#help-36
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so you can just calculate the potential
since it should be very easy for all of these
idk what you're saying 
it's just contrapositive
curl not 0 => not closed => not exact
idk i feel like i got mixed information
ok lets recap
ok hear me out dawg
big dawg
we have exact => closed
so
i need to find a potential function
so solve the system of PDEs
find that
if i can find it
ok cool
then
and we are done?

so like
- check curl = 0
- if curl is 0 then you might be able to find a potential
- if you can't find a potential, try to find a loop over which the integral is nonzero
irrotational 
not conservative
conservative means is the grad of something
usually called exact
irrotational means curl = 0
usually called closed
Are we checking curl = 0 because it is necessary for exactnesS?

ok i calculated it by hand
uh
yep seems 0
so curl f
= 0
so this is irrotantional
irrotiatonal
irrotational
so now the PDEs
just do the thing and boom boom it idk
u get xyz
ok
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could someone explain to me plz how they iterated this
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I dont get the choice of increments for the function
as in, why not the bottom is F(x + delta x, y)?
oh nvm
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yes
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A 415kg container is dropped at an altitude of 300m, ignoring air resistance, how long will it take to reach the ground
use
s = ut + 1/2 gt^2
sqrt(61.2)seconds?
also if this is the answer, would the speed of the container just before it hits the ground be 76.7m/s?
yeah
yep
if the container is attached to a parachute designed to produce a drag force that allows the container to reach a constant downward velocity at 6.0m/s, the magnitude of the drag force is 4070N?
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can you differentiate inequalities
not if you want the inequality to remain true
depends on the function points
lmao
so not usually
say f(x) < g(x), that's equivalent to g(x) - f(x) > 0, so you're basically asking, if a function is positive, does that mean its derivative is positive?
e^(-x) is a counterexample
found something
also, if g(x) is always larger than f(x), it doesn't necessarily mean that the derivative is larger
if g(x) = f(x) + c, g'(x) = f'(x) while g(x) might be greater/less than f(x)
(just one example)
^
1/x as well
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✅
apparently you can actually differentiate inequalities
no
not if, as bungo said, you want the inequality to remain
let's say f(x) > g(x), where f(x) = g(x) + 2
if you differentiate that
f'(x) > g'(x)
$\cos x > \sin x \implies -\sin x > \cos x$
NEON
BUT f'(x) = g'(x(
does that make sense
doesn't always hold
exactly
you can take a definite integral though
no i mean the original statement doesn't hold
on some restricted domain
oh
indefinites no
yes
aha
definites bc area under curve, remember
so you can do definite integrals
yes
but indefinite integrals and differentiation don't make sense here
yes
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Do not bother about the French text. I'm stuck on question 3. (b). Here is what is written before:
"We want to show that among random variables of given variance, those with the greatest entropy are those that follow a normal distribution. Let X1 → N(0, σ²) have density φ and X2 be a centered variable of density ƒ and variance σ². For simplicity we assume that ƒ is strictly positive on |R." (translated).
I've tried using the fact that they have the same expected value of 0 and the same variance, but I get nowhere. I don't get how we can find that considering there is no information on the position of f related to φ.
Wait I'm onto something
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if $f(x)$ is a periodic function on an interval say $[-T/2, T/2]$ with a period T , prove $\int_a^Tf\left(x\right)dx$ is periodic with the same period
Why am. I here
!original
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If you prove that $\int_{0}^{T}f(x)dx = \int_{0}^{2T}f(x)dx$, you are donr
just a min
made a mistake while posting the problem
It is known that $f(x)$ is an odd function in the interval $[-T/2, T/2]$ with period T. Prove $\int_a^xf\left(t\right)dt$ is also a periodic function with the same period
Why am. I here
You need to do two things in order to prove that the integral is periodic with period T.
- prove that integral from a to x = integral from a to x+T
- prove that T is the smallest such positive number
When you prove the second condition, you are showing that T is the "fundamental period"
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I am trying to prove the Cauchy-Schwarz inequality for complex numbers by algebraic manipulation.
the inequality states, for $z_1,\dots,z_n,w_1,\dots,w_n\in\mathbb{C}$ it holds that\
${\vert\sum\limits_{j=1}^n z_j\cdot w_j\vert}^2\leq\sum\limits_{j=1}^n\vert z_j\vert^2\cdot\sum\limits_{j=1}^n\vert w_j\vert^2.$
🇵🇸Mína🔆
i used that $z\cdot\overline{z}=\vert z\vert^2$
🇵🇸Mína🔆
basically two sides, on either one a product of two sums, which should yield a sum of $n^2$ terms. I don't understand how that is always not an equality?
