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np ^^
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Hi, what do we call this in english ? ($f(x)=x^2
f'(x)=2x$)
ramey
i study math in arabic & french lmaoo
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derivative is incorrect
nvm, got it
alright
wait what
i just realised that 5-(1/2sqrt1) gives 9/2
yeah don’t have my glasses on i’m smart 👍
hahaha it’s no problem cheers for the help 👍
attempted this a few times and got the same answer
the answer is 5/64🤷🏻♀️
which line?
when you compute the derivative
very bottom left
you plugged in positive two
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in the first question, the triangle is drawn a little misleadingly, i would start with annotating everything they give you and see what it forces as an outcome (don't trust how it's drawn)
for the second i would start with cubing both sides of the given equation
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how would I go about solving this question?
Are you familiar with the fact that the collection of (x,y) pairs in the plane satisfying each equation defines a line?
I'm not sure what that means
Have you worked with equations of the form y=ax+b?
yes of course
The define a line in the plane yes?
yeah makes sense now
Would you agree that each equation in the problem you gave defines a line then? Since you can rearrange the terms to make them look like "y=ax+b"?
yes
So, solving the systems of equations stands for finding the points at which the 2 lines ( 2 equations ) intersect, agree?
Since each equations defines a line so if I have an intersection that point "satisfies" both
With all that in mind, what do you think is going on geometrically when the system has no solutions?
We'll get there
the lines are parallel when there are no solutions right
yes
If we have 2 lines with equal a but different b then they never intersect
If the B's are equal they intersect everywhere since the equation is the same
That's the infinitely many solutions part of it
So if you reduce both equations to y=ax+b with equal a and different B's it solves the no solution case, if the B's are qual it solves the infinitely many case
yeah
Can you make each equation look like y=ax+b?
The first one is $y=\frac{8}{2}-\frac{m}{2}x$
Brun。
Can you do the second?
m is -4 or 2
There's a problem at 2 tho
oh yeah
We've got ourselves a nasty division by 0 since we rearranged
But looking back at the original equation you see that m=2 just makes the y term vanish
That means we have a vertical line at x=1
Well, let's see what happens to the constant term
Yup
which m = -4 satisfies
oh so it is correct
And this one has one solution
And that's it
so for infinitely many solutions the two lines need to be the same right?
Yeah, same a and same b
is that even possible?
doesn't 4?
you sure?
You can verify it on desmos, it's a great way to catch errors lol, I apologize if I've made any mistakes but I think I am right on that
Write the 2 equations there and let m=4 to see if they don't intersect
4 does work
Wdym by work tho? Let's clear that up first
Huh, that's a thinker
I'd go back and redo the quadratic from before
Maybe there's something there?
This
it makes sense then
so what does the last questions even mean to solve the equation in terms of m for suitable values of m?
m that doesn't satisfy the quadratic
you want the lines to not be parallel
To have a meaningful unique solution
If it lets you chose an m to work with I'd go for a 2 to get rid of the y in the second equation
You will have to sub-in the y given by the first equation into the other
That forces it to satisfy both "rules" at once
Then you just isolate for x and you should get the expression in the answer there
did I do something wrong I'm not sure?
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can someone explain me what is linear map ?
in simple worlds
Linear map is a mapping satisfying the following two properties:
$f(u + v) = f(u) + f(v)$ and $f(c\cdot{v}) = c\cdot{f(v)}$, also $f(0) = 0$
Touch Our Beans
Shortly, a mapping which preserves addition and multiplication
mapping is like a function?
Yeah
Function represents mapping between two sets (domain and codomain)
and linear mapping?
Again, for a mapping to be linear it needs to satisfy these properties:
and transformation matrix ?
Linear mappings are represented with corresponding matrices
and are there other ways to represnt linear mappings?
