#help-49
1 messages · Page 104 of 1
Hint: ||think about picking a basis||
I suppose I extend the basis
@twilit field Has your question been resolved?
We assume $U$ to be a n-dimensional vector sub-space . We assume $V$ to be $(m+n)$ dimensional. We let $W$ be $r$ dimensional
Let the basis of $U$, be $\beta_1 = {e_1,e_2,\dots , e_n}$.
\
We can then extend the basis of $U$ to that of $V$ by taking $m$ linearly independent vectors in $V$, other than the ones already chosen.
\
\
Let the new basis be $\beta_2= {e_1,e_2,\dots, e_n,f_1,f_2,\dots, f_m}$
\
We now propose a linear transformation that results in an identical output.
\
As established earlier, an entire transformation, can be described by describing the transformation of the basis .
\
Let $v \in U$. Then $T(v) = \sum_{i=1}^{n} \alpha_i T(e_i)$ .
\
We now define $S(v)$ as follows , where $v = \sum_{i=1}^{n} \gamma e_i + \sum_{i=1}^{m} \beta_i f_i$
\
$S(v) = \begin{cases} \sum_{i=1}^{n} \alpha_i T(e_i) & \forall e_i \ 0_{w} & \forall f_i \end{cases}$
A dense set
How does this look?
Are u defining both S and T here?
Youve been given S arbitrarily
And your job is to define T
I don't follow
I'm not too happy with how I defined s(v) tbh
There is some not needed cluttering imo but thats just taste, as long as you think the proof is convincing for anyone reading it
Do you know that any lt is uniquely defined by where it sends basis vectors?
Yes, I proved that a while ago
If so you can make it simpler by using that.
I've used that here
Yes I know
You can simply state it, i.e "extend linearly"
My point is if you don't like how you defined s(v) this is a bit more concise
I'm listening
So you map the basis vecs of ur subspace identically and map the other basis vecs to 0. It's the same map you have but you can state it this way more concisely.
"Extend linearly" is a good way to put it.
This way you don't have to explicitly talk about linear combos and sums like you do now.
It's the same map just stated differently.
Well, I think there is a slight mistake in how I defined S(v)
nvm
it's fine
Thanks!

LADR is so fun!
Re stating this
We suppose $V$ is a finite dimensional vector space, with non-zero dimension.
\
Let $W$ be infinite dimensional, then $\mathcal{L}(V,W)$ is infinite -dimensional.
A dense set
Right so far?
We can then extend the basis of $U$ to that of $V$ by taking $m$ linearly independent vectors in $V$, other than the ones already chosen.
this sentence is bad. it makes it sound like you think just taking any m linearly independent vectors (except for e_1,...,e_n) is enough. thats not how that works.
you could just write "we extended the basis of U to a basis of V"
We wish to prove the contrapositive: If $\mathcal{L}(V,W)$ is finite dimensional then $W$ is finite dimensional.
\
We assume $V$ is n-dimensional, and that $W$ has an arbitrary number of dimensions , say $r$
\
We know that all linear transformations $T : V \to W$ are of the form $\sum_{i=1}^{r} \sum_{i=j}^{n} \alpha_i \beta_j e_j$.
\
It follows then that there are $r$ basis vectors of $\mathcal{L}(V,W)$
\
It follows then that $W$ has a dimension of $r$.
\
As $r$ is finite, it follows that $W$ is a finite dim vector space
Isn't that how it works
no
How does it work then
look back at the proof of that theorem
A dense set
How does this proof look?
not good
you cant even write down that sum if r isnt finite to begin with
the dimension of L(V,W) certainly also isnt r
I am not sure how you are concluding that from the summation you wrote anyway. what are those variables
its very much easier to give a direct proof
My idea is basically trying to exploit the general form a linear transformation from an n to m dim vector space
oh right
So a direct proof it is
Let $W$ be infinite dimensional, then $\mathcal{L}(V,W)$ is infinite -dimensional.
\
As V is finite dimensional, and say of dimension $n$, a basis of it would look like ${f_1,f_2,\dots, f_n}
As $W$ is infinite dimensional , a basis would look like ${e_1,e_2,\dots,}$.
