#help-49
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how do you know that?
shouldn't you have a fullstop after the set
sorry
then say ||suppose T is non-empty||
oh, right
Ideally. And the next sentence should be
(what frosst said)
okay good, next thing is not necessary but i think its good to include it anyway. You can mention that you are using WOT. Like "By WOT, T has a smallest element, so let a be the smallest element of T."
got it
is that what WOT says
And you should expand on the => (a-1) ∈ S
WOT says that non-empty subset of Z+ has smallest element
and T is non-empty subset of Z+
i am still confused what we are even trying to prove here. if you want to say that this construction S is equivalent to Z+, we first need some definition of Z+ to compare it to.
this contradicts the definition of T
why does it contradict it?
T is defined to consist of those elements that aren't in $S$, but I've shown that that's not true
ƒ(Why am. I here)=I don't Know
basically, a is both element of S and T
well i've just used Z+ as a scapegoat so he stops saying that T contains everything not in S
so thats how the contradiction arises
. You included the a =/= 1 too lately
also you can just generally expand on that implication and explain it in more detail
like a-1 isnt in T, lest it would be the smallest element
hence either a-1 isnt in Z+, or it's in S
well do we really know that a-1 is in S?
yes
how
Sorry for making you spend so much of your time helping me on a simple proof .
a-1 isnt in T by minimality of a
hence a-1 is either not in Z+ or it's in S
(by definition of T)
the only way a-1 wouldnt be in Z+ is a-1 = 0 and a = 1, but 1 is in S, so 1 can't be in T and so it cant be minimal element of T
so a-1 must be in S
and then a must be in S by definition of S
all of that should be at least partially included in the proof btw
maybe not in that much detail, but it should
when you do it for the first time you should write it in that detail and more
that's true too
until you know you can do it, you should write it in that detail
if you're just going to handwave the parts you dont know then you might as well not be doing proofs
$x\not\in \mathbb{Z}^+\not\rightarrow x\in S$. for example 1.5 isnt in either set
esca (@ with reply)
I never said it does
i used disjunctive syllogism or smth like that
idk how its called
a-1 is either not in Z+ or it's in S
I showed that a-1 is in Z+
hence its in S
how is a-1 in Z+
because A is in T and so in Z+
small a
a was in T, so a was in Z+. but how is a-1 in Z+
you dont know
until that
then i made argument that a cant be 1
since 1 is in S
and so 1 cant be in T
and a fortiori it cant be minimal element of T
i mean $a\neq 1\land a\in\mathbb{Z}^+\implies a-1\in\mathbb{Z}^+$ is literally the thing youre trying to prove, right?
esca (@ with reply)
Well I assume there are some properties about integers that are already established
and this one looks trivial enough
lay them out
so whats a baseline definition of Z+ we can work with
the book says they are assumed to be given, we don't have to bother with them
ok fine S contains all positive integers
sorry yeah
We dont need to use von neumann numerals or anything
we just have some properties that we can use
i assume trivial arithmetical properties
which is what i used
and WOT
which is taken as axiom
in the book
what is an integer i guess should be my question
im pretty sure the exercise wants this part as the meat of the proof
and we dont care whether 2 = {∅, {∅}} or 2 = {{∅}}
we're not looking to prove absolutely everything from scratch
so we take for granted that if a is a positive integer, then a+1 is also a positive integer
yes, I guess
we also take for granted that 1 is a positive integer
yes
and we take for granted that a +b where b isnt an integer is not an integer
a is still an integrt
okay, then yes i guess?
but this is already much less trivial than what i used
look, we just take some basic arithmetical properties for granted, and then we use WOT to derive new a base for new "proof technique", which is induction
I think we can assume that if a is in Z+, then a-1 is in Z+ or a-1 = 0
its equivalent to this btw:
if a is non-negative integer, then a+1 is positive integer
and that's just trivial
Uh, so is anything still wrong with my proof?
