#help-43
1 messages · Page 3 of 1
carrying means replacing the ten 1's with one 10 like i showed
so instead of sixteen ones we will be left with six
so the ones digit is 6
and the tens will be one more than what they were, so from 5 up to 6
thus, 666
so much clear now
We considered ten 1s and add to tens place where five tens are already present so it becomes 6 and that becomes 60
And six 1's are left as it is in one's place
Hence 666
Tysm
How carrying forward works in subtraction and multiplication
@vale perch Has your question been resolved?
for subtraction you don't carry
you borrow, as it's usually called
but it's the reverse of the stuff i said about addition
and instead of combining lower denominations into higher, you make change by breaking a denomination into ten of the next lower one
ie break a 1000 into ten 100s, or a 100 into ten 10s, or a 10 into ten 1s etc.
multiplication is much trickier to look at in terms of money, but the algorithm essentially consists of multiplication by single digits and then following that with addition (which i already explained)
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
How do i even approach this question??
I'd start by realising that $(a+2b)^2=c^2$
What a wonderful world !
Ok
my doubt is
We can find the common point with this relation
so
All the lines pass through that point
so shouldnt the distance be zero (shortest)??
common point is A(-1,-2) right
i think question is poorly worded
You get two families of lines, one passing through A(-1,-2) and another through (1,2)
and from that u can find maximum distance between two lines from the families
||so all the options would be correct, as the distances range from 0 to root(20)||
how can u find max distance?
is there a formula?
wait
oh yes
no try to visualize it? first obviously the lines need to be parallel
now think of different possible parallel lines
yes if they are not parallel the shortest distance would be zero yes?
Wouldn't the distance between the points be the largest distance needed (since apart from one pair of line all the other lines will have shortest distance less than the distance)
so all of the options r correct
yeah
ty gng

Closed by @quasi wind
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 just trying to find this mystery function.
Can someone tell me what that math is called or a link to where i can find resources
,rcw
maybe just some subject related to the mystery function anything anyone?
@unreal moon 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Could someone explain how to do this please
Please ping
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
I got the answer by manually counting since it's easy in this case
I wrote all subsets (16 including null) and then counted them
But I can't think of a formal solution
suppose some A and B are the disjoint subsets of S that u want
now each element in S can go in A or B or neither
Yeah
what do u get from that
So there'll be 3^n possibilities in total, and since they're asking unordered, it should be 3^n/2
almost
u need to subtract 1 from 3^n. the case where both A and B are empty sets
(3^n - 1)/2
The answer key says (3^n+1)/2 tho

wait i think we dont need to subtract this case
Why not
Why are they considered disjoint tho
well their intersection is also a null set
ok so we are still missing one case
So (3^n-1)/2+1
oh wait
No we need to count the null pair only once right
Yep i got it, thanks a lot

.close
Closed by @trim path
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 do not get this definition at all
why are there two S??
he never defines what S is (the regular one)
the only one it can be i assume is the S here and below in the page but i only see them in context of dS
never on its own
They're all the same S. it's poorly written
what about here
Yes
The same
A set $S$ is a smooth surface if for any $P$ you can find an open ball $N$ around $P$ such taht inside the ball there is a smooth function $g(x,y,z)$ that has a nonzero gradient near $P$ and near $P$ the surface is the set of points where $g(x,y,z)$ is nonzero
Oliver
artemetra
should it be ≠ instead?
