#help-10
1 messages · Page 387 of 1
I'll check.
ok ty
Hey @feral tide
ye
Look at Q.3
its wrong?
I think you are wrong there
ok
Say the distance is x
You get tan40=x/45
x=45.tan40=37feets
Q4 is correct
Q5 is correct
Whatever he said is wrong
U cannot do that
U have to convert sinx - cosx purely as sin or purely as cos function
So u have to multiply and divide by the square root of the sum of squares of coefficients of sin and cos
In this case that evaluates to root(1² +( -1²))
So 2 times (sinx - cos x)/root2
2 times sin(x-pi/4)
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what are the subgroups of the dihedral group D6 as permutations of the numbers 1-6?
<@&286206848099549185>
it doesnt, its wrong
then what do you want exactly
Wait so you know the subgroups
But not how to represent them?
Very different problems
@fresh copper
i want to know both
ill show u what im making
when i press the subgroup, it should highlight the elements
@rigid plaza
@rancid shadow
i dont know what the subgroups of D6 are and what elements are in them
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
1
Think of rotations and reflections
And how those act as generators of the dihedral group
How can use a subset of them as generators for the subgroups
Once you can identify all the subgroups
The next part is easy
Do you know what a dihedral group is?
so D6 is a regular hexagon
and the group of D6 means the ways u can rotate/reflect it to keep it the same
"Is" is a very strong term
ok not is, but you can interpret it as one
and i am using a hexagon with vertic as 1 2 3 4 5 6
You said it here
r60, r120, etc, and then a reflection over each vertici
You need a single reflection and a single r60 to generate the whole group
What other rotations will give you sub groups?
mupltilpes of 60?
Which ones give you unique subgroups
120,
Anyways after you have analyzed the structure in terms of reflections and rotations
Just draw a hexagon with vertices labeled to find permutations in terms of numbers
wdym the strcuture
@fresh copper Has your question been resolved?
hell naw
☠️
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i know the answer is 0 i just dont know wtf went wrong
ill rotate it
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.
is that the original q
^
ye
r u sure the answer is 0?
x/(x-1) + x
yep, the lecturer told so
what do you guys think
idk what went wrong
is that a ceiling function or a floor function
ohh its a floor function
yeah its 0
lemme explain
i do not know 
me neither -_-
The floor function ⌊x⌋ returns the greatest integer below the input (basically the nearest integer below it)
gif is also known as floor function
erm is this hs math or uni math or smth else
therefore, if x is approaching 1 from beneath it (from the negative side), the floor of all of those values no matter how close they are to 1 will be 0
uni
oh
im trying to study advance because my uni has online lectures uploaded on yt
icl theres not much more to it than knowing wht it is
u with me @outer cargo
!original
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well
we’re looking at values really close to 1, but below it
so x-1 is gonna be really close to 0, but below it
meaning that the floor function of all of these numbers will be -1
remember the subscript -, after the 1, just tells you that you’re approaching 1 from values below it
even the x-1?
okay i think i get it
i need more exercises
thank you
this means the floor function of x - 1 as x tends to 1⁻ is -1
nws
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kinda confused on what to do
in order to combine those fractions, you'll need all of them to have a common denominator
once you've done you can just add/subtract the numerators, while keeping the denominator the same]
whats the common denominator?
in this case it's gonna be 12x^2
ik that becasue, the lowest common multiple of 3, 4 and 6 will be 12
and the highest power of x there is x^2
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I have A^(-1) = [(detA)^2]/detA, can I cancel the determinant in the denominator and the square in the numerator?
Like we do using numbers?
the equation doesn't make sense, the LHS is a matrix and the RHS is a number
wait
let me show the original problem
@gilded needle
I have done this so far
You could stop here
Further simplifying would get you |A|^5 =1
Since the power is odd you could say
|A|=1
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Prove that { tan ( 135° +θ ) * tan ( 45° - θ ) = sin2θ - 1 / sin2θ + 1 }
@rough stump Has your question been resolved?
<@&286206848099549185>
Okay wait I'm doing it on paper
ok thanks
Is your question correct?
