#help-42
1 messages · Page 149 of 1
ok like
graphically
you're asked to prove that the graphs of y=f(x) and y=x^3 intersect somewhere between x=0 and x=2.
do you understand this
they instead went for proving that y=f(x)-x^3 has an x-intercept somewhere between 0 and 2
and beacuase h(0) and h(2) from 1 to -4 crosses the x intercept
theres a value? that exists for c
its so funky and hard to visualise
then just follow the logic
im trying
why are we defining h(x) in the first place im confused about, as in what the function describes
so we can use IVT on h
we have a fucntion f(x) that has a y value for each value between 0 and 2, and subtracting what f(c) is
but i dont see what the end result --> h(x) like shows, what does '1' or '-4' indicate
the existence of a root, thats it
the important thing is this
like esdies the reason thats what the numbers give ofc
f(x)=x^3 <=> f(x)-x^3=0
a solution existing for one eqn is equivalent to a solution existing for the other
so this 'and beacuase h(0) and h(2) from 1 to -4 crosses the x intercept
theres a value? that exists for c'
or rephrased
because f(c) crosses f(x) there must be a value c
more rigorously, 0 is between h(0) and h(2)
so by IVT h(c)=0 for some c in (0,2)
all g now?
Closed by @narrow hamlet
Use .reopen if this was a mistake.
np
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 quadratic polynomial can be written as k(x - alpha)(x - beta).
So k(x^2 - x(a+b) + ab) = (x^2 - x/4 - 1)k
Are these the roots of the quadratic function?
No, a + b = 1/4 and ab = -1
sums and products
mb
The answer is THIS.
This works
That's one possible answer
theirs is yours with k=4
you did it correctly, and in fact did a bit more than was asked by characterizing all quadratics with the given property
Wot the heilll
what's wrong?
This.
Yeah no
also might not want to spell it "heil"
Okay, anyway the question asked to provide a quadratic polynomial, not the quadratic polynomial.
that can have quite unsavory (if unintended) connotations
yes and you are done
unless you have something to follow up with
Closed by @deep violet
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 want to show for $\Omega$, a quadrable domain, that $A(\overline{\Omega})=A(\mathring{\Omega})=A(\Omega)$
tm
quadrable?
quarrable en français
ok bon du coup
y’a juste marqué inclu dans R^2 lol
y’a pas marqué mais ça doit être sous entendu
bref, le truc A^- ça correspond à l’intérieur de omega et A^+ c’est l’adhérence de omega?
si oui jvois pk ducoup
bon bah tu prends Omega quarrable
Alors on va prouver que son intérieur et sa fermeture sont quarrables
et de même aire
ça doit pas être si difficile ça j’pense
hm oui
ui jvois
ensuite faudra prouver les autres inégalités
par exemple
attends excuse moi on a plein d'inégalités en plus si je ne me trompe
A-(fermeture) >= A-(Omega) >= A-(ouverture)
A+(fermeture) >= A+(Omega) >= A+(ouverture)
je pense que toutes ces inégalités sont immédiates
ensuite:
hm ui
on va tenter de montrer que A-(fermeture) < A-(ouverture) + epsilon pour tout epsilon
pour ce faire, si tu considères un pavage contenu dans la fermeture
alors tu érodes un peu chaque pavé
et ça te fait un pavage contenu dans l'ouverture
avec autant de précision que tu veux
oui
mais att 2s 😭 y’a équivalence entre le fait que Omega est quarrable et sa frontière est d’aire nulle ?
si oui on peut le faire + simplement
euh bonne chance pour prouver ça j'y ai pas touché
si oui, $\overline{\Omega}=\Omega \cup \partial \Omega$
tm
et on utilise les propriétés de l’aire
et ensuite que l'aire se comporte bien pour l'union disjointe
ui voila
il y a aussi des chances que la frontière ne soit pas quarrable
donc pour l'instant je m'avance pas trop
si omega est quarrable ?