Shit. my bad. I meant $g(x,y,z)$ should be zero. the gradient should be nonzero. @young raft
Oliver
but yea in all images the $\mathcal{S}=S$
Oliver
this is the part that confuses me
how can there be a neighbourhood where the function is only zero but the gradient isn't
wouldn't it be a constant
Becuase we're only thinking of surfaces, not all of space
Take $g(x,y,z)=x^2+y^2+z^2+c$ for any constant $c$. The surface defined by $g(x,y,z)=0$ is a sphere with radius $\sqrt{c}$. Which works. Also $\nabla (g) = (2x,2y,2z)$ which is not 0 anywhere on the surface - it's 0 only at the origin
Oliver
the condition that grad g != 0 is the condition that the surface has a tangent plane at each point
this ensures that S locally is actually a surface, rather than some singular looking thing like the union of two planes
okay i get it now
i am still unsure why they use two S's and keep them clearly distinct
$\mathcal{S}$ seems to be the surface of integration while $dS$ is an area element
artemetra
that is unrelated
Closed by @young raft
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
someone help this was in my school olympiad
i guessed the answer in the test it was right some how
search up the formula for the inradius of a right triangle
then you can set up an equation for sides ST, TR and also don't forget Pythagoras
so you will know what sides ST, TR are
oh
yes then this is the next step
@heady hawk Has your question been resolved?
the idea is that you let the radius of the big circle = r
i clicked x by accident
oh rly?
and then using similar triangles you can get an expression for the red length in terms of x
npnp!!
like side-chasing okok I'll leave you to it!
tyy
.close
Closed by @bleak dock
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
well if $S = 0 \cdot 1 + 1 \cdot nC1 + \cdots + n \cdot nCn$
Yeah
south
Sun r=0 to n
rncr
then you also have $S = 0 \cdot nCn + 1 \cdot nC(n - 1) + \cdots n \cdot nC0$
south
so you can add the two sums together
But how can I add them?
Can you type this step in latex?
$0 \cdot nC0 + n \cdot nCn = 0 \cdot nC0 + n \cdot nC0 = n \cdot nC0$
south
$1 \cdot nC1 + (n - 1) \cdot nC(n - 1) = 1 \cdot nC1 + (n - 1) \cdot nC1 = (1 + n - 1) \cdot nC1$
south
You are adding one from left end and other from right end
Now i understood
@deft tangle Has your question been resolved?
.close
Closed by @deft tangle
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Got anything ?
i dont think this is even right
,w derivative 2cosx -sin(2x)
well
from here either $-2=0$ or $\sin(x) + \cos(2x)=0$
Percy
Cos(2x) = ... in terms of sin²
= 1 - 2sin²(x)
Now its 2nd degree polynomial in sin(x)
u = sin(x) if you want to visualise it
ok so -2sin^2x + sinx + 1 = 0
take sin(x) = u not x
$u \not x$?
Percy
im assuming you mean $u_0 x$?
Percy
you get what i mean bruh
The second step does not directly follow.
Factorize it again.
@copper lion 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
can someone help me with this
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).
Lol
!occupied, not for you
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).
@slate sequoia 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 got the infinite sum as 25
could you share your work?
wait can i dm u
Oh my bad
Should i send it here
I didn't derive the n^2/2^n summation because it was kinda lengthy and i found it online
i dont have phone to send my work but what i did was
just like how you calculate sum of an AGP
But this is not a simple agp right?
Can you send me the steps or is it too lengthy
write the series S = -1/2 + 2^3/4 - 3^3/8 +......
divide by 2 and shift one term to right
S/2 = -1/4 +2^3/8 -3^3/16 + ....
now add them
3S/2 = -1/2 + 7/4 -19/8 + 37/16 - ......
do the same step again
3S/4 = -1/4 + 7/8 -19/16 +....
shift one term and add
9S/4 = -1/2 + 6/4 -12/8 + 18/16 - .....
add 1/2 both sides to get
9S/4 + 1/2 = 6/4 -12/8 +18/16
now you can see an AGP forming
@trim marsh
@slate sequoia@glacial mortar
yeahh you are going correct @acoustic stump
the final S should come out to be 2/27
uhh yeah it might be, not sure
@trim 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Need help here i think i messed up rounding ill show work below
P(x=0) c (10,0)=1 p^0=1
(0.71)^8 0.0646 * .71^2 = 0.0646 * .0541 ~ 0.0326
P (X=1) C(10,1) p^1 = .29
q^9 = (0.71)^9 = (0.71) ^8 *.71 ~ 0.0459
P (x=1) = 10 .29 *.0.0459 ~ 10 * 0.0133 -= .1330
0.0326+0.1330+0.2445= 0.4101
@scenic holly Has your question been resolved?
