#help-43
1 messages · Page 9 of 1
schools only teach you to use the first two decimal digits: 1 and 4 to calucate stuff related to circles and the first 2 decimal digits of 22/7 is the same as Pi
I take half of that because the area of one half of a petal is 1/4th of the circle - a half of 1/4 of the square
that triangle
ah i see mb
The area for a triangle is 1/2 times base times height.
Yeah
yeah i didn't realize they were doing it by the triangles mb
That makes sense because you get a half of the petal
and since there are 4 petals you multiply it by 8
yeah
this is what they are intending you to think off
So if we were to take the area of the petal, and one of the 2 unshaded areas of the quadrant, we would get 1/4 the area of a circle
correct
Moreover, if we found the area of the square, we could subtract it with the unshaded areas to get the shaded area
And times it by 4 to find the area of ALL petals
So Area_Sq - Area_US = Area_S
Using this, we can prove that Area_S + 2Area_USHalf = Area_Quad
Or Area_US Half = Area_Quad - (Area_C)/4
yeah but how do i know what's the are of the unshaded parts?
Therefore, find the area of the entire quadrant, then find 1/4 of the area of the imaginary circle
…using this statement
@gaunt wave What is the area of a square equal to?
Which area are you trying to find?
the area of 4 petals
The shaded here?
the inside of the petals
Okay.
Then how will this work?
@eternal pulsar Start here
That’s for the entire square, divided into 4 quadrants.
196/4 =49
@gaunt wave Next, how do you find the area of a circle (Hint: Give me the formula and we’ll work it from there)
144
That’s radius squared 👍
not really
Oops
that's the area of the entire circle
doesen't matter
Why do you say that?
they ask you to use 22/7 so i just reduce 7/7 to 1
that's their implication
they want you to do that in this test
Hold up…
the are of the circle is 22/7 multiplied by 49
Correct
That’s the area of the circle
But to find the unshaded area, we need to use 1/4 of that value
but how to we derive that conclusion?
By using this
Wait
I updated the equation
i don't quite get how do we get the unshaded half by removing 1/4 circle from the entire square
@gaunt wave Go back to here
1/4 * Area_Circle = Area_Shaded + 1/2 * Area_Unshaded
that statement is true
OH
i think i am getting what you mean
Ok
So, Area_USPart = Area_Quad + (Area_Circle)/4
Let Area_USPart = X
X = 49 - 154/4
Once you find X, then 49 - 2x = The area of the shaded part per quadrant
HELL YEAH
THAT MATCHES MY ANSWER
I'VE DONE THE CALCULATIONS
I get 112 either way
i did the system of equations
Unshaded + Shaded = 1/4 circle= 38,5
That works
2 Unshaded + Shaded = 49
Unshaded = 10,5
Shaded equals 28
There are 4 petals
112
YES!!!
Thanks man
that's what i was trying to do. i just wanted to check if i was correct or not
.close
Closed by @gaunt wave
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.
cuz abs(g) isn't upper bounded
I like maths but WHERE ARE THE NUMBERS
there won't be 🙂
I'm still in grade 9 doing grade 10 add maths🙏
guys please #discussion
they showed $|g(z)|=e^{-y}\app[y][-\infty]\infty$
ロケットジャンプ
e^iz so it will be e^ix,e^-y
yep
Yes
But when S is domain like -π<=x<=e^π
Can it be not bounded?
x is restricted not y
y in R
np
Closed by @deft tangle
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
When differentiating (taking a derivative) and in the question there is a variable called a/b/h/whatever and it is a constant do I treat it like a constant when taking the derivative
if it is a constant then you treat it as a constant yes 
show us the original question just to be sure though
Even if it's called X or Y
!xy
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.
let's just make sure there's no funny business there
I don't have a question a want to solve
Just couldn't find the answer on google
ok then we cannot possibly answer
you need to actually look at the equation and its variables in context and what is asked of you
a constant is a constant no matter what it's called. so you have to use your judgement on whether a given letter represents a constant in the context of a given problem
if you're taking the derivative of a function anything inside that function that does not depend on the variable in respect of which you're taking the derivative is a constant
so unless they say something like a = sin(x) then you should just treat it as a constant
yep
Why not writing aX³ though? 😅
Habit
That's all of the question
Thanks for all ur help
.close
Closed by @cedar stump
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 we find OQ:QM? A friend sent me this
@runic nimbus Has your question been resolved?
