#help-10
1 messages · Page 357 of 1
2^4x?
no
SORRY LOL
3(something) + (something) = ???(something)
what is ???
4
ok
let something= 2^(2x)
what is this now
2^2x + 2^2x?
where are ur coefficients disappearing into though
like there is a 3 there
Oh i thought
But how do I have it inside
what does that mean
How do I have it inside the equation
similar to how I did it here
3*2^(2x) I'm not sure what you are looking for
8^2x
no
Im not sure
Oh
you already got this
3(something) + something = 4(something)
you dint have to do anything else
just
replace something with 2^(2x)
and that's it
no more no less
4(2^2x)
yes!
Yay!
Aaah i see!
I got it:)
Thank you!
.close
Closed by @torn roost
Use .reopen if this was a mistake.
u can further simplify this if u want
2^(2x) = 4^x
so like 4*4^x is Like
Liike this?
yeah that works
you can also make it a 4
2^(2x+2) = 4^(x+1)
all good either way
Oh wow
I dont know how I could find the +1 in the second equation
Other then by knowing the first
u can
,, 2^{2x+2} = 2^{2\8{x+1}} = \8{2^2}^{x+1} = 4^{x+1}
Aah yes!
But that’s what I mean
Unless that is what you mean by further simplifying
Then that is another perspective!
it's usually all factoring but yeah
it's all equivalent
Yeah!
How do I become better at math over the summer lol
that's a big ask haha, anyways just pick up some decent looking precalculus book and go through it on your own and solve as many problems as you could
that's what university people do and it's been working well for me
Okay! Lol im taking calculus next year lets see how it goes
your typical calculus 1 course is much easier if you have good precalculus knowledge
so yeah definitely worth working on that
Yeah lol
Even now im starting to have trouble with the next problem
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.
same principle
Just make ax^-3 - bx
?
well there is an extra step here
so like
,, a^{m-n} = \4{a^m}{a^n}
8
ok i mean don't just summon it from nirvana into the second coefficient somehow
LMAO
Lets see
its [
\4782^x-2^x
]
like you had originally
Yes
ok now same procedure
7/8(something) - (something) = ???(something)
don't let the fraction scare u its the same thing
but anyways what's ???
-1/8?
ye
so what is ur thing now
-(1/8)*2x
Iii thinkk
no
you kinda just
ok i mean you could've typo'd 2^x for 2x so im guessing its that
but yeah -(1/8)2^x
Oh yeah I typoed that lol
but yes thats correct
but we can simplify
remember how we said 2^3 = 8
can you figure out a way to use that such that u have something of the form -(???^???)
1/8 = 2^-3
Yeee
So u just
-2^x-3
? :OO
yeppie
Yeeiiipiieieiie
Now now 😈
Its time to go to bed
lmao Alright
goodnight and good luck
You too! Thank you for all the help!
Goodnight
.close
Closed by @torn 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.
Im a bit confused
This I understand (Orange)
But how did they get
3/2 kT
Because from what I understand is that v^2 is the same as Crms^2
they replaced m(Crms)^2 with 3kT as mentioned at the top of the page
In the context of finding Ek of one particle and finding Ek of multiple particles
Oh
Ohhhh
I seee
Thank you
.close
Closed by @graceful marten
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 ‘xy=1’ not a linear equation?
Do you know wut is linear equation?
The highest power in equation is 1
tell me, what is an equation
Expression = Expression
Just assume that xy=0 here btw
.
Ok, that's not
Why? (Literally my main question)
x and y both have a power of 1, also xy has a power of 1
The highest power is still 1
Linear Equation Definition: A linear equation is an algebraic equation where each term has an exponent of 1 and when this equation is graphed, it always results in a straight line. This is the reason why it is named as a 'linear' equation.
Ok, xy doesn’t give a line
But I want a more algebraic, intuitive reason
Cuz it’s not an equation
Edited
It’s not tho…
It’s in 2 variables, but not a linear equation
How?
