#help-4
1 messages · Page 25 of 1
Yeah it only works when there is exactly 1 root in an interval, emphasis on exactly one
Alr man cool thanks a lot
Np
.close
Closed by @harsh jolt
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.
Not sure if this counts as math but this is some chemistry calculations I’m really confused with! 😭 Could I possibly get some help with how I should approach the calculations for the last column?
Closed by @vague gulch
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.
Any advice on how to do this problem?
So far I notice that if you connect all the midpoints you either have a parallelogram or trapezoid:
But that is all I got ;-;
I am thinking to consider what happens when angle ACB and angle ADB is 90 degrees,
@faint cave Has your question been resolved?
<@&286206848099549185>
@faint cave Has your question been resolved?
Closed by @faint cave
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 solving for the system of equations using substitution because y is already isolated but the quadratic that I got can't be simplified without using the quadratic formula and the video I'm watching for help doesn't tell me what to do if this happens.
well then you use the quadratic formula lol
I know but idk if I'm allowed to use a calculator with this problem
I also just wanted to double check and make sure what I did so far is right too
just leave it in surd/radical form lmao
Closed by @hasty nest
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 would anyone go about doing this?
Let $z=\left(\left(x^2-1\right)^2-2\right)^2-3$
SWR
Not quite. Well, I suppose you could, but not the idea I had in mind
You mean z, not z²
SWR
what was ur other way of doing it?
Now, let $y=\left(x^2-1\right)^2-2$, so $y^2-3=\pm2$
SWR
i'm doing that bit rn
yeah since i don't actually need to know the roots but i just need to know how many
So, what are you getting so far?
i am on 4 roots w x^2 - 1 = 4 of them
and so then u get an extra 2 from that
and hence yk we got 6 roots
so b ig
six roots huh?
x^2 - 1 = 4 of them
Not sure what you mean by this
Looks good

and +-0 is 0
i was thinking of doing it that way
but i then like doubted it anyways
but thanks for all the help
yh cheers
have a goodnight
.close
Closed by @pallid smelt
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 we use Cauchy to prove f(x) = 0 for all x in the interval?
do you have to specifically use this criterion?
I don't know any alternatives
i can think of a method that's simpler conceptually
Monotonicyty doesn't say anything about what we are trying to show
What's that?
ok so you know that integration is monotonic in the sense that if f <= g pointwise then int[a,b] f <= int[a,b] g
right
Yeah
so what i recommend here is to go via contradiction: suppose f isn't identically 0. then there's a point x_0 in [a,b] with f(x_0)>0
construct a piecewise linear function that will serve as a lower pointwise bound for f but whose integral will be positive
it may help to try to draw a graph
Contraposition is how id do
Superior way:
this literally begins the same way i suggested????
It isn't.
my construction would have proceeded in a similar way, only that i would have made the lower bound function identically zero away from the point
ann said that it begins the same way she suggested, not that its the same proof all around
rather than constraining to the interval [c-delta, c+delta]
yeah but who doesn't like pointing out how wrong Ann is :))))
you hear the tone from this guy and youre taking him seriously?
Doesn't matter
at least think your words through before you say them
was just about to say youre focusing so hard on being right
Id go with this proof too instead of constructing a piecewise but look at how much youre talked yourself as
I think you need to slow down on the copium
please learn to understand people
Mabe subliminate that into something more productive
theres one change I could do for this proof
the definition for continuity only really works if domain intersect (c - delta, c + delta) is also an interval
so that we can guarantee a nonzero area over it
presumably we should be able to assume that this interval exists since f is continuous? but
personally I used a different method to doing this which used FTC so its not that much better
@ebon thorn so which direction are you going to take proving this problem in?
