#help-10
1 messages · Page 424 of 1
we can take x^r/2 as x^z/2
nah you helped me thanks 🙏
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did this example just choose to leave out the other orbits
on 2 to 5 because they are the same as 1
nvm, we just dont count them because then X/<sigma> would have repeat elements which doesnt make sense
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I need help with an induction problem:
I proved that it's true for n = 1.
if we plug 1 in, we just get r+s = r+s which holds true
For the inductive step, I want to try to show that p(n-1) implies that p(n) is true
I tried plugging n-1 into the right hand side and i just got (r-s)/(r-s) , which is just 1.
I'm really struggling with induction as a whole, as you can probably tell
<@&286206848099549185>
I would try to write it as a sum
bacc (unhelpful)
Assuming this for some n in N you wanna show
bacc (unhelpful)
it would be helpful to me if we did it with n-1 implying n
i know its the same thing but this is the way i'm used to doing it
if you now manipulate the left side it's simple
factor an r
and make the sum go from k=0 to n
then use the assumption
the rest is algebra
I'll work on this then. Do i keep the channel open?
yes
also whether n -> n+1 or n-1 -> n doesnt matter
you can still apply the same strategy when you solved it
Also it wouldn't work with k = 0 to n-1 because in what you wanna prove you would miss the n-th term
@proven karma Has your question been resolved?
why exactly
do we wanna show this?
Aren't we supposed to assume this is true, and then have that imply the n case ?
i know i'm probably sounding silly
After the base case you assume for some natural number this is tru
The induction step would be to show that it also holds the consecutive n+1-th
and use that to imply that the n+1 case would be true?
alright i've gotten this far, and i think this isn't bad
my thinking in this is that since we're choosing to sum to n instead of n+1 now, we're supposed to add a term to the new sum to compensate for this
i'm just not sure what this term is supposed to look like
@restive gorge i also pulled the r^1 out of the sum, that seemed reasonable since it doesn't depend on n. that's allowed, no?
the n+1-th term
which would be also be multiplied by r
you look at the expression in the sum
and plug in
k=n+1
thats what you need to add manually if you reduce the sum from n+1 to n
isnt that achieved by factoring out my r^1 and having that multiply into the whole addition?
yes
so if you now write the last term manually it also needs the r term
since it was part of the sum
the last term for me looks like this now: r^(n+1-k)*s^k
if we multiply the r into that we get: r^(n+2-k)*s^k
,, r \cdot \sum_{k=0}^{n+1} a_k = r \cdot \sum_{k=0}^n a_k + r \cdot a_{n+1}
bacc (unhelpful)
that's the logic
,texsp so in your box you would have [ r \cdot r^{n-(n+1)} s^{n+1} ]
bacc (unhelpful)
i have the same fraction now but with n+2 in the r's exponent. and we just add s^n+1 to all of that
common denominator, do the addition
ye
and this should give us the fraction seen here?
the right hand side of this
what we wanted to show
using our assumption that A(n) is true
that's right, yes
can anyone help me with my algebra 1
it's a common strategy to rewrite it as a sum, manipulate in a way you can use the assumption and basically hope it works out
can someone help mer
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
grab a channel, post the q and people will come by 
you forgot the r
the s^n+1 being multiplied by r is causing a jam in things
jesus christ you're right
r^(n+2) - rs^(n+1)
i should stop doing math when i'm tired
that solves the problem
i need to practice this a lot
the problem is each question just looks so different
thank you bacc
i'll close the channel now
.close
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guys help: calculate the length of the height of a straight circular cylinder with a base radius of 10 cm if the area of the base section is equal to the area of the base
i need help with this beacuse text book wont show answer
base section and base are two different things?
Hi
?
