#help-36
1 messages · Page 271 of 1
wait for 20 what did you get from differentiating
Okay, well lets differentiate step by step then
Do you remember any differentiation rules
Thats an issue then
Okay, uh do you have your notes by your side?
With these
uhhh
Its fine if you dont
I suggest having a brief look at some differentiation rules for starters
Power rule, chain rule, etc
true
we didnt get deep into differentiation, i just remmeber teacher teaching the most basic rules
if u guys recall some rules, i think ill remember
what r u doing here
can u help me remember
For starters, what's the derivative of x⁴
?

Incorrect
ok
Start from right to left to avoid confusion
Give it a try then!
The idea is
You're given an expression of dy/dx AND an expression of y
yes
Which means, if you derive that y, you'll get an expression that's either the same as the one given
Or, and more importantly, an expression that's equal to it
how do we derive y
Evaluate dy/dx
ok so then
Have you tried differentiating the y ?
If you have: y = 2x^k + ux⁷
What's dy/dx ?
Try applying them
ok
You want to do each of them at a time
i see
so we add d(2x^k)/dx and d(2ux⁷)/dy ?
Yes
but how are we finding k and u out of this
We know that d(u+v)/dy = du/dx + dv/dx
yes
Remember that we already have an expression of dy/dx
yes
The interesting thing is, that expression has not u and k values
But when we differentiate y ourselves, we'll get an expression that has k and u
hmm
Just try differentiating
got it
ok thanks
-# for future reference, it’s best to memorize this! it will help a lot with calculus
@tall dagger Has your question been resolved?
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lim x tends to 0 $\frac{\left(\tan\left(\tan x\right)-\sin\left(\sin x\right)\right)}{\tan x-\sin x}$
doctorstrangejr
why is this not just 1, like I tried to multiply and divide tan(tanx) and sin(sinx) with tanx and sinx respectively to get $\frac{\left(\tan x\ -\ \sin x\right)}{\left(\tan x\ -\ \sin x\right)}$, which should give 1, but the answer is 2
doctorstrangejr
Please ping me if you're responding to this
what do you mean "respectively"
he means denomitr and numeratr
I mean presumably you just have to use l'hopital and not screw up
I'm here
also this step was wrong!
I mean yes but why does what I did not work
Howd you cancel tanx - sinx
only black magic would turn a tan(tan(x)) into a tan(x)
and the numerator
okay okay guys listen
give me a minute
let's say you have tan(tanx) as x tends to 0 yes
you multiply divide with tanx
take tanx as t for now
so t*tan(t)/t
or just t, which was tanx
tan(x) and sin(x) don't approach zero at the same rate
you cant say thi
I'm doing them independently of each other
tanx > sinx > x when x tends to 0
atleast thats what i remember
guys I did them separately, if it helps I broke them into two limits
thats fine, but the step of writing tan(tanx)) as tan(x) is wrong
at least when x>0, presumably it flips going the other way around
and then recombined them after simplification
Yes but how, that's what I'm having a problem with
then your limits are
tan(tan(x)) / (tan(x) - sin(x))
and
-sin(sin(x)) / (tan(x) - sin(x))
assuming those limits exist which is not obvious
yes, and now for the first one multiply divide with tanx, and for the second one do the same but with sinx
if the limits exist and you're able to compute them then you're golden
good luck with that
In the end I think you have to do the same amount of work as with l'hopital
doctorstrangejr
$\frac{\frac{\tan\left(\tan x\right)}{\tan x}\cdot\tan x}{\left(\tan x\ -\ \sin x\right)}$
doctorstrangejr
valid
Now, tan(tanx)/tanx should simplify to tanx (we can take tanx as y if it helps to understand why, as y tends to 0)
$\frac{\tan x}{\left(\tan x\ -\ \sin x\right)}$
doctorstrangejr
tan(tan(x)) / tan(x) is not tan(x)
?
he applied it correct
thats 1, he just multiplied both numertor and denomintr
I mean if it isn't then that's my conundrum, why is it not that
,w plot tan(tan(x)) / tan(x) - tan(x)
that should be the zero function if they were equal
if it helps I computed this on desmos and got 1 for odd values of pi and 2 for even values
they both are tending tozero, its applicable acc to limits for his grade
its a rule dude
you can try applying l hopital
same answer
tan(qwerty) / qwerty =1
when qwerty tends to 0
(they're doing a small angle approximation, albeit with some rigor missing)
Right, but for his grade its fine hopefully
I'm not saying what I did could not be wrong, what I'm saying is if it is wrong then why is it wrong
Grade?
