#help-33
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any examples?
nice question
and
See what happens when u square both sides of the equation you start with
Actually sorry
Wait would that work
and think about conjugate
do it for me!
Can't sorry
🥲
Usually if I do someone's labor I get a payment in return
But I'll help you come up with your own answer for free
i can give 0.1$
Tho in this case I might not know how
Nvm I forgot how OP the conjugate operator is
Try multiplying x-iy by it's conjugate
And then the right side by its resultant conjugate
Note that $\overline{z^n} = \overline{z}^n$
hiidostuff
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hello ,does anyone know hoe to do excel ? i did some in elementary school and i dont remember anything and i need it now if yes please text me ill see it probably after uni !
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I still cannot understand what is so called proof of work through his explanation
Can someone elaborate the term
any reason you didnt just link the yt vid itself?
anyway, you should elaborate on what you dont understand
The math behind cryptocurrencies.
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Some people have asked if thi...
what is proof of work exactly
I'm so confused, the explanation is so vague
there is a hash function. you can put values into it and get "random" values out
its impossible to "predict" what you get out
so if you want to get some value with a special form, then the only option you have is to try over and over again
this is a lot of work
eventually you succeed with getting a special input so that the relevant output has the form you want
and the fact that you even know this input is "proof" that you went through a lot of values to find it
because its very unlikely that you found it quickly
so the fact alone that you have it says that you did a lot of work
I do not have to put a lot work to find the number with 30 0s at its beginning. Maybe, I'm a lucky guy, I just throw a value randomly into it and get what I want
So the term "proof of work" is so vague, for people are not necessarily put a lot effort to find a special number.
its very unlikely that you got lucky
yes, its only a "proof", not actually a proper proof
but in practice its very much good enough
Like I said earlier a number with more zeroes doesn’t necessarily mean ppl put more work to find the number!
I dont know the actual numbers but you are legit just very very unlikely to be lucky
and this isnt just once, dont forget that
getting lucky once is easy
How do people tell which ledger got more computational “work”
getting lucky twice or more often? on average you just will have to do a lot of work
Let’s say I have 2 numbers which are 00001 and 10101
Which number has more computational work
That’s BS
this isnt about 2 numbers
this isnt about a coinflip
this is about billions of numbers
How the computer judge which ledger has more computational work
The video did not explain it well
But vague his way through it
@compact crescenteach hash counts as 1 hash
it's only about quantity
there's a target difficulty, but it's either met or not met
it's what people call "tha amount of zeroes" for some reason
ohhh
it's actually just compared against a number
target = 5
i make hashes that equal 3,4,5,6,7
3 and 4 get counted
now my ledger has 2×5 work
i guess 2 × (1/5)
what do you means you make that hashes equal 3,4,5,6,7. Hash is just some 256 bits of 1s and 0s with random order.
yeah they are large numbers
how can you make them equal 3,4,5,6,7
they are equal something
but not 3,4,5,6,7. Hash only contains 1 or 0.
i mean i convert the binary number to decimal
I see
how do you know it is 2*5 of work
how could you tell
lets say we have 7 bit numbers 0−127
(so the examples are easy to write)
if the target is 10, then each hash has 10/127 chance to be correct
what do you mean 0-127? from 0 to 127?
0 to 127 converted to 7 bit numbers that mere contains 1 and 0
is that what you mean
yes
would you mind explaning the term "target" like why each hash has 10/127 chance to be correct.
if the hashes were 2 bit, there would only be 4 difficulty settings
25%, 50%, 75% or 100% chance to meet the target
so like at maximum difficulty
00 counts
01 doesn't, 10 doesn't, 11 doesn't
which means if i show you 6 hashes it "proves" I actually "made" 24
and in my example my target is 10, so like the smallest 10 hashes count
That makes no sense, 6 hashes are 6 hashes.
would you mind explaining why the 6 turn out to be 24
if i want to find 6 blocks i would expect to make 24 hashes on average
because the chance is 1/4
the hashes have more bits, so the chance can be granularly adjusted
I see
difficulty is literally hash per block
(except in bitcoin they use units of 2^32 traditionally)
I see.