I dont like this part
you should explain in more detail why (a-1) is in S
start by (a-1) not being in T, by minimality of a
then use definition of T, exclude the possibility that (a-1) is not an integer and conclude that (a-1) is in S
sorry, this is it
right and thats the thing we're trying to prove 😭
no it's not?
I see. You should assume that T is non-empty efore you use WOT
you repeat the same thing twice actually
delete the first one and it will be fine
and seperate your sentences
suppose T is non-empty let a be the smallest element of T (a-1) in S which by definition...
this should be 3 sentences
other than that, you should expand the proof there
explain why (a-1) should be in S
ƒ(Why am. I here)=I don't Know
What do you mean?
the explaination of this
Currently, you have that a is the smallest element of T. Use that and proof that (a-1) is in S
by definition...
that explains that if (a-1) is in S, then a is in S
But what you need to explain is that if a is smalelst element of T, then (a-1) is in S
this is the big jump in your proof
it's correct, but the jump was too long
you skipped like solid 2 lines of proof
and not exactly trivial one
youre saying the only thing we know about Z+ is it has certain properties. and we're constructing S as some set that has exactly the same properties. then i dont understand whats left to prove
We are not constructing S
we have some set S that has the properties that it contains 1 and is closed under successor
and we are proving that it contains all positive integers
but all we know about Z+ is that it contains 1 and is closed under successor
I'm really confused now, sorry
That's assuming a specific set theoretic construction
we dont always need to use the same construction with same properties
can we move this to DMs esca?
sure
at what point?
sorry physics rocks
here
ok, so if $a-1$ is in S , as is $a$
ƒ(Why am. I here)=I don't Know
I suppose this is supposed to be
"Let a be the smallest element of T. Then (a-1) is in S.
Is that right?
yes
okay, that's not so trivial conclusion though
so this approach is wrong?
that shows that if (a-1) is in S, then a is in S
but it doesnt show that if a is the smallest element of T, then (a-1) is in S
by construction if an element isn't in T , it has to be in S
assuming it's an integer
exactly
and that's not so trivial
and you stuffed all of that in one single step
ooh, ok
while it should be mentioned in the proof
got it
you need to say that (a-1) is not in T, which follows from minimality of a
then you need to establish that (a-1) is a positive integer
and only then you can conclude that its in S
you already partially did this part, though at wrong place
and partially
so this shouls be near the beginning of the proof?
it should be mentioned somewhere during the process of proving that "if a is the smallest element of T, then (a-1) is in S"
meaning somewhere in between those 2 things
np
one minute
I'm lost
I think I'll just try this again later, sorry
is that fine?
yeah
np
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you can finish it whenever you want, the progress is already quite good
the proof outline is correct
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for part b, i had $\int_{0}^{1} \int_{x^2-x+1}^{1} \int_{2-x-y}^{1-x^2} (x) dz dy dx$. I am wondering why this is wrong.
Secret
do you have the drawing of the regions?
@versed ridge Has your question been resolved?
<@&286206848099549185>
@versed ridge Has your question been resolved?
@versed ridge Has your question been resolved?
That geogebra drawing looks terrifying lol
Lemme take a look at the problem
where did you get the bounds for y from? for example, couldn't y be 2? (if x=z=0)
@versed ridge Has your question been resolved?
so to find the bounds for x and y, i set the two surfaces equal to each other
and that gave me $2-x-y=1-x^2$
Secret
which meant $y=1-x+x^2$
Secret
That makes sense for the lower bound, but what about the upper bound of 1?
Where did you get that from
i think i figured that if $z=1-x^2$ and we are bounded by the plane $z = 0$, $-1 \leq x \leq 1$ but we only really consider $0 \leq x \leq 1$. Now, looking at the second surface, we have $z=2-x-y$. If $z \geq 0$, then $x+y<=2$ and i think i plugged in $x=1$ into this inequality.