No no this is for JEE
arey bhai tauba tauba
which year?
drop, it's tomorrow, evening shift, I'm tensed because I can't understand why this is wrong
holy shit
You can't say that something simplifies to something else just because their limits are the same
<@&268886789983436800>
are you familiar with the x tends to 0 tanx/x = 1 rule?
acha sun na
Haan bhai
I do agree that the limit of tan(tan(x)) / tan(x) is 1
but we still haven't solved the problem where the denominator is zero
ek min jee method try karne de🥀
yes, but remember we multiplied a tanx too, and did the same process for sinx so should have a similar sinx left there, so tanx-sinx/(tanx - sinx), it should cancel out and be 1
I don't understand what you mean
I'll just solve the question with the way I did and send a pic
sure
Wait sun
Jab tu ye lagayega ki tan(tanx)/tanx =1
And same cheez for the sin wala
tum ye mislead kar rhe ho ki dono ka actual rate ignore karke literally same man rhe ho dono ko
ek tarah se aise socho jo tum kar rhe ho usse ye aayega ki tan(tanx) is same as sin(sinx)
taylors ki expansions ki tayaari ki hogi na
ye padh
yahan taylors se kar
Dekh, tan ka expansion aur sin ka expansion different hai
Bhai Taylor's se kar to loon lekin exam mein kaise samajh aayega ki ye galat hai, udhar to yaheen lagega na ki simply answer aa gaya
Haan isilye bol rha hun ki yahan par tumne literally ye bol diya ki tan(tanx) is = sin(sinx)
Haan vo to hai, lekin x tends to 0 pe to donon same hain na
true but tan aur jaldi increases as compared to sin
Haan lekin tends to 0 pe to infinitely small dekhte hain na, udhar to rate matter nahi karega, in general karega lekin idhar thode na karega
hain, lekin donon mein to 1 aana chahie, bhai ye kya hai
bhai traahi, hamse na hoga, is sawaal ke chakkar mein baaki sab chhuta aur ja raha hai
lmao
sun
simple tip
jab kuch aisa ganda ho na
fist l hoptial laga kar dekh
BC itna sundar sa method dikha tha, uski bhi maar li in logon ne🥲
Haan idhar l hopital shayad kaam aaye bhi na, Taylor hi lagaane padenge
yes
mains mein yahi hoga
but sach bolun toh lcd zyada aise type ka nahi pich rha hai iss saal jee
mein paper analysis dekh rha tha
Chhodo bhai phir, channel khula rehne deta hoon in case koi Euler aake kuch bata de ki kya galati hai
Bhai hopefully scam na ho bas
wo zyada waisa nahi hota f(x) = abcd for -1<=x<=1 efgh 1<=x=<3 aisa type ka
aisa type puchta hai
Abeeee
board waale sawaal pooch rahe hain
bhai scam na kar dein bas
Haan pata hai but iska thoda higher level
india hai bhai kya lagta hai tujhe
aakhri shift mein bomb phod ke jaayein
Chalo bhai phir, baakiyon ke liye angrezi mein ye likh doon
lmao
okay so I'm not stressing much on this as there are more topics I need to cover, as of now I don't really understand what went wrong, I'm leaving the channel open, if anybody is able to figure it out then please mention it here
-# mein chalta sone (hagne)
-# atb gng
all the best bhai, machhar bahut hain aaj kal
@shell condor Has your question been resolved?
<@&268886789983436800>
Glt h
Limits hmesha ek saath dlti h u can't just put partial limits ki ek jgh kuuch daal diya u let the other part stay as a variable
Also why this
bhai partial limits thode na daal raha hoon, agar koi function hai f(x) = g(x)*sinx/x, to udhar sinx/x ko to 1 karoge na bina baakiyon ko consider kare, waheen kara hai maine basically
scammer tha
Nhi hota aisa imo bhai limits to ek saath hi dalega na
That's just ki agar ek case m shi ho gya to u make a formula out of it which ain't true
are bhai, ye kar sakte ho, ye standard limits hoti hain, problem ye nahi hai ki jo step maine kara hai vo galat hai, vo sahi hai, lekin koi exception hai jiski wajah se ye galat ho raha hai
thode aur questions dekhoge to har jagah ye allowed hai
baaki anyways bhai thank you for attempting
Idk bhai i haven't studied limits that extensively but idts ki aise hota h i could be wrong tho. Im gonna ho sleep ab but can u dm me the original question and this thing u did
haan bhai sure, ek baar tum bhi idea le lo
Thanks
^ (helpers)
@shell condor Has your question been resolved?