For some reason multiplying products means no linear equation
Idk literally why I opened this post
I’ve got 3 sources tho, my book, Gemini, and DaWhirs
Well yea, cuz it’s not linear
It’s curving
Also I want an algebraic reason
The graphical one is not satisfying me
the term xy isn't "linear"
it has degree 2
you'd say that it's a quadratic expression
the degree of a term is the combined degree of each variable
to see the quadratic nature more clearly you can make a substitution x = u + v, y = u - v
If you have xy=1 and solve for y, what do you get?
then the equation turns into u^2 - v^2 = 1
@gritty drum Has your question been resolved?
Closed by @gritty drum
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• 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 following graph is a third degree polynomial
calculate the amount of real roots $f(f(x))=0$ has
FunguDeu
my solution is 8, apparently its wrong and i dont know where i trip
or rather 8 is where im stuck
so i differentiate this and got f'(x)f'(f(x))
f'(x) has 2 roots, f(x) has 3 roots, which maps to a total of 6 roots when plugged in f'(f(x))
so the total amount of roots this has is 8
but from this i cant find the amount of roots f(f(x)) has
why did you differentiate?
find the amount of extrema, to see if variation table works
if there's 8 extrema then there's 9 roots no?
it's a cubic
yeah but well
this can't happen lmao
oh
wait im a dumb
yeah f(x) has 3 roots
so when plugged to become f(f(x)), each root maps to another 3 roots
which total to 9 roots
yeah
degree 9 polynomials usually have 9 roots
maximum 9 roots?
well most of the time there's no multiplicity
again who knows if its decides to be funny and has only 1 or 2 roots
but yeah you got a poiny
(most of the time you work in an algebraically closed field too) 
Closed by @ember frost
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 what the professor is doing in this clip regarding the numerator. Why does it go from all 1’s to x0 - (x0+ delta x). He kinda skips explaining it but I don’t know how he got there
Remember the definition of the derivative
That's $\lim_{h \to 0} \frac{f(x + h) - f(x)}{h}$ and $h$ is the same thing as $\Delta x$
south
So if you substitute in f(x) = 1/x
You get the same as what the prof has
Well, $f(x)$ evaluated at $x = x_0$
south
How would you add $\frac{1}{a} + \frac{1}{b}$
Frosst
After factoring it becomes $\frac{1}{\Delta x}\left(\frac{1}{x+\Delta x}-\frac{1}{x}\right)$
And now just simplify the thing within the brackets
Use \left( and \right) to make the brackets auto size
Ah right I didn't explain the step you wanted
Sulphur
Nice
It reduces to this problem
You should know this by heart at the level of doing calculus
If you’re rusty on your fractions do go back and revise on it
Calculus will assume that you can do all sorts of algebraic tricks with ease
yeah I am rusty. I haven't done true math in a while. I can keep up w most of the basic calculus but some of this algebra slips past me and i need the reminder
Wait I thought you opened this channel
Mb
no i did
Yeah, it’s a bit rough if you aren’t on top of the algebra, nothing wrong with taking a look back at old topics to refresh your memory
I just kinda let solidworks do it for me when i design something
but i see your point. I'm kinda jsut relearning it as I go, but once its there i remember it pretty well
wait a sec I already understood this. The part i didn't understand was how multiplying it together gives you x0-(x0+delta x)
like the factoring out makes sense. Even multiplying the denominators together makes sense, I'm guessing that's where I'm forgetting something about the numerators but still
<@&286206848099549185>
@little coral Has your question been resolved?
@little coral Has your question been resolved?
.close
Closed by @little 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.
Given complex number $z$ such that $|z-1-i|=1$, complex number $w$ such that $|\bar{w}-2-3i|=2$. Calculate the minimum value of $|z-w|$
ngDe
using the information i can construct the locus of z and w, which is
respectively
but i struggle to see what |z-w| would be
The minimal value of that is the distance between the closest points on the loci
Closed by @ember frost
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 i do this one?