Secret
tho ig i should plug in x=0 if i were to find the upper bound for y
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Wait does 2-x actually work lol I haven't checked
imma try it out and lyk
kk good luck!
ok this is the revised integral and it gives me the wrong answer. Do you see anything else wrong with it?
.reopen
✅
So my question is
Are you sure you're looking at the right region
Because the bounds you've set make me think you're looking at this region
Between the blue parabola and the red plane, and so on
But it seems like that region would just continue on forever to the right 
Lemme try plotting it
what I'd assume is you're trying to find this region, under both the plane and the paraboloid?
In that case, you should have that x+y+z ≤ 2 and x^2 + z ≤ 1
ye i think the one that is bounded should be the region
Before, you were assuming, I think, that x+y+z ≥ 2 in order to find lower bounds for y and z
ye
The inequality should be the other way around though
So that we can have a bounded region
wait so if the region is under the plane
then would it be less than or equal to the plane
yea
So you've got
0 ≤ x
0 ≤ y
0 ≤ z
x + y + z ≤ 2
x^2 + z ≤ 1
ye
wait wouldn't it be z between 0 and 2
No bc x^2 + z ≤ 1
oh yea you take the lesser bound
Yeah this is tricky
we can do y as innermost
and then go from 0 and 2-x-z
and x goes from 0 to 2-z
does that make sense?
Then you're not really using x^2 + z ≤ 1, are you
ye ig i have to take cases for x
i have two possible inequalities $0 \leq x \leq (2-z)$ and $0 \leq x \leq \sqrt{1-z}$
Secret
@versed ridge Has your question been resolved?
0 ≤ x ≤ 1
0 ≤ z ≤ 1 - x^2
0 ≤ y ≤ 2-x-z
Do these bounds work? @versed ridge
They feel like they should
Awesome
how did you get there?
So, I noticed that if you look at this picture, the y-axis is the only one where the bounds are not piecewise
y always goes from 0 to the plane
So I figured that one should go on the inside of the integral
Once we've got that covered, that ensures we're always under the plane
And then we just need to deal with the x and z being inside the parabola
You can either do this like
0 ≤ x ≤ 1
0 ≤ z ≤ 1-x^2
or I think
0 ≤ z ≤ 1
0 ≤ x ≤ sqrt(1-z)
should work fine too
And then that solves it
ah i see
So like, even though the region of integration is somewhat complicated, if you project it onto the x-z plane, it's actually really simple
(just the area under a parabola)
ig you should be able to do it with x and z as innermost too, right? it would just involve taking two different cases
you're welcome!
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let $f(x) = x^2 \ln x$ $\\1)$ how many solutions does the equation $f(x) = \frac{-1}{6}$ have $\\$2) for which values of $k$ the equation $f(x) = k$ has exactly one solution
938c2cc0dcc05f2b68c4287040cfcf71
938c2cc0dcc05f2b68c4287040cfcf71
well
Try sketching the graph
I don't think you actually need to solve it
try finding the number of turning points and the concavity of the graph
how to sketch the x^ 2 lnx doe
ok so lets calculate the critical points and the points of inflection, no?
wdym concavity
how do I find concavity and convexity of this
?
I don't meanu numerically
,, x^2 \ln x \ \frac{d}{dx} \left(x^2 \ln x\right)
938c2cc0dcc05f2b68c4287040cfcf71
neitger?