!noping
Please do not ping individual helpers unprompted.
apologizes
,w binomialcdf(10,0.29,3)
,calc 0.0325524 + 0.377346
Result:
0.4098984
Preciate 💯 it was correct
.close
Closed by @scenic holly
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
@floral fjord
@quartz yoke Has your question been resolved?
writing log_e 
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
A and B throw a pair of dice one after another. A wins if the sum on the dice is 5. B wins if the sum on the dice is 8. Find the probability of A winning given that A starts first
for A to win sum can be 1+4;2+3;3+2;4+1
for B to win sum can be 2+6;3+5;4+4;5+3;6+2
so P(A)= 4/36
and P(B)= 5/36
also P(A')=32/36
and P(B')=31/36
what we are looking for is
= P(A)+P(A')P(B')P(A)+P(A')P(B')P(A')P(B')P(A)....
right?
I think I have done this one before. Jee?
Yes
yeah
Figured
ok nevermind i figured what my mistake was
i wrote 3 instead of 36 in P(A) in the final sum
got it, thanks
have a nice day
You too
.close
Closed by @stark ridge
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
oh
.close
Closed by @primal ledge
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 can someone explain why the integral value is like this?
my working is like this
(-1)^n is constant right?
no it is not a constant
don't drop the brackets
my bad
ohh wait so (-1)^n is a constant in the integral so we take it out first and then integrate the rest?
okk thanks
.close
Closed by @fast frigate
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
how to find the curve of intersection between the plane z = 0 and the cylinder x^2 + y^2 = 4
you want the intersection curve of those two surfaces, you will then have both equalities verified
so z = 0 and x^2 + y^2 = 4
how do u get the curve of intersection without graphing
Well let's think about it
z = 0 means that the freedom of movement in z is removed
so it's kinda like we removed that dimension
from there, what does x^2+y^2 = 4 represent if there were no "z dimension"?
a circle
exactly
?
Didn't I tell you how you should visualize it in your head?
you look at your cylinder
and you remove the freedom of the z dimension
it's like you squashed your cylinder in 2D
to where you cut it with the xy plane
i know but we can't get it from an equation
one is a function of z, the other is a cylinder
i can't set them "equal" to each other
where did I mention equations in this
I know you didn't mention any equation
so apply that
I was just saying that there's no way to find it using an equation
if u have z = 4-y, and z = 0, u can set them equal to each other and find the intersection
here, u can't do that
I do
you can tho
z = 0
and x,y independent from that equation
and x^2+y^2 = 4
z independent from that equation
in that case
we can do cylindrical coordinates for example
(x,y,z) = (rcos(t),rsin(t),z)
->
z = 0
r = 2
there's not much else to think about
and so if you want the formula for the path that describes your curve
f(t) = (path for a circle for x,y ; z=0)
so f(t) = (2cos(t),2sin(t),0)
and that's it
Closed by @keen glacier
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Why can I only divide top and bottom by a polynomial when the limit is of the form 0/0
the reason you can factor out (x-2), and then cancel it out, is because num and denom are both polynomials and have x=2 as a root
Closed by @drowsy tusk
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
can anyone help with physics help or no
what level?