In confused on how to get help
just og into the available channels
math help available category
idk why nobodys helping me
usually people take time ig idk
What type of math u need help with
.
i used translate because i dont know how to write it in english
O so the hight of a cylinder
What's the volume or area of the rectangle that would be around the circle
what rectangle
nono the tbing inside the shape
whatever
its called
idk
oh its that nvm
i dont speak englsj
sorry
your question is not clear
also a cylinder is not 2 circles and a rectangle
откуцајте свој проблем на српском
When finding area that's what you do
Izracunati duzinu visine pravog kruznog valjka poluprecnika osnove 10cm ako je povrsina osnog preseka jednaka povrsini osnove
I have no idea man
im fucking daed
Idk man just use Google I found the same problem but since I'm only in 8th grade have no fuckin clue on what anything means
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is this correct because the internet says otherwise
you get to x^2 = -1/3
so you square root both sides, you dont square both sides
when you do that what happens and what does that tell you about the function?
yes, the values of x where f'=0 are imaginary
so what does that mean for the graph?
there are no horizontal tangent lines?
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I need help
!noping
Please do not ping individual helpers unprompted.
I think it's a not a one to one function because it has 2 points??
do u know vertical line test
Nope
draw a vertical line and if 2 pts are on it then its not 1:1
no
horiontztazl line test
to test if one to one
vertical line test if its a function
I don't get it.?
o right i mixed em up
look at the y axis, that's all the points where x=0. Notice that line hits the curve at 3 places. So it's 1 to 3 there, not 1 to 1
as in, one value of x goes to three values of y
OHHHH
isn't that to check well-definedness?
injectivity is the other way around
the function happened to fail both line tests though, so it's okay
I don't follow what you mean
It just looks like they are in 1 the same position?? for x and y?
you said for one input (x = 0), we got three outputs
one to one means it maps each single point to its own single point
but that's not what injectivity is, no? 
if the graph is not a function then injectivity wouldnt make sense anyway
So it has to be 1?
prove it
;P
it is what injectivity is, this is equivalent

let me get back to you on this later 
to Kiomi: I can't exactly help rn, I gotta go finish my own hmw
sorry
apply the definition of injective function
I dont get it
that is, $x_1\neq x_2 \implies f(x_1) \neq f(x_2)$
is this asking for the inverse
oops, i thought its asking to verify if its injective
OHHH SO LIKE
- f(x)= 7x - 5
skip to
x = 7y - 5
x + 5 = 7y
x = 7y/5??
yes
I feel like im wrong here
ur supposed to find y
Something like
- f(x)= 7x - 5
skip to
x = 7y - 5
x + 5 = 7y
(x + 5)/7 = y ??
yeah it's perfect now
YES
Wait dang it now I don't know how to do number 2
All I did is
x = 1/3y + 4/5
x - 4/5 = 1/3y
Idk what to do else
So something like
All I did is
x = 1/3y + 4/5
x - 4/5 = 1/3y
x - (4/5)/3 = 1/3y/3
x - (4/5)/3 = y?
x - 4/15 = y?
its - 12/5
AHHH BECAUSE -4/5
minus
you need to multiply both sides by 3y-2 first
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2?
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2?
yes
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
-x = 2x + 2?
whats next?
wait what did u do
you can't minus 3xy by 4y
also ur trying to find y, so making y disappear is not a good idea lol
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
x = 4y + 2?
3xy and 4y both have y, so u can factor out the y
I don't get it
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y(3x - 4) = 2x + 2
yes
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
how do u make y the subject on the left side
You put 3x - 4 on the other side
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
y = 2x + 2 (3x - 4)
You must put parenthesis when writing fractions, like this: x = (4y + 2) / (3y-2)
Everyone who ignores this is doing you a disservice
you divide (3x-4)
nvm I don’t feel like talking about this anymore @fallow wharf 
lol well for your own sake you should know what injectivity means
because its y * (3x-4), dividing by (3x-4) will cancel the (3x-4) on the left side
"one to one" means literally what it means, one thing is mapping to one thing
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
y = 2x + 2/ (3x - 4)
y = 7x^2 + 4x - 8
correct?
no
x = 4y + 2/3y - 2 is incorrect
y = (2x+2)/(3x-4)
I'm just confused because it seemed to me that what you said was injectivity was reversed from the definition I know
f(a)=f(b) means a=b
namely, f(x) neq f(y) => x neq y
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
y = 2x + 2/ (3x - 4)
but you said that f(0) = {0, 1, 3}
that's not f(a) = f(b) not => a = b
u don't need to do anything else after u get this: y = (2x+2)/(3x-4)
just leave it as it is
cause we didn't start with f(a) = f(b), no? 
