#help-0
1 messages · Page 308 of 1
Nooo, this is one of the worst mistakes you can do in math 😭
$$\frac{A}{B + C} \neq \frac{A}{B} + \frac{A}{C}$$
Alberto Z.
Instead, this rule is correct: $$\frac{B+C}{A} = \frac{B}{A} + \frac{C}{A}$$
Alberto Z.
If $y = \frac{1}{2 - x}$, what is $y'$ (or if you prefer $\frac{dy}{dx}$)?
Alberto Z.
$$y = \frac{1}{2 - x} \implies y' = \frac{dy}{dx} = \frac{1}{{\left(2-x\right)}^2} $$
Alberto Z.
Do you agree with this?
Chain rule
Because you have to multiply by the derviative of 2 - x, which is -1 (and this minus cancels the previous one)
Yes
$\frac{d^2y}{dx^2} = y''$ simply
Alberto Z.
It's another notation for the second derivative
Nope
$$\frac{dy}{dx} = \frac{1}{{\left(2-x\right)}^2} \implies \frac{d^2y}{dx^2} = \frac{2}{{\left(2 - x\right)}^3}$$
Alberto Z.
@alpine sable 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.
How do I find the quantile value of chi square with 5 degrees of freedom and 0.1 significance level
Using table
@crimson tundra Has your question been resolved?
@crimson tundra Has your question been resolved?
.close
Closed by @crimson tundra
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'm having trouble understanding this proof
particularly starting at the last line, when it says, U intersect S closure is a subset of U intersect V closure equals the emptyset
Also, I don't see why they ignore this case. How is it demonstrated that neither set intersects the closure of the other?
this is my other confusion
are you explaining the top image cogwheels
ah
and U intersected with the closure of V is empty why?
because we suppose U and V form a disconnection of S closure
nevermind
Because closure of S is disconnected
okay so what about the first confusion then, I understand that part now
Still I prefer to transform your condition of being connect to a equivalent but more convenient form
What is your version of definition of being connected again?
it is connected if it is not disconnected, and it is disconnected if it is the union of two nonempty sets that do not intersect the closure of eachother
no
This gives us U contained in X-cl(V)
that can't be true
because U and V form a disconnection of S closure
oh sorry you are right
I mean the condition of disconnectness
Then X-V=U in X-cl(V) in X-V
Therefore U=X-cl(V), meaning U is open
what is X
total set?
Then this shows U is open in X
Similar V is open
I'm not following this
I don't know what X is, or why it matters that any of our sets are open
… never mind then I use your notation then
okay
Because if they are both not non-empty, and it isn’t a disconnection of S
Then we have S=(S intersection U) union (S intersection V). S is union of two non-empty subsets. This isn’t a disconnection meaning
Cap is notation for intersection, cup union right?
yes
Then
cl(S cap U) cap (S cap V) is non-empty or (S cap U) cal cl(S cap V) is non-empty
Contradiction
what is that contradicting?
Because cl(S cap U) cap (S cap V) is contained in cl(U) cap V
The latter is empty
So the former can’t be non-empty
Similar for the another one
why is it contained in cl(U) cap V
S cap U in U
S cap V in V
Yeah
so then from this earlier
we conclude that
this means that U must be empty
and that contradicts U union V forming a disconnection for S closure
right?
That’s why I was
Trying to give you a more convenient equivalent definition of being disconnect
But anyway you can prove it yourself
X is disconnected <-> X is disjoint union of two non-empty open subsets <-> X is disjoint union of two non-empty closed subsets <-> X is disjoint union of two non-empty subsets who are both open and closed <-> X has a proper subset that is both open and closed
But anyway, they are all equivalent, it’s just I personally feel these are more convenient to use
Sorry Cogwheels I was just trying to completely wrap my mind around what'd we just done and get the proof all settled
reading now
ty
Np
@vapid shuttle Has your question been resolved?
Closed by @vapid shuttle
Use .reopen if this was a mistake.
@oak perch my completed proof if you were interested in seeing it
ty again for your help
I was having lots of trouble on that one
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.
construct a box and whisker plot to display the number of pets owned by a number of randomly chosen students. The data are, 2, 0, 5, 1, 2, 1, 0, 8, 4, 3, 9, 1, 2, 3, and 1
Please don't occupy multiple help channels.
@rancid tartan Has your question been resolved?