mais si omega est dans R^2, sa frontière sa sera une courbe
mec j'ai fait tout un papier de recherche sur les fractales donc à un moment "la frontière sera une courbe" c'est pas vrai xdd
😥😥😥😥😥
t'as des frontières quarrables qui sont fractales
ah ouais relou aussi
j’me disait l’aire d’une courbe c’est 0 et tout ça aurait peut être fait un truc 😥
reste là dedans pour l'instant
oki
ça c'est peut être vrai sachant que A(frontière) = A(ferm) - A(intérieur)
mais pour le prouver avant de prouver ce qu'on fait là maintenant je pense que c'est pas une bonne idée
En tout cas Omega quarrable => A(frontière) = 0 (peut-être?)
mais la réciproque mmmh
dans mon cours y’a marqué si la frontière est une courbe continue , de classe C^1 par morceaux alors omega est quarrable, la frontière aussi et son aire vaut 0
ouais bah C1 par morceaux c'est important comme hypothèse 😭
allez tente de faire ça c'est pas si mal
att faut que je m’y remette
faut faire ça ?
ouais je pense
c'est un truc classique
pour montrer que A = B avec A <= B évident
la technique classico c'est montrer A >= B - epsilon pour tout epsilon > 0
donc là la technique
comme A- c'est un sup
je prends un pavage de la fermeture
je peux toujours trouver un pavage de l'ouverture "aussi grand que le pavage" à précision epsilon
donc Aire(ce pavage de fermeture) < Aire(le pavage de l'ouverture trouvé) + epsilon
en passant au sup
Aire(ce pavage de fermeture) < sup(des pavages de l'ouverture)+epsilon = A-(ouverture)+epsilon
on passe au sup
A-(fermeture) <= A-(ouverture)+epsilon
hm mouais mais c’est à dire genre mathématiquement ?😭
bah ça mathématiquement
mais enft jcomprends pas meme intuitivement
l’intérieur c’est plus petit que l’adhérence
oui
donc si tu prends un pavage de l'adhérence
pour créer un pavage de l'intérieur
bah va falloir raccourcir les pavés
mais pas trop
pour respecter la précision
ui mais si l’adhérence c’est + grand, pk les deux ont la même aire 😭
parce que j'ai besoin de rétrécir mes pavés, mais tant que je les rétrécis, l'aire que je perds elle peut être aussi petite que je souhaite
mais
je vais te faire un dessin si tu l'as toujours pas
quand tu dessines comme ça oui
mais faut comprendre que la différence entre les deux c'est la frontière
qui est super riquiqui en aire
bah elle a une aire nulle (si c’est une courbe c1)
Si je prends un pavage de mon adhérence
bon bah chaque pavé c'est un rectangle fermé [a,b] x [c,d]
qui est complètement dans mon adhérence
mais qu'est-ce qu'on peut dire du rectangle ouvert ]a,b[ x ]c,d[ dans ce cas?
il est contenu dans quel ensemble?
dans l’intérieur
fin c’est l’intérieur de l’adhérence ça
oula att
bah c’est la frontière ?
?
oui
ça c’est l’intérieur de l’adhérence alors
ah mais c’est l’intérieur tout court mdr
alors...
bon
je réfléchis de mon côté moi aussi mais c'est pas hyper évident non plus
si A est fermé
@nocturne heron 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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
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.
why did we equate 4 with 2ab
Because two complex numbers when both the real and imaginary parts of them are equal
2ab is imaginary?
In other words, the reason is the same for why you equated 3 with a² - b²
The imaginary part of the right hand side, yep
cause they typo'd
Oh yeah I didn't even notice it
how is 2ab imaginary tho what
@remote mural
what does this mean
It should have been 2abi
3rd line should be 3+4i = a^2 + 2abi - b^2
Closed by @jaunty acorn
Use .reopen if this was a mistake.
You're welcome 🤗
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 it is me again
if i need to find all the roots, both purely real ones and complex ones
how do i go about doing that
for a polynomial of any degree
if the degree is ≥5 and you need the exact roots and no rational ones can be guessed, then you are cooked.
okay in this case they seem to have spared me from being cooked then, it is of degree 4
can you show yours
yes, and i want to say i did try to think about it before asking
i thought maybe i could substitue then use the quadratic equation
then divide it into two new polynomials
and use the quadratic equation again
z^4 + 2z^2 + 4
quadratic formula not quadratic equation btw
sry that's what i meant
this is your polynomial?
yes
it is biquadratic
so indeed factoring t^2 + 2t + 4 and then substituting t = z^2 works.
i was gonna do z^2 = t
yep typo sorry
it has to multiply to the coefficient
and add to the constant right
for the fast way to do the quadratic formula
the fastest way here is completing the square actually.
oshit
also if you're going to go for the quad formula then there is no question of "add to this" or "multiply to that" at all.
i forgot about that
that's when i add and subtract a number so it becomes a perfect square right?
yes
yes
i forgot how to continue with completing squares
sorry it has been a few months
i get (t+1)^2 + 3 = 0
now i treat this as a difference of squares??