When we mention target in bitcoin, it would be a string made out of 1s and 0s.
yes
but it's just a number that the hash must be less than
and that number divided by 2^128 is exactly the chance to do that
or 256
i don't remember
yeah 256
target = 1/difficulty essentially
the more zeroes in the beginning of a string imply a harder target difficulty, am I right?
so yeah, you literally prove you made half quadrillion hashes by showing just one
yes more zeroes would imply harder difficulty
it's just that zeroes don't matter
it just sounds less boring i guess
so people don;t bounce off the explanation
I see it now
So the proof of work of a hash depends on how many zeroes are in the beginning of string
For example, there are two 4 bit numbers which are 0001 and 0011. The former have more proof of work done to it.
no
it matters what the target was
what was the chance that the hash is correct
i can;t tell from the hash how hard it was, it was easy if half the range was accepted when it was found
does it mean these two numbers have same amount of proof of work
I see
if the target has more bit, then the target difficulty would get higher. And if the bits of a hash matches the target more then it has more proof of work.
nah
the bits don't matter, just think of decimal nuimbers
and it's hard to write examples with realistic numbers, so i used 0 to 127
and then you think it's not how it works, like it's only an analogy
you show me a hash that says 7, the target was 10, so you hit the target, the size of the target is 10/127 of the range
I show you a hash of 7 while the target was 10 and I hit the target?
that is quite singular
why thank you
the target was 10, I'm supposed to get a hash that encoded the number 10 so I can hit it.
10 or less
ohhh
otherwise the target size doens;t change, it would only have one difficulty setting
you can imagine a literal target with a certain size
i don't care where you hit it
i care that you did
i can estimate how many arrows you had to shoot
I see
it's not harder to hit a 7 than a 9
but it's harder to hit a small thing than a large thing
so the amount of work is the sum of difficulties
inuitively it should actually estimate what happened, how much work was done by people
but of course luck is involved
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dim(W) < dim(S+T)
dim(S+T)=dim(S)+dim(T)-dim(S n T)
S :
- 4x1 + x2 - x4 = 0
- x 1 + x3 = 0
x1 = -x3
x2 = x4-4x1 = x4 -4(-x3) = x4 + 4x3
(x1,x2,x3,x4)=(-x3,x4+4x3,x3,x4)
x3(-1,4,1,0)+x4(0,1,0,1)
S = <(-1,4,1,0),(0,1,0,1)>
Which book so you follow for lin alg?
S n T :
a(-1,1,0,0)+b(4,0,1,1)
(x1,x2,x3,x4)=(-a+4b,a,b,b)
4x1+x2-x4 = 0
4(-a+4b)+a-b=0
-4a+16b+a-b=0
15b-3a=0
15b = 3a
5b = a
x1 + x3 = 0
(-a+4b)+b=0
-a+5b=0
5b=a
(-a+4b,a,b,b)=(-5b+4b,5b,b,b)
(-b,5b,b,b)=b(-1,5,1,1)
S n T = <(-1,5,1,1)>
the bibliography of the course is based on multiple books
dim(S+T)=dim(S)+dim(T)-dim(SnT)
dim(SnT)=1
dim(S)=2
dim(T)=2
dim(S+T)=2+2-1 = 3
dim(W) < dim(S+T)
dim(W) < dim(R^3)
dim(W) < 3
we need dim(W) not equal to 3 because then dim(W)=dim(S+T)
and if dim(S+T)=dim(W)
and W ⊂ S + T
then W = S+T
if W intersects with the orthogonal complement of S
and W is contained in S+T
then the orthogonal complement of S intersects with S+T
if W intersects with the orthogonal complement of T
and W is contained in S + T
then the orthogonal complement of T intersects S + T
@buoyant jetty Has your question been resolved?
Did I do anything wrong? I think I’m missing a term
I’m supposed to use a Pascal’s triangle to expand
But I’m unsure if I’m doing this right
I used to wrong one
That’s why
This can be closed now
Same issue
Am I doing the wrong row on the triangle?
@buoyant jetty Has your question been resolved?
is this question from like last year still
wdym
how long has this question been unsolved for
like a lot of time
I remember this question was active before I deleted discord lol
I am solving it
did you find the basis of S?
ye
can I have that for free 
basis vectors?