!da2a
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/
sorry
Closed by @astral cipher
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
ho do i calc this without calculator? r = 1000 X 0.125 X 1/12
can you write 0.125 as a fraction
its percentage
Personally, I would do it (1000*0.125)/12
calculate 0.125 * 1000 first
keep in mind that you're just multiplying by 1000, so just shifting the decimal point
using one significant digit is very inaccurate, and it would add extra steps to calculate 1/12 by hand then multiply by hand
you can put it together in one step by dividing 125 by 1/12
how do i calc that on paper
Closed by @opal stirrup
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
it was a tricks video for matrices where he mentioned if we put r and n as 1 we get the determinant value as zero which i understood how , but i couldnt understand how that would also mean that the summation of all determinants would be 0
that sounds quite suspicious, can you link the video
entire determinant where r would go from 1 to n would also be zero
do you mean sum of the determinants?
️🔥 JEE Main 2025 Test Series [Join Now] : https://links.mathongo.com/ppSM
Binomial Shortcuts: https://youtu.be/TiM85bJ73Is
Trigonometry Shortcuts: https://youtu.be/sQGBo9oXP2U
Quadratic Shortcuts: https://youtu.be/n0lZf9W__sE
Inverse Trigo Shortcuts: https://youtu.be/qpRwHLiTd-Y
#mathboletohMathonGo #jeemain2022 #mathshortcuts
Maths ...
yess
🫠 hello?
Are you sure it's sum of determinants and not sum of matrix and then determinant?
yes its jus the sum pf determinants
ok let me watch this
@lament token it looks like the guy just arbitrarily decides to see what happens if n were 1 and the summation had only 1 term
in the name of speedrunning, not math
Okay I checked, and it does come 0 for all of it. It's like you take a sequence of sum but the sequence is just one term and that term is 0.
$
if we abandon speedrun strats, i think we can have $$\vmqty{r-1&n&6 \ (r-1)^2 & 2n^2 & 4n-2 \ (r-1)^3 & 3n^2 & 3n^2-3n} = n(r-1) \vmqty{1&1&6 \ r-1 & 2n & 4n-2 \ (r-1)^2 & 3n & 3n^2-3n}$$
Ann
does that help us any?
Ohh ikay
at least the first row is now constant
Math on go ahh 😔
Ek week pehel hi dekha tha ye lmao
Okay so that's mentioned wrong in the video
but still i guess we have to place trust in the question that there even exists a correct answer option
Ye tabhi kaam karega agar options mai constants hain
Nahi toh cooked
We can just apply summation formulas for a n, n^2 and n^3
Natural numbers
$$n(r-1) \vmqty{1&1&6 \ r-1 & 2n & 4n-2 \ (r-1)^2 & 3n & 3n^2-3n} = n(r-1) \vmqty{1&1&0 \ r-1 & 2n & -8n-2 \ (r-1)^2 & 3n & 3n^2-21n}$$
Ann
,rccw
Okay then do u jus multiply them or can we simply further
Ohhhh
Well the first and last column are same soo
It's like saying ki sin^2x+cos^2x ki value batao
Would only work substituting the value
Agar koi identity hai
😭also I can't seem to understand why we use n(n-1) here instead of n(n+1)
Cause you have r-1 and not r
Summation for natural no. starts from 1, here it will start from 0 if you put r=1
i don't know how to proceed further without going through some rather unpleasant bivariate polynomial simplification
Ohhhh okayy got it thankyou
🥲 right so i guess ill go ahead with the summation method
The determinant will be 0
you mean the dirty trick
it is a trick. it is trickery.
When i use the summation method i understood how when we get two columns we get it zero but i didn't understand how here u called two columns common
Let them use it lol, it would help them good in exams (if you are giving jee)
,w det{{r-1, n, 6},{(r-1)^2,2n^2,4n-2},{(r-1)^3,3n^2,3n^2-3n}}
No mean
oh that is so ugly.
😭gosh
It is a mcqs based exam wouldn't it be time saving if we just substitute some values (assuming the options are constants)
plus that question was never meant to be solved using conventional methods
Agreed
yes, it was meant to be solved using trickery.
ok i am done tooting this horn sorry
Yes yes understood these two are the same
So the determinant will always be zero
whats going on
😅yea i know that part i actually meant it for the one Ann sent above mine , but thanks
Oh ok
what even is the question.