\
A transformation would thus look something like $T(e_i) = \sum_{i=1}^{\infty} \sum_{i=1}^{n} \alpha_{i,j} e_i$
A dense set
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nah, this is messy
and assumes the infinity is countably infinite
I think I'll push problems on infinite dimensions, until I formally study kinds of infinites
this feels really nasty
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✅
Yes?
it suffices to prove this for dim V = 1 and W with countably infinite dimension
since that'll be a subspace

We suppose $V$ is a finite dimensional vector space, with non-zero dimension.
\
Let $W$ be infinite dimensional, then $\mathcal{L}(V,W)$ is infinite -dimensional.
\
Let $V$ have dimension $1$ and $W$ be a vector space of countably infinite dimension.
\
\
Let $e_1$ be a basis of $V$
It then follows that $\mathcal{L} (V,W)$ have elements of the form $T(v) = \eta \sum_{i=1}^{\infty} a_i e_1 ; \eta, a_i \in \R$
A dense set
what do you mean e1 is a basis of V
I'm supposing $V$ is 1D
A dense set
if V is one dim then L(V,W) has same size as W
it's when dim V > 1 that L(V,W) increases in size compared to both
I'll havr to prove that, no?
since V is finite dim (suppose basis e1,...,en), to choose a linear map T of L(V,W) you need to choose T(e1),...,T(en)
and that's it
Blake advised me to create a mapping from a 1 D space
there's no loss in that simplifying assumption i guess
find T(v)
I'm trying to figure out how the LT would look for an arbitrary vector space
use the fact that linear maps are uniquely determined by how they act on bases
you dont need to write down the most general linear map V -> W
you just need to show that you can find infinitely many which are lin indep
you don't need to write down all maps
if W has basis f1, f2
and V has a single basis vector e1
then i can define T(e1) = f1
alternatively i can define T(e1) = f2
so i've just given you two different linear maps V -> W
and two linearly independent ones at that
I was told that a linear mapping had to be expressed as a function of the elements of the first set
unless I'm missing somethng
like (x) \to (2x,3x)
sure
if you want to give a name to the linear form that gives you the coordinate of x onto a certain basis vector
we usually call it $e^*$
rafilou is not not born in 2003
so you want a function {e1} -> {f1, f2}
if $x = ae_1 + be_2$ for example
rafilou is not not born in 2003
and you can boost it up to a linear map on the whole space
$e_2^*(x) = b$
rafilou is not not born in 2003
eh you don't really need to bring duals into this
yes, and since T is linear
this is before axler discusses duals presumably
if he wanted the exact form of the linear map "in function of x"
But yeah didn't you already go through the fundamental theorem that says
T is uniquely determined by the images of a basis
?
you really just need that one theorem
I do know that yes
define functions on the bases and boost it up to a linear map
if you know what the images of a basis are
I can define $T(e_1) =\sum_{i=1}^{\infty} a_i f_i$
A dense set
yes for example, with the a_i almost all zero
though you don't know if W is countably dimensional
so that sum is sketchy
oh wait you wrote it in your assumption ok
again, you really don't have to write down the most general map there is
just write down infinitely many that are linearly independent
Suppose $dim(V)=1$ and $W$'s dimension is countably infinite. We then define $T(v)= \alpha T(e_1) =. \alpha \sum_{i=1}^{\infty} a_i f_i$.
\
a basis of $\mathcal{L}(V,W)$ would be ${f_1,f_2,\dots, }$, which is countably infinite. Thus $\dim(\mathcal{L}(V,W)$ is countably infinite too
f1,f2,... are not vectors of L(V,W)
A dense set
Hmm>
Why not
they are presumably elements of W
they are
f1, f2, ... is a countable linearly independent set in W
so they are not elements of L(V, W)
Okay, so now I have to find elements of $\mathcal{L}(V,W)$ right
A dense set
yes
i gave you an example earlier
\begin{itemize} \ii $\dim V = 1$ with basis $e_1$ \ii $\dim W = 2$ with basis $f_1, f_2$ \end{itemize}
you can define
[ T_1(e_1) = f_1, \quad T_2(e_1) = f_2 ]
I don't see how that helps me
ah
I mean that gives me the same basis I gave earlier
,, T_1, T_2 \in \LL(V, W)
A dense set
you still should convince yourself that theyre linearly independent
i havent provided any proof of that
I mean thease are
wait
oh
okay
yeah
makes sense
thanks
Can I close this now?