@runic nimbus Has your question been resolved?
Imagine lots of lines from O to AB, and what the ratio the line AP splits into
Can you see how everything moves proportionally
If M = B, then OQ:QM = OP:PB = 2:1. And if M = A, then OQ:QM = 1:0. So, when M is between A and B, the ratio OQ:QM is proportionally between OP:PB = 2:1 and 1:0
@runic nimbus 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 this expression, why does it simplify to this:
and not (-cosn+ xn) / (sinxn +1)
well you could just multiply the negative sign to the denominator see it yourself
but the numerator and denominator must be multiplied by -1
no thats not how it works, your saying -(-2/3)=(2/-3), see where your wrong?
yeah
so a negative sign should only be multiplied to either the numerator or the denominator
Closed by @mighty 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.
note that:
[L=\lim_{x\to -\infty}\frac{\frac{-4e^x}{x}+\frac{2}{x}}{\frac{3e^x}{x}+1}]
PajamaMamaLlama
why we multiplying by 1/x
i thought it should be multiplied by 1/e^x
@keen granite
@mortal elbow Has your question been resolved?
because then ur dividing by 0 if u plug -infinity in
if we did we'd have:
[L=\lim_{x\to -\infty}\frac{-4+\frac{2}{e^x}}{3+\frac{x}{e^x}}]
Note that as (x\to -\infty) we have (\frac{2}{e^x}\to\infty) and (\frac{x}{e^x}\to-\infty) which in total gives us:
[L=\frac{-4+\infty}{3-\infty}]
or that too lol
PajamaMamaLlama
ok ty
do u know what the definition of continuity is
theres a more formal definition
f is continuous at a if $f(a) = \lim_{x \to a} f(x)$
shiru
okay
try using this to find the answer
since f is defined separately left and right of 0
to find the limit as x tends to 0, u need to find the left and right limits separately
if they are the same then you have a limit
then see if that limit is the same as just regular old f(0)
u have to use that to find the right hand limit
so find the limit of both and if they are equal then the function is continuous at that point?
no
find the limit of both
if they are equal then the general limit of 0 exists
and is equal to that number that is the limit of both the left and right functions
if that limit then equals the actual function value at 0, then it is continuous at 0
this last step is needed cuz imagine this function
the left and right limit is at the empty dot but the actual function value is the solid dot way above
this function is therefore discontinuous
for this function, the left limit is at the solid dot but the right limit is at the empty dot
the general limit then doesnt even exist since the left and right limits dont match
this is also discontuinious
Closed due to timeout
Use .reopen if this was a mistake.
.reopen
✅
r u sure its not continuous
for this?
yes
i am sure its not contiunuos
u have to figure that out
on ur own
i am here to teach u how to solve this question not to do it for u
ok so the limt as x approaches zero of 1-2sinx is 1
and the limit as x approaches zero of e^-4x is e^0 so also 1
ok so the limit of the whole function as x approaches 0 is 1 since the left and right limits are both 1
now whats the actual function value at x = 0
we use the 1-2sinx function since that part of the piecewise contains zero
so its also one
Hi
Nvm y’all are good
great
so we now have
left limit = right limit = function value
that means that the function is continuous
by this definition of continuity
ok
did u try the first thing to try when u have a limit problem?
substitute?
if u get stuff like
0/0
infinity/infinity
0^infinity
u have to do extra math to try and resolve these problems
these are called indeterminate forms
0 is not an indeterminate form
its just 0
these are problematic
and they require u to try and resolve them
simply getting 0 or infinity is not problematic
thats just teh answer
anyway i gtg now sorry
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
.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.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Closed by @buoyant knoll
Use .reopen if this was a mistake.