Mine
do you need help on this problem then
I got my answer
.close sounds good
Closed by @sharp whale
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
hi
so for the vertex form
if it were to be (x + 8)^2
i mean
(x + 6)^2 + 18
would it be
(-6, 18)
👍
.close
Closed by @tight lark
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
Can someone help me to solve
What’s the question
$x=\frac{12*ln(x)}{ln(8)}$
\frac
Nicolas Matheisen
At this Point I am stuck😭
cis(x) = cos(x) + i sin(x)
where c is a positive number not equal to 1
Maybe use the transformation $y = e^x$ and refactor to get $$e^y = ky : k = \frac{12}{\ln 8}$$
Shuba
might be easier to solve than logs (I hate logs, and love exponentials XD)
Ahhhh jeahhhhh 100 points tyyyy
$\frac{x}{12}=\frac{\ln{x}}{\ln{8}}$
hint: you'll need the lambert W function
cis(x) = cos(x) + i sin(x)
$\frac{x}{12}=\log_8x$
cis(x) = cos(x) + i sin(x)
This is my goal
By the way the Original task is
$8^x=x^{12}$
Nicolas Matheisen
why did you convert to log
Cause I try to understand the lambertsche W func
Or I did. it wrong?
I am confused😰
this is equivalent to solving (e^{\frac{x\ln2}{4}}=x)
Use y := ln(x)
Then you can rearange into -y e^(-y) = - ln(8)/12 which the Lambert-W function can solve
It's generally a good idea, when presented with an equation of logarithms, to turn those logs into exponentials
logs are terrible to work with imo
Closed by @wooden 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.
what up
this is the hw help a brotha
!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
Then can you please show your work?
(Or what your idea is)
e.g. have you found the zeros?
recall that is a Polynomial has a factor (P(x)=(x-r)Q(x)) then (x=r) is a root of (P(x))
PajamaMamaLlama
do i replace x w negative 18
so we have (P(x)=4(x-6)(x+1)(x+3)) right?
PajamaMamaLlama
we have that (x-6), guy right?
that's part of the polynomial
since this guy is multiplied by the rest of the polynomial
then x=6 is a root, I'll give you this one
,calc 4(-6)(1)(3)
Result:
-72
how did you get -18? 
ahh yeah that 4 is very important 
but yeah that'll scale is correctly
then you got your polynomial!
cool thats ez asf
this is fs wrong it doesnt y-intercept at -72
o maybe it does
nvm it was right
the next unit lwk look scary lol
i believe in u 
you have to include all the powers of x in the division, so they added 0x
synthetic division is pretty light fr
no, like the original polynomial is technically $$-9x^4 + 10x^3 + 7x^2 + \textit{0x} - 6$$
oh bc its has to go 4 3 2 1
yee exactly
haseeb
no harm in writing it a different way, if it makes sense to you
personally i think about it as adding downwards
i lied they adding its js bc it was negative
o
yea it makes sense i was just being stupid
whered they get 1
oh nvm
if you can’t read my atrocious hand writing lmk
hmm
when you're synthetically dividing by x-r, you use x = r
i believe you used x = 2 in this case (which is incorrect)
so -2?
the quotient is the big answer you get
yeah
wym big number
almost not quite
the polynomial that you got as your answer
oh the whole equation under the line
are they just asking for me to write it in the format its alr in
yes 👍
what did i do wrong
no way this is correct
seems fine
do you have your work
ah
oh
you forgot to account for 0x^3
its the exponents
you need a 0 between your 1 and -2 in your setup
how do i rotate
nvm
its supposed to be -3
this is really starting to piss me off
0 + (-4) = 4?
this looks good to me idk what could have happened
maybe a typo when inputting? 😬
Closed by @proud vault
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 please show me how to do this.
can you solve a cubic equation
cool, neither do i
where is this problem from
its a practice quiz
for what unit
its advanced functions
yes that it
then because we know the height, we can set h(t) to 980
so we need to solve $980=-2t^3+3t^2+149t+410$
cis(x) = cos(x) + i sin(x)
just move the 980 to the other side and use rational root theorem
i know that part but i’m not sure exactly how to do the rational root thearem
is it possible for somebody to send a picture of the answer so i can analyze it and try and figure out the steps
basically the roots are in the form $m/n$ where m is a factor of 570 and n is a factor of -2
cis(x) = cos(x) + i sin(x)
and u use guess and check
so for example, one possible root is 2 because it can be expressed as 2/1
and you have to check all of them
until you get one
@hybrid gyro 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.