sure but make sure you can explain why this is true
its a short calculation but its not trivial
T_1(e_1), T_2(e_1)\dots are LI
e_1 not e_2
but why are the functions LI
we are talking about linear independence in the vector space L(V, W)
the elements are functions
f_1,f_2,\dots are LI, so \alpha f_1,\alpha f_2 \dots are LI
these are the outputs of the functions, not the functions themselves
yes
so that doesnt let you conclude that the functions are LI
you must make an argument here about the functions themselves
Okay, so I have $\sum_{i=1}^{\infty} T(v)=0$
no infinite sums, only finite ones
A dense set
okay
and you are not looking at T(v)
the sum in question would be something like
[ a_1 T_1 + a_2 T_2 + \dots + a_n T_n = 0 ]
where the $0$ on the RHS is the $0$ linear map
$a_iT_i= T_{i,i}$ we then have $\sum_{i=1}^{n} T_{i,i} =0$
A dense set

the argument essentially falls back onto what you've been saying
but theres one step that makes the connection that you should state
@twilit field Has your question been resolved?
okay
so
if $\sum_{i=1}^{n} T_{i,i} =0$ , it follows that the transformation is the zero transformation
A dense set
What do I do now
hiding the a_i probably doesnt make this simpler
all you want to do is plug in e_1
,, a_1 T_1 + a_2 T_2 + \dots + a_n T_n = 0 \
a_1 T_1(e_1) + a_2 T_2(e_1) + \dots + a_n T_n(e_1) = 0(e_1) = 0
$a_1 T_1(e_1) + a_2 T_2(e_1) + \dots + a_n T_n(e_1) =0$. We know that this is LI as the basis of one vector space, map to form a basis of another vector spac
yeah
A dense set
no the justification is wrong
hmm
remember what T_i(e_1) is
defined here
Yes , it's a linearly independent set
what is?
and how does this help us
That's what you akse
yes but what is the conclusion from this
we have this equation right
T_i is linearly indepndent
and you know this because?
f_i is LI
i mean okay
to fully spell it out
,, a_1 T_1 + a_2 T_2 + \dots + a_n T_n = 0 \
a_1 T_1(e_1) + a_2 T_2(e_1) + \dots + a_n T_n(e_1) = 0(e_1) = 0
you have this, which rewrites into
[ a_1 f_1 + a_2 f_2 + \dots + a_n f_n = 0 ]
yes, and this is the same as $a_1f+a_2f_2+ \dots _anf_n=0$
A dense set
yes
Why can we just sub $e_1$ in though
A dense set
because its a function
,, \overbracket {a_1 T_1 + a_2 T_2 + \dots + a_n T_n}^{\text{a linear map, element of $\LL(V, W)$}} = 0 \gets \text{the zero map}
well this is an equality of functions
so
[ (\underbrace {a_1 T_1 + \dots + a_n T_n}_{\text{a function}})(e_1) = \overbrace {0}^{\mathclap{\text{a function}}}(e_1) ]
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3x +1 need help
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.
they're talking about collatz conjecture aren't they
indeed
Could someone send me the solution of problem 1,2, 3, 4 and 5
!occupied
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and btw we don't send solutions, we help you guide yourself to the answer
@shut ingot Has your question been resolved?
@shut ingot Has your question been resolved?
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What is the difference between $f$ and $f(x)$?
crazytime
f refers to a function and f(x) refers to the value of the function at a point x
So f(x) is a number?
can i get help
not necessarily, but it could be
For example, if a is a constant, then $f(a)$ is a number
crazytime
f is a function, f(x) is the function f evaluated at the point x
Why?
because f does not necessarily have to be a function whose inputs and outputs are numbers
define $f: {\text{cat}, \text{dog}} \to {\text{love}, \text{hate}}$ by $f(\text{cat}) = \text{love}$, and $f(\text{dog}) = \text{hate}$
needlessly complicating it for them 
higher!
f is the function, f(cat) is an output
perhaps
a function is just a mapping from one set to another, but most of the time you have functions from numbers to numbers
Yes
so yes, depending on what f is, f(x) is a number
point is that f(x) is the output that f generates when the input is x
while f is the function itself
crazytime
Oh no

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I don't know where to start with this one.