LHS is coming -1
wait let me re check
Real
sorry one this is wrong
Prove that { tan ( 135° + θ ) * tan ( 45° - θ ) = sin2θ - 1 / sin2θ + 1 }
sorry guys
Ok now it's right
I did this way too often 
can u teach me
It just takes some practice
ok
Exactly
That happens initially to all of us
Yeah there are some general patterns
True
Like if lhs has theta and rhs has 2 theta, usually you have to use sin2 theta or cos 2 theta stuff
Sure
The absolute least value of sqrt(2)* sinx - sqrt(2)*cosx is:
Absolute least value mean function smallest value? right
Yes.
-1 < = sin < = 1 , -1 < = cos < = 1
That approach won't work in this question
Haven't you heard of the concept of maximum and minimum value of f(x)=Asinx +Bcosx?
There's a general formula
I can show you if you haven't
hmmm
Hmmm means?
- sqrt ( a^2 + b^2 )
Yes
thinking
So in this case you need to use it.
it is 2
Not really
Yes.
but this is not correct option
Huh
nope
I believe the given answer is incorrect then.
0 will surely be a vaue at x=π/4
But that isn't the min.
I am from Pakistan
You Indian
Yep
Same here!
Can u tell me
Ooh
where minus go in above question when we solve tan (135)
What grade
12th
The - sign is multiplied inside the bracket
Also buddy sleep it's like 1.30 here I am done with school so I can do anything 😂
Same
Nicee
Nah I am going to us
Oh nice
Wbu?
I study late at Night it is 1:00 AM here
Yeah prepared for JEE now going to Jadavpur University EE
Us bro
Nicee, good luck!
No worries just take care of your health
12th was so stressful 😭
Thanks
Cbse?
Real, lost my socializing skillz fr
Ikr 💀
Nahh west Bengal board
Either way it's stressful 💀
Which uni are u going bro
!redir
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ok
Carnegie Mellon
Sorry
Woahh 😭
all good :)
Ok we'll leave now
Byee so nice talking to u
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I am 🙏
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wtf does this even mean
thats not even echelon is it
type 2 echelon matrix, is a regular upper triangle
with extra columns
and to say first and third colomns are basic, what?
basic columns are sometimes called pivoted or leading
pivoted
as in, that column has a pivot in RREF
meaning 0s infront
pivoted columns have a nonzero entry in that position in RREF
the first pivot is the 2 in the first column, so the first column is pivoted
then stair-stepping down by moving one down and one to the right, there isn't a 0 there so the second column isn't pivoted
the next nonzero entry at that level is the 5 in the third column, so the third column is pivoted
you could technically further simplify the second row by dividing by 5, yes
so summarising
2 and 5 are the leading elements of their respective rows so those columns are the pivots
or basic columns
you usually refer to the 2 and 5 as being the pivots
hm
and you say those columns are "pivoted" or "leading" or "basic"
just a terminology thing
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Hi I am confused why there are 2 cos^2
Where did this come from?
because the denominator of the fraction is cos^2
Ohhh
you could do sin/sin sure but it wouldnt be useful in any way
They just want it to be same?
they need a common denom to combine the terms into a single fraction
they have a/b + 1, and they want to write it as one fraction. by writing 1 as b/b, that becomes a/b + b/b = (a+b) / b
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✅
Sorry one more question
Why do we need to simplify this to begin with?
tan^2 looks simplified?
i wouldnt say you need to, its just what it wants you to do, having a single term is arguably simpler than multiple if possible
unless it asked you to i wouldnt stress about it
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I was studying for descrete mathematics(not really sure if it's the right name since im not a native english speaker). It's basically the base of the computer thinking, graphs, combinatorics, relations etc.. so not to prolong it too much the topic im confused about is combinatorics precisely combinations, for example question says you have a 5 digit number then, it has to be palindrom and the sum of all digits has to be 6, i have couple of setups im thinking about. I would split all possible forms of 5 digit number in "categories" so 1) the "shape" of the number should be aabaa 2) abbba etc.. the part im stuck at is the how do i set this up as a combination like n over k for combinations since aabaa can only be 1 number and it's 11211 but that's just using logic i want to know how to "mechanically" get to the answer coz i assume there won't be always logical answers or there might be just too many of them to do it this way. here's also a picture of how i was thinking
a
honestly its probably the best way of doing that, its a very simple problem and theres no need to overthink it. Once you get to more difficult ones they will force you to produce elegant and efficient solutions, since if there are for example 10^9 combiantions, you cant just count them.
