#help-13
1 messages · Page 65 of 1
thats undefined for obvious reasons but i dont understand whats wrong with the radii
oh sorry i wrote it wrong, i meant the larger radius to be (4/y)-1 and the smaller radius to be 1
yes but you need to split into two integrals
at y=1 its bounded by x=3 now
drawing a graph makes these 10x easier
yes
i set it up this way and im getting an answer but its off
ohh so its another washer?
yes
thank you that makes a lot more sense
in general when do u know to split it into multiple integrals?
Closed by @balmy chasm
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
not really sure where to start with this tbh
I think its false
i think i get a
ok
so whats an example of that?
but b im struggling with
o alr
one sec ill send an image
@crimson sedge
i found a counter example so its fase
but b i have no idea
i cant intuit if its true or false
actually
with a bit of a shit venn diagram i kind of do see why
wait no i dont
lmao
element chase.
If x is in A and C, then x is in A n C then x is in B n C, so x is in B
Can you do something similar if x is in A-C using the union statement to get that x is in B?
not really following
If x is in A and C, then x is in A n C
isnt this the same thing
yes
yep
Closed by @honest bobcat
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I don't think the indefinite integral can be solved analytically by simple means
Is this for complex analysis?
Are you supposed to just be approximating this with series?
More context please
I don't remember series stuff, so I can't help you further. 
Closed by @bold mauve
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
soo ik the formula for a circle, A = pi(r^2)
what would the radius be? im confused from that point on
<@&286206848099549185>
Look for the formula for solid of revolution
could i do semicircle cross section and then multiply it by 2 since the graph is symmetrical
I guess u could. But not a good practice.
Because as I remember it did not work every time
oh
if i did the area of a circle, could A = pi(b/2)^2
then pi/2 (integral 0 to 4) with an integrand of (2(sqrt x))^2
@runic prawn Has your question been resolved?
Closed by @runic prawn
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I need help with 1ii
Closed by @lofty perch
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hm
u=root(x)?
yea
improperfrac
yeah i see it now
,rotate
ok so i got this
yes i know
and at 0 too but idk if u rly care
i got 2(20pi/4)
for ur final answer?
,w integral from 0 to inf of 10/(root(x)(1+x))
yea looks right
comparison test
id assume
wait
The comparison test let's us deduce the convergence or divergence of some improper integrals by relating a complicated function that is challenging to a simpler one we can do. If we compare two functions f(x) greater than g(x) greater than 0, we can deduce things about the convergence of the improper integrals. If the larger integral converges f...
dct or lct no?
what do i compare to?
you cant
unless you prove that converges too
with another test
yea ic that
show its smaller than like some f(x) that converges honestly my brain is dying lol
yea that works
is this correct?
mhm maybe you could have done like < 5x/root(x^6) which is just like 5/x^2
wait i dont think thats correct
isnt 1/x^6 smaller?
,w 5/(root(1+2^6))
,w 5/(1+2^6)
yeah i dont think that works
ok
this seems fine tho
@merry tinsel Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
got an answer but its wrong
what are you supposed to do?
Show your workings
gimme a sec ill take a picture
i sorta got stuck here
i just expanded all three brackets with every possible combination
Geez don't tell me you actually tried developping the equations
but when i got to line 3 i couldnt factorise
Poor soul there was a shortcut
Also clearly you did something very wrong because without even expanding it I can tell you the first term should be y^3
three roots of a equation it should cubic
Yeah
If the product of 3 numbers shud be 0 at least one of them numbers must be 0
Those aren’t even quadratics
(y-1)(y+5)(y+2)=0 implies that either y-1, y+5, or y+2 is 0
Becuase multiplying 3 non-zero numbers together just gives you another number that isn't 0
So it must be that one of them is 0
And, vice versa, multiplying 0 by any numbers is gonna give you 0
Hey that’s called the null factor law
yup i got it now thanks for the help everyone
Why do mathematicians feel the need to name everything?
Closed by @lime harbor
Use .reopen if this was a mistake.
Same reason everything gets named, easy to refer to
.reopen
✅
Never heard that name
When realistically do you need to refer to it though?
Right now
Right now I did not need to refer to its name to explain it
https://en.m.wikipedia.org/wiki/Zero-product_property
It has a Wikipedia page so it must exist
In algebra, the zero-product property states that the product of two nonzero elements is nonzero. In other words,
if
a
b
=
0
,
then
a
=
0
or
b
=
0.
...