🤡
.
Yea so i shouldn't use the a=n= 1 part as it doesn't always work?
Its on the board
okay.
No, substitution is a great trick to use, and it works. Just check whether all options are constant.
i dont like the word 'trick'.
Why? "Logic" is better?
Advance ki prep kar rahi hai toh solution dekh agar mains ka kar rahi hai then you are wasting time
Okay but like as shown when we did a and n as 1 we got delta 1 as zero
But its a summation from 1 to n right
So when we add the parts like delta 2+ delta 3.....+delta n how do i know its still zero
Going to 12th 🤡9 months hai - what do i say
kar 'rahi' directed to who
🤡🙏
Dekhle solution
you're gonna get banned soon
Koi batayega
you dont know that, you just know its not any of the other options
Ohhhh
which is why substitution doesnt even work when its not mcq
chill bruh
No. Try not to assume pronouns.
it could be some complex polynomial in n you just dont know but if u put values and see it might match with only 1 option
Vehencho 😭🙏🏻
Okayyy
.close
Closed by @lament token
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
hm so how do i apply this to the problem
the only thing i can say is that "when x is less than 1 it converges"
What would your r be?
no, your r isn't x
huh how
look at the series more closely
it is not $\sum x^n$ and it is also not $\sum \text{(constant)} \cdot x^n$
Ann
wrong again
the series is $\sum_{n=0}^{\infty} \paren{\frac{x}{3}}^n$; if it were as you say and $a=x$ and $r=\frac{1}{3}$, the series would have been $\sum_{n=0}^{\infty} \frac{x}{3^n}$.
Ann
you see that those two series i wrote aren't the same at all, yes?
you do not need to do any splitting or other such surgery
so series x^n * series 1/3^n
i genuinely have no clue then
in the series $\sum_{n=0}^{\infty} \paren{\frac{x}{3}}^n$, the common ratio is $\frac{x}{3}$
Ann
and the first term is just 1.
i didnt consider that because how can i evaluate it when i dont know my x
1/1-x/3
no, you are still overthinking it
in math sometimes you do not immediately know the "value" of every single letter involved
and you should make yourself OK with leaving an answer in terms of one or more letters when it is appropriate to do so (and in this case it is).
x, right now, is just x.
the expression $\frac{x}{3}$ is not something that needs to be exorcized by ``evaluation''. it just is.
Ann
okay so how do i find out its divergence/convergence
with that in mind
it diverges when x is this and converges when x is that?
thinking back to this
the condition under which a geometric series is convergent is |r| < 1.
here, the role of r is played by x/3.
write down the inequality in x that describes the convergence of your series.
do NOT attempt to solve, simplify, or otherwise manipulate it until i tell you otherwise.
hmmm
so it converges when |x / 3| < 1
no, you wrote down $\frac{x}3<1$.
Percy
is that not an inequality
this is what i think of when i hear "inequality"
those are properties of inequalities
right. this is less than that
ie they are like rules of the game by which you can transition from one inequality to another
an inequality is a relation between two values that is not an equality.
anyway, now that we know the inequality we're looking for is $\absv{\frac{x}{3}} < 1$, now you need to solve it.
Ann
okay yeah too handwavy fair enough
hmm i havent done inequalites in ages
do i do -x/3 < x/3 < 1 and then like, simplify something
something like that ik its wrong
no
ok....
then you have to review those tbh]
yea probably but not rn. last time i did them was 2 years ago in pre calc algebra
can i do |x/3| < 1
|x| < 3
like we can fumble our way to a solution here kinda but it is just objective fact that if you have not worked w/ inequalities in ages then you have to revisit them as a topic in their own right
can i do |x/3| < 3
bad notation
but yes, you can multiply both sides by 3 and get |x| < 3.
that is a good step in fact.
well that tells me x is always between -3,3
(-3,3)
sure, that's the interval notation for it.
i never care about the importance of notation i probably should 😭
do you understand why you need to use () and [] ?
yes you really really REALLY should.
in math, notation is important.
yes i know notations
so the conclusion i should come to is "x is between -3 and 3, and only converges to the sum when |x| < 3)
diverges otherwise
the conclusion you should come to is that the interval of convergence is, as you mentioned before, (-3, 3).
yea but if i wanna explain what its interval of convergence means here
i dont like that
is that how i would word it
x is between -3 and 3 exclusive
(Redundancy.)