x2 = x4-4x1 = x4 -4(-x3) = x4 + 4x3
(x1,x2,x3,x4)=(-x3,x4+4x3,x3,x4)
x3(-1,4,1,0)+x4(0,1,0,1)
S = <(-1,4,1,0),(0,1,0,1)>
oh don't worry
oh thanks
I thought you didn't have the basis vectors when you sent that first message
,w rref {{4,1,0,-1,0},{1,0,1,0,0}}
have you found any W yetm
ii) x2 = 4x3 + x4
I found one vector from it
like, W is
dim(W) < dim(S+T)
because it cant be dim(W)=dim(S+T)
because W ⊂ S + T
dim(S+T)=dim(S)+dim(T)-dim(SnT)
dim(S+T)=2+2-dim(SnT)
S n T :
a(-1,1,0,0)+b(4,0,1,1)
(x1,x2,x3,x4)=(-a+4b,a,b,b)
4x1+x2-x4 = 0
4(-a+4b)+a-b=0
-4a+16b+a-b=0
15b-3a=0
15b = 3a
5b = a
x1 + x3 = 0
(-a+4b)+b=0
-a+5b=0
5b=a
(-a+4b,a,b,b)=(-5b+4b,5b,b,b)
(-b,5b,b,b)=b(-1,5,1,1)
S n T = <(-1,5,1,1)>
dim(S+T)=4-1 = 3
since dim(S+T)=3
and W is not S + T
dim(W) < dim(S+T)
dim(W) < 3
yeah that's fine
you know the span is the set of all possible linear combination of the vectors
ya
so S + T is the span of all the possible linear combination of the basis of S with the union of T
but strictly speaking union of subspaces does not exist because is not closed under addition
so S+T = span{S ∪ T}
yeah that's fine
anyways, lets assume W is dim 2
like if its dim(W)=1 then there exists a vector
v that intersects (S+T)∩(orthogonal complement of S) ∩ (orthogonal complement of T)
but thats too complicated
its simpler to find a W that is dim(W)=2 that satisfies this
let W = <w1,w2>
w1 ∈ (S+T)∩(orthogonal complement of S)
w2 ∈ (S+T)∩(orthogonal complement of T)
I can find a basis for S+ T
that is just placing the vectors S and the vectors of T as rows in a matrix and eliminating the redundant vector
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This question is wrong right? The pdf given doesnt integrate to 1? Also i cant find a cdf that works
,w int (x+2)/3 from 1 to 4
oofington
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question about sobolev spaces:
we know that delta dirac function is not in Lp hence not in Wmp and int he other hand we know form the definition of the sobolev space Wmp functions in Lp that have their derivatives in Lp. but for discontinuous functions that their derivative includes delta dirac function thus it iz not in Lp ? i need help to see how to deal with this
I would ask in #diff-geo-diff-top
thank you good sir
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how did we come with 2^5
Det(2B) = 2^5 * det(B) where 5 is the number of column in B
For A in M_n(K)
@split vigil Has your question been resolved?
Ohhh
Is this for any lambda in R
What is K
So it depends on the context right
Its just to make a generalisation
And what is n? Amount of columns in matrix
Got it
you matrix is a square so either column or row
As you want
Is the determinant of a nonsquare always zero
None
Non square doesn't have a det
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How to change y = -x² + 4x - 3 into a vertex form?
I know the basic but for this one it seems I can't factorize because -x² confused me
-x² + 4x + 4 -3 - 4 = y
if it helps you can factor out -1
you can rewrite it as -(x³-4x+3)
I see
-(x² - 4x + 4 - 3 - 4) = y
-([x - 2]² - 7) = y
-(x-2)² + 7 = y
Alright thank you
.close
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So the rule for inverting a circle is Rz (In this case I’m inverting the admittance, admittance is the inversion of impedance, Y = 1/Z, Z=1/Y)
Rz = (Zmax-Zmin)/2, where Zmax = 1/Ymin and Zmin = 1/Ymax. in this case we just read these values off the already drawn in circle. So let’s say Ymin is 0,11 - 0,26i and Ymax is 0,43 - 0,54i. For the calculation of Zmax and Zmin respectively, do I need the value of the Ymin and Ymin arrows, aka, would the answer to Zmax and Zmin be 1/sqrt(a^2 + b^2)?
Rz is the radius of the inverted locus/circle
Yellow here represents Siemens and blue represents ohm, but for the sole purpose of this being essentially maths, just think of the y axis as the imaginary axis and x axis as the real axis
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is 5 the only positive integer $n$ s.t. there exist positive integers $x>y$ satisfying $n=\frac{4xy}{x-y}$?
babario
clearly not, try $x = 3, y = 2$ for example
south
oh right, so any x=y+1, x=y+2, x=y+4 anymore?
also is there a way to generalize all $n$?
yes but I have no idea if that's exhaustive
babario
7 cant tho
Yes there is, but I won't guarantee there's a closed form
But first
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
find all positive integers as such
Do you have a pic or screenshot perhaps?
there
Hmm, start by cross multiplication and try factorising
uhh like b(4a+n)=na?