Well you call a line a line without having to define a line
It’s the same with any names concept
I mean they even have a name for the fact that you can add the same number to both sides of an equation
I think it’s pretty ridiculous to argue that things should have names
Is that necessary
Yeah you can
But I regularily talk about lines
Now you’re on the how regular is regular enough to have a name spectrum
I think it's faster to explain ab = 0 => a=0 or b=0 then tell null factor law
cause you'll need to anyway explain what "null factor law" is
Ah no don't hit me with the "How many grains of sands is a beach?" argument
Which is why I said “hey that’s called the null factor law” so hopefully they could remember it’s a thing, I didn’t start off the explanation with “null factor law, google it.”
I employ it all the time
Lol
fair enough
But for real though every f'ing time I find out some basic shting had a name the whole time
I mean it’s easy to put as a topic too
Like "Oh yeah that rule you've been using for years has a name actually it's called Goober's law" or something
In a content sheet or something
It’s just easier to refer it as the null factor law compared to “the one where if ab = 0 then either a or b or both = 0”
That also doesn’t fully describe null factor law
Mhmm it looks like being able to refer to this with a name helps with talking about abstract algebra too
So it is indeed useful
.close
Closed by @buoyant latch
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@solemn dune Has your question been resolved?
No problem
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Could someonme help me with this question? Work out the percentage change when a price of £20 is decreased to £3.
Closed by @ornate dagger
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Closed due to the original message being deleted
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
.reopen
How do i do this?
how would i make a back and forth movement with linear interpolation? (i only know basic math but i need to know to implement smooth walking animations in my game)
I put a picture
Here
No i hav to go to school in less than 10 minutes
9
know how to do this
I believe you have to isolate either the Y or X
I don’t know how
wait are they connected to each other or just are they just separate questions
for example 3
are they connected or separate
I have to find x and y with both of the equations
are you stuck at like somewhere or do you just completely not understand what to do
@shrewd tinsel
i completely dont know what to do
do you know the elimination method?
i would recommend watching a video on the elimination method first and then try to solve it yourself
if you still don't understand come back
i don’t have time
alright ok ill try to explain
ok so basically in the elimination method you either add or substract the equations so you get an equation in one variable. When the coefficients of a variable is the opposite you add the equation so you can eliminate a variable but if they are equal you can just subtract the equations to eliminate a variable
so do u know what i would do for the first one here
so lets take question 1.
5x - 2y = -48
2x + 3y = -23
for them to eliminate x or y
they have to be equal yes
so its equal to 0
wait let me word it better
to eliminate x or y
they have to be equal to each other so that when you subtract or add each other it becomes 0
and you successfully eliminate x or y
what would i subtract and add on 1
you can choose from x or y
lets try y
so -2y and 3y
if you add them to each other it isnt 0
so we have to make them equal
Do i subtract 2x from -23
no
you want to isolate
x or y
from both equations
and there's a variable in 2x so you cant substract it from -23
so i move it to the right side then not subtract
yes
to eliminate both
they need to add to each other
so it becomes 0
because there is a negative number
-2y + 3y doesnt equal to 0 right?
No
so what can you do to make them equal to 0
no because there's a variable
so you cant do that
so your only option is to multiply
you have to multiply -2y by 3 and 3y by 2
so that it becomes equal to -6y and 6y
-6y + 6y = 0
but
since you multiplied
the others in the equation also has to be multiplied
so in 5x - 2y = -48
5x has to be multiply by 3
because -2 got multiplied by 3
and same goes for -48
and it becomes 15x - 6y = -144
and 2x + 3y = -23
has to be multiplied by 2 because you multiplied 3y by 2
so 4x + 6y = -46
be back soon gotta finish this class
alright ill finish this and you can read it all after you're done
and then try solve the rest
and you get
15x - 6y = -144
4x + 6y = -46
and now you add them all to each other
19x = -190
and now you've isolated the x but not completely
because of the 19
19x is the same as 19 * x
so to remove the 19
you divide it by 19 to get 1
because 1x is the same as x
and since you divided
the other side also has to be divided
so x = -10
and now that you have x
you just put it in one of the original equations
and you can solve y
@shrewd tinsel Has your question been resolved?
Are u here
@shrewd tinsel Has your question been resolved?