For example in real functions we have an identity function f(x) = x (it leaves the input unchanged), and in linear algebra there's an identity matrix (which similarly leaves the input unchanged)
For example this is the identity matrix in 2 dimensions
A matrix which leaves the vector unchanged
*when multiplied to a vector, that is
So $\mathbb{I}\cdot{v} = v$
Yup
Touch Our Beans
Where I is the identity matrix and v is an arbitrary vector
a linear map is a map that satisfies:\
$f(a+b) = f(a)+f(b)$\
$f(na) = nf(a)$
just bob
Yes I already told him that
oh ok
but how can i represent it in
didn't notice that
matrics
Then view that as $f(v) = A\cdot{v}$ for some matric A
Touch Our Beans
matrices transform vectors
if you want a function with 1 variable, don't use matrices
also, it's matrix btw
(redundant also)
but whatever
There's a lot of different things going on there, which part interests you?
it's talking about some matrix
which isn't shown in the picture
so i have no clue what this means
For example in first lines there's a matrix $T: \mathbb{R}^3 \rightarrow \mathbb{R}^3$ and the writer is trying to find the unknown vector given in the equation, I suppose
Touch Our Beans
This is something about using different basis in the vector space, can't tell in details
but what does it even mean
Every nxn (n by n dimensions) matrix has n^2 entries (numbers) in it
and something about ker
ker is the kernel (the set of vectors that gives the 0 vector when multiplied with the matrix)
kernel of linear map
In terms of linear transformations, kernel is always just a set with the zero vector
As far as I'm concerned
the defn is the same, yes
Linear transformations are matrices, in some sense
what does it mean L (v)
L is a linear transformation applied to some vector v
and v belong to v
but this definition is multiply with some vector in order to get 0 vector
why in the formual there is no multiplation/?
This is the same definition
L(v) it means to multiply with some vector in order to get 0 vector
Again, L(v) means that you're multiplying v by some matrix
Yes
is there a diffrence between nullspace and ker ?
i think i started got it
a little
"Kernel is also known as the nullspace"
so it is the same thing
Yes
Linear operator is the same as what?
it seems like you have no knowledge of linear algebra whatsoever
and he told me that L(v) is not multiplication it is like a function it can be multiplaytion but also addition
it's matrix multiplication, which can result in various different things
how much time will it take me to learn it
is it possible to master it in 2-3 days from the begining and know how to solve problems ?
personally it took me 1 month at 10 hours of math / day
wow, why so much time
thats pretty a lot of time
is there a lot which I still dont know ? ? ?
yes
Inner product space
is the last subject of mine
eigenvalue
Eigenvalues and eigenvectors
wow this is pretty complicated (not that complicated, it's a vector field with the inner product on it) (but still kinda complicated)
these are properties of matrices
are you kidding ?
For every matrix there are some vector(-s) such that $A\cdot{v} = \lambda\cdot{v}$
where lambda is some scalar
Touch Our Beans
The solutions to that equation are eigenvectors
And values of lambda are corresponding eigenvalues
wat is eigenvalues?
basically
v is the eigenvector
A is your matrix
lambda is the eigenvalue
Imagine solving equation f(x) = kx, where k is some constant, this is similar thing
lambda that satisfies beans's thing
beans's thing?
this
what about dimension of matrix
For nxn matrix there are n eigenvectors/eigenvalues
(sometimes eigenvalues are repeated)
(1 1)
dimension 2?
thats not about 3D ?
LIKE MOVIES 3D 2D GAMES ?
THERE IS NOT RELATION BETWEEN THE TWO ?
??
What do you mean
how do i know the dimension
if i have matrix 2x3
is it just doing multiplaction for knowing the dimension?
2*3=6
thats the dimension??
i mean is there a diffrence between dimension of matrix and dimension of vector spaace?
dimension of vector space = number of vectors in its basis
and dimenson of matrix
is like that
@hybrid moat Has your question been resolved?
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Hey guys,
I have this function, a solution to a differential equation
I1 = ]-inf; 0[
I2 = ]0; +inf[
mb not finished
We want to even find the solution when t=0
So we find the limit when t --> 0
The problem is I don't understand how they got to the limit exists if C1=C2=-1
I used l'hopitals rule and I got the limit equals 0 no matter what constant we use
So thats wrong
Can someone help me with determining C1 and C2?