One message removed from a suspended account.
✅
One message removed from a suspended account.
You could find y = f(x) using polar to Cartesian transformation
But I suspect there's a better way I can't think of right now
One message removed from a suspended account.
tan(theta) = y/x and y = rsin(theta), etc
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Closed by @buoyant knoll
Use .reopen if this was a mistake.
dy/dx = dy/dtheta / (dx/dtheta) might be easier
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.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
woas
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Better
Kenzo
One message removed from a suspended account.
One message removed from a suspended account.
I don't understand
on the right track
also just a reminder than it's r^2 when integrating
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
yeah that should give you the intersection point
One message removed from a suspended account.
alternatively (assuming you're allowed to have practice doing it by hand), you could use a graphing calculator
to find the interseciton
One message removed from a suspended account.
though by hand is always good
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
what's wrong about it?
One message removed from a suspended account.
One message removed from a suspended account.
you do
One message removed from a suspended account.
theta is just a weird decimal in this case
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
alr so that's our point of intersection
what's the next step
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
yeah
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
well
ok well we're looking for the common area
so let's try setting up an integral
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
missing the 1/2 and the squares
and almost
not quite
also for reference u don't add πn
you just use the decimal
polar functions have domains
Kenzo
1st integral also has 1/2
One message removed from a suspended account.
yeah
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
ok you're almost there
One message removed from a suspended account.
not quite
dyk how a cos(theta) graph traces
or have abt this
im gonna give you theta values for cos
you tell me what they equal
One message removed from a suspended account.
cos(0)
One message removed from a suspended account.
cos(π/3)
One message removed from a suspended account.
One message removed from a suspended account.
cos(π/2)
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Closed by @buoyant knoll
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 a slight confusion. The problem goes like this: we choose 3 points with uniform probability independently on a circle. What is the probability that after they form a triangle that one of their angles is greater than 90 degrees? I get that we use Thales theorem for this, and I understand part of the solution where we rotate the circle such that we can extend one of the points to form a diameter with both other points lying on one side, but here is where I’m confused. Why is the probability of the angle at one of the points not formed with the diameter 1/4, and why is the same as the probability of the point being formed with the diameter?
the problem is basically out of all triangles inscribed in a circle, what is the probability that the triangle is obtuse
Oh wait I think I get it now
.close
Closed by @slim 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.
Hello! I’ve missed a lot of probability, and I was wondering how I should go about starting this question? Thank youuu!
I was wondering if Bernoulli comes in here at all? For part (a). I’m pretty sure expected value is what I need to use for part b.
Nvm I got it T_T
.close
Closed by @upbeat bramble
Use .reopen if this was a mistake.
how to solve this
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 is the difference between a satisfiable set of wffs and a consistent set of wffs
@mortal scroll 
@whole vigil Has your question been resolved?
@whole vigil Has your question been resolved?
@whole vigil Has your question been resolved?
I assume you're talking about propositional logic?
Or are you talking about first-order logic
this is just propositional logic along with forall right
does the meaning change with it
the basic meaning is the same, the details change
which one are you learning about right now
i asked chatgpt for a proof of compactness theorem for wffs and it was using the completeness theorem
but in the book the theorem was in the propositional logic section
okay
satisfiability = you can assign each variable a value (true or false) such that all the wffs become true
consistent = there is no proof, using the rules of propositional logic, that shows that the wffs imply a contradiction
the soundness and completeness theorems tell you that these two conditions are equivalent for propositional logic
which is perhaps very surprising
by variable you mean the sentence symbols right
any true implication, you can prove
the propositional variable symbols
I'm not sure what you mean by sentence symbols
i think they are the same
like the symbols by applying the functions to which you can construct all wffs?