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
y = (2x + 2)/ (3x - 4)
this is the answer?
parentheses for 2x+2
you're working with the contrapositive, maybe that's your confusion?
.
even from the forwards direction, I don't see how what you said is equiv
Should I divide them?
subtract?
x = 4y + 2/3y - 2
3xy - 2x = 4y + 2
3xy - 4y = 2x + 2
3x * y - 4 * y = 2x + 2
y * (3x - 4) = 2x + 2
y = (2x + 2)/ (3x - 4)
this is the answer?
yes
because if f isn't injec. (which it wasn't), we should be able to find an pair (f(x), f(y)) st f(x) = f(y) and yet x neq y
but you didn't find a pair of equal outputs, so far as I could tell? 
(sorry Kiomi)
No
oh no
I ONLY HAVE AN HOUR AND 14 MINS
i'll just tell u the answer for this one then
WAIT
please stop enabling this user
ok
yeah you're right, I'm thinking backwards, not sure why I'm saying that sorry!
DANG IT WAIT LEMME JUST IM SO SORRY
no worries, I had suspected you just went backwards haha
yeah weird LOL brb getting my brain checked
you really do need logs for to calculate the inverse function of i(x) = 3^(x + 1) 
That should be regularly done (I am not stating your mathematical ability)
there's no getting around it 
Log to the base 3 to be precise
yeah Mero is usually very sharp with math, so I thought that I had messed up the def of injectivity 
indeed
well.. you don't need a base of 3, but it helps
Do every honourable need to be extremely smart
I would argue otherwise
I think I'm just used to things being functions, then you already know it's never "many to one" so it can only ever be "one to ???" and so injectivity on top of that forces one to one.
I probably just sort of applied this shortcut in thinking without really thinking it through.
good thing I'm in these question channels, learning I gotta remember to slow down too I guess 

@timid silo Has your question been resolved?
<@&286206848099549185>
you need to use the natural logarithm ln(x) here
it is the inverse of the exponential function e^x
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4 sin thetha - 5 = 3 and the answer is 30 degrees and 150 degrees how
that shouldn't have an answer
unless im mistaken
sin(theta) = 2 should have no solutions
that's exactly what I am thinking
sin(θ-5) or sin(θ)-5
nope one second
sin(30) and sin(150) are positive values of sine in the unit circle with answer 1/2
that's possible?
ran it through wolfram and got these solutions
those angles will result to -3
maybe a typo?
given this fact that indicates that 4sin(theta)=2 so it would work with -5 and -3?
yea it's literally a complex value of θ
probably meant to be a +5 🤔
holy crap why are there so many
7 cot thetha - 4 = 6 cot thetha - 5 one of the answers would be 3pi/4 rad right?
Yeah I am guessing so
cuz cot thetha = -1
I'm pretty sure it's a typo
if it's 4sin(theta) - 5 = 3
30 and 150 degrees is the answer
ok thank you
double neg is correct
even then the answers are for positive 1/2
oh wait, no, = -3
ya
. 4sin(theta)-5=-3
or 5-4sin(theta)=3
ok ty
yes
i am stupid
yippers
ty
all that helped
I will close this channel down
I forgor how to close
I'll just say close
uhh
.close
.close
@stark moon
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i've done this problem over 3 times, help pls
time to do it a 4th time
😄
what have you done so far
can you show me ur work
i got to -2x=sqrt(25-x^2)
1/2
-x/(sqrt(25-x^2))
yeah that matches with mine
that's what i got as f'(x)
bro can you compute it for me rq
what 😭
i already tried like 5 times 😿
-sqrt(5)
what is the decimal of -sqrt(5)
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Person A and Person B are taking the same 5 classes, a person takes a total of 8 classes. Assume that there are any 3 periods a class can take place in, ex.
- Math, History, English
- Science
- History
- English
- Math, Science
- Science, English
- History
- Math
and so on(thats just an example of what could happen). Calculate the probability that Person A and Person B will have atleast 1 class together in the same period.