🇵🇸Mína🔆
Because the terms are different in each side
In the left they will look like $z_iw_i\overline{z_j}\overline{w_j}$ and in the right like $z_i\overline{z_i}w_j\overline{w_j}$
d
and how can i shoe one is bigger than the other?
I don't remember the proof by algebraic manipulation, sorry
Well I found a proof
It is for real numbers
You just have to change a few things so that it works in the complex case
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I don't understand (G:H) = |G|/|H| if G is finite
doesn't |G|/|H| mean the number of all cosets?
But (G:H) means the number of "left" cosets
I'm confused
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|G| / |H| is just the number |G| divided by the number |H|
It's indeed the same as G:H, the number of left cosets, which is also the same as the number of right cosets
yes therefore |G|/|H| is the number of all cosets
so then
are all left cosets also right cosets?
does there exist b in G such that aH = Hb?
oh I see
If G is divided into some cosets
In the partition, they are either all left cosets or all right cosets
Is this right?
left cosets and right cosets cannot be mixed when I make a partiton of G
Not necessarily saying this. I'm just saying the following:
- The amount of aH
- The amount of Ha
Are the same number
They need not actually be the same cosets, but you'll find the same number of cosets. This number can quickly be found as |G| / |H|
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is my steps right to evaluate this limit?
sin(4x+4) = sin(4)cos(4x) + cos(4)sin(4x)
(sin(4)cos(4x) + cos(4)sin(4x))/sin(4x) = sin(4)/tan(4x) + cos(4)
lim sin(4)/tan(4x) = sin(4)/pi/2
so final ans is 2sin(4)/pi + cos(4)
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I believe I got Q1 and 2 but Im struggling on 3 and 4, I dont really know what to do.
Q1 I got 1/6(sin^6(x)) + 2x^3 + 1/3 e^3x + C
and Q2 I got 1
Idk of those two are even right
I have this as an example
but its not the same I dont think
unless L3 means 3 rectangles?
<@&286206848099549185>
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guys someone help me with this please
bro first one iseasy
1st eqn, 3x+3=4y+8
so 3x-4y=5
but the 2nd one is weird
cnt i write (1/2)3+x to the power of 2 cuz 1/2 squared is 1/4
so 6+2x=3y
bro but why, techincally 1/2)^2 is 1/4
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i'd use ${(\frac{1}{2})}^{3+z}={(\frac{1}{2})}^{2*(3y)}\
3+z=2*(3y)$
nico
yeah...
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My goal is to model the relationship between the track the front wheel produces and rear wheel of a bicycle in terms of functions. I have used a tractrix formula and derived it and found a paper online who had the following function but gloss over how they found it. How do I arive at that function from the tractrix function? This is what im stuck at -
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don't open multiple channels
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I dont see my other channel sorry
look in your history
nvm found it thank you .close
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How do i make a equation of a circle out of 3 points
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The arithmetic mean of the number of employees per floor in a given commercial building is equal to 45 employees. The first two floors of this building will undergo renovation and the employees on these floors will
will be distributed across the other floors. If during
reform, the arithmetic mean of the number of employees
per floor that is not under renovation will be equal to 50
employees, the number of employees in this building is...?
consider two unknowns, total number of employees, call it T and number of floors, call it n, can you write two equations relating these two quantities from the given info?
@steel ether ?
T = (A1 + An) . n / 2 The total number of employees is the sum of A.P.?
if we have n floors and there are an average of 45 people per floor, how many total people?
i'm not sure what you are trying to do there, but it is a lot simpler than that
I need to find the total number of employees but I just have the Middle term, basically
Can you do a step by step?
so if we have n floors and an average of 45 people per floor, we have this equation for the total people:
45n = T
i think you are overthinking this
now for the case where 2 floors are being cleaned, if we have 2 less floors in that case we have how many floors in terms of n?
yes
and we have an average of 50 people per floor
so we have 50(n-2) = T
so now this becomes easy to solve: we have
45n = T
50(n-2) = T
so we can set:
45n = 50(n - 2)
what is n?