Closed by @sleek sapphire
Use .reopen if this was a mistake.
This is an unacceptable thing to say. Particularly to helpers who are just volunteering their time to help other users. If I catch you saying anything like this to a helper again you will be banned. Further, for moderation purposes you need to use english.
Once the mute expires do not make this same mistake again
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
How to draw a closed surface on 3D desmos?
I know how to draw a volume or an open surface. How do we draw a closed surface? I'm trying to draw a capped cylinder for example.
Here is my attempt. I'm getting an open surface, not a closed one.
add the caps separately
I want to draw the net overall surface.
how do I do that
i know I can easily write the equations for the caps on another line
can i use braces to draw the overall surface here
this isn't a desmos server
@keen glacier Has your question been resolved?
@keen glacier Has your question been resolved?
x^2 + y^2 <= 5? if thats what youre asking
wdym net?
this server might be helpful https://discord.gg/unofficial-desmos-655972529030037504
@keen glacier 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
the ratios of the area is the ratio of the number
So u times 9(pi) by 378699/2599000
then u divide the answer of that by pi
Then square root it after?
@pliant beacon
sounds good
what do you get
Closed by @gray stirrup
Use .reopen if this was a mistake.
seems a little bit off
I redid it and got 3.6cm
3.62?
Yeah
cool
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 need help with this Poisson probability question. I used excel like the question asked and it’s just not correct can someone please let me know what I did wrong?
Show your work, and if possible, explain where you are stuck.
I don't know, perhaps stupid question, but why 134 instead of 1.34?
I thought since n is 100
I thought the 1.34 defects is for one vehicle
But ima try that rn
Fairs, I'm not knowlegable enough (been a bit long since I've needed to do stats, and I forgot it
) but that sounds a little bit sus 
why would in excel the cumulative = 1?
It’s just there as placement I think because 0 means false not cumulative
did you calculate the solutions to the other problems with excel's POISSON.DIST?
No I used =NORM.S.DIST
My friend has the same question but different numbers
Okay I just found out what I did wrong ugh 💔
.close
Closed by @rough raft
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
why is this line incorrect?
maybe because you put a random dot after the top 0
formatting issue
that random dot is a multiplication sign
idk if youd call plugging in numbers algebra
Closed by @proud coral
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 where the extra p is coming from
rho, not p
also, from context it looks like they are going for cylindrical coordinates
does it say that anywhere earlier in the text
Yes
ok then yeah the jacobian is $\dd{x}\dd{y}\dd{z} = \rho \dd{\rho} \dd{\phi} \dd{z}$
Ann
it is basically the same as the polar jacobian, but with a dz tacked on
can think of it that way, why not.
yeah
So it's always r or rho when you use jacobian for clyindrical?
...yes
Okay thanks!
it is basically the same as the polar jacobian, but with a dz tacked on
.close
Closed by @pure spear
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
help
i took logarithm on both side and double diffrentiated it but i dont see where the e^e comes from
it asks you for the result of multiplying the second derivative with e^e
Closed by @stark terrace
Use .reopen if this was a mistake.