@steady bay Has your question been resolved?
@steady bay Has your question been resolved?
@steady bay Has your question been resolved?
No
@steady bay For the limit to exist, we need the right hand limit to equal the left hand limit. So that's what they did.
The right hand limit is lim t-->0^+ [(c2(t^2 +1) + 1)/t], left hand limit is lim t-->0^- [(c1(t^2 +1) + 1)/t]
since t-->0^- in the left hand limit, we have lim t--> 0^- [-(c1(t^2 +1) + 1) / |t|]
Yes i understand that part
since t-->0^+ in the right hand limit, we have lim t-->0^+ [(c2(t^2 +1) + 1) / |t|]
equating these, terms cancel out
you get c1+c2 = -2
if u dont understand the absolute value stuff, then there is another way. lim t-->0^- means t approaches 0 from the left so it's gonna be a smaller and smaller negative number
you take the negative sign out, send it to the numerator
This one i understand
and what u have left is a positive number
This is to find the value of c1 which we replaced by c2
thats why i wrote |t|
But how do we know that the limit exist to begin with
What I dont understand is that if I try to get the limit with whatever C i get 0
the limit is 0 yes
Did you get it using lhopitals rule?
Because i get it like that and on top if t goes to 0 it doesnt matter the coefficient so even if c1 is different than C2 we get the same limit.
Thats why i dont know what i did wrong
lets take c1 = 5
so you have lim t-->0^- [(-5(t^2 + 1) +1)/t]
and this limit doesn't exist
,w limit of [(-5(t^2 + 1) + 1)/t] as t goes to 0 from left
same for lim t-->0^+
so if we want the limit to exist
we want it to have the form 0/0 or inf/inf to apply LHR
what u are doing is just applying LHR(not thinking whether it even is of the form 0/0 or not)
so u get the first equation c1 + c2 = -2 by equating left and right hand limits
For second equation, we see that the limit is of the form (constant/0) which means the limit doesn't exist, so for it to exist, we must have the form 0/0 so that we may apply LHR
so applying lim t--> 0 to the numerator of either limit, you get c1 + 1 or c2 + 1 which must equal 0 so we have c1 or c2 = -1
and then from the first equation, we find the value of the other constant
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sinx+1/√3cosx=1
What is the smallest positive value of x?
I find sin(30+x)=2/√3 and this looks so strange, and I don't know what to do next.
$\sin(30 + x) = \frac{2}{\sqrt{3}} \iff 30 + x = (-1)^k\arcsin(\frac{2}{\sqrt3}) + \pi{k}$ for some whole number $k$
Touch Our Beans
I understand this but, I still can't find the smallest positive value of x :/
Btw it should technically be 180degrees instead of pi there since we're working in degrees
Here I'd consider cases k being odd/even and looking for lowest positive values of x in both of the cases
And then compare the results
I agree, thank you for your help Bean. I made it :3

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Can someone help with these here?
Take tangent of both sides, use the fact that $\tan(a+b)=\frac{\tan(a)+\tan(b)}{1-\tan(a)\cdot\tan(b)}$
Dmytr
@candid orchid Has your question been resolved?
this is exactly what I needed
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thank you both!!
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What is the probability of a 2% event occurring 4 times out of 10?
any arrangement of this occuring will have the same probability
so the first step is to find how many arrangements are possible
is each time independent?
question just came out of the blue, i just high-rolled on a game
don't know the difference :^)
So.... I asked a yes or no
.
If you had the event happen, will that affect the next time it happens?
no
$X\sim Bin(n,p)\implies P(X=x)=\binom{n}{x}p^x(1-p)^{n-x}$
Mosh
wat
That's binomial distribution..
don't know how to use that :^)
what does the squiggly mean
Follows.
and that means?
and tilde
X the random variable follows a binomial distribution w/ parameters n and p.