<@&286206848099549185>
@gleaming spear Has your question been resolved?
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how do i find the oblique asymptote of this function
ive done up to here i dont rly know what to do with this
is the oblique asymptote just f(x) = 2x-1
@terse mural
yo
figured it out?
no
so to find asymptotes
You need to explore different cases
There are 3 types of asymptotes you can in general find
Horizontal, vertical, slanted
u just set denominator to = zero and solve x right
Good job
for horizontal
You just take the limit of x to infinity or minus infinity
i havent done limits yet
💀
the way i learned horizontal is if the degrees in the numerator and denominator r the same i gotta take the numerator leading coefficient / denom. leading coefficient
and if the bottom degree is larger its = 0
I mean I just googled
apparently the rule is that if the degree in the nuemrator
is larger than degree in denominator
you have no horizontal asymptotes
yea
Okay, lastly slanted
i learned that if the numerator degree is +1 the denominator degree then theres a slanted asymptote
You just ignore the remainder
is the asymptote just y=2x-1?
This is the answer I got when I used an online calculator
But yes, if you did your long division correctly, the asymptote is just the answer you got, and you can ignore the remainder
all good
But just important to know, that remainder term, you just take it and divide it by whatever was in the denominator
alr i did it again and got x-1 instead of 2x-1
i think i just wrote 2 instead of 1 for some reason
Ya, x-1 is your slanted asymptote
case closed, the question is solved
It's pretty much just a repeat of this
Now you just plot with the information you have
yo real quick
Ya?
how do i do the end behaviours for the slant asymptote
☹️☹️
wdym end behaviour?
as x approaches infinity, y approaches [?]
so would i just put y approaches x-1
and then for when x approaches -infinity
what happens if x goes to infinity?
would i just put y = -(x-1) or something
HELPPP
What happens when x goes to infinity
It goes forever
gets closer to but doesnt reach the asymptote
what happens if you have 1 million minus 1?
999999
and if you have infinity minus 1?
You still call it infinity
Because 1 is so trivially small
compared to infinity
y = x - 1
when x goes to inifnity, y also approaches infinity
because - 1 is so small, that it won't change the y value that much
R u a bot??
ye
You can see it is strictly just growing
so for larger x, you get larger y
and for infinit x, you will get infinitely big y
Help
i dont get how i would write it tho
<@&268886789983436800>
Bruh
cuz for postiive infinity u can just write y approaches (x-1)
!occupied
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I already told this person, but they don't care
@fickle cradle this channel is occupied, see #❓how-to-get-help
That isn't how it works
bro died of dead
why not
as x gets bigger, y gets closer and closer to the x-1 line
You are correct, for the function as a whole
When the whole function you had from beginning
approaches inifinity
it approaches the line x - 1
aka the slanted asymptote
yea
That is correct
if that was your original question
I misunderstood it, since I thought you were asking what value the asympyote approaches
idk what i need to write for negative infinity
same thing, approaches the slanted asymptote
so my final thing would be
slanted asymptote: fx = x-1
as x approaches infinity, y approaches x-1
as x approaches negative infinity, y approaches x-1
Yes
i know how to do those
when x approaches 2 from positive and negative direction
Then after that you have all the info you need to plot the graph
i just plug in 2 numbers super close to the vertical asymptotes and then see if its negative or positive
Pretty much, that's one way to look at it
been told there was a way to do it with calculus stuff but i kinda just havent learned it cuz its not a calc class lol
Ya, you'll understand it better when you do limits
But if you look in the image I sent
Blue line is our slanted asymptote, red line is our function, green line is vertical asymptote
yea
You can literally see
that for infinit x, and minus infinit x
it really does approach our slanted asymptote
just gets closer and closer, but never really touches the blue line
yea
And if you look on the green line, if you approach it from right side (the positive side)
you see that it just turns to minus infinity
and from left side it goes to infinity
so that's how you would plot it, you draw out your asymptotes
and then you just graph it, from the information you got
right
ty for the help
Because your question did ask to plot it, I remember I had to plot those in the exam
so really practice plotting, it will be important
yea
Good luck my friend!