Closed by @rancid tartan
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.
...
Nevermind, we posted a problem at the same time
Hi, so why was ls 2 delta r^2 like that? shouldn't it have a pi as well?
when it was distributed?
or there is some rule I don't lnow about this
it should be pi delta r^2
this part
Why is the left part delta A / delta x?
I thought so
@worn hinge Has your question been resolved?
<@&286206848099549185>
@worn hinge Has your question been resolved?
@worn hinge 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.
is this the most simplified form or is there anything more i can do?
That's fine as is
oh ok
i have another problem
The cells in a culture in a lab grow according to the logistic equation dP/dt=0.02P(1-(P/2000)). Initially the population of cells is 300. Estimate the amount of cells after 3 hours.
I got 315.6, but the answer says its 315
here are my steps
,rotate
@flat roost Has your question been resolved?
@flat roost Has your question been resolved?
oops my bad
did you get 315.6 too?
,calc 6000*e^0.06/(17+3e^0.06)
Result:
315.62340475972
yea
Closed by @flat roost
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 have a lot of problems in geoemtry specifically triangle congruence. i have a worksheet that i have left mostly blank cuz i dont understand how to do anything at all.
wow so many
i just dont get it
for the proof problem 7, i know i have to prove the triangles are congruent then use cpctc
and for everything else i have aboslutely no idea
oh okay, i never heard of cpctc
corresponding parts of congruent triangles are congruent
do you know these? @faint frost
that's good!
let's start with Q7
what do we need to prove BD=EA?
(i use = instead of the congruence sign for ease of typing)
like which pair of triangles should we use?
sure thas fine
so, what info will we need?
for this to happen
i think its one of the angles right
its gotta be the included angle
nah, we need to angle between 2 lines
between the 2 corrosponding congruent lines
which one tho
oh wait
nvm
bcd and ace
wait a second
@nimble fern since we already know that the corrosponding lines are congruent, bcd = ace
right
what reason is that tho
not sure what the postulate or theorom would be
good question, do you know angle sum of triangle / exterior angle of triangle?
the exterior angle is the sum of the 2 remote interior angles?
is that what ur talking about?
yea
how would i use that
like we know, for now, the base angles of the inner triangle are same
and base angles of the outer triangles are same
we can use this to prove
angle BCD = angle ACE
how do we know that the base angles of the outer triangles are the same
and bcd and ace arent exteroir angles
so i dont get it still
ok, I'll go through step by step then
ah, btw can you repost Q7 for easier reading?
angleCDE = angleCED (base angles, isos triangle)
angleCBD=angleCAE (base angles, isos triangle)
angleCDE=angleCBD+angleBCD (exterior angle of triangle)
angleCED=angleCAE+angleACE (exterior angle of trianlge
all good till here?
yeah i got it
good
next step will be
angleCDE-angleCBD=angleBCD
angleCED-angleCAE=angleACE
now that since
angleCDE=angleCED
and
angleCBD=angleCAE
we have
angleCDE-angleCBD=
angleCED-angleCAE
therefore
angleBCD=angleACE
therefore we can finally prove triangle BCD congruent to triangle ACE
all good till here?
@faint frost 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.
If a²+1/a² = 786, then a-1/a = ?, I know it can be solved by adding/subtract 2 on both sides, but can it be solved by finding out the value of a, from the first eqn
Jshy
some people respect the order of operations
I am not one of those people
It's a²+(1/a²) and a-(1/a) sry
As I'm good in just solving by linear equations in 2 variables that's why I asked to find a firs
you could convert the first equation to a quartic equation
for which you'd get 4 solutions, which may not necessaily be nice
and end up doing something like 4 cases
I'm not so good in maths so I just know some basic techniques like solving using 2 vars, it would be very helpful if you could solve it using an efficient method and a method which would be in my context of understand like using linear eqns
it's a biquadratic so it wouldn't be impossible just annoying
@vivid basin Has your question been resolved?
what part of your question hasn't been resolved
I want know the methods by which it can be solved, till now I know just the method of solving it by adding 2 on both sides
the most efficient way to solve this problem is subtracting 2 on both sides
If I solve the first eqn for a I get √343
Ok np I will use the efficient method
.close
Closed by @vivid 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.
• 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.