,w graph x^2ln(x)
what's the derivative of x^2ln(x)
,align x^2 \ln x = \ \frac{d}{dx} \left(x^2 \ln x\right) &= \frac{d}{dx} \left[x^2\right]\ln(x) + (x^2)\frac{d}{dx}\left[\ln(x)\right] \ &= 2x \ln(x) + \frac{x^2}{x} \ &= 2x \ln(x) + x

pretty sure that's wrong
what's the derivative of ln(x)
yes
this is right
now notice it's 0 at a point between 0 and 1
938c2cc0dcc05f2b68c4287040cfcf71
ln(x) in here x > 0 strict
ye so e^(-1/2) is the exttema
wdym
,, 0 = 2x \ln(x) + x \ 0 = x(2 \ln(x) + 1)
ye
938c2cc0dcc05f2b68c4287040cfcf71
so either x = 0 or
2ln(x) + 1 = 0
cuz f(0) doesnt exist
ye
then $2 \ln(x) + 1 = 0$
938c2cc0dcc05f2b68c4287040cfcf71
thats why e^-1/2
,w solve 2\ln(x) + 1 = 0
can you draw 2lnx + 1
if you can ur gonna realize that f(x) is gonna look like a quadratic
with vertex at x = e^(-1/2)
how do I draw it doe
you dont know how lnx looks like?
,w plot ln(x)
ye
it looks pretty much the same
you dont have to be precise when using derivatives to check where the function is increasing/decreasing
thats why i ignored x in the first place
cuz x>0
u did it?
if you cant do it you can check where 2lnx+1 is positive n negativd
its simple
here root is 1?
ye but its now 2lnx+1
yeah but were doing 2lnx+1
Result:
0.60653065971263
u now know where the function is increasing or decreasif
gimme a sec
sure, I will scroll tiktok real quick
which one
unsure how to answer 1 and 2 from my original question
I am getting confused all over again
I need more handholding
can u plot fx from this
u know this
so
something like this
(0, e^-1/2) is decreasing
this is enough to solve those 2 questions btw
(e^-1/2, infty) increasing
u dont nesd that much detail
what is that
f(x)
look
i just used the definition of decreasing n increasing
whats f(e^(-1/2))
tangent zero
,calc e^(-1)*-1/2
Result:
-0.18393972058572
ye now compare that to -1/6
,calc -1/6
Result:
-0.16666666666667
so -1/6 abit bigger
,calc -1/5.5
Result:
-0.18181818181818
its not 1/6 doe
what
,w 1/sqrt(e) = 1/6
-1/6 is abit bigger than f(e^(-1/2))
slightly, agreed
im not saying f(e^(-1/2)) is -1/6
so can u tell how many roots there are in f(x) = -1/6
1
why
ye how many intersections are there
two
938c2cc0dcc05f2b68c4287040cfcf71
this ?
ye
how do I do that
okay
what should k be so that those 2 have 1 intersection
how would I know that
the intersection has to be at the turning point
at the vertex of the parabola
how do I do that
is there a condition that says k <0
in the og question
this
let $f(x) = x^2 \ln x$ $\\1)$ how many solutions does the equation $f(x) = \frac{-1}{6}$ have $\\$2) for which values of $k$ the equation $f(x) = k$ has exactly one solution
wdym
938c2cc0dcc05f2b68c4287040cfcf71
@tidal turret Has your question been resolved?
Can someone help my fatass
I'm here
And in f(x)=-1/6 multiply 2 on both sides
Do you now know what to do
lambert w won't help, it's not in most curriculums
some calculus will help, basically 1 solution occurs at the min of f if we think of this k value as a vertical translation
this
I'm not sure if I understand that
what part
The assumption that k is a vertical translation
Also how can we be sure there's only 1 solution
move k so that the minima lies on the x-axis
Ok i see
also these are increasing functions on the domain [0,infty)
ok cool I'll let you work on it now
@tidal turret Has your question been resolved?
Mero my dumb brain is not getting what to do T_T
well ok first off, were you able to solve for the x value of the minima?