Honestly not sure where to go from this
first, remember that the cos is the x value and the sin is the y value
-21/29 isn't quite the y value of that terminal point 
wait i mistyped LOL
mhm 
okay and tan would be sin/cos right
yep!
so how is -21/20 incorrect
well…your sin value is -20/29 and your cos value is 21/29; what do you get if you divide that?
@gilded horizon
the division is not quite right 
Closed by @gilded horizon
Use .reopen if this was a mistake.
minor note: you could also have canceled out 29 from the start
ah i see, thank you for the help
Minor note: you can always reopen a channel if you wanna replenish anything 🙂
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.
prove that $6(6a^2+3b^2+c^2)=5d^2$ does not have a nonzero integer solution
skissue.in.a.teacup
i remember my teacher said something about infinite descent?
Ideal for this typa shit
It's pretty hectic sometimes tho
this was the cleanest i got it to, idk how to continue this though
if this just breaks the possibility of infinite descent i wouldnt be that surprised cause i subtituted alot here
Hmm , you get any common gcd of the fours?
That's insta kill
wdym
The gcd
Take any solution (a,bc,d)
Is there any prime or anything dividing all four of them?
i couldnt get anything of that sort no
In that case, do you get individual factors of those 4?
No infos on a?
Look it's clear that d² has a 6 in it, so there should be another 6 of pair there
So 6|d, all good
$2a^{2}+b^{2}+3c_1^{2}=10d_1^{2}$ that's where it boils down to
Licht
@rough talon Has your question been resolved?
Aw shucks man
We see $b$ and $c_1$ are of the same parity, let both of them be odd. Then $b^{2}+3c_1^{2}$=$4(mod 8)$.
Now,
$10d^{2}=2$ or $0 (mod 8)$
$2a^{2}= 2$ or $0(mod 8)$ so that's a contradiction
Licht
@rough talon so b and c both are even
interesting
if we can get 2|a then infinite descent works now
Easier to devise a contradiction here
It's pretty simple looking
is it not +6c_2^2?
Oh yeah
True
We had a three there
OH
It's easier now
$$2a^2+b^2+3c_1^2=10d_1^2$$
$$2a^2+4b_1^2+12c_2^2=10d_1^2$$
$$a^2+2b_1^2+6c_2^2=5d_1^2$$
skissue.in.a.teacup
Licht
d_1 I mean
maybe you can do the same thing?
Yeah that's where I'm going to
Maybe infinite decent will work , but I don't have a constraint relating to 5 yet
So they won't factor out either or it's gonna be a hassle
Wait we do have something interesting, we can get back to the equation maybe
yeah it was simmilar just it needs to be a 3 instead of a 2, and you want a factor of 6 on the lhs
Can you see that no matter what it is $2b_1^{2}+3c_2^{2}$ is divisible by 8?
Licht
Three case bash
6*
huh?
Do three case
One is b and c both odd, then b and c both even and leaves remainder 4, and then b and c both even which leaves remainder 0 mod 8
(0,2)+(0,3,4)
so possibilities are 0,2,3,4,5,6
bro why u here
@rough talon Has your question been resolved?
@rough talon your infinite decent
👀
Yuh check it , was hectic
Closed by @rough talon
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
Hi

im a bit of overwhelmed
What are the ratio of the standard deviations
a1, and d are real constant
I need someone to answer, then I can throw you a lot of question based on it
I believe I will learn more about standard deviation through the process
🐯 :It is 2, for the interval of <x2> is twice that of <x1>
So the standard deviation is actually the interval of any sequence?
🐯 :not quite so, it is because both of <x1> and <x2> are arithmetic sequence.
does it change anything?
<@&286206848099549185>
help me please
please
please
plesae
lend a hand
SD is a real number, how are you getting an interval?
Its just sqrt var [x]
🐯 :do you know, in arithmetic sequences, the middle term will always be the means of the sequences?
Yeah
Does it imply anything?
Imply what, and how are you getting a relation with variance?
and youre avoiding my question
where is the interval
🐯 :indeed, it would be much easier for you to interpret it, if you take some examples of arithmetic sequences with sample numbers.
🐯 :for it can spare you doing the laborious calculation
@stark wedge sorry for the sudden ping, but i'm not getting anything out of this convo, mind to take over?
maybe im too dumb for this chat
uh why me
You were there
.
i have no idea what this dude is talking about
Ann, can you explain why in arithmetic sequences.