thanks for your time and replying, i'd just correct you i am not overthinking it i just really need to know the usual route for exactly those purposes because i do know for a fact there won't be such easy problems so im trying to set up this particular "easy" problem so i can learn from it
oh and yeah the area of maths is called discrete mathematics
amazing
its a good way of learning, but this problem might just be too easy to look for another approaches. I think any other approach here would have to start with setting some constraints on the numbers, which is what you did, and that basically gives the answer
Discrete maths is in my opinion very intuition based class, you need to practice attention to details, this is essential especially when it comes to combinations and stuff like that. Concepts arent that difficult(they get more difficult at higher level), but yeah theres a lot of room for silly mistakes or wrong assumptions.
i understand that but i just got to it several days ago because i couldn't follow the lectures from university because of private reasons so any info on anything will be helpful in passing this exam
the only reason im just a bit irritated about this is that i can't see that way, for example counting all palindrom 5 digit numbers i just wouldn't know how to set that up that's what i was asking in the first place since there are a ton of them i can't count them
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If you labelled the digits $a_1, a_2, ...a_5$
For a palindrome
$$ a_1 = a_5, a_2 = a_4 $$
The number of non-negative solutions to this equation
$$ 2a_1 + 2a_2 + a_3 = 6 $$
StrangeQuarkAL
0 <= a_1, a_2, a_3 <= 6
a_1 > 0
Still gotta use some logic to count it but it's slightly easy I'd say
thanks for replying, im a bit confused on how do i use these i did pull them out as seen on picture i just had no idea how to use them so i just left it there
im assuming my labling is fine as well?
Yeah that's fine
i did get similar solution where it says 2a+2b+c=6 i just had no clue how do i use that
My answer was more in response to "how to mechanically"
yeah and im seeing the pattern, in these im just not really getting what these equations are telling me and i feel like im missing out on a lot
Well, all the variables are non-negative and definitely less than or equal to 6
so let me get this straight, not to bother you all night, is that equation able to tell me what the solutions are and if not what at least how many are there ?
like the exact numbers
It should be possible but I can't say I'm familiar with the methods unfortunately
yeah yeah understandable, doesn't matter imma dig anyways thanks a lot for reaching out you did put me on a right track tho so i appreciate it a lot
I usually just the equations to make it into a simpler exhaustive process
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theres a second part to this question\
b. Calculate an estimate of the lower boundary of the masses of the heaviest 50% of these animals.
a is 159 and b is 636
could someone explain to me how and why the answer to this is 23.5kg
like i first did 50% of 2226 which is 1113 so we know we get heaviest starting from number 1114
but afterwards then i calculated cumulative freq which showed me that 13-32 has 1590
but if we bring that in half to 13-22 and 23-32 which is a freq of 530 and 530 each
then we get to now 1060 which is even closer
then finally using that i got 23kg
but how do u get 23.5
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How do I solve this if the tangent of 270* is undefined?
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is this saying $s = \sqrt{((R-r)^2}+h^2)$
pixel
Well that extra parenthesis is unambiguously telling you it’s $s = \sqrt{(R-r)^2+h^2}$
Aslan
the root is all thw way
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whenever i put the matrice into my calculator it doesn't give me an answer, what am i doing wrong?
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am i supposed to reject?
at 0.05
@drifting nova Has your question been resolved?
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Just making sure I’m right on 2. I’m not exactly sure how to do this so I could be wrong, but the RREF form of the matrix just doesn’t make sense to me if U is a linear combination of those vectors. Do I have this right?
If your rref is correct then you’re right
Row 3 shows that the system is inconsistent right?