no problem in this as long as both limits exist (product rule of limits)
when you do $$\lim_{x \to 0} \frac{ \frac{\tan (\tan(x))}{\tan(x)} \tan(x)}{\tan(x) - \sin(x)} \quad = \quad \lim_{x \to 0} \frac{\tan(\tan(x)}{\tan(x)} \cdot \lim_{x \to 0} \frac{\tan(x)}{\tan(x) - \sin(x)},$$ you have to check that both limits exist. and while $\lim_{x \to 0} \frac{\tan(\tan(x)}{\tan(x)} = 1$ (checking with WA), the other limit is $\lim_{x \to 0} \frac{\tan(x)}{\tan(x) - \sin(x)} = \lim_{x \to 0} \frac{1}{1-\cos^3(x)} \to \infty$ by L'Hôpital's

haseeb ♥
Compile Error! Click the
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(You may edit your message to recompile.)
yaar
limitsexist🙏
when you split the limit you get $\lim_{x \to 0} \frac{\tan(x)}{\tan(x) - \sin(x)}$ as one of the products which goes to infinity by l'Hopital's
haseeb ♥
and the same happens for $\lim_{x \to 0} \frac{\sin(x)}{\tan(x) - \sin(x)}$
haseeb ♥
oh wait yeah
so basically all I need to do is check with l'hopitals whether this stays indeterminate or not?
well you check if it's indeterminate by direct substitution
tan(x) -> 0 and (tan(x) - sin(x) ) -> (0 + 0), so the limit has form 0/0
then apply l'hopital by taking derivatives
but more importantly, you have to double-check that both limits exist after you split a product or quotient
i think it's possible for addition and subtraction too
Alright thanks man that should be it, so basically if I do anything after which even the final l'hopital results in an indeterminate form, then I probably messed up, yes?
if you do l'hopital and you get an indeterminate form again (0/0), you can differentiate again
however if you are differentiating 4+ times on a test maybe l'hopital isn't ideal
if you do l'hopital and you get infinity, then that just means the limit DNE
I mean in cases where I can't apply l'hopitals anymore, like in $\frac{1}{1 - cos^3x}$
doctorstrangejr
yeah, then the limit is now determinate (a known value), but of course that known 'value' is infinity
so l'hopital stops
wait so then the limit does not exist, and assuming this is on a test that shouldn't happen, that means I messed up somewhere earlier yeah? (like that multiply/divide with tanx)
yeah that means you didn't use the product rule of limits correctly
but I did here though
no, because for the product rule, both limits have to exist
otherwise you could do $$1 = \lim_{x \to 0} \frac{ \sin x}{x} = \left(\lim_{x \to 0} \sin x\right) \left(\lim_{x \to 0} \frac 1x\right) = 0 \cdot \infty$$
haseeb ♥
oh yeah makes sense
Alright then, that should do it
thank you for your help🫡
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How the fuck do I take the limit here? I can't take the limit here.
to what?
Take screenshot of your questions, this picture resolution so bad
Much better
you would need to take a_n+1 divide by a_n
$\frac{x^{n+1}}{(n+1)^44^{n+1}} /\frac{x^n}{n^44^n}$
Minλ
Yup, that's what I tried to do. And with whatever rule that causes you to flip the denominator and multiply with numerator
What do I do about this?
now, isn't it be: $\frac{x^{n+1}}{(n+1)^44^{n+1}} \frac{n^44^n}{x^n}$
Minλ
n^4/(n+1)^4 is the part affected by the limit
but when n approach infinity, what does it say
infinity over infinity? I tried putting 1 for the limit and it didn't work.
notice $\frac{n^4}{(n+1)^4}$
Minλ
Minλ
it didn't accept zero either
which is: $\frac{x}{4} \frac{n^4}{(n+1)^4}$
Minλ
if infinitely decreasing is what you're implying
so, is n+1 similar to n if they both approach infinity?
the results are all infinity
and yes, I tried seperating that out, I don't know what the limit of n^4/n+1^4
do you agree that if n approach infinity, then n+1 and n also approach infinity?
which means: n and n+1 are equivalent as n -> inf
yes, so it's infinity over infinity. That leads to 1, which it did not accept
Minλ
what, the limit?
yes
ohhhh, I tried x/4, I probably should have put in the absolute value
yup! that's correct. and it was my last attempt too.
lucky!
