#help-36
1 messages · Page 211 of 1
@rain sentinel Has your question been resolved?
<@&268886789983436800>
What was the ping for, may I ask? Something that already got deleted? 
yup
Fairs I guess 
scambot, banned for activity elsewhere
@rain sentinel Has your question been resolved?
Closed by @rain sentinel
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
<@&286206848099549185>
I want to show l^2 is strictly convex
You need to send your question first, and then if no one responds for 15 minutes then ping helpers mate
!15m
Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.
!show
Show your work, and if possible, explain where you are stuck.
I actually showed $ | | x + y | |_2 \leq 2$
But I can't figure out how to show the equality doesn't hold
Can you do differentiation?
Yes I can
Well apologies, but i am not qualified for this question, I could possibly try and decipher it in some time and then do this, but then I'd be wasting your time
Sure man, apologies again
@spare plover Has your question been resolved?
<@&286206848099549185>
I wanted to argue by contradiction
So, as $l_2$ norm is $| |x | | = \sum_{n=0}^{\infty} \ |a_n|$
Gol D Roger
I apply it at $| | x + y | | = | | x | | + | | y | | = 2$
Gol D Roger
But I still can't conclude a contradiction
<@&286206848099549185>
Please, I just need to deal with that sum
I tried squaring both sides
I tried substracting both sides
<@&286206848099549185>
triangle inequality?
think about the unit ball
is it open or closed
@spare plover
Let $x,y \in l_2$ be s.t. $ \Vert x \Vert_2 = \Vert y \Vert_2 = 1$. Using the triangle inequality (which we know we can use since $l_2$ is a Banach space), we have
\begin{align*}
\Vert x + y \Vert_2 \leq \Vert x \Vert_2 + \Vert y \Vert_2.
\end{align*}
By hypothesis, we also know that $ \Vert x \Vert_2 = \Vert y \Vert_2 = 1 $, so
\begin{align*}
\Vert x + y \Vert_2 \leq 1 + 1 = 2.
\end{align*}
Now, suppose that there exist some $x,y \in l_2$ (with $ \Vert x \Vert_2 = \Vert y \Vert_2 = 1$) such that
\begin{align*}
\Vert x + y \Vert_2 = 2.
\end{align*}
Then, by definition of norm in $l_2$ , we have that $ \Vert x \Vert_2 = \sum_{n=0}^{\infty} \ |a_n| $ and similarly, $ \Vert y \Vert_2 = \sum_{n=0}^{\infty} \ |b_n| $.
Then,
\begin{align*}
\sum_{n=0}^{\infty} \ |a_n + b_n| = \Vert x + y \Vert = \Vert x \Vert_2 + \Vert y \Vert_2 = \sum_{n=0}^{\infty} \ |a_n| + \sum_{n=0}^{\infty} \ |b_n|.
\end{align*}
Where $|x|$ denotes the usual metric in $\mathbb{R}$ (i.e. $ |x| = \sqrt{x^2}$).
Yes it is
But how can I conclude a contradiction there?
I sense is some arithmetical trick
But I can't find it online ):
Gol D Roger
I tried squaring it, idk if I can use GM AM inequality
Any ideas?
<@&286206848099549185>
idk apart from showing the line segments for any $x,y \in l_2$ is in the interior of the space
frisysics
since ur working in euclidean space the contradiction is kind of easy to do
I feel the same but I am just too dumb to figure out lmao
the unit ball being closed makes the way ur doing it so weird to do
Yeah... I just tried using definition and algebra, not geometric arguments
you can have a line connecting x to y, and do a contradiction through that
But if ball was not closed, I don't think statement is still correct though
if the ball was open then if
Is that the same as saying $ \Vert x - y \Vert$ and using inverse triangle inequality?
$\Vert x + y \Vert_2 = 2$ then that would be a contradiction since the open ball must have d(x,y) < r where r is 2
frisysics
instead of $\leq$
frisysics
I tried it, but substracting an infinity amount of numbers works awful for me
Oh I see, so if ball was open, result may be trivial?
Hmm I see, but then again, ball is closed
I need to figure out how to use that $ \Vert x \Vert_2 = \Vert y \Vert_2 = 2$
Since norm is an infinite series, then it must be that at some point, entries are zero, isnt it?