(t+1)^2 - (sqrt(-3)^2) = 0
(t+1 - sqrt(-3))(t+1 + sqrt(-3)) = 0
better to write those as sqrt(3)i not sqrt(-3)
so what you've got here now is that your original quartic is partially factorized as $$(z^2 + 1 - \sqrt{3} i)(z^2 - 1 - \sqrt{3} i)$$
Ann
now you need to factor each of those brackets again
by finding the square roots of $-1 \pm \sqrt{3} i$ by whatever means
Ann
okay wow
there are 2 more roots
and you can write i instead of sqrt(-3) because sqrt(-1) * sqrt(3) = i * sqrt(3)
btw im still here im trying to factor them right now im just very slow
i have to go now sorry
no problem thanks for the help anyway, i didnt know i had to actually go down this road to find imaginary roots
but now i do
.close
Closed by @fickle flume
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.
can someone pleease just do this problem for me
you can rewrite the left as the chain rule
i did that but i got it wrong
what did you get?
shawarma
this?
dont forget about the +C
ah yeah okay the problem is you
forgot the constant
yeah
oh ok thank you i was so confused lol
$yx^3 = \sin x + C$
shawarma
then divide by x^3
yeah we find c by using sin to the power of x
what
do you guys have any reccomendations for calc 2 like study tips or anythiung
because y and x can =sin
honestly it's mostly just practice
<@&268886789983436800> can you stop this guy please
especially with integrals and stuff, the more you do the better
because it's about recognizing patterns
and DONT FORGET THE C
@rigid lintel Has your question been resolved?
Closed by @rigid lintel
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 ass law is this bro
"rate of separation is directly proportional to their separation"
as if we didnt know
I think what it means is that larger the universe is faster is the rate of expansion
maybe you're misunderstanding something
yes probably
its not something obvious
ohhh
okay now help me solve please
lets say milky way and andromeda are x light years away from each other.
Then they are separating at a rate of kx from each other.
and this k is the same no matter what x is
oh ok
Idk the value of 1 mega light year that's why I can't solve the part (a) but i can help u with part b
okay so the velocity (v) = Hr where r is the separation
Do yk that we can write velocity as dx/dt?
.close
Closed by @spice venture
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.
Yeah I was about to say that
I) If 2^3a =729 the result of 2^-a is equal to 1/3
II) the result of the operation (numbers above) is equal to (numbers above)
III) if x^2 = 25^12 ; y^6 = 25^12 : w^7 =25^63. The value of the expression (XtimesYtimesW)12 is equal to 25^168
and then I imagine it's "only 1 is false", "only 2 is correct", "only 1+2 are correct", "only 1+3 are correct", "all 3 are false"?
Oh yeah I forgot about that
so for I, you can use a power law to split it up right
a) 1 false
b) 2 true
c) 1 and 2 true
d) 1 and 3 true
e) 1, 2 and 3 false
$x^{ab} = x ???$
PrettyPrincessKitty FS
but you must know about how to deal with powers right?
yeah - and if you have e.g. 2^3 * 2^5
2^8
exactly, you do know the power laws 🙂
Nice but I still have no clue how to do that
so let's take 2^3a; ideally we want to get rid of the 3 somehow
Ok
How come tho
so we know already that $x^{a+b} = x^a * x^b$
PrettyPrincessKitty FS
Mhm
what's the equivalent one for $x^{ab}$?