Here you go! This is an excellent explanation of the basics. With visual aid and everything 🙂
https://www.youtube.com/watch?v=8idr1WZ1A7Q
At least this will give you a really fun starter and if you have any specific questions there, it might be more helpfull to come here. Mosh probably tries his best explaining this topic to you, but since it could take a while i thought this might help.
Also some games are programmed so that the results of each attack (or whatever) aren't independent. But that's probably not helping you with your question.
I do know that some games are programmed to not be independent, but would like to know the answer if it were independent.
Then the buzzword Mosh gave you with this video should help you a lot! I think its great that you are trying to get into math with real world problems you encounter 🙂
I have no clue what the big x and the small x in that equation means
Did you try wathcing that video? It might be hard to explain this whole topic of binomial distributions in an easy to understand and short way here 🙂
don't really understand what this means / how i'm supposed to use it
factorial idk
n x n-1 x n-2...
until n-whatever reaches 1. Correct 🙂
Oh you were asking what the n and x stand for right?
Well its called "n over k" (at least i think it is. english isnt my first language)
To calculate it, you use the formula above. But what do you think the n and k could mean?
the guy in the video says choose
n over k is like n/k
I don't really know how it can be used or what it would mean
https://youtu.be/8idr1WZ1A7Q?t=418
Here he explains what n over k is.
So out of 50 tries, 48 "went right"
what does it mean in your case?
btw its the same video just with a timestamp
Oh and just as a small motivation:
At the end of this you will be able to solve lots of problems you will encounter in games! You could basically calculate if some builds or bossraids are worth your time 😉
perfect thats n over k!
i don't really know where to go from here even after watching the videfo
can i get a really rudimentary explanation as to what I would do with knowing n over k?
what did you get out of the video is this
$$p^x(1-p)^{n-x}$$
Arne
i mean you got the n over k part down, now you are just missing this thing from the equation right? A little hint: It's in about the same timestamp i send you earlier.
no no
i don't know how to apply
n over k
I know how to plug everything in
but I don't know how to use n over k
Does this help?
looks about right
so approximately a 0.003% chance?
i got 0.0003%
But i (probably) used the same numbers.
oh am i not supposed to multiply by 100 to turn it into a percent?
oh and i guess its worth mentioning that many calculators use 10 nCr 4 as 10 over 4
I had to look it up, since it was a while ago i used it. So sorry for only telling you now
thanks for the help
I hope that helped you!
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hey so according to the right hand rule should the magnetic force be pointing upwards or downwards in this problem?
I've gotten the magnetic force to be pointing ||upwards|| but it is ||downwards|| in the book
<@&286206848099549185>
@minor warren Has your question been resolved?
okay got a solution for my answer
it is pointing downwards cuz the charge is negative and the right hand rule is supposed to be used for positive charges
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well i thought it was the 5000 1000p vector + t(2.5cos70 2.5cos20) but ms says this
Ohhh
How do we do that then?
I'm guessing you gind the velocity from the 2m/s speed?
yes. His speed and the bearing he's travelling at.
So the speed is the hypotenuse in this case?
yuh
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Ha car accelerates from 0 km/h to 100km/hr in 2.5 seconds. if the acceleration is uniform how much does it accelerate in 1 second
a = (v1 - v0)/deltaT
Can yiu tell answer i can't understand what yiu gave
And convert the km/hr to m/sec
First do this tho
wheres 10000m coming from
change km/h to m/s not just km to m
Ohh
do we need to do any unit conversions here though
27.7778/s
ew decimals
Lol
(also missing units? idk)
we aren't asked to find the acceleration, we're asked to find by what amount we accelerate in one second
and answering "the car speeds up by ___ km/h" is perfectly fine
My brain is dead
okay then maybe you could revive it and come back here once it's back up and running?