okaayy
so satisfiability is you start from the propositional symbols and try to make wffs true
and consistency is you start from the wffs, assume them to be true, and hope, with the rules of propositional logic, to not arrive at a contradiction?
yeah
yeah, satisfiability is about semantics and consistency is about proofs (syntax)
can you explain what you mean by semantics here? doesnt it not matter what the propositional symbols mean as long as they are assigned values such that the set is true?
the true/false is the meaning
with consistency you don't ever talk about propositional symbols being true/false
you talk about syntactically manipulating them in various ways instead
ahh
like proofs
understood ty @mortal scroll 
.close
Closed by @whole vigil
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 give me a brief rundown of how fields work? My teacher is not very good and he refuses to help outside of class.
what class are you in right now?
You might be better served just opening an algebra book
Modern Algebra
I take abstract next semester
ah
I can't read very well so textbooks have never been that helpful
the prototypical examples of fields are the rational numbers, real numbers, and complex numbers
Are fields just sets then?
basically sets where you're allowed to add, subtract, multiply, and divide objects
So sets with closure?
(except for division by 0)
yes they are sets with operations with them
"closure" is too unspecific
and the operations have to satisfy certain axioms
the axioms make sure that the operations capture all the essential properties of addition, multiplication, etc.
The commutative associative transitive thing?
yes, although idk what you mean by transitive
so a field is a set F along with two binary opeeations on F, + and *
and there are a number of axioms, like for example a * (b + c) = a*b + a*c for all a,b,c in F
transitive
that one doesn't belong
also it must be said
the field axioms essentially encode the basic rules of arithmetic that you are/should be already familiar with
Yeah these look familiar from analysis
https://en.wikipedia.org/wiki/Field_(mathematics)
I think this would be helpful
In mathematics, a field is a set on which addition, subtraction, multiplication, and division are defined and behave as the corresponding operations on rational and real numbers. A field is thus a fundamental algebraic structure which is widely used in algebra, number theory, and many other areas of mathematics.
The best known fields are the fie...
I think most of our fields are regarding matrices for this class

do you have any questions about the field axioms?
take a look at the full axiom list on wikipedia
Wow Google does not like that search. Started giving me real estate agents
the link is right above in chat
For the most part it seems understandable
I'm trying to study for this quiz on Gilbert groups in 20 minutes. I've been extremely sick for the past 2 weeks so I'm pretty behind
I'm still sick, but I can't be missing quizzes
😔 that sucks
Not when the grading is so wonky
the prof won't let you move the quiz?
He's not a very understanding person. Every move requires documentation, and I don't have any since I do not have health insurance.
I hope you feel better soon
Yeah wtf is a gilbert group 
Did the prof just name something after themselves ?
What am I even looking at?
I still haven't found out. My classmates don't understand it enough to give a description.
Bruh I'm dumb. Gilbert is the author of the textbook. It's just groups.
Oh I see you're not just talking about fields, also about groups and algebras
Additive inverse is they add to 0 and multiplicative means they produce to 1?
yup
that allows you to do subtraction and division
This looks like the big idea for this quiz.
yeah that theorem is pretty important
it seems like your quiz is on groups then, not fields? maybe you should focus on groups
Yeah not fields. Fields is next week apparently
How does this work? Order is like how many times you need to operate on an element to get to 1?
yes, an example is the rotations of an equilateral triangle
if you rotate it three times, you go back to where you started
so the order of a 120-degree rotation within that group is 3
That's a lot of letters.
you should be able to draw those tables just from the descriptions given in that picture
I know a cyclic group is just cutting the unit circle up into p sectors.
That's how it was described, anyways
yeah, g could be a rotation of angle 360/p degrees
and then g^2 is applying g twice
and so on
g^p is then equal to the identity, so the order of g is p
Heard. I should be OK for today then. Fields is our last unit then the final
I just need to figure out what an isomorphism is
an isomorphism is basically a way of saying two groups have the same structure
do you know what a homomorphism is?