If the interval of one sequence is twice that of the another.
then their ratio of sd will be 2:1 as well
!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.
that's the original mr. Alberto Z.
how many sequences are there
Apart from the photo being blurred, where did you copy that from?
Exactly lol
Original means the picture of the textbook where you picked it from
I dont think this dude is getting it
i want an explanation
Lol
😭 I heard of that for the first time
It is true however
So unintuitive that noone is knowing what you're talking about
@lime bone wait
Yeah me too
I hate it when my teacher acts like it is a common knowledge
fk
wait twin
sure
yes sir
Also, SD comes up with random variables, why are you talking about them with arithmetic sequences?
Now I understand
No its ok, the distribution is in AP
Ahhhhnnnn
those datas are arithmetic sequences
It is not that fking intuitive
Two distributions
I hate it
u guys better give me an intuitive explanation
so to claim that it is intuitive
I can do the computation on my head
and find it is ture
true
but fk
it is not intuitive
dyk that the variance of an ap is given by $\sigma=d\cdot {\frac{n^{2}-1}}{12}}^{0.5}$
because you have to do some computation
to get that to be true
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
I do not want to see any number
an intuitive explanation
is that exists
*does
.close
Closed by @lime bone
Use .reopen if this was a mistake.
Licht
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
.reopen
are you fucking dumb twin
Let me write the number
why tf are you crashing out
I have to stay productive
I have to move on to the next question
I can dwell on one too long
I only want the perfect score
Then dont fucking post it in a math channel if you have that much less time and dont have the interst to make it intuitive to you
Be quiet
and listen
I have faiths in you guys
Yeah so listen
dont crash out
The variance of an ap with n terms is given by this
dyk that?
@lime bone stay with me
.close
but there's no intuitive explanation
...
Crazy
Indeed
What is this weird typing 
god this guy is just
Im crying

what industrialised education has done to us
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.
are there any realistical ways to prove this? i've tried doing it through trigonometry, but it still didn't make any sense to me
try this, f(x)=sgnx and g(x)=-sgnx. Now clearly f(x)g(x)=-1 and so its limit exists at x=0
whereas they individually do not at x=0
thank you. this helped
.close
Closed by @zenith osprey
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.
my question is how does showing that d(n+1) > an or d(n+1) < an correlate to showing a_(n+1) > a_n or a_(n+1) < a_n
Is that imo?
yeah
i mean the problem is shortlisted meaning it doesnt make into the actual imo
@lament flicker Has your question been resolved?
Can i have the pdf
?
Or where can i find it
you can search the question online
they have plenty of it
if you are wondering the book im reading it is modern olympiad number theory
Thanks
@lament flicker Has your question been resolved?
Closed by @lament flicker
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.
heeeeeeeeeeeelp
So it is only given that Xn+1 = Xn + sqrt(Xn) - 1
without a base value?
Yeah thats weird we should atleast get the value of Xo
@modern crater 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 in proving that the integral of 1/(x^2+ax) is equal to 1/a ln(x/x+a) +c
the images are taking forever to load
I can see now so
unfortunately you can't decompose 1/(x^2 + ax) into partial fractions like that
huh
$$
\int \frac{dx}{x^2 + ax}
$$
$$
\frac{1}{x^2 + ax} = \frac{1}{x(x+a)}
$$
$$
\frac{1}{x(x+a)} = \frac{A}{x} + \frac{B}{x+a}
$$
$$
1 = A(x+a) + Bx
$$
$$
\text{For } x=0 \implies 1 = Aa \implies A = \frac{1}{a}
$$
$$
\text{For } x=-a \implies 1 = -Ba \implies B = -\frac{1}{a}
$$
$$
\int \frac{dx}{x^2 + ax} = \int \left( \frac{1/a}{x} - \frac{1/a}{x+a} \right) dx
$$
$$
= \frac{1}{a} \int \left( \frac{1}{x} - \frac{1}{x+a} \right) dx
$$
$$
= \frac{1}{a} (\ln|x| - \ln|x+a|) + C
$$
$$
= \frac{1}{a} \ln \left| \frac{x}{x+a} \right| + C
$$
Ren🍓
!nosols
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
i stand corrected
It took me like hours of thinking how to solve but I could not come up with a correct way so I took it here
I did not know it was this obvious but this helped me, thank you so much for the time
your approach was on the right track tho
just a bit of try and you would have solved it
@lethal cloak 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.
anyone could make me understand ts?