PrettyPrincessKitty FS
X^a * X^b
no-o, that makes x^a+b
we don't have something that looks like $2^{3+a}$. we have something like $2^{3 * a}$
PrettyPrincessKitty FS
yeah great. so if we can put the 3 on the outside, and then take cube roots of both sides, we get 2^a = stuff
$(2^a)^3 = 729 => 2^a$ = cube root of 729
PrettyPrincessKitty FS
and of course $2^{-a}$ is just $1/(2^a)$
Oh ok cause we got rid of the 3
PrettyPrincessKitty FS
So where do u go from here
well you can work out the cube root of 729
yeah cool. if 2^a = 9, then 2^-a is 1/9
yeah - a is not gonna be a nice number but that's fine because we can leave it as a
lol
I have a project I need to do and I gotta learn how to do 10 questions and I’m gonna have to present how to do 1 of the 10 randomly chosen by the teacher and I also gotta have all 10 on a paper explained nicely so this is really gonna help
the other 2 are quite similar but obviously they use e.g. the x^(a+b) rule
These are way harder questions than I normally do
For the 2nd one can I do like (1,25 - 1,16) 10^-4-7
unfortunately not
😭
what you can do is take 10^-4 * stuff and make it into 10^-7 * other stuff
Huh
if you make the 10^-4 1000x smaller - to get 10^-7, and you make the other term 1000x bigger - you'll have the same number
but now it'll look like a * 10^-7 and now you can do your bracket stuff
0,00125*10^-7 - 1,16*times*10^-7
Oh ok
or you can use ` backticks ` to get this
Yeah that I know
be careful - you've made both parts of the a * 10^-4 1000x smaller
so 0,00125*10^-7 is actually 1 million times smaller than 1,25 * 10^-4
But if I change 1 I have to change the other no?
Isn’t it scientific notation
Ohhh
I did it the wrong way
1250*/10^-7
$1.25 * 10^{-4} = 1.25 * (10^3 * 10^{-7}) = 1250 * 10^{-7}$
PrettyPrincessKitty FS
Yeah
and now you can do the subtraction because you can take a common factor of 10^-7 out
Mhm
I gotta write this on paper so gimme a few minutes
Ok I did it
1,24884*10^3
Is the answer for 2
So it’s also false
(X^2) *6 = (25^12)*6
@desert nymph
Does this work?
If ur busy lmk so I stop bothering you
For III)
sorry! I was away
Don’t need to say sorry Dw
note that if 1 and 2 are both false, then your only possible answers are "only 3 is true" OR "1, 2, and 3 are all false"
and only one of those is a valid answer 😉
Yeah ik but I have to be able to prove it cause imma be presenting it to my rescuer
Teacher*
Rescuer 😭

haha fair fair
so yeah for x^2 and y^6 and w^7, what we really want is to have them just like x = 25^a and y = 25^b
because then $xyw = 25^a25^b25^c = 25^{a+b+c}$
PrettyPrincessKitty FS
But we need it to be ^12
yeah, but we just want to put the ^12 around the whole thing - which is fine
Yeah
first we need to get x y and w on their own
So just divide?
yup
I think I get ^204 but yeah either way it's false 🙂
Oh yeah I added wrong on my multiplication 😭💀
x=25^6, y=25^2, w=25^9, 6+2+9 = 17, 17*12 = 204
Yeah
but yeah otherwise spot on
I did that too
@desert nymph again, lmk if ur busy so i stop @ you
So like isn’t this just memorization
determine...in general...the something of 3^2009?
ahh, I see. yeah this is just asking you to be look at the table and see a pattern
I see that it goes n*3 each time
Is that what I’m supposed to see?
I’m guessing not
Wait I see that if u add up the digits
the question is asking u to find unit place yes?
See if u are able to observe something in unit place of the exponents
It’s a mutiple of 3
It’s asking me to determine 3^2009
That’s the divisiblity test of 3 yes
Does it help with the question?
What? It must be asking to determine the unit place of 3^2009
Erm
What does “unidade” mean..???
Unit.
yeah
oh the last digit
Yes
Oh yeah ur right
Unit digit means the ones place or the last digit (unless there is decimal)
Yeah
Portuguese isn’t my first language
It’s ok
(Roughly translated from Spanish lol)
I’ve lived in Canada most of my life but I went to Brazil like 4 years ago cause my grandparents are from here so we came back for some times
So I’m still learning
too much exp w such questions lol
Easy to guess it can’t be asking the value of 3^2009
🙏🙏
I doubt even calci can work that out
Yep.
Yup
So take 2009 mod 4.
Yup
(Find the remainder when 2009 is divided by 4.)