20
yeah exactly, so the question is asking for the total number of people which is T, now we can finally solve for T by plugging n into the first equation
T = ?
900?
yeah, you can double check if the number seems to make sense and we can see that yeah if we have 900 total and 20 floors then we will have 900 / 20 = 45 average people per floor
and if 2 floors are getting cleaned, we have 900 / 18 = 50 average people per floor, numbers seem to check out
Awesome! Thanks a lot for help!
sure just remember this relationship between total = number of containers x average
in this case the floors are the "containers"
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hiiii
“The position function of an object moving along a straight line is represented by the
function s(t) = 2t^3 - 3t^2 - 36t + 6, where t
is in seconds and s is in metres.”
When is the object slowing down?
do i just use inequalities here?
idk
fixed
look at the sign of the appropriate derivative?
whether it's positive or negative
positive?
what does slowing down mean? what is happening with the velocity?
which derivative tells you whether the object is slowing down or speeding up?
when its below zero?
oh whoops
if i am going 60 miles an hour and slowing down to 40 miles an hour in my car, is my velocity negative at any point?
but on desmos after t = 0.5 it goes up
so its slowing down bsckwards?
the acceleration goes up
,w second derivative of 2t^3 - 3t^2 - 36t + 6
is it speeding up or slowing down when t < 0.5?
you might have to consider signs here since for example if something has velocity in the negative direction and the acceleration also has a negative sign then technically it is "speeding up" in the negative direction
yea this is rather poorly worded
velocity is going down right?
so when less then 0.5
speeding up
should probably be examining the derivative of |v(t)|
yeah, something like that or look for cases where: v is positive and a is negative OR v is negative and a is positive
at t = 1/2, a = 0 right?
like with math
yes
so at that instant it isn't slowing down, the reason you solve for that is because you want to examine intervals on either side of that, since you are working with polynomials which are continuous everywhere we know that the sign of a will not change for the interval t < 1/2 and it also won't change on the interval t > 1/2
so you can pick some random t in either of those intervals and use that to know the sign for all t in the interval
this is something you would have learned in some chapter discussing derivatives and continuity and whatnot
okay so should i plug in a t value bigger than 0 and then do v(t) * a(t)?
my teacher said when v(t)*a(t) is negative, its slowing down
bigger than 0.5
that's kind of a bad way nonintuitive way (at least if you don't understand the reasoning behind it) to think of it but yeah what they are saying is what i said here in so many other words:
"yeah, something like that or look for cases where: v is positive and a is negative OR v is negative and a is positive"
basically if you are traveling in the negative direction, then slowing down means accelerating in the positive direction right?
and traveling in the positive direction, then slowing down means accelerating in the negative direction right?
v(t) * a(t) will be negative when the signs of v(t) and a(t) are NOT the same i.e. what i said above
so yeah you can do that or just check sign of v(t) and compare against a(t)
no...i...don't have energy for this rn 😛
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What did I do wrong
you want to bring 5 to the other side to make it equal to 0#
You're missing an x = 0
That, too
Oh I didn't know I'm supposed to do that
Also, you've written out your work incorrectly... one sec
This makes it look like you're multiplying (x^2-x) with (3x-3)
The end result would have a 3x^3, which is why I thought you were missing an x=0
(you aren't, by the way - but the ones you have are wrong, because of the 5 mentioned earlier)
Also, why did you separate your 2x into -1x and +3x?
To get them back together, you'd need an addition sign here..
one set of parentheses butted up against another is for multiplication, not addition
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Hi so I got the correct magnitude and angle but the answer says above the horizontal. Using component method how would I know the it’s above the horizontal
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the left one has the right values
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Any good way to solve #39 mentally?
do you know trig/ ratios of sides of special triangles
No, do u need trig for this?
no, you don't but its one of the simplest ways to do it mentally if you do
Oh ok
Could u show me? I’m learning trig in school in the next few wks so I wouldn’t mind learning
look up special triangles
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Hellooo
you can subtract the curve from the line, which is the same as translating it up
then its just a normal disc integral
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@ember zodiac Has your question been resolved?
just wanna say u made me think i opened a channel lmao
:o hows the wife biggus
is your username a monty python reference ?
my favorite scene
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Don't you have to make one side =0 so you would subtract 3??