@lucid furnace Has your question been resolved?
maybe you should try #algebraic-geometry
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.
Question 2.1 and 2.2 are giving me trouble
So far for 2.1 I've found M to be
(x; -2x-4)
A i don't know how to find Y in terms of x
and 2.2 is undoable if i don't know that
You realise that we are talking of a family of circles here right?
Uhm no
i thought it was just 1 circle
is the circle tangent to the y-axis?
That's what i was thinking
Yea, we are talking about all such circles which touch the y axis and pass through (-1,-1)
But it doesnt make sense
Oh
And you basically have to trace this family
hmmm okay
As in, find an equation which all centres of the circles in this family will satisfy
That sounds complex
Similarly for the points on which these circles will touch the Y axis
It's not
So if i find distance BM and AM and equate them will it give me the correcr answers?
Ok but at the end they have given an additional piece of information
That was my initial thought and it gave me 2 x values, which is probably what you mean by a family of circles?
That M lies on the line 2x+y=-4
Ahhhh
So among this family of circles , we are talking of one member
The member who's centre lies on 2x+y+4=0
Ohh so i have to find out which X i found satisfies the straight line equation
Do you know the general equation of a circle?
Yes
So this equation represents all circles possible in 2d plane
Now we have to slowly isolate this family, and subsequently this member
I found (x+1)²+(y+2)²=1 and another one
So we substitute the information we have into the equation
The general equation is
(x-a)²+(y-b)²=R²
Yes
For a circle with centre (a,b) and radius R
Mhm
So we now have a family passing thru (-1,-1)
Mhm
What will the equation become then?
The equation of family of circles passing thru (-1,-1)
.
Okay lemme redo
.
Here the Radius is not known
(x+1)²+(y+1)²=r2
(-1,-1) isn't the centre
Oh
Ohhhhhhhhhh
the distance from the center to B
is what you want
Basically
Wait
f im confused
Okay
Yes
How does that help
We got one piece of info
Hmm okay
Now we can substitute the other piece of info
That it's tangent to Y acis
Axis
How do you think we'll do that
Okay we can use maybe A?
ermmm
Maybe im rushing lemme think
We can distance AM is equal to the radius?
Lemme calculate
Hmmmmm
When a circle is tangent to Y axis, it's centre's x coordinate will be?
Okau
And tangent to Y axis
i see it
So it must be on the left side of Y axis right
So in the general eq
.
What can you say about R and a
Do u get why
Nice
in line with it
a=R
(a+1)²+(b+1)²=R²
Yes
Simplify the second equation using first equation
Last thing we need is to isolate the circle from this family
For that we use the last piece of info
.
Yes
That basically gives us
2a+b =-4
Ohhh you're making x and y into a and b
Yea, here x is the x coordinate of the centre
and the other x and y are the same
That makes more sense, where I'm from they don't do that so i was kinda mixed for a second
Lemme sub it into a and b here real quick
So we have
a=R
(a+1)²+(b+1)²=R²
2a+b+4=0
Okay lemme simplify so i can send it in one msg
I got
x=-1 and x=-5/2
now are both of them correct or do i use the answers in the strsight line to verify
Mhm
Oh that a must be equal to r
Yes i did that
and got 4x²+14x+10=0
So after that
i can resub in my a to see if it gives me the same as r?
We get two values of x right
So correspondingly we get two values of y
Which make two circles
I see
Ok
If they don't, then discard that circle
I think you got the basic idea now
Just verify
There may be some algebra required here and there
I gtg rn sorry💔
Someone will help u out
are both circles x=r?
Hope u got some idea tho
I did thanks
Uh, the x coordinate of the centre is -R where R is radius yes
Closed by @steady glacier
Use .reopen if this was a mistake.