Is this possible
my friend and I are wondering if its possible to be in the same class next yr
@magic geyser Has your question been resolved?
the easiest way to do this is probably simulation
what is that?
like write a program to generate a class assignment and then run it thousands of times to get an idea of how likely it is
oh
i can probably write this quickly
ohh okay
although I dont really understand - each person has 8 classes over 8 periods, but they each share 5 of the same classes
and each is taking 3 the other person isnt?
@magic geyser
well heres the thing
each class is present 3 times
in 2022 say calculus
it was period 1,4,8
in 2023
it was period 2,5,7
so its random
okay
it gets changed up each year
its surely not random but yes
i think it's like...
he and his friend are both taking Accounting, Biology, Calculus, Danish, and Economics
yeah something like that
but he's taking French, German, and Hungarian while his friend isnt
is this the same as assigning both schedules at random and seeing if theres overlap
yes
like does the 3 timeslots actually matter
i mean the 3 timeslots are the same for everyone, like for everyone
theyre either in periods 2, 4, 6 for history
but they dont choose that and cant do something like period 5 history
i think since i dont know them id have to randomly generate them anyways so i can just ignore i think
if that makes sense
doesn't feel like you can ignore them but maybe
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hello can anyone help teach me how to do cubic spline interpolation?
this is my set of data and im ask to find the value of y when x is 5.8
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how do i use triple angle formulae for 1a?
.close
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Is it possible for me to describe an explicit sequence for a pattern of 1, -2, 6, -12
This is actually kind of an XY question so I will provide the context as well
Oh my a dr du student?
wassup
I am given a linear, and time invariant transformation described by the following equation: [
\7yn + 2\7y{n-1} = \7xn + 2\7x{n-2}
]which is initially at rest $(y[n] = 0 \tss{for} n < 0)$. I am looking to find the response under $\7xn = \7\delta n$
i basically just checked the first 4 values of n
you get h[0] = 1, h[1] = -2, h[2] = 6, h[3] = -12
but how do i describe this non-recursively 
Does [
\7hn = (-1)^n \2 2^{n-1}\2 \floor{\4n2}!
]
work
h[0] = 0.5
Yeah right
what the heck
this is so dumb
i think you are bound to have it recursively
my recurise formulation is currently
[
\7hn =(-1)^{n}\7h{n-1} \2 3 \q \t{If } n = 2 \
\7hn = (-1)^n \7h{n-1} \2 2 \q \t{otherwise for } n >2
]
with initial conditions $\7h0 = 1$ and $\7h1 = -2$
i think this makes sense?
ok maybe i should just include the n =2 case as an initial condition as well? lol
.close
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I even wonder how you came up with this lol, it's clear that's alternating but the rest
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Given $0 < a < 180$ degrees satisfies $2 * \tan(a) + 2 * \cot(a) + 5 = 0$. Calculate $P = 4 \sqrt{5} \cdot \sin(a) - 16$ with $\tan a > \cot a$
cffex
dunno how to approach this
do you know how to find tan(a) from the given equation?
no not really
let tan(a) = A for some real number A, then cot(a) = 1/A, from the equation you'd have
2A + 2/A + 5 = 0
then you would have A + 1/A = -5/2, (A^2 + 1)/A = -5/2
and tan(a) > cot(a) so A> 1/A -> A^2 > 1
id multiply both sides by A in the original equation
yep
you'd get 2 values of A though, which is why tan a > cot a was given to choose only 1 value
cffex
$\frac{\sin a}{\cos a} = 2$
cffex
$\sin a = 2 \cos a$
cffex
$\sin^{2} a + \cos^{2} a = 1$
cffex
since $0 < a < 180$ degrees which means $\sin a > 0 \forall a$
cffex
cffex
cos(pi/2) = 1/sqrt(2) > 0
cos can be either negative or positive in this range
but you only need sin(a)
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yw
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just realized i was wrong
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I would like a hint to start thinking
taylor expansion could be useful
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Lets take a function that is piecewise defined. In order to find the derivative of the function, do we need to check the continuity of the function at the point where the definition changes? Or does the LHD-RHD takes care of that?
if the function is not continuous, then one of the LHD-RHD doesn't exist
Okay so I can directly jump at LHD-RHD, right?