So that means the rest of it is wrong
so how am I going to see what they did "right" if they messed up in the first line
because x^2 is the only instance of x in the problem youre able to directly solve for x rather than factoring
this is probably a better explanation actually
I know how to do the math but I dont understand when
Cause like idk when I have to isolate the x or isolate the 0 or make the square root variables for the final line
Like it could go 4 different ways
so like if you had for example
ax^2 + bx = -c
you would watch to move the c over and set everything equal to zero
(ax^2 + bx + c = 0)
because x appears twice in the problem and theyre not like terms so they cant be combined
bx + c = 0
you would want to move the c over (bx = -c)
and then divide both sides by b to find x
idk if that was clear because the variables make it slightly confusing
lets say you have x^2 + 5x - 6 = 0
Can you put it in numbers
in this case you wouldnt want to move anything around because you have 2 instances of x that arent like terms
I dont understand this ajy+494
Okay so why dont I make it =0
so in your specific problem
-4x^2 + 19 = 3
so do you see how like
theres an x^2
and thats the only time that any variable appears in the problem
oh and I forgot the x squared
so do you see how in step 1 you initially subtracted 3 to make the equation equal 0
yeah
instead of that you could have subtracted 19 from both sides
which would have gotten you to the same place you are at in step 3
oh
do you see what im saying
Yeah
I did this at the end
How would I make it x=-2 and x=2 though
Make the 4 negative?
so basically
im not sure how to like explain this super well
but
if you square 2 what do you get
4
4
so everytime you take the square root of a number
the answer is positive or negative
because both -2^2 and 2^2 equal 4
also
i dont know if youre doing cubing as well
but
for like
even roots (square root, fourth root, sixth root, etc.)
the answer is pos or neg
For each cube is an equal amount of variables as well right
but that rule doesnt apply to odd roots
wdym
you automatically know that its cubed because the highest exponent is 3
do you need help w/ that one as well or do you know how to do it
im trying to do it right now
alright if you get stuck lmk
Is this right
since theres no perfect square in the square root of 27 it just stays
Hope I did it right
Wait it asks for x=
I dont think I did it right
9 * 3
3 times square root of 3 is like 5
wait okay r u allowed to use a calculator
ya
alright
i was doing it like
(7-3x)(7-3x)
49 - 21x - 21x + 9x^2
49 - 42x + 9x^2
9x^2 - 42x + 49 - 27 = 0
9x^2 - 42x + 22 = 0
yes
So how is that wrong
Is it 3 times square root of 9
i just think it might be more complex
wdym
I dont undestand like the number times square root stuff
And idek how to get the answer to this
It says x=
Idk how im going to get square root of 27 out
okay so
youre original equation was
(7-3x)^2 - 27 = 0
so
if youre wanting to do the square root method
you would move the 27 over
I did that
i did that
7-3x = sqrt27
yes
and okay so
with sqrt27
within 27 theres 9 which is a perfect square
so that gets to come out of the radical
sqrt of 9 is 3
so we bring a 3 out
no
9 times 3 is 27
but if you square 9 and 3 it doesnt equal 27
ya
so if you put the sqrt back its still true
ookaayy
does that make sense
so okay
because its 9 and 3
so we have
sqrt(9*3)
well we can take the square root of 9
and get 3
Square root of 9x3 is 5.196152423
dont multiply them back
we started with sqrt27
and we said okay well 9*3 equals 27
right
oik
so we have sqrt(9*3)
so
we can take the sqrt of the 9
and get 3
rigt
right*
yes 27 is 333
ok it
ok discord made it odd
3 times 3 times 3 is 27
yes
so when we have sqrt(9*3)
if we take the sqrt of the 9
and we get 3
we can now take that 3 out from under the sqrt
so we now have
3sqrt3
do you see how i got there
well ok so
sqrt(27) = sqrt(9*3) = sqrt(3 times 3 times 3)
right
all the same thing
yea
so
square root
when you square something you raise it to the second power
right
yeah
yeah if you take a number square it and then square root it is the same
4
yeah
like the number goes with the word
okay we want the square root
and we have 3 3s
so
we can take 2 of those 3s
out
because
squaring goes with the number 2
so u need a group of 2 of the same number
do you get what im saying
I dont think its supposed to be this deep
im in 9th grade
if this was what it was actually about none of my class would know a thing
ok the parentheses are to show that that is a group of 2
ok so like
normally in math
if you have a number that isnt a perfect square
like 3
and you have that as a part of your solution
unless they say to give it in decimals
they normally want you to just leave it as sqrt3
okay
yeah
so thats why you have to simplify the radical
instead of doing
Bro my teacher cannot be real
okay wait what r u confused on ab this
How to solve square roots that arent perfect
Like if it got square root of 36
What do I do
3 times square root of 3 is just 3 times square root of 3
because they dont want you to make it into a decial
decimal
they want you to leave it as 3 times square root of 3
But how does that equal 27
no
i'd have no idea
3 square root 3
okay
so
to put that 3
that is on the outside
back under the radical
you have to square it
because square and square root are opposites
under?