Do we always get the same derivative if we simplify the function first before getting its derivative in multiplication and division, and if we use the rules first before simplifying?
like f(x)=(x-4)^2 (2x=3)
does the 2x=3 a condition for the f'(x)?
I don't get it 😔
@vague iris Has your question been resolved?
i suspect you meant (2x-3)
and yes you'll get the same answer
although you may have to factor one or expand the other, to easily see that they're the same
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.
Hey
Trigger Warning: Arachnophobia
A spider wants to crawl the shortest way from corner a to corner b
So my book says 64 cm
Idk how it got to that
Is it like a box
So then it can go up then across diagonally
Maybe it can go straight from a to b
sqrt(40^2+20^2)=44.72
Pythogoras in 3d
No it can't, spiders can't fly 😅
Webs
Besides, 50^2(diagonal of box) +20^2 (height) is 53.85, so shorter than 64
64 doesn't sound right
I have no idea what the book wants me to do
It's a chapter about repeating the Pythagoras
Nothing advanced
Is there like a solution at the back of the book
Sounds like it
Closed by @high mauve
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.
\dm
I think it is to safe to start with the fact that
[
\s{a+b+c} \mathbin{\c r \ne} \s a + \s b + \s c
] in general
\dm
horizontal asymptotes are defined by an asymptotic/convergent behaviour in the function as it approaches $\pm \infty$
yeah
\dm i.e. check if $\ds \lim_{x \to \pm \infty} \map f x$ exists
@chrome dagger 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.
how interquartile range is calculated here?
here in image 1st one denominator is always 365 why so and in second case with replacement approach is used ? what is the reason for this denominator thing
please help!
how is interquartile range defined?
or is that the question
hmm
are your messages getting deleted?
yeah
odd
why so
here how they found inter q range i did't understand
This is a good video for your question
no but how to find that if only 2 or 3 terms are there
its understood for 10 and so terms but this i didn't understand
If there is 2 terms
Then it is simply the difference between them
If it's for 3 terms then it is the difference between the final and the first one
oh just like range?
okk
Yeah
can you help with this too @charred summit
What is the question of the left one?
oh wait
so instructor showed an exaple for 6 people
To solve this we need to know how many ways can 2 persons have birthdays
So do you know about combination?
yes i do
but i was thiking it would be like (365/ 365) *( 364/364)... like that as without replacement it is? right?
Nice
So to get all the ways for their birthdays
We do a little easy equation
,calc 365 * 365
Result:
1.33225e+5
,calc 365^2
Result:
1.33225e+5
but why then the denominator is all 365?
I don't understand anything about the solution you gave to be honest
So now we want to know how many ways they can have the same birthday which will be
365 ways
this they did after that using the logic
ya the first person
Getting the probability of two having the same birthday is
$\frac{1}{365}$
Sherif Player
bro my doubt was why denominator was not altered like it is when no replacemnet case is there in the second q that happend
Which gives us the percentage 0.274%
Meaning to get a 100%
That there is at least 2 people have the same birthday
We do
,calc 2 / 0.274%
Result:
729.92700729927
So we need 730 people just to get 100 percent probility to have 2 people of the Same birthday
you tried man
but the ans is 23 thats what
i wasn't asking the ans just the denominator concept
noo need to solve
Hmm I think that it is 365 which represents the year days
no why not like this (365/ 365) *( 364/364)...
Do you mean the way he said
$$\frac{364}{365} \times \frac{364}{365}$$?
Sherif Player
Look I think I understand it now
When
To calculate the probability that bunch of people doesn't share any birthday is easy
We will just take one out of them then say that
The second one needs to be different than this person so it will be
$$\frac{364}{365}$$
Then the third one needs to differ from both of these guys so
And as both of the conditions needs to be applied we will use multiplication
$$\frac{364}{365} \times \frac{363}{365}$$
Sherif Player
And so on
Now to get that at least 2 of them has the same birthday we will just say
1 - the result
So we get
$$1 - \frac{364!}{(365-K)! \times 365^{k-1}}$$
As K is the number of people
Sherif Player
@simple saddle 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.
Where did I go wrong?
honestly looks alright to me
i think there was a mistake in the answer key. The denominator was raised to positive 2.
Thanks!