4ab - na + nb - n² = -n²
we can consider a and b as any two consecutive +ve integers right
or also a-b=2p or a-b=4p
and we wud get inf values of n?
p is?
Suppose a = dm, b = dn with (m,n) = 1, it follows that (mn, m - n) = 1 => N = 4dmn/(m - n) => (m - n) | 4d, or 4d = k(m - n), for some positive integer k
=> a = km(m-n)/4, b = kn(m - n)/4 and thus, N = kmn for positive integers k,m,n
From here, can you introduce a step to make sure a, b are integers indeed? As, for now you can see the 1/4 part sticks around
So for any +ve k,m,n s.t. m-n=0 mod 4 or k=0 mod 4?
Or like u said no closed form?
No, GCD(m,n) = 1, so m - n can't be even
So 4|k?
We must have 4|k or k = 4k'
Replace and we have, n = 4k'mn for any positive integers k',m,n
Mb. This can indeed be considered a closed form ig.
Yep thanks so much
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How do I deal with question c?
@brisk saffron Has your question been resolved?
<@&286206848099549185>
im pretty sure there is a physics and/or electrical engineering discord
probably going to get more responses there
this question was in my differential equations course assignment lol
but fair enough i'll try asking there too
thanks
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@brisk saffron Has your question been resolved?
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is it too late at this point to find difference of squares for denominator?
i should have done that first to get (x + 4)(x-4) and cancel the (x-4) factor on the numerator?
so there's no going back at this point?
how do you know what order to do things? i started here with the conjugate but it screwed me
someone asked the same question a while ago
u can put x as 4 wherever it doesnt make a difference
but if I put x as 4 i will get 0 at the numerator
i dont understand
like in the denominator
you can find the limit of just the denom?
for the 1st term
i didn't know you could do that
i thought you had to find the limit of everything once you start plugging in the limit value
wait that doesn't make sense tho, lets say i find limit when things are scaled by 1000, now my answer is 1000 times bigger
i shrink that and find the limit again
wouldn't it mess things up if i am just using limit for one term only?
oh
so L'hospital can save me
if I forgot to find difference of squares to begin with
it depends
i prefer plug and chug, i don't wanna be second guessing everything
lol, wrong advice?
bruv
they don't cancel when they're still x
or just take x-4 out common and cancel
No you so cannot do that
hahaha
That's bs
same shit bro
lol
no

did you try plugging x=4 into this?
Cancelling just a part of the expression in denominator by plugging whatever is bs
also why are you expanding the denominator
he told he expanded bymistake
the whole point of doing what you did was to eliminate the factor of x-4
like he didnt think much abt it
did you?
huh
Yes, $\frac{2\cancel{(x-4)}}{\cancel{(x-4)}(x+4)(\sqrt{2x+1}+3)}$
Arya
After cancelling you can go on with the plugging
knief
fuck it
that’s useful
that would be ideal first, before conjugate. but my question is, am i screwed if I do conjugate first?
you can’t do it before conjugate
No, that would not be possible as you do not have a (x-4) factor before rationalising
isn't it already tho? check the original
So rationalising, then cancelling is the right call
this is difference of squares for den before conjugate
the 2x-8 came after you multiplied by the conjugate
ya but difference of squares first is what i mean
what?
well where was i wrong 😭
before it becomes this mess
brother
Yeah, you need to do only that, just don't multiply conjugate in denominator also @long cape
this is FOIL before difference of squares
you could multiply by conjugate and then do difference of squared but you don't want to expand the demoninator. no FOIL needed
$\frac{2}{(x+4)(\sqrt{2x+1}+3)}$
knief
the x^2-16 to the (x-4)(x+4)
this difference of squares
that was canceled already
again, why are you expanding??!
we're talking about before then
no, just listen for a sec
i used conjugate first
multiplied everything by 1, but it screwed my denominator
made it messy
you're not following lmao
because you are supposed to leave it in factored form
ya, you really need to check original @wary kite
no dingus, you are not following
what they did was utterly useless
yes, whenever you multiply by the conjugate DO NOT FOIL. leave it in factored form

and counterproductive
i agree with that
this is the original question
but they're asking a question and you're not answering it
yes
just gimme a sec to ask it again knief
one minute i will ask it
ready?