Closed by @shrewd tinsel
Use .reopen if this was a mistake.
thanks @silk osprey
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
height of a picture is (x+4)cm and the perimeter is (6x+14)cm. the width of the picture is 15cm. find the area of the picture
im doing work due in like 30 mins
so it would be helpful if people could get some questions done with me
yeah
This is a picture, which is just a rectangle
yep
so there are (x+4) + (x+4) = 2(x+4)
Um, isn't 2×(h+w) = p?
there
this is the values u gotta sub
equate it to perimeter
U forgot the right side
U have the equation for perimeter
here
here
at the first step
what u did is 2(width + THE PERIMETER)
The formula for permieter is this
this one
2(15+ x+ 4
yeah
30+2x+8
aight thanks
i know now
imma copy this down
and then close this
and ill open another
when i need help again
yea yeah
i got 2 more pages to get through
gl
Closed by @tribal plank
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Do you know which is the surface?
The idea is to combine shape
Noice
But let me note more for you
A hemisphere has 2 side (let's call it that way)
- the curve
- the flat (a cricle)
A cylinder has 3 as you said
- top (a circle)
- bottom (a circle)
- middle ( a rectangle)
Middle is not a square
Oh mybad

Now if we combine these shape the same as the picture
The surface is
Top: Hemisphere
- the curve
Middle: cylinder
- middle (a rectangle)
Bottom: hemisphere
- the curve
When you know what is the combination of it then you can work on it
The surface is
Surface of curve of upper hemisphere
- Surface of middle part of cylinder
- Surface of curve of lower hemisphere
And that's it
You can browse on internet for formula
@crimson sedge Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
while finding the mean of 18 observations is 10 if each observation is increased by 4
What's the question...
while finding the mean of 18 observations is 10 if each observation is increased by 4
Thank u for respoding sir
That's a wonderful statement with no directive.
what do u mean ?
it an mcq
while finding the mean of 18 observations is 10 if each observation is increased by 4 the mean is ?
Yeah 'the mean is ?' is kinda important tbh
Recall mean = (total)/(number of observations)
fx / f
You can find the total of the observations before the increase, the total afterward follows nicely
Then divide by the number of observations again
Done.
Sorry but not able to understand on how can i do it
What part don't you get?
as i know that total addition of f divided by total addtion of f + mid point of ci
fx/f
That doesn't answer my question, but ok.
Ig if you're not gonna read anything I say, someone else can help you.
can u tell me waht i am doing wrong or whom should i contact
<@&286206848099549185> who ca help me ?
So 18 different observations right?
while finding the mean of 18 observations is 10 if each observation is increased by 4 then mean is ?
yes
So to formulate this problem let’s just do it like this (O_18+O_17…O_1)/18=10
That’s the basis of the question if I am understanding correctly right?
Sorry I’m back now
idk tahts y i am asking for hel;p
Well assuming it’s correct
an MCQ with options
hmm i not understabding it are u using the addtion of f and x and multiplying it ?
Using the basic formula for finding the average
And then it says observations increased by 4
Gimmie a bit to work it out
average same thing as mean
oh ok
Yeah the answer is as I thought I was just double checking
Thing of averages in terms of percentages
No problem
If every number was 1 the mean would be 1
Same for 2 the mean would be 2
So with that in mind if you increase every number by x the mean also increases by x
Makes sense?
Where are you getting 18 from
No your fine just gimmie a sec
ok
Let’s go back to this formula
And do some basic algebra
hm hmm
We want to isolate O so we can add 4 to each
No
That would be proof by contradiction
bro to be honest , i am not good at maths so if possible can u tell me by easy wordings ?
Let me write this out to make it easier this may take a bit if this closes I’ll dm you if it’s not already solved
ok np
@whole chasm Has your question been resolved?
Closed by @whole chasm
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
what does it mean when i write something like this 10^^^10
Closed due to the original message being deleted
what does it mean when i write something like this 10^^^10??
nothing?
looks like the next step after tetration maybe
though that also has different notation
so like instead of writing 10^10^10^10 just like 10^^^10?
no
?
~Martin
or
what does that mean?
$10\uparrow\uparrow 4$
~Martin
that is the notation used for tetration
and we could continue this further to achieve something like 10^^^10
Stack 4 10s in a mad exponent tower
but it would not really be useful in most cases
I haven't seen tetration being used tbh
so this is 10^10^10^10?