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helpppppp
what is the definition of a prime number
a number w no factors
ye
how can we apply that definition
make the right bracket on the RHS equal 1
in particular if (n^2+\sqrt{2}n+1) is a integer
greater than 1
what does that say about n^4+1
I dont know
well if n^4 + 1 has those two factors and one of them is one what is the other?
assuming it’s prime of course
the other one is n^4+1
im cooked
nah you’re not
hmm i don’t see how the first part is useful
unless they’re trying to tell you to factor n^4 + 4
oh maybe?
,w (n^2 + sqrt(2)n + 2)(n^2 - sqrt(2) + 2)
ugh
guess not though
because that isn’t the anti derivative of n^4 + 4
maybe the middle term is wrong
ye
hmm
ye but im pretty sure if u expanded the top one it wouldnt be n^4+1 either
the original?
ye
,w (n^2 + sqrt(2)n + 1)(n^2 - sqrt(2)n + 1)
why
bruh
wolfram so shit
ye ikk
,w expand (n^2 + sqrt(2)n + 1)(n^2 - sqrt(2)n + 1)
no it is
oh right
,w expand (n^2 + sqrt(2)n + 2)(n^2 - sqrt(2)n + 2)
maybe the square root 2 is wrong then
oh i forgot the n
ye it is
oh it’s close
so i guess we need the 2n^2 terms to cancel with the sqrt(2)(sqrt(2)n^2
because we get
4n^2 - 2n^2
so the coefficient needs to be 2!!
,w expand (n^2 + 2n + 2)(n^2 - 2n + 2)
😤😤😤😤
so it’s prime for n = 1 for sure
$n^2 + 2n + 2 = n^4 + 4$
knief
$n^4 - n^2 - 2n + 2 = 0$
knief
n^2(n^2-1)-2(n-1)
knief
ahh no other solutions
fun problem
ye it from MAT which I taking tmr
yeppp
good luck
thx
tom rocks math
ye
this year they changing the format of the MAT there are more multiple choice now and less longer questions
which sucks cause I like the longer questions more
multiple choice can sometimes be more tricky
ye so real
because you look at the answers instead of trying to solve it yourself
going in reverse
ye
at there aint loads of logic questions like TMUA
I get so confused with that only if and if and if and only if stuff
but thanks for the helppp
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you’re welcome
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I dont understand
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#5
to start
how am I supposed to get the y coordinate
to find the equation for the line AB you need two points, you can use geometry to find the height at L(0) and it's given that L(1) = 0
"sketch a graph of each function. describe each special case."
what is a special case
what are you referring to with L
point A
?
wait no
just the leg lengths
basically right
L is the line function for AB
oh
just see at 1 the height touches the x axis, which means the height is 0
yeah
oh wait
point B is 0,1
I thought the right isosceles triangle it was talking about was a smaller triangle bruh i thought line AB was the hypotenuse 🤦♂️
sorry I had to help my group on another project
slope is -1 and so the equation for line AB is y=-x+1
wait so the y coordinate of P in terms of x would just be plugging in x for x which would just give you -x+1 right
area = 2x*(-x+1)
a=-2x^2+2x
got the answer
.close
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yo
what is your question?
i need to review all of this
ive done a couple questions but i need help on the 3 term equations
because i struggle when there's 3 terms
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but i didnt
you still haven't asked a question. I'd recommend you to send a problem that youre struggling with and explain what you've tried and where you get stuck/confused so that people can help you
I JUST WANT TIPS TO STUDY FOR THE EXAM I HAVE TOMMOROW
AND IM STRUGGLING WITH THE 3 TERM EQUATIONS IN THIS IMAGE
sorry for the caps
if you cant help me and dont have the helpers role
then
idk what to say
honestly
and its taking a minute to type
just let it out
find a question related to the problem, try solving it and if you can't post it here
k
and be more respectfull
i needed a explanation like that
forsure but when i repeat what i said 2x times
It would help if you asked more clear questions
Rather than an image and ''lecture me on these topics''
@austere pawn Has your question been resolved?