before we jump ahead
so essentially you did the right think by multiplying by the conjugate. your mistake was that you foiled the denominator when you should have left it in factored form
yes exactly
$\frac{(\sqrt{2x+1}-3)(\sqrt{2x+1}+3)}{(x-4)(x+4)(\sqrt{2x+1}+3)} = \frac{2(x-4)}{(x-4)(x+4)(\sqrt{2x+1}+3)}$
then cancel the x-4
knief
but i am asking if i ONLY do the multiplication of conjugate first, leaving the den exactly as it is
i understand exactly what you did but as we tried explaining, what you did was wrong
you are doing both in that step
it doesn't matter which one comes first 🙂
i am trying to tell you that i did conjugate first, i did foil, and i ended up with a mess. is it too late to salvage it at this point?
yes. foiling it messed it up
$(x^2-16)(\sqrt{2x+1}+3) = (x-4)(x+4)(\sqrt{2x+1}+3)$
knief
it doesn’t matter if you decide to factor it later
dang, so even L'hospital's rule can't save it after foil?
why lhopitals rule
😭😭
it was suggested, i dunno
i dont see a way it could
he didn’t know what he was talking about
read above, someone else said it could be salvaged that way
the whole point of doing it this way was to not do lhopital
i'd argue that's incorrect
Yes, erase the second step, do not foil in den, only num, cancel the common factors, voila bon appetite
don't listen to whoever told you to use l'hopital
alright, so FOIL totally screwed me here
yes
after doing it with the algebra and canceling the x-4 it is no longer 0/0
🙈🙈
so my question here is: how do you know which to do first? start with conjugate, game over
start with difference of squares, you can solve it
it doesn’t matter what you do first
i just realised how wrong my answer was 😭 😭 😭
you're going to have to do both either way. multiply by conjugate and then factor the difference of squares, or factor difference of squares then mutliply by the conjugate
so why does FOIL mess it up?
knief told you like 5 times
that's the added step that is not wanted here
because then you lose the difference of squares and the (x-4) which went on to cancel
but even if we FOIL theres no method to UNFOIL?
say the question comes in that messy form
factoring, which would get you right back to where you started
ah, but it's just not too obvious here. no magic method to do it easily
right. foil just makes things messy
i always like to think of math as having equal forward and backward operations, you can always undo or redo, like a computer
but maybe some math doens't work like that?
brother the entire point of multiplying by the conjugate was to be able to cancel a factor in the numerator and denominator which was leading to the 0/0
sure it does but why would you ever distribute it just to go back to factored form?
ya i know, i'm just asking if i mess up and use FOIL by accident
then erase it and go back to the point where you didn't use foil
distributing never helps when we are finding limits?
almost never for these problems
in the denominator, distributing after rationalizing rarely helps
numerator you're usually good (but not always) to distribute
Bruh, we distributed in the numerator
sometimes it does?
any reason for that?
Similarly, you might need to distribute to rationalise the denom sometimes instead of the num
i hate to make a general statement that may be not true, so I didn't say never. I have not found a situation in which it is a good idea to distribute
so the denominator is usually the problem. we want to keep the factor that causes issues alone so we can find a way to cancel. often in these problems simplifying the numerator allows us to find a factor that will cancel
but like @tulip idol we did distribute in the numerator already
i mean it’s entirely possible that we have the reverse scenario though, where the radical expression is in the denominator
yes i was talking about the denominator, my bad
the whole point of distributing in the numerator was to utilize the difference of two squares to get rid of the sqrt
true, which is why i didn't make a general statement in the first place 😭
so you can’t generalize it to be exclusively forbidden to do so in the numerator/denominator
so it could be 50/50 chance to distribute or cancel in num/den?
it depends on the problem
there is no chance here..
you don’t just wing it lol
you use it when appropriate
essentially what I think we're getting at is you have to know what you're after. you find a problematic factor, and then simplify the other part (numerator or denominator) to cancel that factor
multiplying by a conjugate is designed to simplify the place where you have the conjugate, so it makes sense to distribute there
distribuiting in the other place often makes it worse
so as knief said, if you had the rational in the denominator, and you multiplied by the conjugate, you would want to distribute the denominator and i would hold off on foiling the numerator
consider going for a run
it's not a good use of time to try to generalize a method to all problems. you generalize more the more problems you do
OK, I think I just gotta find patterns maybe
I see something that can be factored (difference of squares) I should do it when finding the limit
and there's almost no way you're going to generalize from one problem alone

just use lhopital bro
the x-4 cancelling should be a common pattern as you do more problems. so go do more problems avid
if you don't use /s they might take it seriously
broo 😭 i get, my mistake 😭
You should really understand what it means for something to be of the form 0/0. You are just multiplying by the conjugate and doing arbitrary algebraic manipulations without a sense for what the end goal is.