no problem man
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$2026$ towns want to create a security network, such that $\$ $(i)$ between any two towns, there is a connection between them. $\$ $(ii)$ each connection has an encrypted number, which is a positive integer not exceeding $k$. $\$ $(iii)$ A towns security number is defined as the sum of the encrypted numbers of every connection to that town. $\$ A group of towns is called secure if all security numbers between each town are pairwise distinct. Determine the minimum $k$ such that all 2026 towns are secure
Copter
i dont really know how to think of this
but clearly k = 1 isnt possible
now if k = 2 the possible values of the 2026 distinct numbers are {2025,2026,...,4050} but then 2025 is only possible if all connections leading to it have only the number 1 and 4050 happens if all connections are 2
which clearly cant happen at the same time
idk about k =3
@lime crest Has your question been resolved?
For $n = 2026$, let's check if the sum of the set is even: The sum of $2025$ to $4050$ (a total of 2026 terms).$\text{Total} = \frac{2026}{2} \times (2025 + 4050) = 1013 \times 6075$. The result is Odd. Since the result is odd, this set of numbers is impossible to use. We must raise the largest number by at least 1 place to make the sum even. Therefore, the maximum security value ($S_{max}$) we need is at least $2n - 1$.
ShiroSharata
because the result of the parity calculation is odd
then you have to increase the largest number by at least 1 level so that the total is even.
what does n represent here 
2026
$$2n - 1$$
$$2(2026) - 1$$
$$4051$$
ShiroSharata
i dont understand what youre trying to do, sorry
$$(n-1)k \ge 2n - 1$$
This is the formula for determining the minimum value of K.
ShiroSharata
try find the K, i will explain it more
k should be 3 then?
true but do you really know how it works?
not really ;-;
go try find the K, n=2026
@lime crest Has your question been resolved?
Ignore the above because I think they’re conflating obtaining a bound with exhibiting a construction
Consider making each town’s security number a monotone function of its index
If you think of the edge labels as a symmetric $2026 \times 2026$ matrix, then the security number of town $i$ is just the sum of row $i$, meaning you want to fill the matrix so that all of the row sums are different
Civil Service Pigeon
A natural way to do this is to consider making a rule based on ||i+j|| (why?) if you don’t see why, ||consider diagonal bands||.
tldr:
,texsp ||Label the towns $1, \dots, 2026$. Then try to fill in the blanks:
$$w_{ij}=\begin{cases} 1, & i+j \leq \boxed{\cdots} \ 2, & \boxed{\cdots} i+j \leq \boxed{\cdots} \ 3, & i+j \geq \boxed{\cdots} \end{cases}$$||
Civil Service Pigeon
wij is the entry right
@lime crest Has your question been resolved?
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why did I get this wrong?
For $x$ you should've brought the $-2x$ to the other side first. What you shoud have is $3x - 7 = -4$.
Azyrashacorki
And similarly for $z$ : you should have gotten $z + 7 = -14 - 2z$ whence $3z + 7 = -14$.
Azyrashacorki
Yes :c
what about this
I understand this shoudve been one of my response so dont explain this
just this
As you take x to infinity, cos(x)/x goes to 0, but sin(x) oscillates between -1 and 1 so it doesn't set on a particular value
dont forget about this one
the limit of sin(x) DNE
also i know why i got this wrong but "are continuous" should also be a correct answer
because they the lhs and rhs limit are equal
there should be continuous
limits being continuous is wrong terminology
Functions are continuous or not
You are messing up the math vocabulary
fair enough
A limit can exist or it cannot and that's about it
And if limits agree on both sides then you can conclude continuity, given the function value is the limit
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Prove that zeta(3) + zeta(2) < 3
a kind of silly way to do it would be computing the first few terms and then bounding the rest by doing the cauchy condensation thing
this kind of works btw, you dont need too many terms
but there might be more elegant sol
hmm possibly integral
yeah that might be nicer
maybe remove the 1's first and then do an integral upper bound
yeah, removing first few terms and then integral upper bound is prolly the intended way to do it
my bound comes out to be exactly 3
@orchid coral Has your question been resolved?
Hi, please take casual convo to #discussion or #chill
oops I thought this was the general one 😅
Thank you for reminding
one last way i can think of would be making it telescope
@orchid coral can you explain where you're stuck at btw?
or what do you not understand about what ive said
or what else are you looking for
@orchid coral Has your question been resolved?
