#help-27
1 messages · Page 271 of 1
k
a little bit clearer
i need a sec to think
Tough question
it is
can't wait to do the math for it
anyway I've been slowly differentiating the first one while we've been talking
and I'm getting a substantially different value than what I first got
Fun fact: If you let yourself use any shape (not just a straight line), the biggest possible thing you can fit through the hallway is an open problem. Nobody knows the answer
In mathematics, the moving sofa problem or sofa problem is a two-dimensional idealization of real-life furniture-moving problems and asks for the rigid two-dimensional shape of the largest area that can be maneuvered through an L-shaped planar region with legs of unit width. The area thus obtained is referred to as the sofa constant. The exact v...
woh
Not really that surprising, your thinking looked confused. Quite easy to pick up an error somewhere
Hope you do well with the rest of the problems
thanks, I need all the luck I can get
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helloo could i please have an explanation on how to do this problem? it's hyperbolas
what have you tried
set the functions equal to each other
😭
i haven't really tried anything because i don't know where to start. i'm pretty sure i need to rearrange the equation but i don't really know how to do that 😓
sorry, could you please elaborate? i'm really slow at math and i'm especially bad at this topic
we have y=? and y=??, since y is the same value, try setting ?=??
i'm really sorry, i'm already lost
I'll give you a for free
y=1/x, y=3, so 3=1/x
or 3x=1 and x=1/3
is it okay if you explain this please?
just divide by 3, 3/3=1 and 1/3
you can do the same operation on both sides and the equality holds
yeah
do you know how quadratics work?
or I mean x^2
somewhat, but i don't fully understand it
try b like I did here
i don't really know what to do after 4x = 1/x . am i meant to divide both sides by 4x?
multiply by x, 1/x*x=1
bro seriously needs to review how to solve rational equations
I don't judge
neither did I. just an advice
equations involving rationals like 1/x
um.. what is a rational
a fraction?
4x^2 = 1
fractions involving polynomials
rational functions rather than transcendental functions
oh ok
do you know how to squareroot?
something like this might help? idk
oh yeah
but when you take the square root of x^2 make sure it's + or -
what happens next?
you might also find this helpful
we need to find x=? so we need to take the square root on both sides
i don't really understand sorry 😓
4x^2=1 look at the perfect square chart and use the rules for square roots to show that it is the same as 2x=+-1
i'm sorry, i don't get it at all
which part
do you see how 4x^2=2^2x^2?
and 1=1^2?
i don't understand this
but this one i definitely understand
i do not, could you please explain it to me?
i don't know that either
1
-1 too?
x^2=4 x=+-2 right
yes
so x^2=a x=+-a^1/2?
see the pattern?
1^1/2=1
4^1/2=2
thats how you solved x^2=1 and x^2=4
sorry I got busy
i'm starting to get lost here
no worries, prioritise yourself before others always
look at x^2=4. the way you arrived at x=+-2 is by taking 4^1/2
yep, sorry for the late response, was looking back at this message
so you do have a pattern. taking +-a^1/2 yields answer?
so what would i do now?
i'm still lost, really sorry about that. thank you for your time and effort into trying to help me though (same for the previous guy). i'll skip over this question and come back to it and review this conversation to see if doing more hyperbola-related questions will help me further deepen my understanding as well as understand the steps for this question. have a good day/night ^^
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which answer is exact and which is aproximate i forgot 
the one in terms of logs is a formula which gives an exact answer whereas the decimals is approximate (because it really has infinitely many decimals which you have to round off)
sorry can you rephrase the first part?
an exact answer is a formula which doesn't involve any decimal approximations
basically the thing you put into your calculator
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i'm on my last attempt and i dont wanna waste it before im sure of my answer, why does my answer feel like it's wrong here
my final answer is -137/3, just doesnt seem right for the question but i'm not sure
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help i dont get it im wrong
@distant wave Has your question been resolved?
what have you tried
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Just a quick question I have a list of numbers (7,345.78, 604.77, -166.64, -120.69, 631.96, -4,421.43, -4,345.38, 2,299.27, -2,136.86, -293.14, 2,271.25, 698.79 ,-754.43, -1,504.32, 848.66, 2,476.32, -3,120.95, -414.77,68.33, 812.07,-1,605.58,-535.75,-1,330.55,306.01, 329.85) I know the average of these numbers are -106.78 does that mean there average gain or an average loss of 106.78
It seems like there's some context missing (they should have told you that the numbers represent a gain or loss of some kind) but since the average is a negative number, I'd assume that represents a loss
@robust scarab
yah
@robust scarab Has your question been resolved?