An inconsistent system means there does not exist a, b, c ∈ ℝ such that v = av₁ + bv₂ + cv₃
We’re allowed to use a calculator for RREF so I just did that
So you can’t make v out of a linear combination of v₁, v₂ and v₃
It’s correct!
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Hey! Trying to solve this problem regarding subspaces. It's from the "Linear Algebra Done Right" Textbook. I know how to prove if a set U is a subspace of a vector space V. There are 3 rules: 0 element in U, closed under addition, and closed under multiplication.
However, I am really struggling to understand what "set of continuous real-valued functions on the interval [0,1]" means, and what R^[0,1] means. I've been searching the internet to find an explanation and I can't.
In addition, I don't know how a "0 element" could exist in a set of functions. Also how can we be closed under multiplication if there are only functions and no scalars?
iirc, R^[0,1] is notation for the set of all functions f: [0,1] -> R
[0,1] is the domain (continuous interval)?
yes
would the function work on any number outside of [0,1]?
its defined domain would be specifically that interval
for example, f(x) = 0 is an element of R^[0,1]
any value in [0,1] is in the domain and gets mapped to a real number
ah okay awesome
so clearly continuous functions f: [0,1] -> R is a subset of R^[0,1]
just a matter of showing it's a subspace, i think you can prove all three conditions pretty easily
adding continuous functions gives a continuous function and since R is closed under addition, it's still real valued
scaling a continuous function by a constant gives a continuous function and since R is closed under multiplication, it's real valued
Ah
as for what the zero element looks like in a set of functions
the zero element is the unique "vector" such that if it's added to any other vector, that vector's value is unchanged after the addition
f(x) = 0?
Ohhh my gosh
are they the same?
are the two spaces the same?
yes
no
R^[0,1] is the set of all functions that map from [0,1] to R
but not every function is continuous
which means the space of all continuous functions mapping from [0,1] to R is a subset of that space
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Hi, I'm studying matrices and I had a question. If the rows of a matrix are linearly independent, does that also menat the determinant of A is 0?
Because I think its right in saying that if the columns of A are linearly dependent then the det of A is 0
Not as stated no
So I was thinking from another angle
May I ask why?
if the rows are LI (and it's a square matrix) then the det is nonzero
determinant is 0 when there's linear dependence, otherwise nonzero
Yea sorry I should mention that the matrix A is n * n
this could be column-wise or row-wise linear dependence since det(A) = det(A^T)
Ah sorry I see now
Okay so that means if the rows of A are linearly independent, then the detmerminant of A is not 0
I see, thank you all
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Consider the square ABCD and the points K (AB), L (BC) and M (CD) such that the Triangle AKLM is
rectangular isosceles, with the right angle in L. prove that the right AT and DK are perpendicular.
I think that the problem is really easy, yet I'm missing on a theorem or lemma.
Here's the drawing.
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@mint nebula Has your question been resolved?
<@&286206848099549185>
@mint nebula Has your question been resolved?
<@&286206848099549185>
theres not T in your drawing or in the explenation so AT is the T suppose to be something else?
I meant to say AL
not AT
oke well lets see then
oke so to prove that those are pupandicalair you got to prove that DKL~ ALK
and for that you need those variables that you already put in a and x
are kbl and lcm congruent?
we have ML = KL
and i think the agles LMC and KLB are congruent
@warm sparrow why do I need to prove that these triangles are similar
i don't think they even are similar
<@&286206848099549185>
yes?
i need help with this problem Consider the square ABCD and the points K (AB), L (BC) and M (CD) such that the Triangle AKLM is
rectangular isosceles, with the right angle in L. prove that the right AL and DK are perpendicular.
kk wait
alr
You can just length bash the whole thing
Solve for x
Solve for relevant lengths, And use converse of Pythagorean
assume teh square has side length 1
i'd rather go on a synthetic solve
rather than calculus
but idk
Can i get help with something in this channel?