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if $u, v$ are linear maps in finite dim such that $uv - vu$ has rank $1$, show that there's a base in which both are upper triangular
In the solution, they first proved that either Im $v$ or Ker $v$ is invariant under $u$. In the latter case we find a common eigenvector and we find the other eigenvectors by induction. However in the first case I don't see how to conclude
bloubbloub
in the first case, we have $Im(uv - vu) \subset Im(v)$ also
bloubbloub
@shadow marlin Has your question been resolved?
what if Im v is the whole space
@shadow marlin Has your question been resolved?
@shadow marlin Has your question been resolved?
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test
test 2
.pin
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w Civil Service Pigeon
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hi
what are level curves?
the level curves of a function of two variables, say f, is the set of all points (x,y) satisfying f(x,y) = C where C is a constant
for example x^2 + y^2 = 9 and x^2 + y^2 = 25 are level curves of the function f(x,y) = x^2 + y^2 (which also happen to be circles)
okay right – and sorry if this sounds rude but what is the significance of them? How can they help me understand other multivariable concepts? The way I understand it is that they are conventionally taught early in multivar courses
well they are used in visualizing multivariable functions, for example a contour plot of a function is just plotting a bunch of level curves (usually picking the constants to use at even intervals)
you can also understand the gradient of a two variable function geometrically as being perpendicular to its level curves
sorry i am thinking
is it silly of me that i have trouble understanding contour graphs
i cant tell whether a layer is higher than another
i feel like im drawing a heat map except there is no heat
how do i determine which level is above another level by looking at a contour graph
@latent gazelle Has your question been resolved?
you can only tell what the values are based on the labels
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I love help channels without comtext
Note that any prime factor of k^2q will be a factor of either k or q
Then what does the fact that k and q are coprime tell you?
i got stuck dont know how to continue
dont understand
the prime factor it cant be a factor of both k and q bec gcd(k,q) = 1, k and q are coprime
gcd(k,q) = 1, so?
@spring haven
You can note k²=l
And you get d=7⁶gcd(l×q,7²(l+q²))
|| I think that's right||
@gentle zephyr Has your question been resolved?
the person who responded didnt cared to explain how he got there, and the idea of a help channel is to guide someone to the solution instead of spitting out the answer?
well u need hand holding not guidance
what?
do you understand how the other person got there?
seems to me like he kinda skipped a lot of steps and dont care to explain
he just spitted the answer without explaining how dude
nobody is helping really
nobody really understands how the guy got there, he just skipped a bunch of steps and wants me to guess until I get to what he got\
@gentle zephyr Has your question been resolved?
They just looked at the expressions in the gcd and found multiples of x and y such that their sum is just in terms of k. Then did the same for q
Like say you want to just keep $q$'s in there. \
On the left you have $x=k^2q$ and on the right you have $y= 49k^2 + 49q^2$.\
Surely for terms with $k$'s to cancel, you want some term of the form $k^2q$ on the right, and if you multiply $x$ by $q$ you get $49k^2q + 49q^3$. Now the only thing missing is that in $x$ you only have $k^2q$, not $49k^2q$. This suggests you might want to take $49x = 49k^2q$. \
Then since the gcd divides any integer combination of $x$ and $y$, you get that it must divide $qy - 49x$, which is just $49q^3$.
Azyrashacorki
If you want to just keep $k$'s, then you want $q^2$ on the left, so $qx = k^2q^2$ seems like a good choice. \
Now $y$ contains only $q^2$, so we need a term in there with $k^2q^2$. Then if you take $k^2 y$ you get $49k^4 + 49k^2q^2$.\
So far you get $k^2 y = 49k^4 + 49k^2 q^2$ and $qx = k^2q^2$, so if you take $k^2y - 49qx$, you end up with $49k^4,$ which the gcd must divide.
Azyrashacorki
So now you know $d = 7^6 r$ where $r$ divides both $49k^4$ and $49q^3$
Azyrashacorki
ok so
x = k^2 . q
y = 49k^2 + 49q^2
so if d' = gcd(x,y) then d' | ax + by forall a,b in Z
qx = k^2 . q^2
k^2 . y = 49k^4 + 49 . k^2 . q^2
k^2 . y = 49k^2(k^2 + q^2)
49qx = 49 . k^2 . q^2
k^2 . y - 49qx = 49k^2(k^2 + q^2) - 49 . k^2 . q^2
k^2 .y - 49qx = 49k^2(k^2 + q^2 - q^2)
k^2 . y - 49qx = 49k^4
but now what?
What do you mean now what?