1?
e^-1/2
good
how did you get that can you show your work
that was too quick like you're just plugging this into wolfram alpha 😛
that's no fun
well regardless once you have that, then plugging e^{-1/2} into f will be the height of the minima
!showwork
Show your work, and if possible, explain where you are stuck.
nice eyes drawing
Lol
,rotate
Ik i didn't think that time
oh ok cool
was this just so that we can see the eye drawing more better 😭
so back to this point where we left off
yeah lets lock in fr
lmao
👁️ 👁🗨
👁️ 🧿

bro has math equations for a mouth 💀 💀
I got e^-1/2 as min
specifically the x value of the min
we want the y value of the min since that's how much we need to translate the graph by so that it's the only point tha ttouches the x-axis
1/2e
I think it's -1/(2e) unless you mean the translation amount up
Thus k=1/2e
Yes I meant that
then k=-1/(2e)
My bad
all good
Well how to do the first w/o W Lambert function?
same sorta calculus stuff
But it is different
Man i have to revise my clac
Well it is my hw for the week
Bye mero
nite nite
k>=0 also works though
I ain't going anywhere tho
wdym, you said bye?
I'm just not gonna slove this
ohh it's alr bro, you tried your best anyways
So "bye"
I got the answer for the first but mero said it will not be accepted in some curriculum
mhmm
But I clearly have no idea how to do with out that method
it's fine bro
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hints please
what is an "intermediate" value
I do not know
yes
and we do then derivative
but what is the interval
as we can see it is not given
Half the questions you bring are incomplete in some way
Do you just need us to confirm that there's nothing to be done?
@bleak pier Has your question been resolved?
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Hints please
Do you have expressions for the volume and surface area
You need a function for the volume in terms of your favorite conical parameter
@bleak pier Has your question been resolved?
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<@&286206848099549185>
@flint heron Has your question been resolved?
you seem to have solved the problem already.
p is congurent to 1 mod 4 only if p-1 is divisible by 4
Yes, I am not sure why that is. Should I learn about Legendre symbols?
This topic wasn't covered in my textbook
One sec let me check some stuff
Thank you!
It seems like you need to use Legendre symbols for this. Is this problem from your textbook?
Not directly from it. I will look this up and try to figure out and come back if I get stuck. Thank you
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solve the following system of equal for real x,y,z,;
x+y-z = 4
x^2-y^2+z^2 = -4
xyz = 6
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help me solve this please
x+y-z = 4
x^2-y^2+z^2 = -4
xyz = 6
real solutions
helpers
nvm i got it.
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Guys, but as I'm practicing finding the maxima and minima of $f(x,y)=\arcsin(x^2-y-1)$ I get some derivatives which seem infinite. Is there a way to do it faster, like parameterization?
card
Domain D:
${(x,y) \in \Bbb R^2 : 0 \leq x^2-y \leq 2}$
card
@steady trail Has your question been resolved?
<@&286206848099549185>
i have a very fast way
for any t, we have -pi/2 <= arcsin(t) <= pi/2, right?
Yes
so now just find a pair (x,y) that makes arcsin(x^2 - y - 1) = -pi/2 and another pair that makes arcsin(x^2 - y - 1) = pi/2
this shows the min and max are -pi/2 and pi/2 respectively
but what gives us the certainty that it takes on those values
we can write the pairs explicitly
for Extreme value theorem ?
no
I mean how do we know that the function certainly has a maximum and minimum
from this and the fact that arcsin(x^2 - y - 1) attains the values -pi/2 and pi/2
Okay
I do not know how to do it
if you want arcsin(x^2 - y - 1) = -pi/2, you want x^2 - y - 1 = -1
pick any x,y that satisfy that equation
yep that works
But couldn't there be others now?
other x,y that make arcsin(x^2 - y - 1) = -pi/2?
x=1, y=1
yea but that doesn't matter
Why?
we have arcsin(x^2 - y - 1) >= -pi/2 for any x,y, and there exist x,y with arcsin(x^2 - y - 1) = -pi/2
that shows the min is -pi/2
think about the minimum value of sin
it's -1
and we have sin(x) = -1 for lots of different x's but that doesn't matter, the min is -1
yep that works
But in fact, seeing the domain, setting x=0 and y=0, solving the equation I find 0≤0
And setting x=-1 and y=-1 i find 2≤2
Here I find precisely the extremes of the domain
Last question: but what does it mean to parameterize this function
wait no that's not what i meant
Okay
nvm i can't explain this well
Maybe with an example ?