You have to find $r_1(s)$ such that $|r_1'(s)|=1$ for all $s$
d
why
Because that is equivalent to the definition of arc length parametrization
ive never heard of that
It is easy to prove
You can try to prove it yourself
y = 5x = <t, 5t>
then what
Transform that
so that the derivative is a unit vector
Or maybe write (s(t), 5s(t))
Where s is a function that depends on t
The derivative is (s'(t), 5s'(t))
And its norm is $\sqrt{1^2+5^2}|s'(t)|$
d
i dont understand
A parametrization is a change of variables
t ---> s
So it can be written as a function
s = s(t)
And you want that $|r'(s)|=1$
d
yes
That is, |r'(s(t))=1|
Since r(t) equals this, you now write r(s(t))
like this
And do what I wrote above
To obtain |r'(s(t))|=sqrt(26) |s'(t)|
This is the derivative
And this is the norm of the derivative
| (s'(t),5s'(t)) | = | (1,5) | times |s'(t)|
Wait
Maybe I did not understand this correctly
What I understand is that r is a curve which depends on s and whose image is the line y=5x
So that r(s) is a vector for each s
Maybe the question is refering to something different
Maybe you could provide some more context
Then why are you trying to do an exercise about arc length parameterizations?
because its on the homework
Then you must have studied it
no
f 𝐫(𝑡)
is any parametrization such that 𝐫′(𝑡)≠0
for all 𝑡
, then
𝐫1(𝑠)=𝐫(𝑔−1(𝑠))
is an arc length parametrization, where 𝑡=𝑔−1(𝑠)
is the inverse of the arc length function 𝑠=𝑔(𝑡).
Recall that the arc length function is
𝑠=𝑔(𝑡)=∫𝑡0‖𝐫′(𝑢)‖𝑑𝑢
i found this
Do you understand this text?
no
Well, then you need to study and understand this before you can do exercises about it
thats what i am actively trying to do
It can be a bit long to explain everything about differentiable curves, and now I can't do that
Perhaps some other helpers could
i need to integrate r'
but i dont have r'
and i also need a t value which i was not given
As I said before, you don't have to
There is a different method
But in this case you can integrate as well
Yes, you do have r'
where
It is the length of the vector
Because r is a vector as well
the length of the vector. What vector
r
ok r = (t, 5t) r' = (1, 5) length = sqrt(1^2 + 5^2) then i integrate that from 0 to t but i dont have t
Then you obtain s as a function of t
If you integrate, you obtain sqrt(26) times t
So s = sqrt(26) t
t = s / sqrt(26)
And then you substitute that here
Closed by @drifting sandal
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 don't understand how I'm supposed to get g(x)
Like am I supposed to translate on the line or
What translation do u see
I mean
It looks like graph got shifted down
Or I’m tripping
@timid silo Has your question been resolved?
@timid silo Has your question been resolved?
Closed by @restive harbor
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 help me with sin cos tan
I don’t have a question I just want to know how you use it
For context I’m having a National test in math on 27th April on sin cos tan and I wanted to learn it early
the usual way theyre introduced is with a right triangle like this
there are a lot of other interesting properties about them but im not sure how much you're expected to know if you dont have a question on hand
Quick quest what is like hypotenuse and the adjacent
the hyp is the longest side of a right triangle
It’s like you want to learn a new language you just want to learn how to talk it
the adjacent is the adjacent side to the angle $\theta$
jack
sure but youd ask questions like 'how do i say...'
i cant know what 'basics' you refer to unless you have a question
'basics' may mean different things for ppl of varying lvls of education
do you have examples from schoolwork
try using the khan academy series then

do you find it hard?
so you're getting tested on things you havent been taught?