True, I am trying things out to cancel variables wherever I can, but FOIL expansion in denominator just makes a mess of things
Following off what hexicle said, i think it's really important in math to understand why you're doing what you're doing so it doesn't lead to issues like this. before FOILing, ask yourself why you're foiling, and what you're hoping to get out of foiling.
Math is interesting where not every operation is reversible
for example integration and derivative, we lose the exact value of whatever C is
You are not trying to cancel whatever you can, there is only one thing that you are trying to cancel.
oh
what is that one thing I am trying to cancel called?
If you multiply three numbers together and the result is 0, do you agree that one of them is zero?
(and possibly more than that)
yes
So I will know I am finished whenever the den doesn't = 0
otherwise it's DNE and limit doesnt exist
so if you have something of the form 0/0 you agree there is some part on the top that is causing the zero, and some part ont he bottom that is causing the zero?
yeah, the top part is fine afaik, it's just the bottom that is the issue?
or both should not be 0? to find limits
You are trying to read ahead, and its not helping, you either agree or not
oh sorry
I thought I was following your logic
what do you need me to say here? agree or disagree?
agree
Okay, so if you plug in x = 4 in this case, some piece is causing the top to go to zero
and some piece is causing the bottom to go to zero
So your goal is to write it of the form (x-4) multiplied by some junk in the numerator, and (x-4) multiplied by some junk in the denominator
OH
because something that looks like (x-4) is causing the 0/0 and once that is gone, it won't go to zero anymore
now the denominator in your example
is (x-4)(x+4)*some_junk
and it doesn't matter what some_junk is
so most likely if the limit is 4 i wanna try to find a factor (x-4) to cancel that becoming 0
or if the limit is -2 i wanna find a factor (x+2) to cancel that becoming 0
all that matters is that it doesn't go to zero when you plug in x = 4
because your whole goal was to deal with the 0/0
so what you are saying, it's no coincidence that the factor i cancel for this function is (x-4) to find the limit towards 4
yes
and that's why distributing on the denominator is a waste of time
ya
you have (x-4) times something times something else
and you don't care what those 2 "somethings" are
as long as they are not 0
so I should be checking for both top and bottom of fraction? does numerator equal 0 at lim, does denominator equal 0 at lim
I don't really know what you are trying to say
is it more important i cancel bottom of fraction to not equal 0 at limit?
or is it just as important to have top of fraction not equal 0 at limit?
there are some number of terms on the top that are taking it to zero, and the same for the bottom
0/something is 0
but something/0 DNE which is a big problem
if there are more on top, like (x-4)^2/ (x-4) then the limit is going to go to 0 because you will have canceled all the terms causing the 0 on the denominator
ya
but either way, once you no longer have a 0/0 case after canceling, you now have separate problems that teach you how to deal with 0/nonzero, nonzero/0 etc
OK
I will have to review this for limits:
you now have separate problems that teach you how to deal with 0/nonzero, nonzero/0 etc
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Does anyone know what theorem is this (sorry it in my language)
what exactly is it saying?
is this the intermediate value theorem
function f is continuous and have derivative between I that have real number m,M and m<= f'(x)<=M and all a,b is in I, a<b
We have a inequality ... (Sorry for the bad translation)
yeah, thats what i thought too
this is intermediate value theorem (IVT)
or something similar to it
yes, its just the inequality version
$f'(c)=\frac{f(b)-f(a)}{b-a}$ for $c\in[a,b]$ for differentiable $f$ on $[a,b]$
I see
;(
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I need help with homework simply because I don't understand and would prefer is someone could help me step by step
post problem pls!!!
23 chicken wings were bought for 25.30$ what was the cost of each of the wings in dollars per wing ( asking me to write problem on the double number line then telling me to use multiplication and division to find the missing value )
use dimensional analysis
What??
we are given dollar and wing and we want dollar/wing
so what do u think we are going to do
I thought divide the 25.30 by 23
yeap
So 1.1 dollar per wing?
yeap
What about the then use multiplication and division part for finding missing value??
thats what it was.