no
Hooooow
yeah i would prefer that but the computation is direct, ill see if theres an elegant way
i'll do the same
i'm thinking ab what this guy said
yeah those are not similar
right
and also this is a 7th grade national olympics problem
they probably don't know computations lol
sorry AK=MC
yeah
so by difference AK = MC
ok note that DAK is congruent to ABC
Right
now you can just calculate the slope of the lines and multiply them to get -1
because if the product of the slopes is -1 they are perpendicular
let me see smth
let <AKD=x
then
focus on quadrilateral KBL(intersection)
what letter is labeled at the intersection? sorry i cant see
I didn't lable it. Let's say it's T
Ok
so KBLT
B has 90, TKL has 180 - x -
and the sum of all angles should be 360
yeah
and this gives <KTL=90
so they are perpendicular
i suggested slope because its also very easy
yeah true
rise/run = slope
so
AD/AK * -BL/AB
using the congruent triangles it simplifies to -1
what's nice about geometry is synthetic solving, at least thats what i like
good
but when you're absolutely out of ideas, you can do that too lol
i love synthetic
when you learn more advanced geometry youll see the beauty of synthetic
its absolutely amazing
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can you make a formula for the distance between the point and the equation perhaps
Yeah d = sqrt((x-3)^2 + (y-0)^2)
who is y?
So y would equal sqrt(x)
yes
we know who y is now lol
yea sorry mb
I don’t know how to get x
thats fine we have an equation for the distance in terms of only x correct?
I kno x = x^1/2
Yeah true
My b
I was trying to get x in terms of y
But I forgot we just need the objective in terms of one variable
so if we have an equation for d in terms of x, and we want to find the minium value of d what do we do
So I have sqrt(x^2-5x+9)
yep
exactly
So I need chain rule
yea
Is that just bringing the (x) to 1/x and putting. x’ on top?
Like x’/2x?
And x is the (x^2-5x+9)
sqrt(x^2 + x - 6sqrt(x) + 9)
Wut
i got sqrt(x^2-5x+9)
you need to decrease the power still
<@&268886789983436800>
Don't troll here.
Sorry, my bad. Read (0,3) instead of (3,0)
Oh yea
Ok let me try that again
Now solve for d’(x)=0
yes
And I can just multiply both side by denominator. So it is just 2x-5 = 0
yea or you can think of it like you cant divide by zero so the only way for the right hand side to be zero is for the top of the fraction to be zero
So i get x is 5/2
correct
Ok now get d(5/2)
we dont need the distance just the y coordinate now
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Hey can someone double check for me. I got 20 for my answer but the website says im wrong
perhaps it's supposed to be 2,000 because x is in 100 dollars
because x=20 is correct
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Where was my sign error?
sin^3(x)cos^2(x)
sin^2(x)sin(x)cos^2(x)
(1-cos^2(x))sin(x)cos^2(x)
(1-u^2)(u^2)
u^2-u^4
you missed the - sign
Where?
what is du?
forgot about the conversion of dx to du
oh
Youre right
Mb I need a break I have been studying for too long 😂
Thank you everyone
❤️
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Can someone please help me with this problem?
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
!showwork
Show your work, and if possible, explain where you are stuck.
1 or 2, I know the formula, but I don't know how to solve the integral from there
I checked calculators online, but they show up as a complex conjugate
can you draw a picture
@glass pilot Has your question been resolved?
What would the picture depict?
just a picture of the area, normal integral
oh
well, show the integral you've set up
@glass pilot Has your question been resolved?
Sorry for the late response I was travelling
you can distribute, and split this into two integrals
both can be solved with trig sub
@glass pilot
How do I do that?
@glass pilot Has your question been resolved?
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How
I see
Go study
ty
@brisk arrow Has your question been resolved?