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can someone please explain why they are using cross product in this ms
Normal vector to plan
the cross product between two vectors returns a vector perpendicular to both
oh ok got it
so thatd be the normal vector to the plane
ok ok thanks guys
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can someone prove identity 4 and
3 ? i tried to ask chat gpt but it kept messing up w the proof
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
also
try simplifying the rhs..
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yeah but then what after? why can’t we write it identity 3 in the form of L^3 + M^3 = (L+M) (L+M)^2 instead of that?
also about this im literally trying to learn my math teacher just gave us this and told us to memorize it but i just wanna know where its deprived from
Because that isn't true. Test almost any two values of L and M to see it
because
expand and simplyfy the rhs and you will get the lhs. there is nothing to do after.
ren
which is what your identity has
okaayy i will try that
if that were true, L^3 + M^3 = (L+M)^3 which is trivially false
okay so i just expand then simplify for both?
and lhs and rhs should be equal?
alright tyy
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Hello! I am trying to follow along on an example about the sum of an infinite series in my textbook. This one is about a geometric series.
[ \sum_{n=1}^{\infty} \left(\frac{1}{2}\right)^{n-1} = \frac{1}{1-\frac{1}{2}} = 2 ]
Neo
I am having trouble understanding the sum notation
hmm… try to expand it..
what about it are you having trouble with?
do you code?
I think everything, I am not very familiar with sum notation
No, sorry ,not really
We started learning Python but
No I don't code
ah i see it would be easier if you knew for loops but alright
I have only heard of for loops but I don't know what they are really
,, \sum_{n=1}^{\infty} \left(\frac{1}{2}\right)^{n-1} = \left(\frac{1}{2}\right)^{1-1} + \left(\frac{1}{2}\right)^{2-1} + \left(\frac{1}{2}\right)^{3-1} + \cdots
cloud
okay
that makes it a little easier to understand
I tried the first problem in my textbook
is this correct?
[ \sum_{n=1}^{\infty} \left(\frac{1}{n^2 + 1}\right) = \frac{1}{2} + \frac{1}{5} + \frac{1}{10} + \frac{1}{17} + ...]
Neo
I still don't understand how we would arrive at a number
Or would this just be infinity?
We're adding an infinity of small things so they should become infinity
No… its approaching a number
Nope, not exactly
How do I know which number it approaches
That’ll be the concept of GP
What's GP?
Geometric progression..
sometimes for a sum like this it can be much easier to figure out whether it has a value at all than to figure out what that value is
every consecutive term has the same ratio…
Sorry my grandma called
alright..
So here… ill explain you with s diagram why the sum is not infinity
do you get it?
sry i will read it in a minute still talking to grandma
Mkk
@granite bough Has your question been resolved?
okay
im sorry
grandma has been spoken to
i am going to read what you have written
I don't understand the s diagram, I don't know what an s diagram is either
I don't understand what the m represents
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Yeah okay
To solve this, can I use the following formula?:
$S=\frac{a_1}{1-r}$
Neo
what is the question?
my bad
[ \sum_{n=1}^{\infty} \left(\frac{1}{n^2 + 1}\right) = \frac{1}{2} + \frac{1}{5} + \frac{1}{10} + \frac{1}{17} + ...]
what am i doing wrong
$$ \sum_{n=1}^{\infty} \left(\frac{1}{n^2 + 1}\right) = \frac{1}{2} + \frac{1}{5} + \frac{1}{10} + \frac{1}{17} + ...$$
AnshumanNeon
this?
we have to compute this sum?
the right hand side was just for me to understand what was going on - i am not veyr familiar with sum notation
I tried to find answers on google
and was wondering if this formula works
$S=\frac{a_1}{1-r}$
Neo
where S is the "answer" of the sum if it can be computed
a_1 is the first term of the sum
so I assume 1/2 = a_1?
and then r = a_2 / a_1
this looks awfully close to geometric series formula
except what you have is not a geometric series
okay that sucks
i dont know the differences between series yet
the original problem is in my textbook
it says this:
"Determine whether the given series converges or diverges
by using any appropriate test
The p-series can be used for comparison as can geometric series.