.close
Closed by @vague iris
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 would like some advice on how to solve the following diophantine equation $x^2+y^2+x-y= 2021$( The question is actually to find the number of diophantine roots, but I would like to find the roots first
physicsrocks
dont take my advice too seriously, but solving for either variable in terms of the other using quadratic formula should allow u to place a few bounds on the values
Yeah, I'm aware of that, but I was hoping for an alternate solution
I have tried a few tricks. Like$(x+0.5)^2+(y-0.5)^2= 2020.5$ and $(x+y)(x+y-1)-2xy=2021$ But neither seem to help
physicsrocks
in this case its possible your only option is my way
reason being its not factorizable
I mean isn't this just the equation to a circle
u sure?
You can find the length of the intercept made on the x axis and calculate the distance from the x coordinate of the center
well yeah it clearly is
+x-y doesnt matter?
He's even got it in center-radius form here
why would it
hmm
well then u have radius as sqrt(2020.5)
oh yeah, I don't know how I missed that
. Thanks!
.close
Closed by @lethal belfry
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 have doubts in this question's solution I found online.
Somebody did this:
Where did x + 1/x come from?
This is ref page I found from that person.
they're using the fact that if f(x)=x+(1/x) then the range of f(x) is [2,infinity)
that's smart actually damn
But why though?
using the information from the four equations, you can see how they got to l+(1/l)=q-2
Yeah.
so they see that l+(1/l) is f(l) in this case and its range is [2,infinity)
Ok I see.
and then they're substituting for l+(1/l) in that inequality to get the range of q
But wait, shouldn't the range by -1 to infinity taking only natural numbers?
Or I'm mistaken?
(probably).
you can find the range of x+(1/x) by completing the square
Oh ok.
wait yeah
im right
ok no i was half right the range also includes the interval (-infinity,-2]
But wait, you can't complete the square for this I don't think so.
yeah that part was wrong
if l+(1/l) was less than -2, it would imply q-2 was less than -2 or q was less than 0
which isnt possible because q is given to be natural
Yeah I got that.
Oh wait.
1/x is a rational function.
So the minimum val. is 1 for natural numbers.
for f(x) = x + 1/x => f(1) = 2
So that's why they did that.
Ah that's acutally smart.
(That's what you said in the beginning).
@frosty swift Has your question been resolved?
Closed by @frosty swift
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, is this the right drawing of the situation
Orthogonal means independent here
@final mural Has your question been resolved?
@final mural 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.
Let v1, v2 and v3 be distinct elements of a vector space V over a field F and let c1, c2, c3 ∈ F . Under what conditions is the subset {c2v3 −c3v2, c1v2 −c2v1, c3v1 −c1v3} of V linearly independent?
i think the answer is never cause c1(c2v3 −c3v2)+c3(c1v2 −c2v1)+c2(c3v1 −c1v3) is always 0
so they're always a linearly dependent set
someone pliz sanity check, thanks!
$\begin{pmatrix}v_{1}&v_{2}&v_{3}\end{pmatrix}\begin{pmatrix}0&-c_{2}&c_{3}\-c_{3}&c_{1}&0\c_{2}&0&-c_{1}\end{pmatrix}$
Cogwheels of the mind
So only when v_i are linear independent and that matrix is invertible
Calculate its determinant
Oh seems like you did
You are correct
thats where i got the idea yea
cool thanks 🫡
.close
Closed by @humble leaf
Use .reopen if this was a mistake.
Np
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 can anyone help me with this probabilities question
hi
i know this is related to pascals triangle and ncr but i dont fully understand how to do it
I think the setup was a bit confusing.
The first sentence basically tells that you are using combinations of four fruit so 4C1 + 4C2 + 4C3 + 4C4.
The next line does not clearly define if Olivia is just adding one fruit to each of the possible combinations or there is an additional fruit to consider in the combinations above. The explanation given would indicate they intended the former.
@alpine sable Has your question been resolved?
thank you sm
i just got one more question, it might be dumb
but what i did was i looked at pascals triangle and i included 4c0 and 5c0 in my calculations so i did 32-16=16, why did you leave out 0?
4c0?
so i did (1+5+10+10+5+1)-(1+4+6+4+1)
@alpine sable 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.
how do you do this starting with dy first? (It will be two integrals added together), what are the limits for dy?
https://cdn.discordapp.com/attachments/689915677431169069/1146997301240397834/image.png
I would do it like this:
y=rcos(u), z=rsin(u), 0<=r<=3, u from 0 to 2π, x>=0
The 3x-y+z=6 condition becomes sqrt(2)rsin(u-π/4)=6-3x
dxdydz=rdxdrdu
@viscid lynx 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.