Or is there some series that converges to 2 and are "nice" in the sense that it has a pretty finite sum
i think there is
I mean, the argument for showing $l_1$ and $l_{\infty}$ are not strictly convex is using the sequences $(1,0,0, ...)$ and $(0,1,0, ...)$.
Maybe I can use them too here?
Gol D Roger
Or use some Cauchy Criteria for convergence to show it can't exist such sequence s.t. $ \Vert x \Vert_2 = 1$
this is probably an insanely dumb way to do it but
take z = 1
$$
\sum_{k=0}^{\infty} \frac{1}{k!} \sum_{k=1}^{\infty}\frac{(-1)^{k+1}}{k} = 2
$$
frisysics
wait no you'd take z to be the first series im getting sleep deprived
$$
\sum_{k=0}^{\infty} \frac{z^k}{k!} = 2
\ \text{where} \ z = \sum_{k=1}^{\infty}\frac{(-1)^{k+1}}{k}
$$
frisysics
I'll keep chat open until I solve it, help may be apreciated
Hmm, and what about 1?
I mean, if some series converges to 1 then argument brokes, but if some series converges to 2, then there is not problem, since splitting the sum does not split the result (in a nice way at least)
So yeah, series should converge to 1, not to 2
But idk if that's possible
i mean z has alternating terms no?
like +,-,+,-
Yeah, but idk how to argue that inserting parenthesis or reordering the series still has the same result
Since it does not converge absolutely
Yes
By assumption
If not, result is trivial again, isnt it?
Bc it's in the unit ball
Yeh
Yes I can
But... how?
Are you trying to say $ | | x - y | |_2 = 0$?
yeah
Hmm, why?
well
i feel like it has something to do with
either
showing the series for $ | | x | |_{2}$, same for y is equal to each other and thus x,y must be non distinct i.e the same
or the distance between them is 0 which means they're the same point
that is d(x,y) = 0
Hmm
So, do I have to compare the nth term of the sum both sides?
And apply some "uniform convergence" argument?
To conclude that the distance is zero?
But is that possible?
yeah
ok i sleep now
There's just one little problem with that answer. I'm supposed to show it without the use of inner products
We still haven't properly studied Hilbert Spaces, so yeh
ok that makes sense
Dont worry man, go to sleep
There may be more ppl here
ye
I'll try
You have done more than enough, so thank you for that
Perhaps you gave me more intuition behind, which is greately appreciated
So <@&286206848099549185> can any other helper give me a hand?
Bro who studies Hilbert space in this age
😭 😭
Idk man, I need to graduate soon, so perhaps, that's why?
I even dropped complex analysis i can't help u...I'll go help out in important doubts like application of Pythagoras theorm
Truly based, go ahead
Chat still will be open
Got it! I finally solved it
Thanks @gray radish 🙂
.close
Closed by @spare plover
Use .reopen if this was a mistake.
im watching a dota 2 vid how did you end up doing it
I'll send it in just a sec
But basically, show inverse triangle inequality using normal one, and since the equality holds in one iff in the other, then I got what you said, $| | x - y | | = 0$
Gol D Roger
But it's a norm so hell yes
@spare plover for future questions i recommend that you ask in the topic channels
since there you get faster responses
the usual level of questions asked in the helped channels is up to hs and the very beginning of uni math more or less
so people who know how to answer questions of more involved topics rarely visit help channels
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Im recreating a video in minecraft and want it to be exact. The player in the video is in adventure mode and can't see block outlines. Can someone measure this hallway in blocks?
Would the measurements for each doorway help? I can figure those out. The video is "Matchbox Round 1"
Here's some lines if that helps
Wair it didnt send righht
Hey I drew new lines they wont send
i love this
math in real world application ahh
"were never gonna use this irl"
Ok but this looks calculatable
How do I do this
Should I consult artists instead
Cuz perspective
i think artists would know better
Is that a calculated or is that a guess
i mean its not any math done but thats what i counted
Also the fov is shown by the nearby blocks so compare the blocks to the size of the first one on the far left
im just gonna guess that the ratio of the pixel length of the left side of the stripped oak log to the right side of the stripped oak log, is the same as the ratio of the length of right side of the stripped oak log to the right side of the next orange concrete block.
lemme test this
@unborn elk Has your question been resolved?
