thats the whole problem
then this means D is circumcenter of BIC, which is true if BIC is 90 deg
my best guess is the wording is just fucked up and they meant like "if DB=DC=DI, prove that D is the centerpoont of BIC"
i'd suggest skip this one
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what they did in last step to get the value of r
factor 1-r^3 (difference of cubes)
then cancel 1-r and 27
multiply everything out to have no denominators
-> at most a quadratic
(in fact it's actually a linear equation on r)
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I think they just solved for r
1-r^3 = (1-r)(1+r+r^2)
r2 + r + 1 = 19(r2 - 2r + 1)
r2 is r^2
@daring barn
What's the problem?
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I need help finding The second derivative of this function! I am stuck
$\frac{1}{\ln{(a)}(x+1)}$ this?
Biscuity
where a is a constant, right?
Yes
so, basically you treat ln(a) as a constant, lets say
$\frac1{\ln (a)}\cdot\frac1{x+1}$
Biscuity
Yes
What I could do is take it back to the original form?
The right side is ln(x+1)
so, we have $\dv{}{x}\left(\frac1{\ln (a) (x+1)}\right)=\frac{1}{\ln (a)}\cdot \dv{}{x}\left(\frac{1}{x+1}\right)$
Biscuity
sorry typo
since it's a constant
$\dv{cf(x)}{x}=c\dv{f(x)}{x}$
Biscuity
1 is constant ?
it's multiplication, not addition
Cheers!
it's .close
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Hello i need help for this :
Let g : R² -> R be a C^1 (R²) function; define
h : R² -> R
(x,y) I-> g(y,x)
Calculate the partial derivatives of h as a function of those of g.
Is there all there is?
I don't see a relation between h and g
I see
You define a function h
that maps to g(y,x)
h(x,y) = g(y,x)
wtf
So basically your partials will be in terms of g
There may be a specific property in this case in my course, but I haven't found it.
for example if g(x,y) = x+y² then h(x,y) = g(y,x) = y+x²
We're not being asked to define a function ...
Also if I rephrase the question a tiny bit:
you have $h = g(u, v)$, and $u = y, v = x$, so
@cerulean sail

That was an example of how it works for a specific function, to give you intuition of how you'd go about it-
The problem is stating it in itself: calculating a partial derivative is not complicated.
Well then, do you know how to find the partial derivatives of this function, in terms of u, v, x and y then?
im inclined to state the general chain rule (the one with matrices) even if its overkill here
have you seen the example?

bet
mb
∂g/∂y(x,y) = ∂h/∂x(y,x) , ∂g/∂x(x,y) = ∂h/∂y(y,x)
actually ill suggest it for real
I'll have the correction tomorrow
do you know the general chain rule?
yes, I saw this a long time ago
for functions R^n->R^m?
nop
do you know the jacobian?
nop
did you take vector calc?
Yes, the basics
ok then jacobian should be a familiar idea
In vector calculus, the Jacobian matrix (, ) of a vector-valued function of several variables is the matrix of all its first-order partial derivatives. When this matrix is square, that is, when the function takes the same number of variables as input as the number of vector components of its output, its determinant is referred to as the Jacobian...
here ill use Df for the jacobian of f
general chain rule: if $f:\bR^n\to\bR^m$ and $g:\bR^m\to\bR^k$ are $C^1$ then so is $h=g\circ f$, and
[Dh=(Dg\circ f)\cdot Df]
with $\cdot$ being matrix multiplication
RokettoJanpu
honestly, charbits approach was the best
your problem is notationally convenient. find f so that h=gof, then use the chain rule
its overkill for this problem but its good to know in general instead of having 100 specialized chain rules
Ok thanks for these answers
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for all x and for all y if x is greater than or equal to 0 and y is greater than or equal to zero then xy is greater than or equal to zero?
Yes, that's what the formula says
sick
are you supposed to prove it? Or just interpret it
interpret
i was gonna ask why there are two for all
but then i just read it and it clicked
thank you tho
havent gone into proofs yet
not thrilled for it but we;ll see
.close
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I found the marginal probabilities using a contingency table. now what? how do I present it like as a answer?
in method of variation of parameters can we choose any y1 and y2 value?
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Is it possible tho show that fsubscriptn of x = x^n E C subscript b,uc(D) where delta in (0,1) and D = (-delta, delta)
Basically want to show that given delta in (0,1) and D = (-delta, +delta), and given Fn(x) = x^n, i want to show that x^n is in the space of bounded and unifromly convegent funcrtions on D
Any ideas on how to do this?
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How can I find the domain?
the argument of the square root must be non-negative
I know
let me show a pic
The -π/4 is closed
I just do't know how to fit the |x|
mmmmmmmm I think I know what to do
it's from <-π/2; -π/4] first
and then
[π/4; π/2>
it's 3π/4
not 5π/4
soo A
I think
yeah
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Can someone help dumb down what this means cause I cant understand it
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It’s related to the free variable thing from yesterday
If the two statements evaluate to the same truth value no matter the specific predicates then they are called logically equivalent
So for example you have a sentence A or B
This is logically equivalent to the sentence D or E
A better example is the pair of statements “A” and “not (not A)”
These two statements are logically equivalent since you can insert any sentence/predicate in place of A and the two statements will evaluate to the same truth value
Take a look at the Wikipedia page for more examples of equivalent statements
In logic and mathematics, statements
p
{\displaystyle p}
and
q
{\displaystyle q}
are said to be logically equivalent if they have the same truth value in every model. The logical equivalence of
p
{\displaystyle p}
a...
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Can somebody explain this to me?
Why wouldn't we set it up as an inequality that has to be more than 0
Since isn't it the denominator of a fraction? \
Also how does the square root work here?
because
if we have any number
squared
it will always be positive right
Yeah
so any other number added
with always be positive
therefore a positive plus a positive will never be 0
ohhhhhh
denominators can be negative, so inequality with >0 doesnt make sense
it just cannot be 0
what if the number wasn't add and it was subtract?
do I still set it up the same way?
you would set yp
x^2-3=0
x^2=3
and solve for x
you want to find where the denomiator is equal to 0
wait, so if I solve for x wouldn't it be the same as the other time with + or - sqrt3
?
like if I set it up like this to solve for x
would domain be like
(-inf, sqrt3) U (sqrt3, inf) ??
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show that if
cos 𝑥 − sin 𝑥 = 1, then cos^2024(x) + sin^2024(x )= 1
How can i solve this
Solve for cos or sin and plug into the right equation?
but they have power 2024