well i can just give my stupid explanation again. the graph of f consists of points of form (x, y, arcsin(x^2-y-1)) where (x,y) is in D. call this set of points G
paramaterizing f means making some real variable functions a,b,c and a set A where [the points of form (a(t), b(t), c(t)) for t in A] is G
so you can get a point on the graph of f by just taking one real number t and looking at the point (a(t), b(t), c(t))
this is how i think about it but it's maybe too abstract
<@&268886789983436800>
<@&268886789983436800>, no advertising especially in help channels
(spammed in lots of channels)
Thank you so much
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Why the hell did u close your previous one
lol
Shush ur just as guilty
can some one just please help me
🤐
maybe the answer form expects the answer fed to it in some specific way, sounds like a pain with this problem. maybe worth trying to factor out the e^ part out of both factors
as far as doing it correctly, seems ok to me
thank you
yea electonic maths things arnt well suited for this i guess
try to factor this out, i think oftentimes they prefer factored versions of answers?
oh wait you forgot a parenthesis here, this will do it
Or that!
whats a parentisis?
oh thanks

I loved this reaction
im english we call them brakets
so?
Why do you have 5he outer brackets
sorry i should have known to use UK english given your username and profile pic : )
Remoce them
Bottom one
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Anyone have an idea of how solve this integral
Write sin theta as u
where do u see x
x as theta so i dont need to write theta
easier to type in discord than theta 😛
:)
damn these mathematicians they see x everywhere
theta is theta.
I'd hardly call myself a mathematician
so
so
What about a weeb

$\int_0^{\f\pi 2}\cos(\sin\theta),d\theta=\int_0^{\f\pi 2}\cos(\sin x),dx$
∫oosh (lemonsaurus appreciator)
just rename the variable :p
There is a hentai joke here somewhere with the x but for the life of me I cant think of it
I got it from this integral when x is sin(theta), I’m not sure if this integral is easily solved, if not it’s fine but would like to know the actual solution
did you use a trig sub?
You lost me
you used x = sin t ?
Yes
seems like what you would do
I wonder if you should just polar this
looks like a pretty standard trig sub integral
trigonometric substition?
okay nevermind
The cosine is tripping me up
Does that to all of us sometimes
Is there a way to turn cos(sin(x)) into something
That would just reverse the substitution though
Btw this isn't a homework problem just made the integral up and try to solve it
maybe you just stumbled upon a hard integral then
kinda easy to do with integrals :p
but attempting it with trig sub seems like a good thought at least
this isn't so easy to simplify because there's no obvious geometrical interpretation, sin spits out some geometric length and now you're feeding it to cos as an angle, so it's just kinda random blarb
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HELO
must be 8?
wait
would it be half the length
i forgot about this not going to lie
any ideas?
.close
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hints please
what?
it is going to infiity
is it? it doesn't look like it to me
i guess theres just a hidden ... at the right
i guess yes
you guess?
do you have the original problem
girlie you're the one who posted the question
acutally NO
Peculiar
my answer by a formula will be e^2-e
Post the original question
as I said I dont have the original
someone asked me and i asked here
Your question doesn’t make sense
.
Lack of context and visibility
ok so the sum $\sum_{k\geq1} \frac{2^{k-1}}{k!}$ ?
Aslan
no
This isn’t even the same sum
right
Then a hint would be to maybe make use of the fact that $e^x=\sum_{k\geq 0}\frac{x^k}{k!}$
2^3-1
What makes you think this is wrong
Aslan
i am just asking
?