No
Shoot its a bot
Why did I reply
Did you do it yet
not yet
Maybe 8? This is just a guess btw
Have you started it or not yet
ye im doing it rn
Alr thanks
Just remember the perspective doesnt have the corner in the middle so the sizes might be different between the left and right of the corner
ChatGPT says 8 but idk how much I trust that
More lines
i think it might be solvable by considering the pixel length of the initial stripped oak block, and the pixel length of the final orange concrete block, gonna need more time to think about it
@unborn elk Has your question been resolved?
Tomorrow if it hasn't been resolved I might just create different sizes in game and see which one looks right
i dont really know too much about 3d projection and honestly you might have better luck asking in #geometry-and-trigonometry
If it helps anyone though, i did capture a few example values on my test world
Closed by @unborn elk
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Does this look okay? I have no clue how to do 1.7 so it is not included
Still need help
Yip, you are very quick, I just sent this message😅
Wait
Determining when the new growth function, (g(t)=150e^{2t}), exceeds the initial function requires the formula for the initial function. The image provided does not include this formula, making it impossible to solve for the time when the new function becomes higher than the initial one [1.1].
Celestial
Is it possible
What the helly
The information I sent was everything I was given plus the questions I answered
did you just pass this into gpt
Seems like it
!noai btw, if so
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
.
1.1 is incorrect for the green leaf beetles
you subbed t = 1 for g(0)
1.3 overspecified: you are asked for the point in time (aka just the time value)
1.4 consider describing what equals infinity here and what it means for the population of the green leaf beetles
1.5: while quadratic is no doubt correct, I think they may be looking for another word (this one I'm not sure about)
1.6: inaccurate explanation for the domain being all of R. the domain is all of R because there is no real number that makes a polynomial undefined (or, polynomials are defined for all real numbers)
1.7 is basically asking you to compare the two functions to see when the new function produces values exceeding that of the old one (for the red bark beetles)
so basically, the range of values of $t$ where $r_{new}(t) > r_{old}(t)$
Hanako(x, y); ∂(fox)/∂x
I think that's all I have to comment on for now
Thank you so much for checking it!
Yeah I'm going to sit and try to do it
is this a live test, or a past year paper, or an assignment?
This is for an assignment, would never paste a test in here. The lecturers just aren't very helpful and I do not have friends to ask if they can check or compare work so I ask here. I do the work myself so I hope it does not go against any rules in the server
if it is an assignment it's generally fine. summary assessments/tests constitute academic dishonesty though
but yeah, all the best!
No it's not a summary assessment or a test. Thank you! May we meet again comrade.
aye. anything else?
That is it for now, I will ask again once I finish question 2.
.close
Closed by @balmy mango
Use .reopen if this was a mistake.
aight
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hel
Well, ask your questions
@strong flax Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello, I don't understand why this is so. 😦
!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
do you know that $\int_a^b f(x) dx = -\int_b^a f(x) dx$ ?
Denascite
Yes
its the exact same idea
going on the line from a to b and going on the line from b to a cancels each other out
David🥛😋
Like this or something else
like that
Closed by @stoic temple
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
!show
Show your work, and if possible, explain where you are stuck.
the big circle’s area is 4pi, you subtract the three semicircles (middle one fully inside = pi/2, sides overlap giving total removed area (5pi/3 − 4 + √3)
so shaded area = 4π − (5pi/3 − 4 + √3) = (7pi/3) − √3 + 4
so a+b+C+d=17
@blazing fable Has your question been resolved?
@blazing fable Has your question been resolved?
@blazing fable Has your question been resolved?
I dont’ get it (after removing 3 semi-circles)
oh so after removing the 3 semicircles we’re just calculating how much of the big circle’s area is left
one small semicircle (the middle one) is completely inside, so its whole area gets subtracted
the other two on the sides only overlap partly
Yes so,
I stuck at finding the part
At both sides, outside the shaded circle of the 2 semi circles
you have to find where each semicircle meets the big circle (the intersection point is at x = 3 − √3), then calculate the overlap area between them
Yeah so basically I know what to find but idk how to do
that overlap for one side comes out to (−2 + 7π/12 + √3/2)
?
ahh okay
yeah so basically to find that part, take the equations of the circles the small semicircle (center at (1,0), radius 1) and the big circle (center at (3,1), radius 2)
yeah then you have to find the intersection x-coordinate between the left small semicircle top and the bottom of the big circle
you take the small semicircle’s top curve y = √(1 − (x − 1)²) and the bottom of the big circle y = 1 − √(4 − (x − 3)²)
(X-3)^2+(Y-1)=4
yso ou find where they intersect by solving √(1 − (x − 1)²) = 1 − √(4 − (x − 3)²)
Yeap
so you should get x=3 − √3
How do I know the intersection of 2 circles?