Be alert for series whose terms do not approach 0"
I don't know what a p-series is
I don't know what a geometric series is
Actually
a geometric series is you go from 1 to positive infinity?
geometric series is a series where each term is of form 1/(n^2)
oh no!
wrong
my bad
no problem homie
its of form a^x
where a is starting term
x is the common ratio
commonly written as r
i have a really hard time visualising that
nth term = a^(n-1)
to get the next term you multiply the previous term by 2
so one such sequence is 2, 4, 8, 16, 32 ...
3, 9, 27, 81 ...
in my textbook it says ar^(n-1)
1/2, 1/4, 1/8
shit man
yeah that's correct
i'm extremely sorry. its messed up in my head
no problem, this messes up my head already
yeah but its true
i dont understand why they are given names
do they have special properties
do we know that all geometric series converge or diverge
they appear a lot, simplify things and yeah have some special properties
why are they named
it looks like your series does converge
i dont really find the answer interesting, but how you arrive at the answer
there is a ratio test which is very simple
take the ratio of two consecutive terms
if n+1 th term divided by nth term is less than 1
then the series should converge
as n goes to infinity
i feel like part of arriving at the answer involves overcoming the hurdle of choosing the correct test
i dont know how to choose the correct test
and do i need to memorize these tests
for exams?
this is messed up
thank God the exam is in january
i haven't reached that level yet
but i'd say keep a few in mind along with knowing when to use which
like often times more than one test can give you the correct answer
start with the one that's less complicated for you, the one you can apply most of the time and you like it
if that doesn't work, then go to the next
you should also take note of when to apply, cuz some convergence tests have conditions
$$ \sum_{n=1}^{\infty} \left(\frac{1}{n^2 + 1}\right) = \frac{1}{2} + \frac{1}{5} + \frac{1}{10} + \frac{1}{17} + ...$$
Neo
so for this question
the expression inside the parenthesis is a_n?
while the terms listed to the right is a_1 + a_2 + a_3 ...
and so on
what does converge even mean
,w convergence
,w diverge
yes
yes
,w divergence
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lol your username itself is convergence
yes it is that
very cool
convergence you seem like the right person to explain to me what a convergence is
wolfram alpha sasod
said
it is when an infintie series approaches a finite number?
when i looked at this
i thought it would be infinity
so my intuition sucks
how can i tell that it approaches a number
how can i tell that is converges
it is by using tests
okay
what tests, since series look different from one another
yes
my textbook lists a few tests
but i am wondering why there arent more
and frankly some of these tests i do not understand very well because of lack of knowledge
e.g. bounded above and bounded below
i dont know what either means
it is something about a graph
i cant remember
there are many
is there a couple of tests that encompass all infinite series?
also what does diverge mean
sorry for so many questions
,w diverge
im not sure what not having a limit would entale
diverge means that if you compute the whole series, the answer will not be a single number. it will just approach infinity
not having a limit means we approach something undefined?
let me give you an example the set (1.infinity) its bounded below what it means is that the there is a value such that the elements in this set cant be any smaller
that's a way to think
but it doesn't approach something undefined. infinity is perfectly defined if i'm not wrong
yes
yes
yes and no
but in general you can consider like that
the elements cant be any smaller?
i dont understand that
there exists a value so that the elements cant be any smaller
is there any element smaller than 1 in that set?
that's what it means
no element is smaller than 1
@fervent hornet did you write (1, infinity) as an interval?
yes
but what about 1 million
alr
there are smaller elements
are we just saying there is a smallest element
is that what you are saying
im just very dense but i really want to understand what you have said
not really
ye sry i dont understand
there is a value so that the elements cant be smaller
and 1 and infinity are the only elements?