Is I the identity matrix and J a rotational matrix here?
yes
Not yet
J is a rotation by 90 degrees
you should think of aI + bJ as representing the same thing as the complex number a + bi
because multiplication by i is also a 90 degree rotation
Oh so it's a hyperbolic number?
complex, not hyperbolic
this is an example of an isomorphism, the 2x2 matrices of this form and the complex numbers behave the same way with respect to multiplication
I don't really understand the purpose of this problem
There isn't really a problem stated at the beginning. He just does math.
Oh well. We starting now
Closed by @mortal scroll
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 make a rational approximation for irrational numbers?
The easiest way is probably using decimals, for example.$\$
$\sqrt{2}=\frac{1414}{1000}\\$
However, I was wondering if there's a better and more accurate way to approximate irrational numbers. I'm curious because I came across the approximation of $R=\frac{25}{3}$ and calculations are a lot easier with fractions like this.
Gilsfen
the infinite fraction of sqrt(2)
I don't think I'm familiar with that.
(\sqrt{2}=1+\frac{1}{2+\frac{1}{2+\cdots}})
PajamaMamaLlama
You could use an infinite seqeunce that converges to \sqrt{2}
if you cut it off at some interation then simplify you'll get a good fractional approximation
But isn't this recursive?
fun fact:
if you repeat this exercise for pi, you can recover the famous 22/7 and 355/113 approximations :)
Maybe the seqeunces $\sqrt{\frac{2n^2}{n^2+1}}$
What a wonderful world !
chose an n of your choice to appxomate $\sqrt{2}$
What a wonderful world !
but yeah, this is the best
But that's specific to just √2. What about the other irrational numbers?
,w pi continued fraction
,w phi continued fraction
Wolfram Alpha doesn't understand your query!
Perhaps try rephrasing your question?
Click here to refine your query online
I think I saw a similar series for pi. However the series followed an unusual pattern, not so clean like √2.
indeed, they're not necessarily easy to remember, I just know sqrt(2) and golden ratio
bcz golden ratio is really nice:
[\phi=1+\frac{1}{1+\frac{1}{1+\cdots}}]
PajamaMamaLlama
notice that if we cut it off at some random point:
[\phi_1 = 1+\frac{1}{1+\frac{1}{1}} = 1+\frac{1}{2} = \frac{3}{2}]
or a different one:
[\phi_2 = 1+\frac{1}{1+\frac{1}{1+\frac{1}{1}}} = 1+\frac{1}{1+\frac{1}{2}} = 1+\frac{1}{\frac{3}{2}} = 1+\frac{2}{3}=\frac{5}{3}]
notice what if we continue we get the ratio of the Fibonacci terms, which is expected
PajamaMamaLlama
Oh, I was thinking about
[
\phi=1+\frac{1}{1+\frac{1}{\phi}}
]
Gilsfen
But this is a lot easier.
Anyway, I guess I'll just memorize this for commonly used irrationals.
Thank you very much!
.close
Closed by @maiden estuary
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.
for part c am i getting 1/2 from estimating based on 1/4 from the graph?
its a point on f
s
so you can just calculate it
wait i thoughts its like x=1/4 and its estiamting it might be 1/2 for y
i can plug and find it right?
i dont think its an estimation
oh ok
1/2 comes from solving f'(x) = 1
this gives some x, which can just be plugged into f(x)
you could check that the solution is actually a solution, if you wanted
i dont think you need to
youd need to back out the equation for the tangent line to f at P
i graphed it but it gives two different y value
then make sure its actually perpendicular to g
wait the point P is on f
it is
so i only need to conisder f right
yea
that the line intersecting P and tangent to f will be perpendicular to g is by design
yea
its the first step in the problem
we dont care about the intersections location, yea
yea finding x that makes f'=1/g' and using that x to find the x,y of point P
i get it
thanks 🙂
.close

Closed by @urban glen
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
I have a few questions
first
angles subtended by the same arc are equal
So MLP is 58 deg
yet because it is a cyclic quad its 180 - 58
Whats up with that
For this one I have some working
It is suggested that you limit yourself to one question per help channel, opening a new one once your original question is answered and your original channel has been closed. This is to make your channel easier to follow for potential helpers and can bring attention to the fact that your question has changed.