Is it like this and find the values
(The second one is -6x not -6y mb)
okay so to find where two circles intersect, you just set their y-values equal because at the intersection point both circles have the same (x, y)
yep exactly that’s the right idea
yep that’s right!
now that you’ve got the intersection point (3/2, √3/2), you use it to find the overlap area between the small semicircle and the big circle
yeah
But the line between (3/2, sqr(3)/2) and (1,0) is a curve
yeah it’s the arc of the small semicircle
so the overlap region is bounded by two curves (the small semicircle arc above and the big circle’s lower arc below)
yeah that’s right the two curves are just the arcs of both circles that intersect
Can you explain me how to get the area
yes, im just calculating one sec
The owner is missing!
from x=1 to x=3/2the top boundary is the small semicircle y = √(1 − (x − 1)²) and the bottom boundary is the big circle’s lower branch y = 1 − √(4 − (x − 3)²) so integrate the difference
oh
from x=3/2 to x=2 the big circle is below the x-axis so the overlap is just the small semicircle part so integrate y=y = √(1 − (x − 1)²)
yes you do an integral
ahh okay lemme find another method
sorry 😭
you can find the overlap using circular segment formulas instead of integrals
do you know those?
?
Circular segment?
Oh I know that
I just searched it cuz I learned it in another language 😩
Hmm but like
hmm but i think it may be a bit complicated later on
you can maybe break the big circle into smaller easier shapes
haha
lol
don't stay up if you're too tired tho
so you can divide the large circle into four easier parts
the top semicircle of the big circle (above the center line), the bottom sector with a 120° central angle, the small triangle inside that sector and the little leftover area under the semicircles but above the diameter
if you can visualise it
You meant the top semicircle by the semi-circle in the middle of those 3 semi-circles
nah nah the top semicircle here means the upper half of the big circle (the large one with radius 2)
I don't get the afterall things
the bottom sector is a slice of the lower half of the big circle
under the line of the bottom of 3 semi-circles?
the central angle of that slice is 120°, because if you draw lines from the circle’s center f to where the small semicircles touch, it forms a 30°, 60°, 90° triangle
yep exactly
I think i get it
that line basically forms the flat base of the three small semicircles, and below it is where the big circle continues that curved portion under that line is the 120° sector we’re talking about
aha
now inside that same sector there’s a triangle made by those two radii and the chord that connects their ends
the angle between those two radii at the circle’s center is 120
then if we make that line,
the semi-circle at one side is divded into 2 which are both
um what should I say
a part of the circles
nah no
?
nothing
did you get the first 3?
then the remaining region is the strip above the three small semicircles but below the line that divides the big circle
that’s the leftover space you still see shaded between the small semicircles and the diameter
yes
can you form the diagram now
You just meant by the region between the diameter line and the line of the bottom of the semicirlces but except the region of semicircles.. isn't it?
kind of like this
yeah
and the next..?
now you calculate the area
the area of part a would be 2 pi
the sector which was the second part would be 4/3 pi
triangle area would be root 3
wait wth
for calculating the area of the fourth part which is the leftover
we are basically finding the area of the white region to get the leftover
yes
fourth part is kinda tricky but if you imagine 2x2 square whose side length is 2, the area of the square is 4
yes
now place a quarter of the big circle (a quarter of radius 2) inside one corner of that square the quarter-circle has area 1/4 pi * 2^2 = pi
wait can you describe it on the picture I cannot send you a picture
so the part of the square not covered by that quarter circle (the four little corner regions if you tile four such squares around the circle) has area 4- pi
yeah sure one sec
okay here's an easier version
you want to calculate the area in blue shaded region so you would subtract the areas of the semi circles from the area of the rectangle
ohhhhhh
so that would be 4-pi
we are imagining the rectangle here
but you are right it is curved but were making a construction here if you get what i mean
like how we did with the triangle
yeah its not gonna include in our answer because we only need the blue part
im just dropping perpendiculars from point e and g
and join them to form a rectangle
we only need the blue part and subtract it from the whole circle
yes!!
wait I just got confused that the answer is blue part
huh are you still confused?