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Can someone explain to me why $\sum\limits_{n=1}^{\infty}2\sin(\frac{3}{n})$ diverges? $n^\mathrm{th}$-term test is inconclusive here, I can't apply geometric tests, I can't apply power series tests, and we're not super far into series so I don't know how sine is described as a series. My gut instinct tells me that it does diverge since it oscillates, and i know that it does diverge anyways, but I don't know exactly why or how to prove it.
lILi
sin(3/n) approaches sin(0) = 1?
sin(0)=0
if it were 1 then the nth term test would have told me it diverges and it's the first thing i checked
when x is small, sinx is approximately x, so in particular greater than x/2
so for sufficiently large n the terms of the series are greater than the terms of a harmonic series
you can do limit comparison with 3/n
m
if you've not seen a formal definition of sine yet, I assume just stating that this is true will be fine in terms of rigour
so, since $2\sin(\frac{3}{n})>\frac{3}{n}$ for sufficiently large values of $n$, the comparison test still applies?
lILi
in calc, its common for people to be given lim x->0 sin(x)/x = 1
also I realise now that $2\sin(\frac{3}{n})$ doesn't oscillate on $n\geq1$
lILi
lILi
also yeah comparison test applies, because you can rewrite the series as (finitely many terms where the inequality doesn't work) + (still an infinite series where it does which is what you actually apply the test to)
0 < 3/n < pi?
Oh
fair
Alright, thanks for clearing that up for me
That makes sense now
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6a
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What do i do with the root
Where did the bottom factor go?
? Wdym
You just multiplied the numerator by 1+sqrt(sin^2(x))
$\frac{a}{b}\cdot \frac{c}{c} = \frac{ac}{bc}$
Azyrashacorki
That should help, along with the identity $\sin^2(x) + \cos^2(x) = 1$
Azyrashacorki
Hm, what do i do next?
Well the point isn't to cancel them out, otherwise you just did..nothing
Leave the factors there and expand the denominator.
Ohh
I think the right answer isn't shown in the answer choices..?
Might be
as is, you can just direct sub
(but that doesn't lead to any of the answer options)
do you have the intended answer?
No..
Oop didn't even think of plugging in 😅
I suspect they may have intended
x to pi/2 (instead of pi/3)
Hmm
I would take that up with the instructor if applicable
Tysmm yall
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hey could someone show me the equation to this?
they've actually given you the expression for the mass of the isotope over time
0.9174^t
just a matter of seeing when that equals 0.2
@rose ferry Has your question been resolved?
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Does Jordan’s Lemma hold true for any $f(z)$or is it only for functions of the form $f(z)= e^{izt}g(z)$? I’m seeing conflicting results online\
I’m looking within a textbook and saw a video which both stated $f(z) = e^{izt}g(z)$ but in a different video I’m looking at, the person just writes a generic $f(z)$\
Did the person make a mistake here or is the $e^{izt}$ just kinda implied here in a $\frac{a}{a}$ kinda way?
KySquared
So you generally use Jordan's Lemma to find the values of a path integral around a particular semicircular arc. The fact that it goes around the arc is where the exponential comes from, it's part of the parametrization of the curve.
So your function f(z) doesn't, in the general case, contain e^(izt), it's just that it picks up the e^(izt) because that's how we walk around a circular arc on the complex plane.
Wait how?
I understand rewriting z as Re^(it) but its not like that can get factored out…?
Wait
Are you considering the e^(izt) as getting factored out?
It's not that it gets factored out
Ok, so starting from the beginning. Let's take an ancient problem I solved once.
So this contains a detailed work up of a particular integral
The complex analysis started at "our contour"
So the idea is, I want to evaluate the integral on 0 to infinity. But I only know how to evaluate it on a closed contour because of the residue theorem, right?