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Does anyone have a explanation/video of why in implicit differentiation you have the dy/dx multiplied by your derivative of the y value?
wdym
how come this does not work?
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Do you mean why differentiating f(y) with respect to x yields f'(y) dy/dx?
I think that’s what it is yea
I just didn’t know how to formulate it lol
im new, is it one person needing help per channel or osm
Ye
Then it's by chain rule
alr
yeah. Check #❓how-to-get-help
And welcome to mathcord
Can you elaborate a bit?
dy/dx=dy/du*du/dx
Can you state what the chain rule says?
where u can be a function in y
so basically, let’s take y^2
2y*y’
our “outer” function is u^2
“inner” would be y
d/dx f(g(x))=f’(g(x))*g’(x)
Right, replace g(x) with y
I’m not familiar with the u symbol
So for example y^2 it would be 2y*dy/dx
it’s just another variable
Is this utilizing the chain rule?
yes
y doesn’t have an exact derivative w.r.t. x so we just notate it y’
This is misleading
It does
But it is not expressable in just terms of x
yeah but how you said it implies that the derivative of y does not exist
Ok ummm……. Why is y^2 a composite function that requires an outside and inner function?
because y is a function of x, and you compose that y function into a function that squares its input
“exact derivative” i didn’t say it doesn’t have one
I said how you worded it implies that.
you said "y doesn't have an exact derivative w.r.t x"
you make it sound like dy/dx does not exist
Okay I think my roots of calculus aren’t super strong so I dont really comprehend it. But dy/dx means how much y changes at a very small movement in change of x?
Or like the slope of y with respect to x?
yes
Ok for y^2 we are imagining it as f(x) because we are trying to find the derivative of the value with respect to x
So how does that plug into the chain rule if we use this
A video I’m watching says that the f(x) becomes the squared value and g(x) is the y
yeah
reference from here
So when you take the derivative of y (the inner function) what do you get?
y'
like, you cant explicitly take the derivative of y and get an output in terms of x
@austere scroll Has your question been resolved?
Do you understand what explicit differentiation is?
@austere scroll Has your question been resolved?
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anyone please example this
i'm so confused by the calculation
how a=02c and how it turn into 004c^2 while substituting
<@&286206848099549185>
(0.2)^2=0.04
can you explain fully i'm still confused
as per your answer 0.04 still have ^2
first of all how does a = 0.2
a/c = 0.2
There is a mistake there, tan Θ should be equal to a/b not b/a.
I think that’s a typo.
ok but what about the equation under the "by the pythagorean thoerem"
That one is correct.
should i change to other book for learning trigo or contince this one
ok
I would recommend you change.
There are better trigonometry books out there.
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hi
i have problem on proving traingle as similar
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could someone please help me with this?
Mock Exam ?
yes its so gay
genuinely need help w it
@tulip idol can you help me?
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@limpid lagoon Has your question been resolved?
3 is also a factor of 15 btw
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*In interviews with 200 individuals in these workplaces, it was found that 85 suffered from mental illness, 80 suffered from alcohol addiction, and 60 suffered from both.
a) Fill out the table.
b) Calculate the proportions.*
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@woven condor Has your question been resolved?
P(A and B)=P(A)+P(B)-P(A or B)
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$6x^2 + (m-1)x - m = 0$ find m knowing that x is 1/2
Simon James B
okay so we have $6(1/2)^2 + (m-1)(1/2) - m = 0$
Simon James B
i am doing something wrong somehwere idk where tho
so then we get $6(1/4) + (m-1)/2 -m = 0$ right?
Simon James B
then we get $6/4 + (m-1)/2 -m = 0$
Simon James B
okay so now $3/2 + (m-1)/2 - 2m/2 = 0$ ?
Simon James B
thanks:) ok now $2 -m /2$?
Simon James B
3 -1 would give us the 2 and m-2m would be -m?
It should be (3+m-1-2m)/2 = 0
Arya
yes and 3-1 is 2 and m-2m is -m
oh
yea
so 2m = 0
no
2-m = 0
-m = 2
m=2
Nice
but there is more to it
If you want to check, you can substitute the m you get to the original equation and check if its right
NOooooo
if you multiply - on both sides don't you get -2
2 - m = 0 => 2 = m ✓✓✓✓
2 - m = 0.
divide 2 on both sides
2/2 -m = 0/2
-m = 0
divide by - on both
m = -2
oh i see it
bruh
i am so dumb
how am i getting so stuck on a equation that easy😭
can i please get a explanation why is m 2 and not -2 i do not understand this
nevermind i got it
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Hi
Does anyone know how to solve through Jordan normal forms?