4-pie + 2pie+
nope I just got it I think
okay
so total shaded area would be (area of the top semicircle (1) + area of sector (2) - area of triangle (3) + the area of the remaining parts (the blue shaded region)
yes
so the top part is 2pie,
the middle part is 4-pie
and the bottom part is 4/3 pie - 2
you don't know the base
2x2xsin120?/2
yeah
sqr(3)
yep, now you get the answer
so the answer is 7/3 pie + 4 - sqr(3)
yeah
wow
compare it with a , b , c and d values which adds up to 17
me too haha
hehe
but integration is the easiest way to solve it
ofcc also im sorry for stealing so much of your time 😭
noo don’t feel bad 😭
I ithink i need to develop how to think creatively to find out the easiest way when doing this competition
haha..
I meant i feel bad for stealing "your" time
yeah the best way would be to always sketch or mentally divide the figure into familiar shapes
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hey i have to approximate a sample using linear regression.
for a straight (ax+b) we had the formula:
$a= s_{xy}/s^2_x$ \
$b= \bar{y} - a* \bar{x}$
So i can approximate the sample pretty easily with that.
My problem is that the next assignment says to aproximate the same sample not with ax+b but with
$x^2 +c$
I have no idea how to approach this tbh. The only thing i have is the sample and the covariance matrix for the samples i used for the linear apporach
VZL
@spare merlin Has your question been resolved?
!original
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
i have thought about it a bit more and the only way i can think of is optimizing:
$\sum_{i=1}^n (y_i -(x_i^2 +2c))$
VZL
but then i still wouldnt know what c is or am i tripping?
btw c translates to:
Approximate the Sample with the function/ model $f_c(x)=x^2+2c$
VZL
@spare merlin Has your question been resolved?
<@&286206848099549185> :(
Hello
hi
Given a bivariat sample (x1,y1) .....
a) is just finding the covariance matrix, i did that
and b is basically just that but with the linear formula
idk if sample is the correct word tho
also this should be
$\sum_{i=1}^n (y_i -(x_i^2 +2c))^2$
VZL
.close
Closed by @spare merlin
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello, doing some Galois Theory work now :3
Currently looking at the 4th polynomial here. We know α = 2cos(2pi/9) is a root, but what we don't know is that Q(α) generates the other two roots too. I'm not seeing a helpful factorisation - i feel like there should be something really obvious im missing since the other 4 polynomials are all pretty much trivial.
specifically, im trying to find the splitting field of $\mathbb{Q}$ for the polynomial $f(X) = X^3 - 3X + 1$.
BoggledToggo
@late trellis Has your question been resolved?
hi <@&286206848099549185> it has been a bit :3
can also try #groups-rings-fields
I’m ngl I’m a lil stupid so <@&286206848099549185> what’s. 9X2X7.192 divided by 92*20
Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
@late trellis Has your question been resolved?
I'll end it since it's being answered elsewhere o7
Oops I pressed wrong one
.close
Closed by @late trellis
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Question and answer
I'm getting -36 for angle DAE, which is not even in options.
Can anyone cross check. Also is there any better way to do this instead of finding all same angles, mark them x, y, z, etc. and try to find relationships between them.
@twilit fern Has your question been resolved?
your eqn 1 which is 2a + z - 2x = 180 should become 3a - 2x = 180 after subbing in a = z, but you instead continued with a = 180 + 2x
<@&268886789983436800>
Thank you. I subtracted instead of adding 😅
.close
Closed by @twilit fern
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I am having trouble understanding manipulating factorials.
Or how to get the number of terms using this:
$\abs{R_n} = \abs{S - S_n} \le a_{n+1}$
NullSquare
NullSquare
NullSquare
@waxen basin Has your question been resolved?
$\frac{(n+1)!}{2} \geq 10^4$
Civil Service Pigeon
$(n+1)! \geq 2 \cdot 10^4$
Civil Service Pigeon
@waxen basin the left hand side is strictly increasing for n__>__0, so trial and error from here
Ok! But how do I get rid of the factorial? Factorials are still not intuitive to me. 😛
I mean sure at infinity k! is effectively equal to (k+1)! But what do I do here?
the left hand side is strictly increasing for n__>__0, so trial and error from here
Factorials of grow very quickly so you won’t be testing for long
To each their own
.close
Closed by @waxen basin
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Find the number of ways in which 8 different flowers can be strung to form a garland so that four particular flowers are never separated.