totally what i asked forsure
and once again someone without the helper role
I don't need the helper role
to teach you these topics
Secondary school level math
But, you maybe should work with your attitude
Good luck on your exam tomorrow
how do you think people get the helper role
He thinks they do an exam for it
never said that or thought of it
if you guys are gonna make wrong claims
yes yes mister politically correct
Let us hope your questions are as correct in the exam tomorrow
i mean the helper gave me a better response then all of you did so i think he has more experience in helping students?
@austere pawn Has your question been resolved?
The best tip is to study now
and stop going on discord
man can we just talk in dms atp
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yo
nope
how
wait let me read again
this is the graph of the deriative of f
so we look where its going from negative x values to positive, or vice versa not the slope
oh wait
I agree that there are 3 points of inflection
ah right A is correct then
ok
oh concave up is just when the second derivative > 0
yep
cool so if cos(x^2 + pi) = 0, we could have x^2 + pi = 5pi/2
or that x = plusminus sqrt(3pi/2)
cos(x^2 + pi/2) = cos(5pi/2)
huhh
so that implies x^2 + pi = 5pi/2
cos isn't an injective function I know
so we also could have x^2 + pi = pi/2
but then this new equation doesn't have any real solutions
actually I looked a solution too far
only x^2 + pi = 3pi/2 has solutions in the domain
it's like how if x^2 = 2^2, then x = 2
yes
or in exponential function problems you must have done at some point, if e^(2x + 5) = e^3, then 2x + 5 = 3
that solution is unique cause exponential functions are 1-to-1
for cos it's like this where this is only one solution
we could have x^2 = (-2)^2 ofc
so everything I mentioned is an example of if f(a) = f(b), then a = b is one solution
I used f(x) = x^2, f(x) = e^x for example
and now f(x) = cos(x)
and with a = x^2 + pi/2, b = 3pi/2
f(a) = f(b) is the equation cos(x^2 + pi/2) = cos(3pi/2)
a = b is the equation x^2 + pi/2 = 3pi/2
you want to find when cos(x^2 + pi) > 0 right
it would be easier to see where cos(x^2 + pi) = 0
then make a sign diagram
Yes
it's in the original question lol
ohhh
$f''(x) = x^2 \cos(x^2 + \pi)$
yea
south's secret twin brother
cs both equal 0
you said x^2 >= 0
ohhh
i get it
but shldnt it be an indeuqality
not a equation
to find where is it greater or equal to 0
yes, so that's when we use the sign diagram
ok
Result:
1.2533141373155
remember our domain is [-1, 2] though
ok
so we only have two regions actually to test
-1 < x < 1.2533 and 1.2533 < x < 2
(the other roots of the function are not in the domain)
so we cant include -1.2
yeah that's outside the domain
so 1.2 is the only critical point?
yep
when we did this
why cant we do cos(7pi/2) or (pi/2)
oh we absolutely can
they just happen not to be in the domain
so try x^2 + pi = 5pi/2 for example
,calc sqrt(3pi/2)
Result:
2.1708037636748
The following error occured while calculating:
Error: Unexpected type of argument in function multiplyScalar (expected: number or Complex or BigNumber or bigint or Fraction or Unit or string or boolean, actual: function, index: 0)
ohh
yeah and also x^2 + pi = pi/2
but how did u know we had to use 3pi/2 in the first place
well I tested on Desmos beforehand
oh
you'd see that this is impossible firstly
then test 3pi/2
then test 5pi/2 and see it's outside the domain
so then the rest wouldn't work, cause x^2 would equal some larger number
so concave up on [-1,sqrt(pi/2)) U (sqrt(pi/2),2]
also like x^2 + pi = -pi/2 is impossible, whenever RHS is negative
it's just (sqrt(pi/2),2)
why not form the left?