No no its running
(final velocity-initial velocity)/time is the formula
for acceleration
plug in the numbers
Well the question asks for acceleration per second but the velocities are given in km/hr
My brain not undertaking formula
what is final velocity of the car
it asks "how much does it accelerate in 1 second"
as-stated, giving an answer in (km/h)/s is perfectly fine
You weren't given the formula before this problem?
UNLESS we are also required to convert it into m/s^2, of which OP has made no indication
Isnt thia formula
I just need answer idk whrre the mam gave this question from
Tbis is the question the q:2
well you did the q1 wrong
but nevermind that can you just tell me the last speed of the car
100km/h
final speed is last speed
initial is first
you just said 100 and 0
so what is the difference
100 is difference
Yes
so how much will it go in 1 second
yea good idea
Time to find my calculator
you can just
40
okay
An object with no net forces acting on it which is initially at rest will remain at rest. If it is moving, it will continue to move in a straight line with constant velocity. Forces are "pushes" or "pulls" on the object, and forces, like velocity and acceleration are vector quantities.
Got from google
yea if it is initially at rest
Ohhhhh
otherwise it will fly like a bird you should write that down
im serious
Ok
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so when you see an object going up and down you should touch it
$_$
in real life too
noob gamer
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
its important
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how i write the symbol theta
$\theta$?
dino dik
do you mean write on a computer or on paper?
yes
which is better
the one on the right looks better
becuz the line on the middle of the circle? it should be horizontal right
slightly curved is fine
yeah, simply make a zero, and put a line across it
I start from the mid left
draw the horizontal line
and continue with the ellipse, anticlockwise
(without the writing implement leaving the page)
but a lot of people wont mind how you write the symbol, just make sure it resembles theta
got it
thank you guys
that looks like it's easy to mistake for e if you're not careful
I never had that issue
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Hello! I’m having a lot of trouble proceeding with this exercise, I don’t know how to get off from here. Can someone give me a hint ? Thanks !
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Can anyone see how i can go from the bottom line in my equation to the below equation
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hello i have a question please on this drawing i need to find the possibilities/numbers of rhombus to create a star and the angles need to be between 10° and 160°. To find the possibilities do i need to take the numbers divisible by 360 and that are between 10 and 160 like 20 ? thx
yeah you should do that
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Prove that for any real numbers a, b, c, so that a + b + c = 3 the inequality a^2 + b^2 + c^2 >= 3 is true
the only thing that comes to mind is
((a+b)+c)^2 = a^2 + 2ab + b^2 + 2ac + 2bc + c^2 = 9
so
and you have shown in a previous exercise that a^2 + b^2 + c^2 ≥ ab+bc+ca, so...
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.reopen
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actually give me a sec
have you heard of rearrangement inequality?
no, but i've solved this q
what is rearrangement inequality?
then whats ur issue
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oh ok
.reopen
✅
@stable breach would you help me with another question?
ok
i have to show that for nonnegative reals such that x>= y the inequality x^4 + y^4 >= 2xy^3 is rtue
here's what i did
(x^2+y^2)^2 >= 2xy^3 + 2x^2 + y^2
(x^2+y^2)^2 >= 2xy^2 (x+y)
and don't know what to do now
maybe write it as
((x+y)^2 - 2xy)^2 >= 2xy^2 (x+y)
and rty to divide by x+y
what do you think
i know at least 2 ways to do it but they both involve inequalities that might not be suitable for your course
1 is by rearrangement which you do not know
the other is by muirhead
have you heard of muirhead?
oh then ig you dont need to muirhead
right
so let $\sigma_1, \sigma_2, \sigma_3, \cdots, \sigma_n$ be a random permutation of the numbers $1, 2, 3, 4, 5, \cdots, n$
A Fellow Human
so e.g. for $n=3$ you could have $\sigma_1=3, \sigma_2 = 1, \sigma_3=2$
permutation was the one where order matters, right?