Why is it not 5! 4!
that would be true if (for example) you only put the four inseparable flowers on the left side of the garland and put the other 5 on the right
How many ways are there to string 3 different flowers together?
but you have the freedom to choose where in the garland the group of four can go
@craggy atlas Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
so how do I do it?
Find the number of ways in which 8 different flowers can be strung to form a garland so that four particular flowers are never separated.
@craggy atlas Has your question been resolved?
<@&286206848099549185>
.close
Closed by @craggy atlas
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hi
i mean can’t u just compute the determinant
of both things and equate them
so like that option always exists
thats what am having trouble with
now whether you can do it quicker is a secondary call ig
do you know laplace expansion?
^ Additionally, ||which column/row looks easiest to expand with on the right hand side?||
or cofactor or whatever algorithm you use to compute the determinant
what i know is theat u can choose the colum on row with the most zeros
then discard that and start multiplying right?>
sounds like laplace expansion
yea idk its name
the 010
i remember the teacher saying if the position is even its positive or if its odd then negative
or something like that
right?
as in a11 or a21
u can just remember it with this
if u like
it starts at +
in a_11
then u keep swapping between + and -
or rather every adjacent element must have a different sign
with reference to whichever "node element" you're fixated on
if that makes sense
alright so going back to the question how would i use this?
do you remember this?
if we're looking at a_13
we can imagine deleting the row and column containing a_13
that gets us the
a_21 a_22
a_31 a_32
matrix
the same logic extends to finding the corresponding "smaller determinant" for a_23 and a_33
wdym?
just this one
u go from a large 3x3 matrix
to a sum of scaled
2x2 matrices
which u can more easily compute
so i gotta calculate 3 matrixes?
in general yes
3 2x2
but in your case
only 1, right?
since the other two matrices
will be scaled by 0
ah so since their outside element will be 0 so we disregard them thats what u mean?
cause the zero will be multiplied by the whole thing
0 \begin{vmatrix}
3 &-2 \\
5 & 1
\end{vmatrix} - 1\begin{vmatrix}
x &-2 \\
1 & -1
\end{vmatrix}
+ 0\begin{vmatrix}
x &3 \\
1 & 5
\end{vmatrix}```
so yeah the ones w the coefficient of 0 can just be omitted
notice that i "retrieved" the signs of the matrices
using this
so it should look like this
and then we just multiply the matrix like usual and find x right?
yes
maybe u should write all of this down
but i guess that's more of a stylistic choice
also there's no multiplication of matrices going on
but if u meant computing the determinant on the right
then sure
after that it turns into an elementary algebra problem
namely, solving a quadratic
yea thats it
1 more thing
when i asked my friend about this he sent me this
supposedly
this is what the professor gave him
am wondering where the extra 1 came from
or is that just something i should disregard?
(-1) corresponds to the sign from this chart
yes
1 * (the 2x2 matrix) is the actual laplace expansion
^
let's assume our a_23 is indeed 1
then yeah 1 * determinant of that 2x2 matrix
so hes not just turning it into a negative, hes multiplying it by negative 1?
we append a - in front of because of the sign chart
they're the same(?)
yea but the way its written makes it seem like it came out of nowhere
but thats what he did right?
not really
the general formula is something like $\sum_{i = 1}^n b_{ij} {\color{red}(-1)^{i + j}} M_{ij}$
mmmm7
if u look at the red part
u just end up raising (-1) to some power
depending on whether i + j is even or odd
it's similar to what u mentioned earlier
"position is even"
but that's ambiguous
in particular, if we denote an element as a_{ij} where i is the row it belongs to
and j corresponds to the column it belongs to
then i + j must be even for the sign to be positive
otherwise it must be negative
alright so if in the chart if its a negative position then multiply the coefficient by -1. thats it right?
yeah the chart is easier to look at
and u can draw it out
it's just like checkerboard
if the sign chart shows + then you multiply by 1
if it shows a - then you multiply by -1
this formula here already incorporated the sign thing btw
i'd be focused more on the
element * (determinant of 2x2 thing) * (sign)
yea i got the chart figured out i was just confused cause hes actually wiriting (-1)(1) instead of just saying -1
should be good now.