uhhh
its been forever since i was your age and i probably had a different schooling system too
you asked about sin cos tan my guy
i'm not an (american?) schoolteacher idk what you're supposed to learn in the sixth grade
you asked for questions involving sin cos tan so thats a pretty basic type
2D figures have area and perimeter to describe the measurements of their interiors and exteriors. With 3D figures, we use volume and surface area for the same ideas. We'll find fractional volumes using cubes with fractional side lengths. For surface area, we'll add the areas of each outside face.
isn't this what you're learning? ^
@forest tapir 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 help me find my error? I've been stuck for so very long
(slight mistake with ± at the last term but it's not the main issue)
I found a complex quadratic in zw, then tried to generate a formula for |zw|², but arrived at a non-integer answer
(I know the answer is an integer but I don't know what it is)
@brittle swan Has your question been resolved?
Closed by @brittle swan
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• 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, could someone check if i am right? i am totally not sure about this
lol Maybe a cheat like ploting the graph and ordering them according to steepness
generally speaking, factorial always wins, any polynomial beats any power of a logarithm, and exponential beats polynomial
Closed by @gleaming karma
Use .reopen if this was a mistake.
@gleaming karma I have some links to some proofs of these facts if needed
yes i would be rl grateful
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.
in a garden there is apple and orange trees. bob picked 300kg from one apple tree andd 800kg from orange tree . from one tree he picked 600kg average what percent of trees are the apple trees
.close
Closed by @hoary idol
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.
.open
the point C(2,6) is translated 2 units right. What are the coordinates of the resulting point, C'?
.close
Closed by @torpid shuttle
Use .reopen if this was a mistake.
.reopen
✅
what is your doubt?
the point C(2,6) is translated 2 units right. What are the coordinates of the resulting point, C'?
i dont know what to do
what did you get when you tried that?
(4,6)
that is correct, assuming "right" means +x
oh
which is the usual convention
@torpid shuttle 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 don't know the equation for 11
think about, what's v'(t) ?
v'(t)=s(t)
s'(t) = v(t)
velocity is the derivative of the position, and the derivative of velocity is what?
a(t)
It is 32?
well what's the most logical way to orient your axes? what's your negative and positive directions?
and gravity is accelerating your projectile in what direction?
down
so a(t) = ?
-32 because it is gravity?
almost, don't forget the constant of integration
v(t) = -32t + C so now we can use the initial condition (the velocity given) to solve for C
you are in calculus \ know integration right? i forgot that sometimes people learn this stuff with just given crutch motion equations before learning calculus
the integral from 0 to 3?
we're just doing an indefinite integral to get the equation
we know v(0) = 90 right?
so v(0) = -32t + C and that allows you to find C
integrate the s function between the times
0 and 2.8125
did you just learn integration?
Yeah I used Math+9 on my TI-84 and got 126.5625
what did you have for your s function
-32t+90
.... that was our v function
when you solved part b) you found the s(t) function right? what'd you get for that?
okay so -32t^2+90t?
when you integrate the -32t you it becomes -16t^2, you forgot to divide by 2
s(t) = -16t^2 + 90t + C but since s(t) = 0 we see that C = 0
so you need to redo the calculation from b now if you used the wrong function
to find the t when it hits the ground
oh it is the s(t)?
right, the s(t) function is our position function right?
in this particular problem we are measuring vertical distance from the ground
so it would stand to reason we can interpret "when it hits the ground" to mean when s(t) = 0
^
there would be no logical reason why v(t) is necessarily 0 when it hits the ground, in fact that wouldn't make sense, why would something not be moving as it's impacting the ground
so learn to think of how to interpret s, v, and t logically
s(t) is like your odometer on a car, v(t) is like your reading of the speedometer at any given moment
t=2.3717082 or 2.372
so you can factor s(t) = t (16t - 90) and set it equal to 0
t (16t - 90) = 0
can immediately see the t = 0 is one of the roots (That's when the projectile first started at t = 0 and was at the ground) and the other root is?