.close
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 havent been able to solve this question if somebody could help please
It's about the different number base systems
Please don't occupy multiple help channels.
Close the previous channel and its ok
One at a time
Closed by @spring warren
Use .reopen if this was a mistake.
I wanna help if you'd tell me what's written cuz I cant understand
basically a number is expressed in the 11 base system
and its 3 digits
when the same number is expressed in base 4, those 3 digits are reversed
like if the number was abc in base 11, it is now cba in base 4
alrightt
✅
sorry I cant
A number, when written in base 11, has 8 digits. When written in base 4, it's digits are reversed. Find the number in base 10.
Wait
3 digits not 8
I read it wrong
That's the question
yes
Idk how to solve it though
aw man : (
well we know that $121a+11b+c=16c+4b+a$
Frances
wait hold on
ah yes i didnt know what to do after this
@spring warren Has your question been resolved?
now you know that a b and c must be digits in a certain range
that narrows things down a lot
is this even possible what
okayy
cud u make the cases then
like they can lie in any range from 0 to 3
well apparently yes 😭
yeah but you can make some inferences about the range
like for instance if a is 1 then it's not possible to create a 3 digit number in base 4 thats large enough
so a must be 0, which means the base 11 number isn't 3 digits but okay whatever
like that you can put a range on what b and c can be
Closed by @spring warren
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 determining Growth Rate for Population Growth Math
Okay, so if we take a growth rate of 1.0012 as a given set rate for humans in a medieval/ancient society, that is our baseline. Humans need two people in order to reproduce, society is usually made up of around 50-50 male and female, they gestate for nine months, primarily only have one offspring at a time, females are primarily reproductively active between 14 and 35 only, and they have an average life expectancy of 25-35 (due to the outlier data of high infant mortality dragging down the metric).
All that is the baseline, now how might I try to address the variables in this equation as we have it above for species that:
only need one to reproduce
gestate for longer or shorter amounts of time
live for shorter or longer amounts of time
have more offspring per reproductive cycle
have less females than a 50-50 split
Essentially I need help finding or creating a formula to find growth rate that does not include final population. One that includes:
of individuals who can reproduce
gestation time, aka possible births per individual per year
offspring per birth
infant mortality
likelihood to reproduce in a given year
I need help making a an obtuse and slightly complicated algebraic equation. I suck at mathmatics, so all help greatly appreicated
Define the states each member of society can be in. Then define how states transition (i.e. non-pregnant woman becoming a pregnant woman). Then draw a graph of this model. Then you can use linear algebra to construct an equation describing how this system evolves through time, given an initial condition vector. (i.e. each node in the graph is represented by a value in a vector, the edges of the graph are represented in a matrix).
I'm sure that is incredibly helpful information, but I'm very sorry I dont know what any of that means
here's what I have so far:
reproductive individuals X likelihood to reproduce X possible pregnancies in a year X avg offspring per birth
What I've yet to figure out how to include is:
possibility of death of the reproductive individual
and infant mortality
.
A Parameter-Based Population Growth Model, you defined it, but here is an obtsuse interpretation:
Nomenclature
- $P_F$: Proportion of the population that is female.
- $A_F$: Proportion of females that are of reproductive age.
- $P_A$: Proportion of an asexual population that is of reproductive age.
- $L_B$: Likelihood of a reproductive individual giving birth in a given year.
- $T_G$: Gestation time in years.
- $N_O$: Number of offspring per birth (litter size).
- $T_L$: Average life expectancy at birth in years.
Deterministic Model For our Params
Assumptions:
- Rates are constant averages.
- Environmental factors are not considered.
Formulation:
The intrinsic growth rate, $r$, is the per capita birth rate, $\beta$, minus the per capita death rate, $\delta$.
$$r = \beta - \delta$$The birth rate $\beta$ for sexual reproduction is:$$\beta = P_F \cdot A_F \cdot L_B \cdot \left(\frac{1}{T_G}\right) \cdot N_O$$For asexual reproduction:$$\beta = P_A \cdot L_B \cdot \left(\frac{1}{T_G}\right) \cdot N_O$$The death rate $\delta$ is:$$\delta = \frac{1}{T_L}$$
--
Stochastic Model
Assumptions:
- Births and deaths are independent, random events.