Hi, I have a question about the definition of a gradient vector field. I know that $for a C^{1}$ vector field F, we have that $F = \nabla f$ (i.e F is a gradient vector field), then for any simple closed curve $C$, we have that
$$\int_{C} \textbf{F} \cdot d\textbf{S} = 0$$ . However; what if F is not $C^{1}$ continuous? For example, consider $$\textbf{F} = \frac{-y}{x^2 + y^2} \textbf{i} + \frac{x}{x^2 + y^2} \textbf{j}$$. When $C$ is the unit circle, $\int_{C} \textbf{F} \cdot d\textbf{S} = 2\pi \neq 0$. And yet, ... F is the gradient of -arctan(x/y).
Maria
@raven coral Has your question been resolved?
@raven coral Has your question been resolved?
Closed by @raven 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.
Hi, guys! If someone could help me with this, that’d be amazing I’m so confused.
I thought I was supposed to use the contribution margin ratio but I’m not sure 🥲
@winter current Has your question been resolved?
I’m not even sure where to start if I’m being honest
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 how do you solve
It’s the same as (2r+4)+(r-2)=18
how
Because C(n,a)=C(n,b) iff a+b=n
What
Why 19
n=18 here
Wait sorry
n
Editing
18 not 19 my bad
Edited
Why do you have to add
You familiar with pascals triangle and the relationship between it and the binomial coefficients?
What do you mean
In mathematics, Pascal's triangle is a triangular array of the binomial coefficients arising in probability theory, combinatorics, and algebra. In much of the Western world, it is named after the French mathematician Blaise Pascal, although other mathematicians studied it centuries before him in Persia, India, China, Germany, and Italy.The rows...
So the coefficients of (1+x)^n are the nth row of this
ok
For instance, the third row is 1 3 3 1, and (1+x)^3 is x^3 + 3x^2 + 3x + 1
Each entry of Pascal's triangle is C(n, k)
Where n is the row and k is the column
And it's symmetric
Meaning that C(n, k) = C(n, n-k)
So we know n = 18, because (1+x)^18
So we just need to find the appropriate k
why n-k
Symmetry
from where
Pascal's triangle
What do you mean
Or simply by definition of binomial coefficient, you can easily show C(n,k) = C(n, n-k)
how
Using the definition of binomial coefficient (if you know it of course, otherwise forget it for now)
The one with the factorials
which one
n!/(k!(n-k)!)
What i do then
what am i doing with this
Write, using that definition, what C(n, n-k) is equal to
This one! This is the definition of C(n, k)
2 and 18
Don't think about numbers for now
This...
Btw I'm going to bed now cause it's quite late
There is for sure someone available to help you
how does symmetry deal with this

I was saying that in few minutes I'm going sleeping and I wanted to let you know that you aren't left alone, but instead a lot of helpers are available to help you
no sorry wrong reply
I thought @twin nimbus wanted to make you note that C(n, k) and C(n, n - k) are equal to eachother
And what I was telling you is one way to prove that
How is this possible
how are they equal
What does the k even mean
You have to prove that they are equal if you don't know it
but how
And I'm trying to tell you how to do that 😅
Oh my god
This...
What does th k mean
I don't know how to explain you if not in this way
is it 18
@weak ridge
No, n is 18
@twin nimbus can you explain it again please? I don't know how to help him 
please explain the relationship between the equality and the symmetry
<@&286206848099549185>
I don't think I'm good enough to explain that
just try please
The only thing I can suggest is going back to the messages and restart to read carefully what @twin nimbus told you
Starting from here
this?
yes
do you know binomial theorem?
yes
then whats the issue?
if the term you are expanding is 1+x, then the coefficient would not change from either the a or b terms
therefore you could just set the nCr terms equal to each other and solve for r
why
so they are the same
;but term 2 and 18 are the same
but they dont give me same r
well each term, according to the binomial theorem, could be written as nCr (1)^r*x^n-r
and you want to find out the coefficients of the (2r+4)th term and the (r-2)th terms
since no matter what 1^r * x^n-r will not have a coefficient
you can ignore those
and you just focus on the nCr terms
so you would set them equal to each other
18C2r+4 = 18Cr-2
18C1 is the same as 18C18
Hello
Are you there
if the binomial is raised to the nth power, the coefficient of the rth term will be equal to the coefficient of the (n-r)th term, given that r starts at 0
like
why is that a condition
i mean then if you want r to start at 1 you could have the coefficient of the rth term to be equal to the coefficient of the (n-r+1)th term doesn't really matter
i mean you wanted the relationship between equality and symmetry of the coefficients didn't you?