16 t - 90 = 0
90t not 90
oh yeah
youre overusing your calculator, this problem hasnt really had any numbers that need it
0 and 5.625
right
anyway i gotta go but i suggest you review the basics of integration and re-read the chapter or whatever you have on s(t) / v(t) / a(t) type stuff
Closed by @proven cape
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 chose B
but apparentl am wrong
my question is how as lim approaches 0 from the positive side, it goes to infinity
well x=0 is a vertical asymptote
and the definition of a vertical asymptote is that $\lim_{x \to a} f(x)=\pm \infty$, where x=a is the vertical asymptote
y0shi
ty
but am trying to imagine it graphically
i tried to do it graphically, i came up with B
u know how the function f(x) is positive
then it would reach a value higher than 0 as x approaches infinity
and since x > 0, if the lim as x -> 0 from the right
it would equal infinity
alr hope this helps
stop spamming people
@late flare 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.
hey, is there someone that talks french or understands it enough to explain me on a call the pdf ?
@pallid light Has your question been resolved?
@pallid light Has your question been resolved?
@pallid light 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 have no idea what the second half of this question means
Sigma is assumed to be 1? And also if sigma is a variable how in the world am i supposed to be able to plot this as a quantile quantile graph
This next question builds off this one and i dont understand
@haughty creek Has your question been resolved?
<@&286206848099549185>
@haughty creek Has your question been resolved?
@haughty creek Has your question been resolved?
@haughty creek Has your question been resolved?
@haughty creek Has your question been resolved?
The idea here is that you take many samples from a normal distribution with mean 0 and variance 1
Just as how the sample mean is almost never going to be exactly 0; it's going to be close to 0 of course
In fact the sample mean for a normal distribution will follow another normal distribution
So the same thing can be said for the variance: the sample variance won't be equal to the true variance which is 1
If you plot the distribution of the sample variance, you should notice that it will compare really well to a normal distribution with mean sigma^2 and variance 2 sigma^4 / (N - 1)
That's the theoretical result and there are proofs online
So yeah if you have a 95% confidence interval for the sample variance, it's just the mean plus/minus (z-score for 97.5%) * (the standard deviation), which you can get from the variance 2 sigma^4 / (N - 1)
And yes sigma^2 = 1 so sigma^4 will also be 1
So you have 2/(N - 1) and you should be able to notice what happens to the variance of the sample variance as N gets larger and larger
Pls help me solve the 17 no question
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185> pls
I honestly don't know how to do it
Just don't spam lol
bruh its urgent
That looks like a quadratic formula
Lemme think
log?
its not logarithm
According to my scientific calculator
X1 = -1 - √(5)
X2 = -1 + √(5)
how
General equation
are you just solving for x?
yes
I used the general quadratic equation
Correct me if I am wrong.
I substituted a = -1, b = -2, and c = 4
According to the R.H.S of the equation
but there should be a zero in LHS to be a perfect quadratic eq
and the answer is not -1?
I see what I did wrong
someone pls help me
Wtf? You're hijacking my question?
Ohh I see
Yes pls move
Also dude why did you ask the same question twice
So since sample variance is chi_{n-1}^2 var/(n-1) that just converges to normal with mean var sigma^2 and var 2sigma^4/N-1
Yeah
That's my point exactly
It's not trivial ofc
so i should just plot chisquare/N-1 vs normal with mean 1 and variance 2/(N-1)
Nice
The question was just so unclear
Something like that
You shouldn't need chi-square explicitly: just get R or whatever software you're using to randomly choose 10, 50, or 100 points
It's about discovering what happens to the sample variance instead of being too rigorous about it
Oh this makes sense
Yeah
Okay
Pretty cool
Well too bad i understood it like 1:50 after the p-set was due
but at least i get it now
.close
Closed by @haughty creek
Use .reopen if this was a mistake.