no
when he wrote (1, infinity) it is an interval (which is a set also)
yes
then i am still confused i dont understand what is being said
so if everything is between 1 and infinity. then no value can be smaller than 1
also no value can 1 too, because we said "between"
yeah
hence we do not include 1 as an element
but how is this different then
isnt that what convergence is saying
in the reals there is no "smallest" element there will always be an element smaller than the element
can you try to explain this in a different way?
there is a value such that the elements in this set cant be any smaller
that makes sense
i am just confused and trying to understand what you are saying
its alright these are usually discussed properly in an analysis class
im taking single variable analysis
is what the course is called
so i guess that would count as being an analysis class
maybe not
i know there is real analysis as well
and i am not taking that
it is taught there but its proof based
could you dumb it down
like in a non-math way
we have a interval/set (1, infinity)
i can try
and you said there is a value such that the elements in this set cant be any smaller
i thought that meant you were saying
that a value exists
so that the elements cant be smaller
i guess i dont understand
alright let me just generalize this consider the interval $(a,\infty)$
what or where that value is
convergence
okay ye
so let we let any element in this interval be x
okay
a is x, infinity is x
sorry
they are nto in the interval lmao
i meant anything between
we can also say that $a<x<\infty$
convergence
yeah
there exists a value for x?
such that the elements in the interval can't be smaller?
i still dont understand what value that would be
and isnt the elements in the interval already set in stone
like they arent changing, so why would they ever become smaller
generally whatever value x is greater than is called the lower bound of the interval (as long as a is not infinity)
so for (1, infinity), 1 is the lower bound?
yes
yes
1 is the upper bound?
yes
okay
so when we have a lower bound its called bounded below and when it has an upper bound its called bounded above
do you get it now @granite bough ?
not entirely, when would an interval not have an upper bound or lower bound?
it completely depends on the set for example (-infty,infty) is not bounded above or below
yes as there will always be an x such that x>whatever number you chose
yes
$$ \sum_{n=1}^{\infty} \left(\frac{1}{n^2 + 1}\right) $$
Neo
for the original problem
i was reading through tests in my book after clearing up my confusion about the sum notation
one test said "If a_n is ultimately positive, then the series must either converge (if its partial sums are boundeda bove) or diverge to infinity (if its partial sums are bounded above).
and i am thinking a_n would be positive
for this
a_n is positive here.
and partial sums
is that just 1
and n^2 + 1?
no
LOL
wiat
i know what theya re
it is when you add the things up one by one n times
so S_2 = a_1 + a_2
or something
and
WAIT
is it bounded below
by 1/2?
yes
okay that's great but come to think of it that doesnt help me with this test since it was wondering what th bound above was
i dont know what the bound above would be
thats the whole point of the question i think
i still dont know how to find out whether that specific series converges or diverges
@fervent hornet does the ratio test work here, as a side question
there are several test for that
i am reading through them but none of the jump out at me
how would i check if the partial sums are bounded above?
a_1 + a_2 is 1/2 + 1/5
no its inconclusive from ratio test
Wouldnt a partial sum just be a single number
how can it have an upper or lower bound
in this case you would not know but in some other cases you may know cant think of any example rn tho
and if it means all the partial sums in general
i have no clue how i would check that
my problem right now is
i am reading through my textbook tests
and they say
"if this sum converges"
huh. how? shouldn't
$$\frac{n^2 + 1}{(n+1)^2 + 1} < 1$$
always
?
or
personally i would not use the method that you used
AnshumanNeon
"if this diverges"
but isnt the point of the test
to find out
if it diverges or converges
the tests in my book say that "if it converges"
but i dont know if it converges, that's why i need the test
i am so confused
yes but when we get the limit to be 1 you dont know whether it converges
you can use other tests to find the convergence of thsi series
i found a page talking about "convergence tests for positive series"
i am gonna read it
FUCK
I am not kidding
that refers back to the
"if the partial sums are bounded above"
thing
from earlier
wtf man
what is this
it is a labyrinth
what book are you even using?