Looks good to me
wym
The sum in question is $$\sum_{n=0}^{\infty}\left(\frac1{n!}\sum_{r=0}^{n-1}a^r\right)$$
kheerii
You can use the formula for the sum of a GP
To simplify the inside summation
And then use the identity $$e^x=\sum_{n=0}^\infty\frac{x^n}{n!}$$
kheerii
Not quite, there’s one term missing
Indeed
@bleak pier Has your question been resolved?
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show that ^ for positive integers n
how much progress have you made?
um i tried it and then i think i did something completely wrong
so barelyt any
lemme give it one more go before asking sos
Yes
yeah so i'm unsure of what do to with RHS
i started with LHS and got 2 cos (cos + isin)
so set say x = cos(..) +isin(..)
binomials yeahh
Aslan
nah haven't done euler's yet
meant to be solved w demoirves and binomials i reckon
ok so ignore eulers
if youre allowed demoivers it deosnt really matter
i used it as shorthand really here
but yeah try using that
then you "distribute" k into the arguments of cos and sin
if that even helps
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$\frac{\left(1\cdot2\cdot3\dots2n\right)}{2^nn!}=\frac{2^n\left(1\cdot1\right)\left(2\cdot2\right)\left(3\cdot3\right)\dots}{2^{n\ }n!}$
is this right?
ƒ(Why am. I here)=I don't Know
no
What are you trying to prove
ƒ(Why am. I here)=I don't Know
just prove it directly
👍 let me think of a way
think of double factorial*shifted double factorial
(2n)!/(n! 2^n) = [ (n+1) (n+2) ... (2n) ] / 2^n
top has exactly n even numbers, so at least n factors of 2
wait, doesn't the top have n/2 even numbers?
I reached until there too
but was stuck thereafter
yeah mb
to be more specific
n/4 numbers divisible by 2 only, n/4 numbers divisible by 4
that should do it
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✅
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is this right?
I can justify myself if need be
yes but don't forget to prove the case n = 1
I'll justify myself, just a minute
$\frac{1}{1^2} + \frac{1}{2^2} \textcolor{red}{+} ... \textcolor{red}{+}\frac{1}{n^2}$
Frosst

why do you say this
it doesn't seem very obvious why it's true
he's doing induction
i know he is
"We will prove it by induction on n:"
Base case:
blah blah blah blah. Base case works.
Inductive step:
Assume 1 / 1^2 + 1 / 2^2 + ... + 1 / n^2 <= 2 - 1/n. [Insert inductive step here]
mention that you are using induction
ah, ok
seperate base case and inductive step
and thats pretty much all you will need to do
so what I'm doing is overkill
write up the whole proof and then post it here
👍
done, let me TeX it
just 2 minutes
To prove : $\sum_{i=1}^{n} \frac{1}{i^2} \leq 2 - \frac{1}{n}$
\
base case:- $1 \leq 2-1$
\
inductive hypothesis :- $\sum_{i=1}^{n} \frac{1}{i^2} \leq 2 - \frac{1}{n}$
\
we now prove that the hypothesis holds true for the (i+1)th case
\
$\sum_{i=1}^{n} \frac{1}{i^2} + \frac{1}{(n+1)^2} \leq 2- \frac{1}{n+1}$
but $\sum_{i=1}^{n} \frac{1}{i^2} \leq 2 - \frac{1}{n}$
so saying
\
\
\
$2- \frac{1}{n}+ \frac{1}{(n+1} \leq 2 - \frac{1}{n+1}$ isn't wrong
\
\
solving this inequality we get this is true for all $n\in \mathbb{N}$
\
\
thus our hypothesis is true
\end{document}
ƒ(Why am. I here)=I don't Know
so saying ___ isn't wrong
I'd definitely replace this with something like
"so it suffices to show that ___"
Also, I feel like you are trying to avoid doing the proof that inequality, so instead you just said that it suffices to solve the inequality
ƒ(Why am. I here)=I don't Know
\leq?
ƒ(Why am. I here)=I don't Know
which shows it's true for all n
yeah
it's good to learn to "translate" between solving an inequation and doing that one-line proof