A Fellow Human
yeah sure
so you could visualise this as getting a list of the first $n$ integers, then randomising the order, then $\sigma_i$ is the ith element of the list
A Fellow Human
if that makes sense we'll go ahead
so let $x_1\geq x_2 \geq x_3 \geq \cdots x_n$ and $y_1\geq y_2 \geq y_3 \geq \cdots y_n$
A Fellow Human
so rearrangment says $x_1y_1+x_2y_2+\cdots+x_ny_n\geq x_{\sigma_1}y_{\sigma_1}+x_{\sigma_2}y_{\sigma_2}+\cdots+x_{\sigma_n}y_{\sigma_n}\geq x_1y_n+x_2y_{n-1}+\cdots+x_ny_1$
A Fellow Human
take some time to take that in
for the case $n=2$ that more or less says $x_1y_1+x_2y_2\geq x_2y_1+x_1y_2$
A Fellow Human
take some time to take this in?
this just says that if you have some order
then terms which are products of numbers in this order are greater than terms which are products of numbers in this order but randomized
yeah
so it seems like some obvious fact, i'm not sure how would you go about using it
A Fellow Human
so by rearrangement $x\cdot x^3+y\cdot y^3\geq x\cdot y^3+y\cdot x^3$
A Fellow Human
and $\frac{xy^3}{yx^3}=\frac{y^2}{x^2}\leq 1$ so $yx^3\geq xy^3$
A Fellow Human
A Fellow Human
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sure feel free
(this should also be provable with am-gm tho i will need to think about it)
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find the number of pairs (a,b) of natural numbers such that b is a three - digit number, a + 1 divides b - 1 and b divides a^2 + a + 2
I would appreciate a step by step explanation coz its not that easy to wrap my head around...
@dense dirge Has your question been resolved?
<@&286206848099549185> ?
@dense dirge Has your question been resolved?
you have to solve it with no computer help right?
yep
Sorry, I am not entirely sure how to solve this
Or what field of math this would go in...
I know though we can limit 'b'
And try to see if we can narrow it down
just 900 numbers to try
Armin
or not XD?
they are not 3-digit
trueeeee XD
I am curious on this solution, can you explain the what appears to be absolute value signs?
2 divides by zero?
no
That doesn't seem right
it basically means 0/2 is an integer
and 4/1 is an integer
it's kinda a backwards division
Oh
at least that's how I look at it
How would that lead us to the answer?
idk
I would approach it by making $c = a + 1$ and $d = b - 1$
Bman
Which would eliminate numbers just above or below prime numbers
And all other numbers who are both not made of the same prime factors
Which narrows it down quite a bit
Then eliminate based on the last rule
a and b are even or a and b are odd based on the first rule
i honstly don't think it has a sol
I added the equations on the right but ended up with a=<0
so either my method is wrong or it really has no sol
@dense dirge Has your question been resolved?
@dense dirge you asked for a step by step solution?
yep
here?
ok here let me try
let there be some integer n such that
b-1 = n(a+1)
thus b=na+n+1
it is known that b|a^2+a+2
or na+n+1 |a^2+a+2
then from further simplification na+n+1 is divisible by -a+2n
now na + n + 1 must be divisible by 0, and then you can just plug in 2n for a and plug that into b and find all numbers of that form
thats a bit tricky
is this a competition problem?
yep
the given answer was way too hard
But then how do you know there's an easier solution? Can you perhaps provide the source and the given one? Maybe someone can explain it if you're stuck
was my solution above similar to the given one
@dense dirge Has your question been resolved?
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$\int_{\gamma} f(z)\abs{dz}=\int_{-\gamma} f(z)\abs{dz}$
Cüneyt
is this correct?
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@timid silo Has your question been resolved?
i remember you asking this very same question multiple times and the conclusion being that nobody here has any fucking idea what this notation is supposed to mean
then why ask here and not your professor?
Because he told us if it is correct and I didn't listen to him at that moment
I don't wanna ask
well you will have to
????