.reopen
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 yk the derivative of y=2cos3x
jan Niku
-sinx
right
why the chain rule tho?
how about $2\cos x$
jan Niku
so in general if the constant is just chilling out front, it doesnt matter, its just along for the ride
$\dv x \qty( 2 f(x) ) = 2 \dv x \qty( f(x) )$
jan Niku
yup
ohh ok
so almost done
lololol
yay
jan Niku
OH
maybe we can drop a lot of the parens and arguments and stuff and write it more simply like
IS it bc theres no x on the cos so its not product rule
$\qty(f(g))' = f'(g) \cdot g'$
jan Niku
the problem is theres another function of x
on the inside
oh
which sometimes isnt a problem like
if you just have cos(x)
then the derivative of x is just 1
and you dont really notice
but here the function on the inside is 3x
since that makes the argument vary more rapidly than if it were just x
you should expect that will impact the derivative some how
and this is how
can you identify f and g here?
i mean, whats the outside function, whats the inside function
jan Niku
ohh ok
so when converting cos3x to
f(x) = cosx
g(x) = 3x
so
derivative of cosx
is -sinx
and then you plug 3x in
i would start here
you identified the functions perfectly
now remember that $\qty( f(g) )' = f'(g) \cdot g'$
jan Niku
yes
and plug in the necessary information
this is also a chain rule?
yes, can you tell why?
because the inside brackets is a function of sin
its because you have another function inside your function
oh ok
when the argument to a function is another function, you expect that to impact how the function changes and what it looks like
chain rule tells you how to account for that
how do you mean?
is that chain rule also?
hmm well you'd have to identify if there is a function inside of another function
maybe I can be clear: a function thats not just x
obviously we know what the derivative of sin(x) looks like
yes yes
so, are there extra functions floating around
yea, nothing left to do except to combine it all
in?
Closed by @mint 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.
I'm so confused on the first and the last
For the 3rd one, they all differ by 5
But I know that rule cannot apply to n =1
And same for the top one, I was thinking of n^2, but that cant apply to n=3
when youre constructing something like this
you can take the common difference it 5
so 5n, then to get to the first term its -1, so 5n-1
or 4+5(n-1) as the generic form of an arithmetic term youd normally see
Okay this makes sense
the back one they increase in distance
first one*
for the first one its a geometric sequence
you multiply by 1/2 each term
1/2, 1/2^2, 1/2^3, 1/2^4,....
any idea when looking at it like that
nice
@fading cedar Has your question been resolved?
Closed by @fading cedar
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 walk me through this step by step i'm totally lost
i know the steps ur supposed to do in this type of question but im just stuck on what to do
that's a little contradictory
like idk how to apply it to this specific one
describe what steps you think would be required here
so i multiply left by the right denominator
and right by left denominator
and then i expand everything
well you wouldn't need to multiply the whole denominator
factorisation helps in identifying common factors
ye
which could lead to potentially using a lesser common multiple
which makes work less tedious
yeh
well technically (x-5)/(x-5) and (x+4)/(x+4) respectively
multiply to both numerator and denominator
my teacher prefers expanding and simplifying everything
i can factor out x from the top i think thats about it
,rotate
4x^2 - 3x^2 isn't 7x^2
,w expand (x+4)(x+2)(x-5)
is denom wrong
you also seem to have messed up the expansion of the denominator
where's the work of your expansion
i used chatgpt cuz i wanted to give u a quick response
i should be good from here its lined up with the answer posted
yea i got bad experiencse w it
if you want a math calculator, use wolfram
ty i think im good from here
Closed by @vagrant brook
Use .reopen if this was a mistake.
,w expand (x+4)(x+2)(x-5)
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.
@open spoke Has your question been resolved?
@open spoke 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 proving a set is an open set using the definition of an open set?
I can probably help. What's the set?