Then you get $k^2 y - 49qx = 49k^4 + 49k^2q^2 - 49k^2q^2 = 49k^4.$
Azyrashacorki
$k^2y - 49qx$ is an integer combination of $x$ and $y$, so $r$ must divide it
Azyrashacorki
So in particular, $r$ divides $49k^4$
Azyrashacorki
by r you mean d'?
i see
at the end we get that
d' | 49q^3
and
d' | 49k^4
@blissful meadow but after that, then what?
d' | gcd(49q^3, 49k^4) ?
Well k and q are coprime, so if r divides both of those it must divide 49...
So that restricts your choice of d', and hence of d, drastically
you lost me in there
wait a second
d' | gcd(49q^3, 49k^4) ?
is this true ^
?
d | x => x = d.k
x^3 = (d.k) ^3
x^3 = d^3 . k^3
let k^3 = m
where m in Z
x^3 = d^3.m => d^3 | x^3
d^3 | x^3 => x^3 = d^3 . m
x^3 = d . d^2 . m
let u = d^2 . m
x^3 = d .u
d | x^3
care to explain?
What do you mean?
This shows that d' must divide 49
What numbers can divide 49?
d' | 49k^3 => d' | 49k
d ' | 49q^3 => d' | 49q
?
Well if you want $d' | \gcd(49q^3, 49k^4) = 49 \gcd(q^3,k^4) = 49$
Azyrashacorki
Since q and k are coprime
how is gcd(q3, k4) = 1?\
.
but why
Why do you think?
i get that q and k are coprime
there must be a gcd property to make it more clear
Think about it.
I will try to prove it
suppose gcd(q^3, k^4) = v with v in Z \ {1}
then v | q^3 and v | k^4
You just need to show that if k and q are coprime, so are k^m and q^n
It's pretty much by definition of k and q being coprime...
i mean if m=n its straightforward
but in this case m ≠ n
.
k and q are coprime so gcd(k,q) = gcd(k,q)^n = gcd(k^n, q^n) = 1
What does it mean that k and q are coprime?
Apart from the fact that gcd(k,q) = 1
the only common divisor in both are 1
Ok, so if k and q don't share any divisor other than 1, what about k^m and q^n?
say for example the prime factorization of q is p1 p2 p3
then the prime factorization of q^n is p1^n p2^n p3^n
like exponentiation is not changing the primes that divide q or k
is just multiplying the exponent by n or m
if they are coprime then none of the primes that divide q are present in the prime factorization of k
Yes, so if you have a divisor of k^m and q^n, it needs to be a divisor of k and q, and the only one is 1.
nice
so d = 7^6 * 7^2 = 7^8
right?
No, d' must be a divisor of 49, not necessarily 49
i see
so d' is either 1,7,49
and d = 7^6 . d'
Yes
Yes, so then you need examples displaying those three values.
you are a lifesaver azyra
I really appreciate your help
I am rn in uni in a advanced calculus class, but I think I can continue from here
i would be busy with the lecture for like 2 hr more so I think I would close this and continue by myself when I get home
.solved thanks
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any math tutor?
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Renato
What have you tried
r is any real number satisfying condition given in each part
how to do this?
for (a) and (b) use epsilon definition of limit and given condition on r
thats only the definition for limit = 0, not the general one
which one is the general one
i shouldnt have to write it for u. should be in ur notes
there is a bunch of definitions
there is essentially only ONE epsilon definition. it should look like what u posted but for a general limit
thats functions not sequences
isnt a sequence a function from N to R
this is function on interval not sequence...
yes
Renato
if u dont understand the definition then ur not ready at all for this type of problem
pls review ur notes. they should have many examples to help u understand the definition
do u have a concrete question about n0?
then u do not understand the purpose of n0 in the definition
what is the purpose of n0
,w threshold
i guess so, it has to start somewhere, is just tough to grasp somehow
n0 always = 1?
i dont really get it, if (an)_(n in N) then n0 = 1
forall epsilon > 0, there exists some n0 in N such that |an - L| < epsilon forall n >= n0
thats for the convergence of a sequence to L
"exists n0" follows "forall epsilon", so n0 generally depends on epsilon
the main part of an epsilon proof is to find the correct n0
for example 3.1.3 n0=1 works and so does n0=100
for other types of sequences the correct n0 is not as simple. see example 3.1.4
my time is up. i need to eat dinner. pls ask follow up questions and maybe other helpers can answer them
TO OTHER HELPERS: do not help with original problem until renato fully understands ALL textbook examples and prior exercises about epsilon definition of sequence limit
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how do you solve in 41 for AF?
and moreso, how do you inscribe the circle?
do i just adjust the compass until something fits? or is there a more formal process?
@hushed imp Has your question been resolved?