back into the root bar
back under the root bar
whatever word
idk
wait
that makes sense
Now how do I get that from square root of 27
Like if I got 3 times 9
then 3 x 3
ya
in my pic u see 9 and 3
and the little dot between them
that means multiply
9 times 3
wait a second
27
it would be 3 square root of 3
why
you did step 1 right
that would be 9
3 square root three
we just said
to get the outside three
back on the inside
we have to square it
right
so then we have 9 • 3 on the inside not 3 • 3
cause 9 square root of 3 would be 81 x 3
step 1 is correct
step 2 you should have divided both sides by negative 4, and gotten x^2 = 4
and then you would take square root of both sides
9 square root of 3 would be the square root of 81 * 3
I thought we have to square both sides
wdym
or is that only when it has parenthesis
wdym
When its like ex : (x+x)^2
You got to square root both sides
to get rid of the square
whats the other side
Idk its just an example
well like
if u said (x+y)^2 = 4
but if it doesnt then I dont because it doesnt habe the parenthesis
then yes ud sqrt both sides
if it doesnt have parentheses
wdym like if it said x+ y^2 = 4
Then you would subtract x
mhm
well like
if u were trying to solve for y
you would subtract x from both sides
and get y^2 = 4 - x
and then sqrt both sides
y = 2 - sqrtx
This has got to be right
Cause 1x2 = 2 x2 = 4
so square root of 4 is 1 square root of 2
Its got to be
the square root of 4 is 2
Is that the same thing
no
How?
Cause thats2x2
1 square root 2 is the same as square root 2
And you get 2x2 once you get it on the inside
okay if you have sqrt4
How??
okay so
uh huh
where
Oh yeah I see tyhat
How did they go from -4x^2 to -2x
Why didnt they just divide by -4
then it would be x^2=4
then square root both sides
they did that wrong
to get x=-2, 2
they should have divided by -4
ok so because we have a pair of 2s
they get to leave the radical
and then theres nothing left under the radical
so we just have
2
the answer is just 2
sqrt4 is 2
woooo
it is kinda wack
" Took the square root of a negative value on each side of the equation "
Wow a negative value that really helps
you cant take rhe square root of a negative
no sol
its not A
Wait
it could be A
But it says select the errors the student made
But answer A says the student should have
so how does that make sense 😭
its not A
yes correct
so if the student tried to do that
then that would be something they did wrong
C is wrong
because you cant do that
Cause they are multiply by -2 not 2
its not C
HUH
Oh its asking for their errors
not what they should have done
Wait I got x=2,-2 by myself
Yeah im trying to do square root of 18 rn
3 6
okay so
but since none of them are perfect squares its kept the same
ya
1 2 3
Yeah
yeah kind of
okay so what do we have a pair of
3s
3 square root 2
ooh
do u understand
yeah
Alright alright
yeah
whats it asking u to do
if u subtract 7 from both sides
u get
-3x = 3sqrt2 - 7
right okay
u understand how i got there right
ok
the other part
u can divide 3 out of the top and bottom of the other fraction
do u see that
yeah
then youd just leave it as -3sqrt2/4
so u have