angles MNP and MLP subtend not the same arc but arcs which add up to 360°
(ie a full circle)
what does that mean
All I see is that the both come from points M and P
so that must mean they are from the same arc
and they both form an angle at the circumfrence
here let me scribble on the diagram...
MNP subtends the red arc and MLP subtends the green arc
red + green = full circle = 360°
WHT
that make it clearer?
WHAT
I feel like I just broke the fourth wall
How am I supposed to know if they came from opposite arcs
Like the 360 deg things you mentioned
Looks can be deceiving
you have to be able to imagine like
standing at the vertex of one of these angles
looking out of it
and seeing what parts of the circle you have line-of-sight to
it is not a guessing game
Can I ask my second question
i cant wait to be like you
youre a gamer
and youre smart
im getting the second part real fast but
when you have N ≥ 2 unrelated questions, it's better to close your previous channel and open a new one for each next question
so if we're done w this one i will say you should .close and take a new channel
Closed by @thorny ridge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
this is so hard
sequence A (b) is in AP lol..common difference d = 4
you’re brilliant
Don’t do the work for them.
Which parts?
@craggy vigil Has your question been resolved?
its easy but i forgot
what is the common ratio
inv
in b
@craggy vigil 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 am trying to understand what's going on here: https://groups.google.com/g/sci.math/c/ofkao7iugNg?pli=1
The family $\mathcal{ F }$ of open subsets of $[0,1]$ with measure < 1 has cardinality $\mathfrak{ c }$.
So it can be well-ordered in such a way that every member of $\mathcal{F}$ has fewer than $\mathfrak{c}$ predecessors. [why? no clue]
Since the complement of each member of $\mathcal{F}$ has cardinality $\mathfrak{c}$, there is a function $f: \mathcal{F} \to [0,1]$ such that for each $A \in \mathcal{F}$:
$$
f(A) \not\in A
$$
and
$$
A \not\subset { f(B)+ q: B \text{ is a predecessor of } A, q \in \mathbb{Q} }.
$$
Thus, the set ${ f(A) : A \in \mathcal{F} }$ contains at most one representative of each coset. Complete $V$ by putting in representatives of all equivalence classes not already represented. Then the outer measure of this $V$ is 1.
artemetra
question is – how?!
what makes the outer measure of V equal to 1?
i think i am lacking a visualization for what kind of ordering or whatever we are working with
@young raft Has your question been resolved?
@young raft Has your question been resolved?
@young raft Has your question been resolved?
@young raft Has your question been resolved?
I AM SO CLOSE
check DMs
Theoretically what do you need help with.
see if this proof is fine or not
Proof on what
that you can construct a Vitali set of outer measure exactly 1
this should go in #real-complex-analysis
@young raft Has your question been resolved?
what is it called when there is an exponet that is in front of the number
A left superscript is quite uncommon
Do u have the context
@young raft Has your question been resolved?
this?
@karmic ravine alright you asked me to ping you so this is the construction of a vitali set of outer measure 1
and then the argument you provided is almost the same word by word
Apply Carathéodory's criterion: Let $T=[0,1]$.