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how would i do b>?
rewrite as y=mx+c and use formula for perpendicular lines
what if formula for perpendicular lines
slope of the line perpendicular to y=mx+c is -1/m
no
well
actually, you can continue with that, but it will be a bit different
oka
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i am working with natural logarithms and would like to know how in this workings out how the -t becomes positive?
yes
Frosty
when you multiply by -10
i am not multiplying i am subtracting
the "take" here should mean multiplying
otherwise you wont get t on it's own
yea
that will give +10.....
but that's not the right equation
$-\frac{t}{10} = \ln(\frac{1}{2}) \ -t = 10\ln(\frac{1}{2})$
Frosty
right
i think i got
multiplying both sides by -10 worked
thanks man i knew i was missing something simple
.close
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hello
quick question
if a triangle has three equal angles does that mean all sides are equal
?
yes
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Suppose I have:
sin(2x) = sin(x)
So I say:
2 sin(x)cos(x) = sin(x)
can someone explain why dividing both sides by sin(x) will hide one of the values of x?
you lose the solutions from sin(x)=0
will hide one of the values of x
in fact you're lose infinitely many solutions
You're right. I was thinking about a certain domain of values of x but yes in a general sense that's right.
Why is this?
Because I'm dividing by zero or because I no longer look for sin(x) = 0?
consider approaching the question with factorisation
you're dividing by something that could potentially be 0
Okay that makes sense
like lets take a cubic equation in factored form
x(x-2)(x-7) = 0
you wouldn't blindly divide both sides by x, (or (x-2), or(x-7)) would you?
That's what my teacher said, referring to the principle of not dividing by sin(x) so I came and asked for why that's a principle. This could also apply to cos(x), right?
generally applies
That's right
This brought the idea closer to me so thanks
don't divide
by something that could potentially be 0
unless you really know what you're doing
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for all n >= 0
is it a subspace ?
i dont know how to check subspace properties when its a sequence
For closure, pick (a_n) and (b_n) from the set. They satisfy the recurrence relation. Consider (a_n + b_n) and (k a_n). Check whether they satisfy the recurrence relation.
Prove that V = {(a_n) in R^N : a_i = a_{i+1} } is closed under scalar-multiplication. Pick (a_n) in V and k in R. Consider (k a_n) = (k a_0, k a_1, k a_2, ...). For any subscript i, since a_i = a_{i+1}, we have k a_i = k a_{i+1}. This shows that (k a_n) is in V.
For closure under addition, pick another (b_n) in V. Consider (a_n + b_n) = (a_0 + b_0, a_1 + b_1, ...). For any subscript i, we check that a_i + b_i = a_{i+1} + b_{i+1}.
We also need to check that the zero sequence is in the subspace.
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can someone explain the steps here
The first term $\frac{ae^{-il_2a}}{-il_2}$ of $I_1$ and the first term $\frac{(1-a)e^{-il_2a}}{il_2}$ of $I_2$ cancel each other out when summed
dino dik
Then the factor of ${1\over l_2^2}$ is factored out, ending up with the top expression
dino dik
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first but x-1 in g(x)
ok
ah ok
put f(x) in the x of g(x)
@dark steeple What's fg(x + 1) simplify to?
No.
OH
fg(x + 1)
f(g(x + 1))
so
Now, to do g(x + 1), you do this:
g(x) = x + 4
g(x + 1) = (x + 1) + 4
See how you replace x with x + 1 on the left?
Do you see how I replaced x with x + 1 on the left?
So because I replaced x with x + 1 on the left, I also did it on the right.
And I put it in parentheses to avoid mistakes.
g(x) = x + 4
g(x + 1) = (x + 1) + 4
Does it make sense what I did?
OK, so
f(g(x + 1))
f((x + 1) + 4)
Now we do the same thing with f.
f(x) = x² - 25
f((x + 1) + 4) = **((x + 1) + 4)**² - 25
See how we had x on the left and replaced it with (x + 1) + 4?
Then you do the same on the right, but with parentheses around it.
kk
So, you do the same thing to both sides.
right
You replaced x with something on the left, so you replace x with it in parentheses on the right side.