Calculus a Complete Course
10th edition
is there a cheat sheet
for the tests
it would help so much
if there was a cheat sheet for all the tests
OKAY WAIT
DONT LEAVE ME YET CONVERGENCE
Is this a p-series?
you can use p series for this
YES
Okay
and then it is OBVIOUS that it converges
using p-series
because all those funny fractions
have a positive denominator
wait
i mean all the denominators
are > 1
WAIT
uhh
yes
yes.
shit, even this shit leads to reimann zeta function
convergence
this is too much for me

i am trying to understand
let me think a little longer
yeah its alright you can just state that it converges usind p series
yes it makes sense
dividing by 1 + n^2
vs dividing by n^2
yeah it would be smaller because of the 1
well i found this:
but i dont understand the and
i will probably just stick to doing this
which is exatcly what this says
my goal is not understanding, just being able to do it on the exam is enough
i dont hate math i just dont have any love for it either
alright 
it is really cool though
i wish i had better intuition for it
1 +1 doesnt even make sense to me
thanks for the help
knowledge collector
no, but seriously thank you for putting up with me
i am very dense
if you are done close the channel,other people aslo need help :)
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you clearly have not seen me in a real analysis class kek
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i realized
the whole point of my original question was for me to calculate the sum
shit
or see what number it approaches
i understand it approaches a number now
because it converges
same thing
kind of
but i dont know how i would actually decide what number it converges to
this is incredibly close to the basel problem
which makes use of the euler-maclaurin method to compute sums
but it might just be overkill
because it goes into integration, differential eqs, bernoulli numbers
and all the shit
i sure hope thats overkill
lol
i'll still try if i can do find the value
i probably won't be able to do it
but let's see
there are many methods to slove it but they involve bit of thinking and by "bit" i mean a lot
im gonna close this again until i have a semblance of an idea of how to start computing non-geometric series
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hello
yeah
did you notice that x = 1/y?
multiply each number with its conjugate in the numerator and denominator
@surreal pivot Has your question been resolved?
still do not understand
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guyss can someone explain the part where i circled pink, i got lost here
im making notes and idk what to write for this part
He added the molar masses of CO2 1 carbon atom and 2 oxygen atoms
OHHH okayy
TYY
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How to understand this?
add the three equations
if those equations hold, any linear combination of the equations must hold.
In this particular case, if the equations hold, the sum of the three equations must hold.
Since x1-x2+x2-x3+x3-x1=0, then b1+b2+b3 needs to be 0, or the equations wont hold
@void knot Has your question been resolved?
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I want to ask what's the second pair here?
The second pair is: the column space (dim = 1) and the left nullspace (dim = 2).
Then what's the two lines😿
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what is the shortcut formula for calculating the variance from grouped data using relative frequencies?
@exotic vessel Has your question been resolved?
Why do you think there's a "shortcut"
I guess you can cancel the n/n
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bc there was a shortcut for calculating the sample variance when using absolute frequencies
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What do I do for finding absolute extrema when the derivative isn't factorable? For example my derivative is (-x^3 + 6x^2 - 18x) and like I was able to factor out a -x to get x=0 for a critical point, but I'm not sure what to do with (x^2 - 6x + 18) since it's not factorable from what I can tell
quadratic formula
even though it's really painful to do
it works
Alright thanks 
I actually just realized I differentiated wrong so that was my issue
But good to know in the future
oh lol
-3x^2+12x-18
yeah I just realized
d/dx of 3x^3 =/= 6x^2 
oh wait
My original function was -(x^4)/4 + 3x^3 - 9x^2
No it's just -x^3 + 9x^2 - 18x
There's a 4 in the denominator of the leading term
Yeah I think I should be good from here
alr
Was just confused what to do when my derivative isn't factorable normally or by grouping
So thanks
yw
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I don't think they'll make you solve by quadratics but idk
I've had to for a problem before in this class so not unreasonable
But only one out of a lot so
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The rent is 225,000 ISK per month. That's 32.5% of my salary. What do I have as a salary?
692,308 ISK
Salary = 225,000 / 0.325
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!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.
?