thanks
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 was thinking that since x* is an interior minimizer i can create a ball around it b(x*, \varepsilon) such that every feasible direction from x* has the following property gradient f(x*) times direction > 0
Now whenever x* is not an interior point and is on the boundry of omega, we cant take into account all fesible directions
do we even know that f is differentiable here
i think you're overcomping it cause we do not need anything like a gradient or any of that fancy stuff here -- we do not even know that Omega is a subset of anything with more structure than a topological space
you are right in that an open ball centered at x* will come into play somehow
Closed by @shell cairn
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
How do I solve for c here?
develop the b(x+c) as bx + bc and use the relations between graphs and expression of function
@pale ocean 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Please don't occupy multiple help 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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
could someone explain how the got the step func equation in B
start by graphing 2u(t). then you notice that between 1 and 2, you have a height of two.
you want a height of 0 at that point, so if you subtract off 2u(t-1), you get what you want.
now you look at 2u(t) - 2u(t-1) and notice that the height between 2 and 3 is 0, but you want it to be 2, so you add 2u(t-2).
and finally you look at 2u(t) - 2u(t-1) + 2u(t-2) and notice that the height after 3 is 2, but you want it to be 4, so you add 2u(t-3)
so you go one little interval at a time and add or subtract the step function (shifted to that point) that gets you the value you want
@trim oak Has your question been resolved?
Closed by @trim oak
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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.
Working Laplace transforms, and I just need to know if I'm starting this problem correctly:
Never seen one that doesn't simply start with F(s).. can I factor that F(s) out and just.. actually, that should be division..
At any rate, is that allowed?
.close
Closed by @trail berry
Use .reopen if this was a mistake.
The inverse Laplace transform is a linear operator.
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 need help with "factoring by grouping"
i chose the pairs shown on the picture but im not sure what to do next
a good thing to do is to write it as (ab + a) + (-ub - u) c:
literally grouping the pairs by parentheses
now you can focus on each pair individually
and hopefully you‘ve seen how to factor each pair
oh sorry it's not a u its A 4
im not sure
hm, if I gave you the expression 8x + 8, could you find factor a greatest common factor from it?
8
ohh ok but what next c:
what do you have now? :o
a and 4
right
after you find the GCF, you can factor it out of both terms in the expression
for example, 8x + 8 = 8(x + 1)
what we’re using here is just the distributive law 
you wanna do this for both your pairs
ok il try!

i meant -4 whoops
wait if i gather -4 from -4 do i get 1 like usual or -1?
do i keep the minus with b or
what do i do in this case
you get 1!
ty what about b
you can leave it c:
have you written down the factored expression yet?
mhm
awesome!
you’re almost done!
now look closely at your two terms
what’s the greatest common factor they share?
b?
b+1?
yes!!
:D
so we can do the same thing one more time
and factor b + 1 out of both terms
can you write down what we get after we do that? 
i dont know how
mhm
mhm
now our expression looks like ac - 4c
now, can you factor this?
same thing as you did earlier for each pair
il try
here (ignore the bottom thing
ty
yes!
wonderful!
now, just remember that b + 1 = c, and we get…?
(just replace c with b + 1)
and write down the final expression c:
yay thank you so much
:).
have a great day! 

.close
Closed by @proper swan
Use .reopen if this was a mistake.
lol
there you go c:
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.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• 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 need to figure out A1 with taletes theorem but i dont know how
proportionality
since two parallel lines divide them
if a line is drawn parallel to one side of a triangle, intersecting the other two sides, then it divides those sides in the same rati
ratio
the ratio of B to A will be same as the ratio of B1 to A1
ok what next
i don't understand what I'm supposed to try
yeah
by the basic proportionality theorem
.
this holds true
5:3 = 6:A1
now you just solve it
you need an example?
@proper swan
im trying to write it down il show you what i get to make sure it's like correct
sure
ok
sorry i was writing it down
its okie
why did 5/3 turn into x
i just multiplied by x on both sides
okay forget those
solve this
6+x=8
what is x
good
addition becomes subration when its taken to the other side of equality
and vice versa
right?
yeah
10:5=2
20•4
nahh