I need to . Write the Jordan normal form of the matrix A, if
A = [[2, 0, - 2, - 1],
[2, 3, - 4, - 2],
[- 1, 1, 1, 1],
[3, - 2, - 2, - 2]]
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What is exactly is the purpose of this equation? I sort of get how they are equal since both find the integral from -inf to +inf but if you can break down the integral from -inf to a and a to +inf, what’s the purpose of breaking it down even more with a point b?
you can break up the interval into finitely many segments, and the integral will still be the same
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HI
sorry
Its ok tro ❤️
do u need any help
yes
tan(3x + pi/4) = cot(2x)
Ive been ripping my hair out over this How are you supposed to solve this
tan(3x + pi/4) = 1/tan(2x)
tan(3x + pi/4)tan(2x) = 1 assuming tan(2x) is not 0
and then what.
And then i tried
have you converted tan(x+pi/4) into something get
cot x = tan(pi/2 - x)
how does that make any sense
u should get pie over 20
hold on
Oh my god this works because x is negative
you can convert the cot into a tangent, then just solve the inside equations
good luck
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✅
Nevermind
UHm
How am i supposed to do this
Im trying to use the general solution but i think i fucked up
i got ( (pi * n) + (pi/4) ) / 6.....
Which does not look right at all
i’m assuming you did tan(3x+pi/4)=tan(pi/2-2x) then equated the insides
3x+pi/4=pi/2-2x+npi
not at all
now try this
Wait how did i get division 6
idk lol
Holddddddd onnnn
3x + 2x = pi/2 - pi/4 + npi
5x = pi/4 + npi
x = pi/20 + pi/5 * n
OHHhhhhhHHh wait i just realized what idid wrong
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yw!
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If a sphere is in equilibrium and is not moving in a liquid of two liquids where a liquid of lower density than the other floats on top of the other one and the sphere's m/n volume is in the upper liquid and 1-m/n part in the lower liquid, how can we find it's density in terms of the m/n and the densities of the liquids?
I understand that we have to equate the weight of the sphere by the resultant force (which is 0) of the two liquids, but I fail to understand how the upper liquid is exerting any buoyant force on the sphere that is beneath it.
@potent reef Has your question been resolved?
it is exerting a buoyant force downward
the buoyant force described by archimedes' law is the net force from the liquid pushing from all directions
Is the weight of the liquid exerting the buoyant force?
How can it even exert a buoyant force from above?
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yo so for question 3
this was the system i put
and then i graphed it. this is the correct graph right? if so, how would i find the vertices
<@&286206848099549185>
pls ping me when u respond
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can u help tho
i can barely read the question
this is my question
<@&286206848099549185>
pls ping when u respond i don’t have notifs for regular mssgs
<@&286206848099549185>
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ping once, did you even read it?
yes it hasn’t been answered for 15 mins
that’s why i pinged
lol
maybe u needa read it
what does this say?
pls stop trying to mini mod
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@hot cloud Has your question been resolved?
no
<@&268886789983436800>
people might not be inclined to help if you insult them lol
The helpers are volunteers
I think it's fine in this case
im sirry im js mad
okay
i would appreciate help
to find the vertices you would have to solve for when the lines touch, so e.g. solve
7x+4y=168
14x+2y=210
to get one vertex, then
7x+4y=168
14x+5y=252
for another, and so on until you've done all combinations
I think this is fine, at a glance
so to get a vertex we find the intersection of 2 lines
@hot cloud Has your question been resolved?
<@&286206848099549185>
didnt they answer you above ?
do you know how to solve systems of equations ?
so we solve
7x+4y<=168
14x+2y<=210
7x+4y<=168
14x+5y<=252
14x+2y<=210
14x+5y<=252
so we should have 3 vertices?
wait so
(12,21) (8,28) (13,14)
are these the vertices?
<@&286206848099549185> this is the question and for the vertices i got (13,14) (8,28) and 12,21 is that right
How many times are you going to use that ping
it’s been 15 mins
That's certainly a creative interpretation of the ping rules
for this question i didnt work it out but given what has been told to you by the others then yes these are the systems that you need
so we should have 3 vertices correct?
based on the fact we’re solving 3 system questions
although you are solving 3 systems of inequalities right ?