why does be n-r+1 be equals to r
why does this have to be so please
why are the equal please
nCr = nC(n-r) => n!/r!(n-r)! = n!/(n-r)!(n-n+r)! => n!/r!(n-r)! = n!/r!(n-r)!
why are we substracting r from n
why
i just proved that nCr is equal to nC(n-r)
where
here
please explain
$nCr = \frac{n!}{r!(n-r)!}$
$nC(n-r) = \frac{n!}{(n-r)![n-(n-r)]!} = \frac{n!}{(n-r)!(n-n+r)!} = \frac{n!}{(n-r)!r!} = \frac{n!}{r!(n-r)!} = nCr$
@weak ridge
@weak ridge Has your question been resolved?
@weak ridge Has your question been resolved?
It’s simply C(n,a)<C(n,a+1), strictly increases for a<[n/2], because the latter is the former multiplied by (n-a)/(a+1)>1. And C(n,a)=C(n,n-a). So increases then decreases, So C(n,a)=C(n,b) we have only a+b=n
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 explain how I get from point a to b
a being where the arrow starts and b the equation its pointing to
or if anything how I get (a^2-2a-2) from combining the two fractions
oh wait never mind
.close
Closed by @terse fable
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 does factoring the denominator end up with (2a+5)(a+5)?
I'm referring to the second denominator btw
nevermind
my brain is being dumb today
.close
Closed by @terse fable
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.
Ok ok this is a little dumb
Me and my friend have been so confused on what to do
EVEN THOUGH WEVE DONE STUFF ABOVE OUR GRADE LVL
cnr+r/n
Can you reduce that into
Cr+r/n
c, n, r are variables?
Yes
Then no. Not unless n is 1 which then makes division by n in second term redundant.
Wait...
c and C are same. Right?
GarlicB
Lol. True. Maybe, they had the first one and ended up with cr + r/n.
@lavish kelp Has your question been resolved?
Closed by @lavish kelp
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.
hay
i wanted do dicusses about roudning to the next dollor but it doesnt add up
What is the issue?
send your problem?
@alpine sable Has your question been resolved?
Closed by @olive pine
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 need help
i got a calculus problem but idk if yall can do it in this section
this is the very last problem of the summer hw and me and my classmates (7 of us) dk how to even approach this
what are some observations you can make about the limit on the left?
its approaching 0
i got to the point where i canceled out the x, but idk where to go from there
well the overall limit should be approaching sqrt3
but do you mean the denominator is approaching 0?
mb
the x is towards 0
which means that we have to somehow cancel out the x in the denominator with another x in the numerator otherwise this limit would be DNE
well... it means that the numerator has to approach 0 as well
or else yes it would be DNE (or infinite, and certainly not sqrt3)
what i did was multiply by the opposite thingy
so instead of a+bx- root 3
i did + root 3
lemme send a picture of my messy work
i thought about doing that but i wasn't sure if it'd be useful
i just used l'hopital's rule but your way is probably better
i didn't solve for a and b tho
we arent allowed to use l'hopital's rule
because we havent learned it yet
so you ended up with $\lim \frac{b}{\sqrt{a+bx}+\sqrt3}$ if i'm reading that right?
hayley!
yeah
then that is equal to root 3
and idk where to go from there because there isn't a system of equations i can use to solve for a or b
after that im just rearranging the equation
yeah you only found one equation so far
i used the fact that the original numerator had to = 0 to get another equation
could u pls explain why it has to =0
the numerator specifiaclly
specifically
w9
w8
a+bx=3
a=3
then solve for b
and you get b -6
b=6
imagine if it didn't
then what would our limit be
w8
this got me confuzzled
lol
but wouldnt that be the function
aka the y-value
and the y-value has to equal root 3
hmm?
the thing is = to f(x)
aka y
which is root 3
so why does the numerator of it have to = 0
well
is it a special rule idk
what's $\lim_{x\to 0} \frac{x^2+1}{x}$?