<@&286206848099549185>
Solve for the radius, use that to construct the centre (it's directly above the midpoint of AB), and draw the circle.

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im trying to self studying math, i know till high school level, from where should i and what should i study
try #study-discussion, this is for specific questions
A square be square see square
which field are you interested in?
computer science
Discrete Maths is a great start in early uni.
discrete math is probably your next stop then, assuming by high school you mean calculus at least.
"Guide to Linear Algebra" by David Towers was an amazing read for me as a first year computer science student
Calculus 1 also highly recommended (at least)
yeah i know calculus
how is this one "Linear-Algebra-by-Kenneth-Hoffman"
i haven't read that book
Help what's 2 + 2
6 or 7 I think
why.
and what about Analysis? , is that imp
<@&268886789983436800> I don't know if I should classify this as trolling or intrusion, but.
not much for CS.
ok
it's a 'nice to have' topic for computer scientists.
2 + 2 = 4 day mute, hope this helps!
but you probably aren't going to be dealing with a lot of epsilons and deltas in computer science.
alright, will try discrete then
thanks for now
!done, if you have nothing else. see you around.
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Someone help pls where i went wrong

,rccw
uhh, whats the issue? $\frac{2}{\sqrt2} = \sqrt2$, you got the answer you were expecting didnt you?
nice handwriting
Bacter14Fr0g

I had to prove LHS =RHS and they dont equal
are you having prob in 2*(1/sqrt2)
Yes but idk how do I get that from what I have
these two are equal
then this?
No thats fine, just to simplify the whole thing is the problem 
rewrite 2 as sqrt2 * sqrt2
huh?
you just proved no?
$2 = (\sqrt{2})^2$
Bacter14Fr0g
what other issue is left? you just cancel one of the sqrt2s
do u mean the fact the Qsn is lil bit too much wacky to simplify
nvm u carry on
no, this is wrong
How so
why did you multiply and divide there?
Oh wait over 1
I suggested a substitution
how u write 2 as (sqrt2)^2 / sqrt(2)^2
the latter side is just 1
and last time i check 2 isnt equal to 1
what is this simplified
a
Ohhk I understand it now
Aight anymore
Sure happens!
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Your wlcm!
Have a great day!!
U too 
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in an n×n grid, how many ways are there to fill the cells such that each row and column has exactly m filled cells?
ive seen alot of these types of questions and i want to know if theres a general solution
theres probably a gf based solution
hmm you could also view the matrix as an adjacency matrix of a bipartite graph
i have 0 clue on what you said

lemme search up the terms
ok i searched it up and the solution seems incredibly messy
yeah nvm then
thank you though
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It's the coefficient of $x_1^m\dots x_n^m y_1^m \dots y_n^m$ in $\prod_{i,j=1}^n (1+x_iy_j)$
kheer257
not that this is very useful
yeah
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If i get a vector addition problem that goes like:
Calculate the resultant vector of a person walking 12m East and then 15m North.
I know that the final answer will have a magnitute ( size in metres ) and direction ( angle in degrees ), and that I'm supposed to draw a triangle and then use pythagerous to calculate the unknown values.
Now this is what I know, but where I get confused is where am I supposed to draw the unknown angle? Because it can be in two different places.
I hope the question im trying to ask is clear if not lemme draw a diagram
If it's given in cardinal direction, you probrably want the angle as a true bearing. Calculate the (clockwise!) angle between your resultants and the vector pointing north, and that's the true bearing.
I'm bad at drawing with a mouse, but here i think is what I mean, inside the triangle I drew two unknown angles ( x ) which of those angles am I supposed to calculate in this question?
Im gonna be honest I have no clue what you're tryna say, whats cardinal direction? like compass direction?
Do you know the cosine rule?
Really sorry I gotta go. Hope someone else can help you
Law of cosines
yes adjacent/hypotenuse, but im not sure how that is relevant here.
No worries, thank you for trying to help. Have a good day!
so you know how to calculate the slanted side using pythogoras right
yeah a^2+b^2=c^2
And what is our goal exactly
to calculate the angle between the 12m and the slanted line?
Yes but thats my question how am I supposed to know that is the correct angle I'm supposed to calculate, because there is another angle that touches the slanted line.