- The time step, $\Delta t$, is small enough that the probability of more than one event is negligible.
Formulation:
The probability of a change in population size $N(t)$ during a small time interval $\Delta t$.
- Probability of a Birth:
$$P_{\text{birth}} = N(t) \cdot \beta \cdot \Delta t$$ - Probability of a Death:
$$P_{\text{death}} = N(t) \cdot \delta \cdot \Delta t$$ - Probability of No Change:
$$P_{\text{no change}} = 1 - P_{\text{birth}} - P_{\text{death}}$$
oops
Sandcrawler
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
bad render
You need to run Monte Carlo with this to gain good insight
and perhaps use confidence intervals to better understand your outputs
What is Monte Carlo?
what are confidence intervals
I'm a History Major I never took anything past math 111
As you can see this is a stochastic model, which means there is an inherent uncertainity baked into this model. When something is uncertain you cannot determine it, you can say 2 = 2 but you can't die roll = 1
it is either 1,2 or ... 6, this equation is like that
to interpret it, essentially you simulate it or run the eqaution a 1000 times. Why 1000? It's a good number and because of various statistical thereom, we know it's good enough
How would you set up a parameter based population goeth model using the parameters you set above?
at the top of that pic
It's not that hard to do for a history major too
hmm as in?
A Parameter-Based Population Growth Model, you defined it, but here is an obtsuse interpretation:
Nomenclature
$P_F$: Proportion of the population that is female.
$A_F$: Proportion of females that are of reproductive age.
$P_A$: Proportion of an asexual population that is of reproductive age.
$L_B$: Likelihood of a reproductive individual giving birth in a given year.
$T_G$: Gestation time in years.
$N_O$: Number of offspring per birth (litter size).
$T_L$: Average life expectancy at birth in years.
DuFresne
this
how would I set this up as an equation where I can input numbers to reach an output?
I'm sorry if I'm difficult to help. Again I can barely do arithmetic let alone complicate algebra
that's a really insightful message you came up with
N_0 = Initial pop
Deltaat is a step size = 1/365 is small enough if you're calcuating rates per year
I'll set M = 1000
FOR run from 1 to M:
Initialize current_population = N_0
Initialize current_time = 0
WHILE current_time < T_max:
at each step we caluclate prob of birht and prob of death where R is a random number between (0,1)
IF R < probofdeath:
current_population = current_population - 1
ELSE IF R < (probofdeath + probofbirth):
current_population = current_population + 1
I just copied what was said above.
will this channel stay open if I dont reply for like an hour? I'm at work and I need to get to some stuff, but I'm definitely coming back. This is the closest I've ever gotten to cracking this nut and getting a good equation to determine pop growth.
store the current pop in current time in a list
sorry i was replying in a caustic manner to the chatgpt copy paste
not replying to you
Don't be put off by his caustc reply
just run the sim first and see what kind of values you are getting and fine tune the values, so it is realistic enough. If you're using it for some clinical work or something research oriented, use better well defined model already published
Not for anyhting published
its for worldbuilding
however Idk how to "run a sim" nor how I'd format the equation in one... sorry
@serene grove 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.
guys help no.15, is there a correct answer??
,rccw
yes there is an answer
yes there is
Factor out 7 first
thats what she did
Yes there
there's also a lot of trap answers 
Difference of square next?
who?
Op
do you know how to rewrite $a^2 - b^2$?
OP is a she 💀
TheVibe
Oh💀
I changed my bad
i forgot abt that..
D is the answer right
It’s the factoring of this
!noans
The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.
Shhh
Oh sorry my first time here
can u explain it to me TT
the formula is $a^2 - b^2 = (a+b)(a-b)$
TheVibe
GUYSSS
I THINK I GOT IT
D. is right cs i literally forgot to factor our the x² and y²
D is right indeed, nice
and if i do foil method the answer will be x² and y²
AIGHT TY, IM KIND OF TIRED LMAO ITS 3:57AM HERE JWHSJAHSJAH
.close
Closed by @near pewter
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.
Brain fart lowkey , needed help in finding AB in terms of AC