hayley!
how do you know that?
cuz you cant get rid of the 0 in the denominator
why not?
you are correct that it's DNE
bet
yea
if i plug in 0 to the originial one its also gonna be DNE
but we know its not
right, we have to stop it from being DNE
yea
thankfully we have some knobs to turn
right, we have to stop that limit from not existing
we know the denominator is going to 0, we can't do anything about that
and if the denom goes to 0 but the numerator goes to some number that isn't 0, then the limit will not exist (or will be infinite)
w8 no thats only if there is an x in the numeraot
numerator
when the function is heading towards positive or negative infinity
w8
im so lost
is this a rule idk?
that the numerator and denominator have to approach the same number?
cuz how cany they both approach 0 if it says = to 3
hayley!
w88888
thats when you plug in for x
then it is approaching 0
is there a yt vid i can watch
probably
so
basically
just write the numerator = 0
solve for a
plug into other one for b
rightttttttttttttt???
.
that is what i did yes
ok perf
what is the thing u were talking abt
what is it called
so i can search it up
@pale granite Has your question been resolved?
Closed by @pale granite
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.
@trail summit Has your question been resolved?
Closed by @trail summit
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.
!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'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
@rapid gate
@rapid gate Has your question been resolved?
so
so either
i dont understand the english part
or the math part
but when it saids 13-19 inclusively
does it mean numbers 14-18 including 14,18
@rapid gate Has your question been resolved?
@rapid gate Has your question been resolved?
,w x^2-6x-27=0
,w log_3 (x-6)+log_3 (x)=3
.close
Closed by @rapid gate
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.
Give me 15 minutes, Ill come back to it if nobody answered
I'm still doing something, but at first glance it seems you have the preimage definition a bit wrong for a)
(g dot f)-1 (E) = {a in A | g(f(a)) in E}
That seems about right. Now I'd advise trying to pick an element from the first set and show that it must be in the second.
I get what you're trying to write down, but there's some things a bit iffy with it. I'll annotate it just give me a minute
ok thank you ill try proving b and c atm
Again, x is not in g-1(E) since x is in A and g-1(E) is a subset of B.
ohhhh
However, you can say that if (g dot f) (x) = e in E, then you have g(f(x)) in E, so f(x) is in g-1(E)
f(x) is in g(-1)(E)
Yeah
But then that means this x is in A
With f(x) in g(-1)(E)
So it's also in f-1(g-1(E))
Makes sense?
It's not as short a proof as it could be, but it should do the trick.
Yeah the x you picked to begin with is that specific x actually
But that's the reason yes
is it correct now?
Yeah looks good
i can draw it or visualized it but i cannot say it mathematically
can i send more proofs?
ok thank you very much im proving b and c now
@waxen seal Has your question been resolved?
Closed by @waxen seal
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 guys
i want to learn, is there a way to answer rational function inequality fast?
like is there a shortcut?
shortcut compared to what
compared to the conventional, just a curious question, im fine with the conventional it's just that it takes me so much time when answering quizzes and test
for example let's have this
and this
what's "the conventional"?
everything to one side then factorization?
I just watched organic chemistry, i thought that was conventional sorry ^_^
any method you do?
no, there is no shortcut around that.
do you ahve a method u can share with me?
well like in this case you can use the fact that a square is always ≥ 0
ok ok thank you
im sorry if im asking too much can u show how that works, i do promise i'm just advance studying, this isn't out homework!
hayley!
you can just multiply both sides by (x-5)^2; because it's always positive we don't have to change the sign of the inequality
so we get $(x-7)(x-3) > 0$ and we can easily solve that
hayley!
and remember that 5 can't be a solution since it's not valid in the original expression (because it would be dividing by 0)
thank you!
that's applicable more generally too
how did the answer went to this?
e.g. in that first example you can multiply both sides by
(x+5)^2(x+6)^2
after multiplying both sides by (x-5)^2,
you'd get
(x+7)(x-3) > 0, (make sure to remember to exclude 5 from the solution set)
and the most intuitive way to identify the solution to that would be the wavy method where you draw a rough sketch of y=(x+7)(x-3)
ah this is wrong
where the main features you care about are just the direction and x-intercepts
it's x + 7
ok ok i see
just a typo, idea still stands