So we set up a contour from -R to R along the real axis, and then a semicircular part with radius R
Our goal is to show that the semicircular part vanishes
Agreed
Everytime I tried so far I would manually show it goes to 0 by expanding and pulling out Re^(i*theta)’s
$$
\begin{align*}
\oint_C \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \int_{-R}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{R} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{\pi} \frac{{\left(R \mathrm{e}^{i \phi}\right)}^{-2/5}}{1 + {\left(R \mathrm{e}^{i \phi}\right)}^2} , iR\mathrm{e}^{i \phi} , \mathrm{d}\phi \
\lim_{R \rightarrow \infty} \int_0^{\pi} \frac{{\left(R \mathrm{e}^{i \phi}\right)}^{-2/5}}{1 + {\left(R \mathrm{e}^{i \phi}\right)}^2} , iR\mathrm{e}^{i \phi} , \mathrm{d}\phi &= 0 \
\oint_{C, R \rightarrow \infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \int_{-\infty}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{\infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z \
\int_{-\infty}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= - \int_0^{\infty} \frac{(-z)^{-2/5}}{1 + (-z)^2} , \mathrm{d}(-z) \
\oint_{C, R \rightarrow \infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \left(1 + \mathrm{e}^{-2\pi i/5}\right) \int_0^{\infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z \
\end{align*}
$$
OmnipotentEntity
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And then explicitly showing it goes to 0 like that
Oh it was cut off, how sad
So you notice that I have a few copies of this integral with minor changes
I don’t wanna do that each and every time and would prefer to just say “its 0 by jordan’s lemma”
But only one copy has the Re^(iφ)
Mhmm
Right, and that's fine
You switched back to writing it in terms of z for sone reason
Because it's pretty well understood that's what you're doing, if you're just doing applications
In the linked post, I had the linear integrals written as a function of z and the semicircular arc as a function of φ.
Is that the f(z)e^(ikz) part?
Mhmm
The point is that Jordan's Lemma only applies to arcs that limit to infinity
Right, im not worried about the limits
And these will have a term of e^(iφ)
Its specifically the functional part
Because they are circular arcs
Okay I think I get it
So your original function can be anything, f(z), but the circular arc part of the integral will be Re^(iφ) f(z) because that's the nature of arc integrals
Because $\int_c f(z) dz$ can be represented as $\int_{0}^{\pi} f(Re^{i\theta}) iRe^{i\theta} d\theta$ that is the functional representation that is satisfied for Jordan’s lemma because of the arc?
Only the semicircular arc portion of the contour integral
It's not the entire contour normally
KySquared
Yeah, I see what you're trying to say now
There we go
Nice grookey btw
I... haven't actually played any game since Red Blue. >_>

I pay a little bit of attention to competitive
Like YouTube stuff
I mostly just play poketwo, the discord game
I played alot of comp a few years back but mostly stopped bc of school
I was kinda losing interest regardless so I doubt I’ll get back to it
Who knows
Gotcha
Kinda wanted to try to make a showdown AI
Most the time I spend w/ pokemon nowadays is shiny hunting
Ooo that sounds cool
But haven't really sat down and figured out how to make that happen yet.
Like, a random battles NN AI would be sick
I know the very very basics of ML but if you’d like any sorta input I could try and throw my hat in the ring
Wouldn’t mind learning more ML
Especially since I considered going into data science lol
Anyway this is off topic. If you want discuss this we can jump over to #discussion or something. But I don't have anything smart to say about it really lol. I have done ML before, but not specifically reinforcement learning before.
@near cairn Has your question been resolved?
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i dont get why the correct answer is A not B. Is there flaws in my works?
<@&286206848099549185>
if you get g(x) from f(x), you must move fx along x-axis -2, multiply 5 along and move -1 along y
that's the reason correct one is A
that sounds kinda counter intuitive, does it have to do with the "operation in parenthesis is always opposite of what you see"
just in the case of x axis
yeah
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how do i do this question im really confused !?
well what’s the formula for speed
Well, the distance he ran is 450m
speed = distance by time
Hmm
exactly so how far has he travelled
but theres no time
you can work out the time
cause you have the speed for some sections and the distance travelled
yes
@marble robin Has your question been resolved?
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hey, how do i find the intersection points between these 2 functions?
the most straightforward way is probably to consider the various cases, where 2x-4 >= 0 vs 2x-4 < 0, and similarly for 6-x
and how do i proceed?
well 2x-4 changes sign at x=2, and 6-x changes sign at x=6
so you want to consider these intervals:
(-infty, 2)
(2,6)
(6,infty)
in each of those intervals, you can get rid of the abs vals and apply the appropriate sign
for example:
in (-infty,2) you have 2x-4 < 0 and 6-x > 0, so |2x-4| becomes -(2x-4) and |6-x| becomes 6-x
and similarly for the other two intervals
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