So I'm practicing for a GED and I went to a site for practice questions i got given
x + 36 = 3x
The site simplified it to
x + 36 = 3x
x - x + 36 = 3x - x
36 = 2x
My questions Is where the hell did the 2x come from?
ok
huh?
u subtacted x from both sides
I thought acting on an X variable with a X variable cancel teacher out and it would end up as 3x
x=18
3x - x=2x
he wants to know why ther eis 2x
Yeah
but x variable still represents a constant
3x is x+x+x
so 3x - x = x+x+x-x
=2x
basic algebra
For you probably because you're at a much higher lvl of math knowledge
But of all the equations I've been doing so far this was never mentioned
So like another example 10x - x
Would that be 90x?
9x
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So my textbook says to use integration by parts by setting u =ln(2x+5) and dv=dx. Why is setting dv=dx allowed? Shouldnt there be two things multiplying each other in order to use integration by parts?
yea it’s 1
1 * ln(2x+5)
that’s how i think about it
i also don’t use the trash integration by parts formula
just do DI or tabular as others call it
yeah i wish i didnt have to, but unfortunately im required to on my exam 😵💫
thank you for the help though, thats a useful way to think about it
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Hey
My teacher told me i didn't have to use substitution
I can't see it
I can't see an easy way
tabular method?
Or guess the antidervitive xD
OHH x² is the derivative of x³
u sure abt that?
Yeah degree wise so i can manipulate the integral a bit by adding -3 instead and putting -1/3 outside
or if you're bored, expand everything
woah
thats one hell of a good method
unless you make a tiny tiny mistake
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How do we know dat angle is in da second quadrant?
Just looking at da unit circle?
I can convert to degrees which is easier, but I wan2 learn to visual radians
so we would like to compare $\frac{5\pi}{7}$ to the 4 quadrant angles $0, \frac{\pi}{2}, \pi, \frac{3\pi}{2}$
cloud
to do this i would recommend you convert all of them to a common denominator
2nd quadrant is 0.5pi to pi
clearly, 5/7 > 0.5 and less than 1
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b
!show
Show your work, and if possible, explain where you are stuck.
i can write the sequence has 1/n - n
i understand from this that the sequence approaches -infinity as n approaches infinity
but im stuck at the proof part
For any M < 0, can find an N large enough so that 1/n - n < M for all n > N?
Say M = -100
i think there si no l for any n in natural numbers for tn in which it holds that l <= Tn
if M - 100, we can take N is 1000 so for any n>N there is no M
l being a lower bound, and tn being the sequence (1-n^2)/n
You should show what you did for a)
for a, i basically contradict the statement that there exists an L in Real numbers, for any n in Natural number s.t. l <= tn
contradicting this leads to for any L in R, there exists an n in N st l > tn
You're missing for all n > N
contradicting this leads to: for any L in R, there exists an N in Natural numbers in which for every n>N , we have l > tn @supple knot
is this better
Yea can you find the N for l=-100
Take N = 500, then for every n>N we have that it is smaller than M
i assume we have to now generalize l instead of taking a specific value
right?
@supple knot
Right that works fine
Yes
but we need not for M = -100 but for any M in Real numbers..?
yes
uh
@blazing crest Has your question been resolved?
@blazing crest Has your question been resolved?
@blazing crest Has your question been resolved?
hi everyone
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@restive river Has your question been resolved?
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can anybody explain to me why we subtract 180 from 210 if 210 is in the south?
because usually if that 210 was in the west it would be west south which doesnt exist so we would subtract 180
to get whats in the south
you're interested in the acute angle deviation from north or south
the south but is it bc it starts at north?
that we minus 180
which you get by subtracting 180 from 210
wait but is that whole revolution not 210
yes
the true bearing, measured clockwise from N would be 210°
because it passes 90 degrees once, 90 degrees twice
which is 180
but not 210
so to find that little angle over there 210-180
yes
ahh are compass bearings never three digits?
no,
as mentioned, they indicate deviation from North or South
towards West or East, depending on which is closer
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I'm a bit confused on what the next step is, I've looked an example question and I'm still kinda confused
The topic is on the top left and the answer next to the green check mark is my working out but it's not fully correct yet
They want you to rationalize the denominator
seems correct
maybee they want to have a common denominator?