They most definitely mean the angle from the 12m line, That's usually how the angle of a vector is calculated
it's called the argument of a vector
So in future questions am I just supposed to guess that the angle closest to the horizontal is the one I'm supposed to calculate? I thought there would be like a rule or something that I could follow.
well, usually vectors are in a (x,y)-plane, not in "north south west east"
and the common convention is to go from the x-axis in a counterclockwise motion
to the vector
I see, and how would a question like this differ if we were using the xy plane?
instead of east, we move 12 along the positive x-axis, and instead of north, we move 15 along the positive y axis
ahh and the angle im looking for is between those two lines correct?
the angle for your vector, is the angle between the positive x-axis, and the vector, moving counterclockwise
really important ^
Yes
okay I have one additonal question if you have the time
Sure
Generally speaking for questions like these when I'm looking for a size and an angle as the answer, is the angle I'm looking for always opposite the side length I calculated using pythagerous?
I hope I worded that properly.
because if i drew a triangle here with a slanted line, the line would be direct opposite the angle im supposed to find
Well I'm covering vectors and resultant forces in physics and im doing revision right now, Ill send you some of the examples from the notes im revising from give me a minute
Thanks!
which is probably a good sign i shouldn't go too into this cause i already spent 30m on this topic 😭
Hahahaha
Yes alright great
but where do we draw/measure the angle from?
when we say "moves 12 meters in the east direction" think of that as an arrow pointing to the right, with it's endpoint at 12
alright
and then "Then moves 15 meters north" think of an arrow from the endpoint of the previous arroww 15 up
and then the "resultant vector" is a vector from the origin 'so where you started' going straight to the endpoint of the 2nd arrow
as shown here
one sec let me draw it and u tell me if im right or not
Sure!
Really sorry I gotta go. Hope someone else can help you
yes compass direction
So like if you drew it on a plane, up would be north
and then you would calculate the angle between your resultant and a hypothetical north vector pointing straight up
@steep nest
sorry for the bad focus dunno what happened with my camera
one more question what is the direction of the hypotenuse in thsi triangle?
since i drew it from the orgin is it going up or down at an angle?
vectors always start from the origin
Okay holdup Ill draw it for you
it's simpler to explain
like this?
sounds good, I appreciate you taking the time to explain this to me btw.
ohhh i think i know what ur tryna say, since the vector started from the orgin i should also calculate the angle from the orgin right?
There we go
ahhh finally it all makes sense now
Good!
wait one last question to cement my understanding
The direction of this vector is pointing upwards so why isn't it the angle drawn where i drew it with the black ink?
They're trying to trick you by having the green arrow point the wrong way
or is it because it was drawn like this
they can do that?
I thought the arrow determinted the direction of the vector
by the way it was drawn i assumed the vector was drawn in the 2nd quadrant
Well you drew it correctly here
Im gonna be honest I have no idea why the arrow is facing the wrong way
sorry not 2nd, 1st quadrant
I think I need to switch resources this is the 2nd time these notes drew a wrong diagram that confused me
Yeah I think so too
Thanks for your help, this has been a productive chat and my understanding of vectors is much more clear now.
I appreciate you @steep nest , have a good day!
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That's good! you too!
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find the first 3 nonzero terms in the series for secx
what have u tried
for this we would have to find the first second third ... derivative
of secx
or we could use the identity
im just wondering which method is easier
i meant like find f' and f'' and f'''
I was trying to see if u could derive the first few terms from cos(x) taylor series
you can
thx
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<@&268886789983436800> mrbeast wants his mone :(
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im not sure what to do for q2
What do you get if you differentiate ln(1+x)
bro
I have had enough <@&268886789983436800>
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so (a) was easy
(b) took me way longer than it should have because i didnt realise since it started at the origin x = 0 when t = 0 for some reason
or at least didnt feel confident thats what it implied
but this keeps being a problem where i cant do a question because they hide the details i need to do it
(c) was fine
(d) im confused with
so where does it say that x has to be > 0
because if it's the mean then i thought zm = (1/2d)*integral from d to -d of 1/v dx
but the limit is from d to 0, not from d to -d
and because of this it's 1/d not 1/2d
but i dont know why
also for (e)
i dont know what they want because it is 1 mark
but thats probably because i cant do (d) so it means i cant do (e) either
and also v it's just really weird
oh wait it's a projectile
that's why for (d)
WHY IS IT TAKING ME SO LONG TO REALISE THIS TF
if this were a real exam i would have wasted 30+ minutes on this one question
just because it's taking me 2 business days to notice details in the question
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isn't this from ncert?
Yes u from cbse?
mhm 11th
Damn which stream?
pcm
well can you construct an equilateral triangle here?
Ohh yess
Yess
Yess
I gotta itt
Centroidd
2:1 ratio
Yes yes yes
Yesss
Tysm
yass
Tysmm
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