well, to be more precise it is 10^(10^(10^(10)))
which is probably what you mean
at least that is what i think it is
tetration is pretty useless normally
i dont get it + thats not what i wanna know i wanna know what 10^(any amount of ^^^)10 means
Tetrate the tetration 
repeated summation for example 10+10+10 is multiplication (here 3*10)
where 3 is the number of tens used
repeated multiplication is exponentiation
example: 10 * 10 * 10=10^3
again where 3 is the number of tens used
repeated exponentiation is tetration
example: 10^10^10=10^^3
again where 3 is the number of tens used
repeated tetration is likely what you are after
so we would have:
x^^x^^x=x^^^3
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
.close
Closed by @marsh pond
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
guys I'm not getting 21(b)
Also find the distance between two other points
but using the distance formula on points $(0, p) and (x_0, y_0)$ I'm getting $d = \sqrt{x_0^2 + (y_0 - p)^2}$
math
and idk how to simplify that to show equality
Well |-y_0 - p|
right right
Because x_0 is on the parabola x_0² = 4py_0
And then u have it
🤦♂️
how long until I start seeing stuff like that on my own 😭
I've read this question like 5 times
🥲
ngl, it's even worse
my algebra is awful, I still don't see how $
$\sqrt{4py_0 + (y_0 - p)^2} = what I need$
math
who can help me with those
🤨
I’m stuck on this one bro and ixl sucks
you're hijacking my channel bud
Oh LO i thought that it’s a channel related to math
Closed by @solemn bronze
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello, if $v(v(t))=t^{8n^2 + 8n}$, what might be v(t)?
lilisworld
Ohh I wanna know this too🥲
Fr 😭
박재현
use \sqrt
I think $v(t)=t^{\sqrt(8n^2+8n)}$
박재현
$v(t)=t^{\sqrt{8n^2+8n}}$
numbpy
I think this should work
Yes thank you both😂 idk why I was hoping for something simpler
don't just give answers
cause if you let v(t) = t^(f(x)), v(v(t)) = t^{v(t)^2}
Closed by @marble ermine
Use .reopen if this was a mistake.
Hmm
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Closed due to the original message being deleted
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
any one know how to do hamming code matrix?
well we dont know how they are given in your lecture notes
lecture is useless does explain anything how to a (7,4) only but not (15,11)
the thing is idk but the chosen positions chosen
well a (15, 11) Hamming code can be represented as a linear transformation in many ways
there's a linear transformation T: R^11 -> R^16 which represents the entire encoding process
one T: R^11 -> R^5 which actually produces the code
all of these include an extra parity bit over everything
@supple fiber Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Something something something F prime is velocity...
What do the first and second prime mean
all i know is that the first prime means the Slope and curvature....
by f prime they mean the derivative of f
f(x) is probably a position function
f’(x) is ur velocity function
etc
whats f''(x)
acceleration function
and f'''(x) means nothing since its goes to zero, right?
depends on the function
lets say the Leading term of the polynomials has 9 as its exponent... what would f'''(x) mean? and every other prime after that
in respect to?
fr?
and it's usually written f(t), f'(t), f''(t), so on
idk if your joking or if that actually true lol
I'm not joking lol
i cant tell if this is a joke or not
wtff
o
well what do these terms mean then?
Is it just another way to describe a certain prime without saying acceleration 2 and 3?
it's literally just like position, velocity, acceleration
just names for different derivatives of position
oh i see it, thanks
@heady salmon Has your question been resolved?
Closed by @heady salmon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I know that a11 must be positive as if it were 0 the decomposition would break down because of the divisions and if it were negative then there would be complex alpha values and chokesky factorizations can’t have those but I feel like I am missing some way to prove it must be positive. The inductive step I can show that the resulting cholesky decomposition from K-ww^T/a11 is still positive definite but I feel like I am missing something on part 1
what do you know about the matrix A
ah wait it says it in the first sentence
A is pos def
It’s positive definite and symmetric Ye
what does that mean
By definition the entire diag must be positive
no that's not the def of positive definite
Is that not true? If any value is negative couldn’t there be a non positive eigenvalue?
but I mean if you know that one then you are done
do you mean the diag of the diagonalization?
or of A itself
Of A itself
well yes that is true but if you know that then clearly a_11 is positive
but again, that's not the usual definition of positive definite
also not sure right now if its even equivalent or just follows from positive definite
Well it’s symmetric and x^TAx is >0 for all non zero x that are elements of the reals
And I see how to use that for 2. To show the inductive step
But I’m confused what they want from me for part 1
I can set x to be x,y where x is not 0 and y is the bottom right term of A
think simpler
Like to prove it by contradiction?
no
we want to find some vector x so that a_11 = x^T A x
and then we immediately get a_11 > 0
by pos def
So just any vector like 1,1?
I
?
Identity
Sorry I haven’t slept for 24 hours .-.