yes, but you have to revert to the definition of LHD-RHD
I dont have to worry whether the function is continous or not
$\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$
rafilou is not not born in 2003
with 0+ and 0-
Got it. Thanks
One more thing
What is the value of the limit if we get something like (tends to 0) x (tends to infinity)
0*infinity is an undefined state, meaning it could tend to infinity, something finite, 0, or nothing at all
you have to simplify stuff to find its limit
for example limit of sin(x) * 1/x as x goes to 0
it looks like (tends to 0) * (tends to infinity)
and yet it goes to 1
another example:
L'H :trollface:
xsin(x) * sin(1/x) as x goes to infinity
this looks like (tends to some infinity) * (tends to 0)
and actually has no limit
since it keeps oscillating between -1 and 1
The examples made it clear. I was wondering if it will be 0 like in the case of 0 x infinity
it can
x^2 * 1/x when x-> 0
Is this applicable to (tends to 0) / (tends to infinity) as well?
0/infinity is 0
0/0 is undefined form
infinity - infinity is undefined form
etc...
And what about (tends to infinity)/(tends to 0)?
depends on the sign
(tends to +infinity)/(tends to 0+) is +infinity
(tends to +infinity)/(tends to 0-) is -infinity
In that case. limit doesnt exist, right?
it can exist
here's an example
$\lim_{x\to +\infty}\sqrt{x^2+x}-x$
rafilou is not not born in 2003
should go to 1/2
How?
$\sqrt{x^2+x}-x = (\sqrt{x^2+x}-x)\frac{\sqrt{x^2+x}+x}{\sqrt{x^2+x}+x}$
rafilou is not not born in 2003
$\sqrt{x^2+x}-x = \frac{x^2+x-x^2}{\sqrt{x^2+x}+x} = \frac{x}{\sqrt{x^2+x}+x}$
rafilou is not not born in 2003
you can forcefully factor the denominator by x:
$\sqrt{x^2+x}+x = x(\sqrt{1+\frac 1x} + 1)$
rafilou is not not born in 2003
$\sqrt{x^2+x}-x = \frac{1}{\sqrt{1+\frac 1x} + 1} \xrightarrow{x\to+\infty}\frac{1}{\sqrt{1}+1} = \frac 12$
rafilou is not not born in 2003
Thank you so much for the deatiled explanation
I had to confirm one more thing about differentiability
Suppose LHD = RHD at a point. Is that condition enough to show that the fn in differentiable at that point?
Or is there some other tests?
Or conditions?
if both LHD and RHD exist, with THIS exact definition
and they're equal
then f is differentiable at that point
all 3 of them has to be equal
if LHD = RHD, then automatically D = LHD = RHD
Ohh I see. Thanks a lot
btw here's an example of why using this definition is important
$f(x) = \begin{cases}-x, & x < 0\ -x+1, & x \geq 0\end{cases}$
rafilou is not not born in 2003
you could "differentiate by sight" both things by being like "derivative of -x is -1, derivative of -x+1 is -1, well they're equal"
except the piece "-x" never actually reaches x = 0
yes, I would have
so this method doesn't work
you have to go through this for LHD :
$\lim_{h\to 0^-} \frac{f(h)-f(0)}{h} = \lim_{h\to 0^-} \frac{-h-1}{h}$
rafilou is not not born in 2003
and suddenly f is not LHD when you use the definition
all because the piece "-x" is not reaching x = 0
This doesnt match with the formula my tecaher gave
Crystal
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this is the opposite of the derivative
dollar signs surround your formula from both sides
$like this$
rafilou is not not born in 2003
$not like this
Idk how to use that tool
no problem
Okayy
but the derivative has always been $\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$ hasn't it?
rafilou is not not born in 2003
$\lim_{h\to 0^-} \frac{f(h)-f(0)}{h} $
oh and
is it?
rafilou is not not born in 2003
you can edit
we were given 2 slightly different formulas for RHD and LHD
well yeah, unless your teacher is weird
Mannn Idk he said the bigger one has to come first and smaller one gets substracted
derivative : $\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$ $\$
LHD : $\lim_{h\to 0^-}\frac{f(x+h)-f(x)}{h}$ $\$
RHD : $\lim_{h\to 0^+}\frac{f(x+h)-f(x)}{h}$
rafilou is not not born in 2003
woooow no
I think you'll find this to be easier
just remember the derivative formula, which should never change
LHD is just we take h < 0
RHD is just we take h > 0
I will be using this one from now then
The RHD is same but the LHD is kind of the opposite
This is easier to remember
rafilou is not not born in 2003
Yes but it was just "h tends to 0" not ".... 0+"
then it makes even less sense!!!!