then he's doing (-1)^(1 + 2) = (-1)^3 = (-1)
but if u use the "sign chart" then it makes sense to just append a negative in front
well obviously they're all equivalent
so this ends up being a more philosophical discussion
Closed by @lethal drum
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hello. could someone remind me what we do when we wanna solve for x in this situation? : x³ = y
cube root both sides
,w cube root of -13
Closed by @plain rain
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@tardy agate sorry for the ping. you asked how I got my left over area for 14. I had the volume of the sphere minus the cyldiner but it doesn't seem to have a way to simplify it
oh yeah np, so u made 2 mistakes
- You took both the spheres radius and cylinders radius as same
- The shape of the part that is removed from the sphere is actually not a cylinder it is something like a capsule
how can the radius of the two not be the same? and why is it a capsule and not a pure cylinder?
I am thinking of the problem in this sense:
the hole is drilled through it so passes through from the top and bottom leaving behind a cylindrical hole. So in ur figure the top and bottom domes on the cylinder will also be removed. If their radius is same then the entire sphere will be gone. In the figure u can see what would happen if they were the same.
It is called a napkin ring
wait I am mis interpreting so when he says it is drilled from 0 to 2h that means the whole sphere but how can we know the sphere is of 2h?
how can we not deduce anything of our radii for our shapes?
it is not, it will look like this
u will get final answer in terms of r,R,h but ig u will be able to eliminate using this triangle
ok so I see that r is the radius of the cyclinder
also in your image the cycldiner goes to the end?
this would mean r is one of the radii for one of the circles that we use to find the volume of the sphere
no
how can it go to the end, h is also smaller than R
yeah r is smaller than R
I am having trouble seeing where it stops then
but for the volume of the sphere we need to take the sum of all the circles that make it and then we wouldn't be able to use either r or R because they are specific radii and we need a general r when we set up the intergrall
use something else to represent it then, or just use spheres equation x^2+y^2+z^2 = R^2, for a circle at height z from centre ull get x^2 + y^2 = R^2-z^2, so the radius is root(R^2 - z^2) integrate this wrt z
it stops at h from centre or R-h from top
ins't your R a speicfic radii though
or you mean that R is the radius of any circle that makes the spehre
yes, R is the radius of the sphere
read the second part
that is any circle that makes the sphere
its radius is root(R^2 - z^2) where z is its distance from center
sorry ive gtg now but click these hints if u understood the above figure and dont know how to move forward. you can ask other helpers if u are still stuck
you can do it in 2 ways:
||1. Volume of Sphere - Cylinder - Domes, find dome volume using integration||
||2. Integrate to find volume of remaining shape, (from -h to h) dz * cross section area|| ||cross section u can find as bigger circle(the eq i gave above) - pi*r^2(smaller circle of cylinder)||
ok. Thanks for taking the time
@left trail Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
...
As $a$ is relatively prime to $n$, $a$ is a generator of $Z_n$.
Let $x \mod n =k$. Then $\phi(x)= \phi(ka) = ka \mod(n)$
wai
<@&268886789983436800>
hmm?
well thats what you wrote
when working in Z_n you should forget the entire mod n notation
note that they wrote phi(a)=b, not phi(a) = b mod n or something
so should just be kb
As $s$ is relatively prime to $n$. $a$ is a generator of $Z_n$. Let $x mod n =k$. Then $\phi(x)= \phi(ka) = kb$
wai
so 2 mod n = 2, so phi(2)=phi(2a)
yea
but if a isnt 1 then now clearly phi isnt injective
then fucking write that
Isn't that exactly what I've written
are you reading what you are writing
the letter a is not even included in the defining equation linking k and x
Closed by @warm python
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Eine dreistellige natürliche Zahl hat die Quersumme 14. Liest man die Zahl von hinten nach vorn und subtrahiert 22, so erhält man eine doppelt so große Zahl. Die mittlere Ziffer ist die Summe der beiden äußeren Ziffern. Wie heißt die Zahl?
Pls speed i need this
Gauss algorhytm is needed
Man nenne die Ziffern a, b und c.
<@&268886789983436800>
Kannst du die Zahl mithilfe von a, b und c ausdrücken?