Then we have LHS:
$$
m^(T\cap V)+m^(T\cap V^c) = m^(V)+m^([0,1]\cap V^c)
$$
Notice that by translation invariance, as well as the fact that $V\cap (V+q) = \emptyset$, we get that for any $q \in \mathbb{Q}$:
$$
(V+q) \text{ mod 1} \subset [0,1] \cap V^c
$$
Thus:
$$
m^(V)+\underbrace{ m^([0,1]\cap V^c) }_{ \geq1 } \geq 1 + 1 = 2
$$
while
$$
m^*(T) = 1
$$
Contradiction.
artemetra
Neat! Does splitting V + q at 1 and moving the right half backward mess with the outer measure? I know translation invariance makes the backward shift ok, but I haven’t thought about problems with splitting
Oh hold on, use Catheodory’s criterion again with T = V + q and the other set = [-oo, 1)?
wtf is this
its called tetration
instead of doing 2 * 2 * 2 as you would with standard exponentiation
you do 2 ^ 2 ^ 2
yea it’s rarely used because it very quickly creates unreasonably large numbers
it doesn't: if you think of the interval [0, 1) as a circle, translating things is the same thing as rotating them
so i don't think splitting it should be a problem
wdym
T is an arbitrary 'testing' set (not necessarily measurable), V is Vitali that we assume and test for measurability
Put V + q as the testing set and [-oo, 1) as the set we want to try for measurability. Then Catheodory’s criterion says splitting V + q at 1 gives two parts whose outer measure adds to 1. Now shift the right part backward to get that (V + q) mod 1 has outer measure 1
$m^(V+q) = m^((V+q)\cap[-\infty,1)) + m^((V+q)\cap[-\infty,1)^c) = m^((V+q)\cap[-\infty,1)) + m^*((V+q)\cap[1,+\infty))$
artemetra
huh that's.. interesting
not sure if this is needed tho
alrighty then
thank you so much!
can finally close this lol
.close
Closed by @young raft
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
i don't understand this how a derivative is equal to a func with two parameters
Chain rule...?
!xy
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.
euler method for 1 order differencial equations
what is I
that seems to just be the differential equation to be solved?
e.g. du/dx = x + u^3 is a differential equation which you could solve with the euler method, using f(x,u) = x + u^3
send the full question dont just take snippets
En mathématiques, la méthode d'Euler, nommée ainsi en l'honneur du mathématicien Leonhard Euler (1707 — 1783), est une procédure numérique pour résoudre par approximation des équations différentielles du premier ordre avec une condition initiale. C'est la plus simple des méthodes de résolution numérique des équations différentiel...
what?
that's where i got this
so basically i just need to solve a diff equation of the first order using euler method
but i don't know why du/dx = f(x, u(x))
wym why?
f is just a function that makes a linear combination
why does it take two parameters
u’(x) = f(x,u(x)) is the relationship u(x) must obey for each x in I for it to be a solution
give me an example of a first order diff equ
u is your candidate solution you plug in the ode
let's say : y' = t^2
y'(t) = t² , f(t, y(t)) = t² + 0*y(t)
thats a candidate f
i still don't get it you can just write F(t) = y^3/3
whats F?
i dont see F in the context you stated
t it's not y my bad wrote it wrong
the ode could also depends on y(t) so for instance y’(t) = t y(t) is also a valid ode f(t,y(t)) = t y(t)
or even simpler y’(t) = y(t)
you plug a function y(t) in this equation and you see if it satisfy the relationship
for y’(t) = y(t) the solution is C e^t
and sure enough if you differentiate y’(t) = C e^t = y(t)
okay okay now i get it thank youu
@devout mountain 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.
!help
To ask for mathematics help on this server, please open your own help channel or help thread. See #❓how-to-get-help for instructions.
this is an equation
alr but i have no clue on what to do
i guess a
like that i can find x
cause i need x for my problem rn
the actual equatio nwas this
5 = a(x-6)^2 + 8
-8 both sides
is a a given number like 3 or is it fixed constant (you don’t know what it is)
then -3= a(x-6)^2
idk what it is
i could tell u the problem though
so a company that fabricates golf sticks implies that their newest product, the stick propulse PLUS, contributes to boost performances of golfers when they encounter an obstacle. In their newest publicity the company affirmed making a experimentation in which a golfer had to hit a ball by surpassing a tree of 5m of height.