Ah yeah they did
It's still not correct yet though But I feel like I've got this now so I'll close this for now
Thanks for the headers
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Any idea is welcomed...I'm cooked

try this it might work
$f_{n+1}(x)=f_n(x) +\frac{x^{n+1}}{(n+1)!}\
\left(f_n(x)\left(f_n(x) +\frac{x^{n+1}}{(n+1)!}\right)\right)=0$
Is this ever zero?
convergence
if a product is null, one of the factors need to be 0.
for n=1 with x = -1.
@void knot Has your question been resolved?
i think this thing is (e^x)^2 when approaching inf
so i dont see how it approaches 0
who is talking about approaching infinity? i see a given n, and f_n(x) times f_(n+1)(x) = 0 is solvable in the reals for some n, not all n i guess.
oh right
then i think it'll always have a root
depends on odd or even n
essentially expansion to what order
and as its the product of f_n and f_(n+1) there is always an odd polynom.
true thats the trick
but that gives only "at least one solution" as answer, but its asked for the number of real roots. could there be more than one?
prove by induction that f_n is positive for even n and increasing for odd n. So the product f_n * f_(n+1) has only one root.
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I think the textbook solution is wrong and should be 3units, I started with double integrals to find my xyz range to get my bounds.
I agree
If you were to compute the volume without integrals, but geometry you end up with 3 as well
appreciate the confirmation, now i just need to get the integral to work
are you struggling to find the bounds?
yes, i watched some videos on it too
Ok I will try to explain it
you basically need two integrals
this would be the easiest if you did dzdydx
now in dxdydz
you consider the yz plane
you integrate the purple surface over the region 0 <= y <= 2 and 1 <= z <= 2
and then you integrate the other surface x=1 over 0 <= y <= 2 and 0 <= z <= 1
I kinda messed up the drawing with the yellow it should hit z=1 ofc
ok, ill try that. ty
like this?
yup 
😁 👍 ty for you time
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Im doing complex numbers. Im last year in highschool and i have a problem in my calculator. I need someone to please help me fix it urgently cause i have an upcoming exam. Idk how to explain it step by step but i can explain what im doing and show u my calculator and my friends one and hope u can please help.
okay, just ask your question
also which calculator model do you have?
Okay so i wanna transform the algebric form into an trigonometric form. I wanna find the R and θ using the calculator. In order to do that, i press shift mode setup and put Rad so i get the angle in rad. I press mode setup and put cmplx. After i write my equation (-1-i) i press equal, then i press shift-> 2 or shift-> [cmplx] and choose the 3rd one r<θ. And there i should get an answer which ill send in a picture, but ill also send my wrong answer.
Calculator model : fx-991ES PLUS CASIO
I should get this
But im getting this
oh turn on exact mode on your calculator
Sorry to say but idk what it is
In this video, I show you and tell you how to change the mode on a Casio scientific calculator. it is really easy to do, and if you are doing some advanced mathematical equations, you will likely have to change the mode on a relatively regular basis. With that being said, it is important to know how to do it quickly and easily so that it doesn't...
Tyy ill be right backk
one sec
press shift then menu
Menu is mode?
yeah
Okay i did
ah shit that gives you the number of decimal places
so not that one
Okay
I get the R right but the θ wrong
Just in this particular rquation of -1-i
Usually it works fine on othee equations
,calc -3/4 * pi
Result:
-2.3561944901923
it's correct
you just want your calculator to display this in exact form
which means a multiple of pi in this case
Like is it fixble?
it should be but I don't know how
to fix this in the meantime, I would recommend you use degrees
so press shift + mode
press the number that corresponds to degrees; I think it's 1
Yeah yeah i can have it in degrees but i dont want to mess up converting degree into rad by my own calculations
Is therw a way to do it on the calculator to like show from deg to rad?
yes press shift + Ans
then press 1 for the degree
that will convert degrees to radians
yes that converts from degrees to radians now
Wait ill try
but your calculator has to be in radians mode
Okay ill try
Ill put -135 press equal
Than i ress shift ans
And press r?
It gave me what i wrote
Sorry if im wasting ur time or something
But im really stressed about it
wait I might have the answer
just press mode
Ty alot btw