Ne
Das ist alles was gegeben ist
Das ist schon klar, damit ergeben sich auch gleich 3 Gleichungen. Ich meinte eher folgendes:
Die natürliche Zahl können wir jetzt ausdrücken als a * 100 + b * 10 + c
Macht das Sinn?
Weil a, b und c die Ziffern sind
Weil das die Zehnerdarstellung ist. Wir haben eine dreistellige natürliche Zahl, ich nenne die Ziffern a, b und c
(die Zahl ist also abc)
und man kann das auch schreiben als a * 100 + b * 10 + c. Ein Beispiel:
Sagen wir, wir haben 684
Das können wir ja auch schreiben als 6 * 100 + 8 * 10 + 4
Oder 432. Das ist dann 4 * 100 + 3 * 10 + 2
Und unsere Zahl ist jetzt halt abc, also a * 100 + b * 10 + c
Quersumme 14 bedeutet a + b + c = 14
Ja
Wenn man die Zahl von hinten nach vorn liest, hat man cba
Also ist der Wert davon c * 100 + b * 10 + a
Liest man die Zahl von hinten nach vorn und subtrahiert 22, so erhält man eine doppelt so große Zahl
Kannst du das also als Gleichung aufschreiben?
@meager relic Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
so I need someone to help explain what the x1x2<1 means here
I understand the first part that 4^2=2 and thats the radius and it includes the inner and the circle
but how do you know where to draw those parabolas
and how do you know what quadrant
the asymptotes
Those are not parabolas
You can rearrange x1x2 <= 1 into x2 <= 1/x1
Wdym
like
if the sign was the other way around
would the asymptotes be in the other two quadrants
only when x1 is known >0
this is just the last thing I got left for my revision so
Can you clarify
If it's positive then 1 and 3
and is it not convex when the asymptotes cross through that region
Top right and bottom left quadrant
yea ik
Oh, then it would be the area above the 1/x curve for x>0
And below the curve for x<0
Do you still need help?
It's quite hard to know what he meant to do by drawing that green line without any context
aight
so just one last thing
by looking at any question they might have like that in the exam
whats the procedure to drawing the graph
I understand the x1^2+x2^2<4 shit
If it has 2 or more equations, find the areas that satisfy the two then find their intersection
If youre struggling with graphing functions then you might have to review your previous lessons
What 💀
Graphing functions is literally one of the most basic things in alg
nah
like this sort of question
I mean
I just dont get where the asymptotes are meant to be drawn
and what quadrant and where they start etc especially on this example
I think organic chemistry tutor might have a video on graphing functions
That might help
Closed by @sonic sky
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
.
i don’t understand this symbol, also i don’t understand how to interpret it as arrows in a graph
heres an example of a partial order
can you please explain
i don’t understand what that means or how it’s interpreted
I can't actually, I gotta run unfortunately
If this is still open when I'm back I'll catch you
no problem
btw jsyk if your message starts with a full stop it PREVENTS channel opening
full stop?
this order relation is not the same as the one from your earlier pic
$\preceq$ is not a symbol with any fixed meaning. rather its job is to play the role of a partial order relation and look similar to, but distinct from, the ``regular'' order symbol $\leq$.
Ann
same goes for strict orders? With the < sign
$\preceq, \prec, \succeq, \succ$ are entirely analogous to $\leq, <, \geq, >$ yes
Ann
I see
btw is every relation a subset of a cartesian product
I forgot the name
and if we say R is a relation of A does that imply R ⊆ A x A?
@tranquil pine Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
,claim
claimed
Hi
claiming happens by sending any message btw.
ohhh thanks
and the first one is normally supposed to be your question
which, yeah, go ahead and post that now.
So basically i got a test tomrorrow which i have to prepare for and the theme is relative frequency cumulative frequency avreage median kvartilbredde variasjonsbredde.
histo diagram
Quartiles and Interquartile Range (IQR / Quartilbredde)
@drowsy epoch
and Range
i know this one
@rustic sequoia
aight yeah you're better off asking in #study-discussion
yeah the help channels are better for getting help w specific math questions, whereas #study-discussion is better for advice about studying
@stoic marsh Has your question been resolved?
@stoic marsh Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Have i taken then second derivative correctly?
Civil Service Pigeon
yes
Closed by @indigo swan
Use .reopen if this was a mistake.

Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.