cause cos(x^2 + pi) is negative on the left
you can test x = 0 for example
oh
yea
srry i just assumed
but yea its negative
@lethal path
for part B
ik how to do it
yeah
so no need to go in full depth
here
oh right
we can use second deriative test
you told me yes, you did b and c already
Yea
i just wanna go over it again so i understand concepts
we can use second deriative test
to plug in 1 in second deriative equation
if f''(1) is < 0 there is a relative max
where there is right
oh right that's smart, so you just need to test f''(1) and find the sign
yep
indeed the sign is negative so concave down
btw we have to justify our answers, the question states that it is a twice-differentiable function do I need to state that anywhere for any parts of the question
yes
Where and for what part
justify basically means give a reason instead of just stating the answer
for part b you need twice-differentiability
but for these problems you won't have any weird edge cases
you can't be expected to find the concavity of a function which isn't twice differentiable to begin with
Ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
function needs to be twice differentibale to use second deriative test
ohhh
yeah
that's the assumption
in real analysis you look at these assumptions in more detail
for now it doesn't matter all that much
but it helps to be aware that MVT for example, the condition is that f is continuous on [a, b]
differentiable on (a, b)
oh nice, you know that
so we don't want or need differentiability on the endpoints
otherwise we'd have to use one-sided limits
he/him or they/them is fine
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Might be a very dumb question, but how is the antiderivative of 1/t^4 equal to 1/t^3 and not my guess -1/3t^3 ?
It is -1/3t^3 but you multiple that by some arbitrary constant
And -1/3 times that constant is just another arbitrary constant
So you call the whole thing just C2
Ah, so bascially C2 = -1/3 C1 ?
Yep
But is it mandatory to give it a new constant? Or would have -1/3C1 have been fine in this case too?
Its fine
And now that I think about it, why isn't it then -1/3t^3 C1 + C2?
Or is that the same aswell?
What do you mean exactly
That they forgot to add the constant of integration
Yeah they did
Yeah some how I'm used to doing it is as follows, for example in a double antiderivative, you get a constant C1, for your first integration, and an another one C2 for your second one.
Like y'' = 1, then y' = x +c1, then y = 0.5x^2 +c1x +c2.
Like in this case you would have two constants.
Yes you would
So then why isn't it 1/3t^3 C1 + C2 in this case?
Or is that still the same as replacing the constants?
Oh yeah I see now that's the same, as we found earlier that C2 = -1/3 C1.
Thank you both very much for your help.
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The general form of triangle number is
idk
I know the triangle numbers are like 1, 3, 6 and 10
<@&286206848099549185>
hi rosy 
omg hi layla
hiii

probably
loll
but also you can do that. there is actually some folklore surrounding how to work it out haha
o rlly
yea totally off topic and probably not even true but people say gauss' teacher when he was in school told him to compute 1 + 2 + ... + 500 (or something, the story changes every time i hear it) for some reason and he came up with that formula
anyway yea this is usually helpful for working with triangular numbers
ok ima memorise it
consider n(n+1)/2 and the next triangular number, (n+1)(n+2)/2
(just putting n+1 in for n in the formula)
oki
the ratio between them is $$\frac{n(n+1)/2}{(n+1)(n+2)/2}$$
generating function courtesan
Oh and then you just cancel down the fraction right
yea

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@calm quest Has your question been resolved?
Hello
cz they've given that they need the answer in decimals(read the last sentence in the q)
but in the formula wouldn't it be pie/5 without in sin(pie/5)
I don't think that's the case @brittle shoal
Here they are asking for area of segment
Not sector
So you must subtract area of triangle from sector
To get the area of segment
They need the purple guy
So the formula is basically
Area of sector minus area of triangle
ohhhh
That's it
I think That's all
?
Anything else you wanna ask?
If not, pls .close the chat
@calm quest ?
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@left badge Has your question been resolved?
Nope
@left badge Has your question been resolved?
@left badge Has your question been resolved?
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i need to find EF where its the divisor of CED (CED is 90 deg)
turns out this is nastier than i thought D:
im pretty sure this blue line is 12sqrt2
so j need to find the rest of it (spoiler:i have no fucking clue how)
je ne comprends pas?
?
Im drawing this out pause
is that a square and a triangle
Ok so what are you trying to find

dafuq thats not a good embarrassed emote mathcord
its pretty good
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!status