because if h just tends to 0 then you allow h to go from under 0
Idk I am just saying what we were taught in class
yeah your teacher is onto some substance
I would personally stick to this
yes, we can say that ig
Thats all! Thank you
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can anyone explain to me whats going on here
so due to the rank-nullity theorem, the nullity of A is 0
that means that Au and Av will never be zero, unless u, v are the zero vectors
then they did the inner product on Au and Av, which is another way of saying the dot product
the norm is a way of measuring the 'size' of a linear transformation
what do you mean by size?
and where did vector u and v come from are they some arbitary vectors or what?
(technically, the inner product is a generalization of the dot product which can be applied to other things as well, but for the case of linear algebra and matrices they are the exact same thing)
yes
Norm measures the length of a vector for some particular notion of a length.
am familiar with that idea but the idea of size of a transformation is new to me
In normal Euclidean space, the most common notion of length is based on the Pythagorean theorem
hopefully from $||u||^2 = u \cdot u$ you can see why the norm is like that
south's secret twin brother
you just then square root both sides
well I mean, the determinant is just the area / generalised volume scale factor
wait so i then square root Au . Av and i get the "size" of the linear transformation
so if the determinant in R^2 is 3, that means the square formed by the basis vectors (1, 0) and (0, 1) becomes 3 times larger under the matrix transformation
it changes shape ofc
oh wait nvm
yeah
pretty much
wait so the size is the determinant
it's another concept of size unrelated to this one
I recommend watching 3Blue1Brown's videos for more detail
I watched his playlist but am still lost like i understand that the determinant shows how much the area/volume gets scaled by but i just dont understand where A comes from and the vectors u and v
Essentially, this is examining what happens to the basis vector (0, 1) under the linear transformation given by the matrix A
The determinant of A is 1. (Given by 1 * 1 - 2 * 0), but space is still stretched and squished by the transformation
So a determinant isn't the full story
This A and u,v pair is just for the sake of an example
They were chosen to illustrate the ideas
Specifically, the inner product in this case.
@random berry does that make sense? Or are you still a little bit unsatisfied?
If unsatisfied, do you have a particular question? Or are you just not seeing the point or purpose?
wait so tell me if i understood it right so the determinant tells us by how much the area was scaled but it doesn't tell us whether the area itself changed shape? so then this inner product of a matrix and a vector tells us? sorry if am being slow and thanks for your effort for helping
Yes, and it can but doesn't have to
It might be possible to select a vector whose length doesn't before and after the transformation incidentally.
(Depending on the nature of the transformation.)
My guess is this is leading up to eigenvectors and eigenvalues
Which does tell you exactly how a matrix warps space
you are correct the set of lectures note right after this is eigenvectors
However, the inner product is still useful, because it's an easier way to tell how any particular direction is affected by the transformation
So if you only care about a single direction (such as perhaps a special relativity calculation where you only care about the direction (inc time) of your spaceship) then the inner product gets you the information you want with less work
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(x-2) (x-1) (x+3) should i let x = 0 so it can be (0,-2) (0,-1) (0,3) ? same topic RRT
!original
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.
i wish i could read minds
same
that is the only problem our teacher showed us 😭
she said we should practice that kind of problem 😭
you haven't shown what the question is to begin with
so we can't help if we don't know what is being asked for
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can any1 explain this to me?
<@&286206848099549185>
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.close
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alright so I need help with exercise 1
Now I am stuck
And no Cezaro Stolz can't work because it isn't 0/0
@ocean stone Has your question been resolved?
<@&286206848099549185>
Yes
What is the continuation or well
Any hints?
I will attempt
If I write it as 1/a_n it will go down with the denominator right?
Like, I don't see another way to write it as
let's do this step by step, what does x_n converge to?
Well 1/n converges to zero
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how to find the component of a vector in the direction of another vector
A ship is sailing in the direction of $\langle3,4\rangle$ when wind pushes it in the direction $\langle-9,5\rangle$. Use vector projection to determine if the wind helps the ship or goes against the ship.