Standard unit vectors like (0,1) and (1,0) with n length and rest of elements 0 yeah?
yes. (0,...,0,1,0,...,0)
I forgot how to do all math
I get a11 alone
With just 1,0,0…
So it must be positive
Cuz it has to be >0 because of positive definite definition
Thanks for the help, I feel like I need to re learn all of linear… I’ve done well in my last 2 classes and this one is just building on content I did well on and I can’t even figure this stuff out 😦
5th year of cpsc in a 400 level computational optimization course and it took me like 5 minutes to figure out how to multiply a vector by a matrix
Is there somewhere I can give you rep or a nice review or soemthing on here
dw about it
Have a good day 🙂
and you have a good night
.close
Closed by @young gazelle
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Do you guys have any idea about my mistake?
Maybe wrong way?
I mean if we say that lnn~n we obtain only e....but i am not sure
That we can say lnn~n
You didn't apply e^lim(f(x) for one.
infinity^0 is one of the indeterminant conditions in which L'hopital applies.
Sorry i dont understand
Seems like you may have skipped some reading.
I mean, i am not apply hopital
I am applying the First formula
But maybe i am wrong and i have to apply hopital
One moment, I need to find a reference for it.
Of course
L'Hopital's Rule and the Forms $1^\infty$, $0^0$, and $\infty^0$.\\
$\text{If } \lim_{x\to a} \ln{f(x)} = L\\
\text{then } \lim_{x\to a} f(x) = \lim_{x\to a} e^{\ln{f(x)}} = e^L$
Kookiemon
Ok but i dont understand how this Is useful to my case
Mehdi_Moulati
Ok let me see
As I said earlier, it seems you may have skipped some reading.
For heavens sake
And when i reached this point what i have to do
M triyng
But i am stucked againg here
Is this ok?
ln(n+1)/ln(n) goes to 1 which results in e^(2-1) = e^1.
It technically requires another application of L'hopital but yes.
Closed by @copper void
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
need help with question 4.3 and 4.6
@turbid charm Has your question been resolved?
Closed by @turbid charm
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@spare turtle Has your question been resolved?
@spare turtle Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
hi, can anyone help me with this?
@muted lantern Has your question been resolved?
Closed by @muted lantern
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello! I'm trying to learn how to graph cosine & sine functions (Precalculus). I have been able to find all the transformations, but I don't fully understand how they affect the graph. The question wants me to use two points to define my graph.
I am pretty sure I put the correct transformations, but the graph is incorrect
<@&286206848099549185>
i don't think it's centred correctly
i think that top orange dot should be at like -pi/4 on the x, but it's at -pi/8
I didn't attempt the graph yet, thats the randomized thing from the question
oh
I don't really know how to use the transformations to plot the graph
i mean ok you just sorta start from something and then go outwards
so start from cos(x)
then cos(2x) is that but like squished right
then cos(2x + pi/2), you move it left by pi/2
wdym
then multiply by 4 and you just gotta make it bigger
plot cos(x)
first
then start changing it like the transformations do
this?
sure
yes
idk how to do the amplitude
no
lol
how is that 4
now it goes up and down 4, but you haven't got the +3 right
at x = 0, 4cos(x) + 3 should be 7
yes
shifted it down by accident
ok now for the other stuff
phase shift
because it was -pi?
was it?
ok i mean, how about this
let's do the cos(x) -> cos(2x) thing first
that'll be simpler
so basically
cos(0) = cos(2 * (0))
cos(pi) = cos(2 * (pi/2))
cos(2pi) = cos(2 * pi)
so when you're comparing cos(x) to cos(2x)
the cos(2x) goes twice as fast, sorta
it changes twice as fast
like, cos(x) goes from 1 to -1 between 0 and pi
but cos(2x) does it twice as fast
it goes from 1 to -1 between 0 and pi/2
yeah
ok
now vertical and phase?
so take this
this is like 4cos(x) + 3
turn it into 4cos(2x) + 3
in the same way
ok
yes
phase shift would = -pi/4?
howcome?
ok so
I was taught its h/b, and h is pi/2 and b is 2 in this equation i believe
oh good
because you can just turn it into 2(x-pi/4)
that's what matters here
yeah that looks good
so you can test it out by looking at the actual function and putting some stuff in
so at x = 0, the function should be equal to 3, and it is
you dont have to do anything for period right?
so cos(x) has period 2pi
so you made it into cos(2x) which goes twice as fast
so it has period pi
so you already did that
good
it gives me two attempts so ill see if this is right and ill try another
ay nice it was correct 🙂
coolio
sounds good
they gave a lot more points for this one lol
ill give it my best shot
I think I have it? Think I'm missing something though
i mean you can always just try stuff
compare what the result for x = 0 should be from the function with what the value for x = 0 is on your graph
and then do a few more
so at x=0 it should be -pi/4?