Let set A = {(x, y) in real | 4x^2 + y^2 < 8x} is the set
okay let me think for a second
okay I think the best way to do this is to show that the complement is closed. let $(x_n, y_n)$ be a sequence in $A^c$ and suppose that $(x_n, y_n)$ converges to $(x, y)$. then construct a new sequence $z_n = 4x_n^2 + y_n^2 - 8x_n$ then $z_n$ is at least 0 for all $n$ so $\lim_{n \to \infty} z_n \geq 0$ which you can use to show that $(x, y) \in A^c$
@nocturne osprey
Awesam
The worst part is that we are only allowed to use the...what is it with open balls and that being subset of A
I like this answer tho
really? because the complement being closed is the topological definition technically it's the more "correct" one (even though they're equivalent in a metric space)
prof just wants us to suffer I guess
@nocturne osprey Has your question been resolved?
Closed by @nocturne 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.
yeah idk what to do if you have to do it by balls. I'd suggest maybe trying to manipulate the ellipse into the right form and choose an r based on that. perhaps something to do with polar form?
.close
Closed by @gritty vessel
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 with a stochastic integral problem?
This is what I have so far, I think that Bt is a martingale, but I am not sure how to show that e^B_t is also a martingale (if that is the right approach to show this expectation is 1)
try one of the advanced channels
#advanced-probability should be the right channel
thanks
where did numbers go; hell why do i understand none of this after too many years of calc
"Measure theoretic probability, statistical inference, stochastic processes, sampling, time series, prediction, game theory, causal inference, stochastic differential equations"
Stochastic processes, there you go
Cause it's calculus of random processes
You've probably never seen it before
.close
Closed by @tacit urchin
Use .reopen if this was a mistake.
and this is why im not a math major
Yeah this would typically be at a graduate level / upper undergraduate level
Difficulty is relative but yes
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.
suppose z = x + iy
suppose f(z) = u(x,y) + iv(x,y)
suppose u and v are functions of x and y of respective order at most 1
am i right to say that f(z) in terms of z, is at most order 1?
and if so, idk how to prove it
like there is no f(z) = p(a(z), b(z^2), c(z^3)...) such that f(z), when in terms of x, y which are respectively at most order 1, is at most order 1 in terms of z
@proven spindle Has your question been resolved?
@proven spindle 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.
Given x,y are real numbers that satisfy x^2 + 5y^2 - 5xy + 2y + 3 = 0. Find the minimum value of P = xy + 2021
!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
i have begun but got stuck midway
Okay then, let's see your working
i tried to i used the above equation to get xy and substitute it into p
which gives (x^2)/5 + y^2 + (2y)/5 + 3/5 + 2021
i was told that i need to complete the square or smth like that
what is that?
They said circle
how do i proceed from here?
that is if its even in the right direction
Yeah it's this reasoning
Basically if you know the minimum value of 5xy, you know the minimum value of xy and hence P
Complete the square
Of $x^2 + 5y^2 + 2y + 3$, then the minimum value of this is the min of $5xy$
south
how do i complete the square????
i have never heard of that
Ok nice
Ah, very nearly
5((y- 1/5 )^2 - 1/25 + 3/5)
You're adding (-1/5)^2 = 1/25 so you need to subtract -1/25 to keep the expression the same
So yeah we have $x^2 + 5(y - 1/5)^2 + \frac{14}{5}$
south
What's the minimum value of this?
Exactly
So the min value of 5xy is 14/5
min value of xy is 14/25
Yeah and just add 2021 to both sides
so min of p is 2023.8?
It's cause you can make x = 0 and y = 1/5 at the same time, to make the rest 0 + 0 = 0
Cause at the very beginning we rearranged for 5xy
Yeah I did it this way
I just find it easier to worry about the last few steps later
ok tks mate for helping out
act can u also help me out in 1 more problem?
a^2 + b^2 = 4
find the minimum value of
Ah, so -(a^4 + b^4)
i got it to ab(a+b)^2 -12
I don't think this is very useful unfortunately