Jash
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Can someone help me finish number 2?
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Hi. Does anyone here know how to use a TI-84 plus to calculate x and/or coefficients if its a quadratic function? (Pattern: 16; x; 25)
U mean nsolve?
I haven't used TI calculators for 15 years so I'm a bit rusty. I'm afraid nsolve rings a bell but not much
do you mean given a couple points
you wanna fit a quadratic?
Yeah
As in what would X be and what would the pattern look like
Ti 84 plus (non cas)
The patten goes 16...x...25
It's up to me to figure the pattern out, but i am allowed to use my ti 84 plus
hmm
can I see the original problem pls
yayy
shoot 😭
It's in swedish but the important parts: a1=16, a3=25
(1) - give examples of what a2 could be if it is a quadratic function.
(2) - solve a for any n.
oh swedish
i love the fish
hmm okay
did you solve a through b btw?
what do you know about quadratic sequences
I can use A B C formula manually or with the TI84 to find coefficients for a pattern with 3 values
let's do it manually shall we?
I try and fiddle with n^2 to find a reasonable pattern
can you give me a general formula
for a_n
in terms of some constants a, b, and letter of ur choice
In the case I dont know hoe to proceed but I can give u the start with 2 values
A+B+C=16
4A+2B+C=X
9A+3B+C=25
Oh
13 or 21
7 the I suppose if it's single digits;)
A+B+C=16
9A+3B+C=25
this is what we know
we can subtract the equations to get
8A + 2B = 9
so 8A = 9 -2B
I'm sorry if this is hard to follow because of the language disconnect
So far I'm onboard
I'm also an English teacher so hopefully language isn't my major issue 🙏
Still understandable
B = (9-8A)/2
plug it back into A+ B + C = 16
to get C also in terms of A
kyle are we still following
Gimme 1m to absorb
Why plug it back in to A B C = 16 and not 25. Can I choose either?
you can choose either
C=3A+11.5 ?
should be something like that
I'm sorry but I cannot proceed with that. Is this usable to solve a2?
I have to head to work now but thanks for your time and effort ❤️
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Is anyone able to help with my mathematica fit? I've been trying for ages and i simply cannot get it to work, thanks.
It depends on the math topic and if I learned it at school 🥲
I’m out of school for like 2 years now ‘cause I already graduated from college
Its just a log plot its nothing crazy, but it keeps coming out with the wrong magnitude and its starting to drive me up the wall
whenever i overlay them the fit just doesnt get displayed at all, which i assume is because of the magnitude difference
<@&286206848099549185>
So I have a .dat file that I need to log plot and then add a fit to
but the fit is coming out completely wrong eveyrtime
(Importing the data)
mylist = Import["C:\Users\liamm\Documents\Wolfram\file1.dat"];
(Creating filtered list and log list)
filteredList = Select[mylist, #[[1]] > 400 &];
logFilteredList = {#[[1]], Log[10, #[[2]]]} & /@ filteredList;
(Defining quadratic function for the fit)
fitFunc = a + bx + cx^2;
(Creating fit)
fit = NonlinearModelFit[
logFilteredList,
fitFunc,
{a, b, c},
x
];
(Plotting everything)
ListLogPlot[
filteredList,
PlotStyle -> Blue,
PlotLabel -> "Quadratic Fit with 95% Confidence Bands",
AxesLabel -> {"x", "y"},
PlotRange -> All
]
Plot[
fit[x],
{x, 400, Max[filteredList[[All, 1]]]},
PlotStyle -> {Red, Thick},
PlotRange -> All
]
Plot[
1 Evaluate[fit["MeanPredictionBands"] /. fit["BestFitParameters"]],
{x, 400, Max[filteredList[[All, 1]]]},
PlotStyle -> {{Red, Dashed}},
PlotRange -> All
]
thats the mathematica code ive used
huh?
any help is much appreciated
ive been on it for hours
thats the .dat,
only use values with x>400
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is it true that Making the trig ratio positive always returns the reference angle itself
@karmic hinge Has your question been resolved?
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@dire violet Has your question been resolved?
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