According to the calculations of the company, this experimentation showed that with the new propulse plus stick, the golf ball got a height of 5m way quicker than the other sticks
By calculating the height obtained by the ball (in m) in function of the time spent (in seconds), heres some details in which the company used
Attempt 1 First competiteur of golf stick: The ball is hit. The ball got a max height of 8m after 6 seconds
Attempt 2 Second competiteur of golf stick: The ball is hit. The ball is in flight for 12 seconds before getting grounded. It's max height was 10m
Attempt 3 The propulse PLUS stick: The ball is hit. It obtains a height of 6m after 4 seconds. But it hits the ground 14 seconds after being hit.
IS The company that makes the stick propulse PLUS right to say that their product lets the golf ball get a height of 5m more quicker than it's competitors?
this is all the info
give me a sec
alr
if i parsed this correctly i think you have to find the equation of the three parabola one different for each attempts then once you have their equations compare which is the one which gets to y = 5 m the quickest
yes sounds about right
we would have to find x for each equation
which would give us the time
that’s once you have the parameters of each parabola imo
yeah you need the parameters of the parabolla first for each attempts, what attempt is this
attempt 1
give me a sec i’ll try it out on my own then i’ll comeback
alr
you are on the right track
but idk why you put the 5 on the left here
since its the
.
ill explain
the 5m represents y
seconds are x
unless u wanna put it in a
but idk how will that work
i would need to understand
I think you are doing 2 step at once and you should not, first we need a so that a(x-6)^2+8 = 0 when x = 0
cause x at 0 seconds means the ball hasn't departed
basically we assume the competitors launch the ball from (0,0) and that the field is flat
yea
but the key to find a is to force the parabola to go through (0,0)
then we will have the parabolla attain y=8 at x=6 and the trajectory will start at (0,0)
in y=a(x-6)^2+8
the parabola is downwards
right?
yup
alr
now we should probably find x when y = 5
or not
you can
ill try t
what is -2/9 x 6
it gives me a decimal number
-1.33333333
what should i do
its -3 = -2/9 (x-6)^2
i did -2/9(x) and -2/9(-6)
= -2/9x -1.33333333
first get to a point where you only have (x-6)^2 on one side and a number on the other
-3 + 2/9 = (x-6)^2
i just got the 2 point where y=5 and it’s not pretty
my math teacher said since we're in advanced maths its ok
is this good tho?
no you need to divide by -2/9 (or multiply both side by -9/2) to get rid of the -2/9 in front
now how could you get rid of the ^2
x^2 has an inverse function
oh you expanded
yeah
i took square roots on this it’s a bit quicker imo
I think you are missing a term when you folded
the middle term
where
(x-6)^2=(x-6)(x-6)=x^2-6x-6x+36
do you know square roots
so igot 13.5 = x^2 -12x +36
yes
to get x on this you would need to use the quadratic formula
but using square roots on this both sides then you get x-6 = sqrt(13.5) and 6-x=sqrt(13.5)
wouldnt that lead to inequations
it gives you x when you have ax^2+bx+c=0
thats to find x
but this is longer than taking square roots each side
lets do square roots
scrap whaty i said
ok so im back to 13.5 = (x-6)^2
now we put square roots
the square root of a is by definition the number b such that b^2= a
so for example sqrt(4) =2 because 2^2 =4
yeah here a b and be where placeholders
they are not related to this
oh
or the problem
I’m trying to explain that taking square roots will get rid of the ^2 around x-6
that’s one of the 2 solutions
alright so when y = 5 for attempt 1 the time it takes to reach 5m is 9.67 seconds
the parabola reaches y=5 for two different x
did u do another attempt?
one way to see it is that when you take square roots on each sides you get two equations
i got only 1 tho
in a simpler setting if i were to tell you to get the solution to the equation x^2=1
ahh
but also (-1)^2=1