What d9es that help with
Okay, calculate the units digit of 3^5. Then 3^8.
Basically it’s repeating every 4 times right
So u can place
1397 as positions
For power 1 - it’s 1
For power 2 - it’s 3
For power 3 - it’s 9
For power 4 - it’s 7
It’s a cycle and u gotta reach til 2009
The last digit?
Yes
502 remainder is 1
Therefore the position is?
So it repeats 502 times and the last repeat ends at 1st
1 or does it like go to 1 forward
Nvm I counted its 1
Is it
Oh no wait
Forward.
It worked, so just keep the method in mind.
Ok
0->1 1->2 2->3 3->4
Even though 0-4 goes through 5 numbers
It’s like 4 counts or whatever
01234
Kinda confuses me
So if it starts at 0 u just add 1 to the number ur remainder got so it got 1 for me so I jump from 0 which is 1st in this and go to 1 which is 2nd in this
Would you say the sequence starts at 1 or 3
Because you have 0, 4... corresponding to 3^0, 3^4...
So?
Mod 4=1?
Remainder is 4=1?
Let’s take 3^3 instead.
Ok
Now we have a sequence 1, 3, 9, 7.
Oh
We start at 1, consider that position 0, then move 3 to the right of 1 to get our desired result.
So u do the power first then u see the result
Right
So starting at 1 we move 3 to the right ok
So if we get 0 remainder it’s 1
Cause 4=4
I see now
Thanks
How do I even write the explanation down on paper
I need to write how I got here cause imma present this in class

I’ll tell you whatever I end up writing
We see that the sequence is 1, 3, 9, 7, so we divide 2009 by 4, the remainder is 1. That means it’s the position in the sequence where it ends up at. You have to move 1 digit to the right from where the sequence starts, so in our case it starts at 1: 1, 3, 9, 7. The answer is 3.
I put an arrow from 1 going to 3 to indicate the digit jumping
@ancient grotto
Sorry for the @ I just thought u might wanna see
@vapid elm 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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
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.
, rotate
It Is correct ?
,wolf integral cos^3(x)/sqrt(sin(x) dx
Wolfram Alpha doesn't understand your query!
Perhaps try rephrasing your question?
Click here to refine your query online
,w integral cos^3(x)/sqrt(sin(x)) dx
yes
which you did
SIN (X) = T
@wintry echo Has your question been resolved?
Closed by @wintry echo
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 it is me again, i need more help with understanding absolute values
if i have |x-3| = 5
i have a number x-3 that is supposed to be 5 steps from 0 on the real number line
and there are two such numbers
because i can take steps in the negative direction or positive direction
and because of that
i can see that one x has to be 8, and the other has to be -2
but i dont get how i actually motivate that properly
how do I motivate that properly
didn’t you just do that
the distance from 0 is 5
i dont feel like my motivation is sufficient
|x-3| = 5 means x-3 = 5 or -(x-3) = 5
like i could write that in a bunch of words on paper
but there has to be a better way to mathematically motivate that
to get points on an exam
^
definition of absolute value
|x| = x if x >= 0 and |x| = -x if x < 0
it’s defined piecewise
that definition hurts my brain and i dont understand why i find it so difficult to understand
im really having a hard time
There is a rule thats says:
|a| = b, means a = b or -a = b. You can multiply the second equation by (-1) and get a = -b
because if x >= 0 then just leave it, it’s already positive but if x < 0 you multiply by -1 to make it positive
Basically, if you want to take an absolute value of 5, you only write 5, but if you want absolute value of -7, you want to get 7, so you use the second rule which is -(-7), and that equals 7
this seems slightly easier to understand
i shouldnt say understand
i dont understand this i just memorise it
I found that giving a concrete example is the way to go at times, an example that explains how the rule works
I don't recommend memorising things in math
i cant seem to do anything else
i dont think i understand anything within math at all
What level of math are you at?
truthfully im probably like a weak high school pre-cal student level, but im actually in uni and im asking questions about absolute values and complex numbers mostly because it is in my course for linear algebra
and i've been doing calculus as well where i got 66.7% of what i needed to pass on the test, but i didnt understand a thing i was doing
i just memorised
it is a very grim situation
i want to learn and i ask over and over but nothing seems to stick, i find a way that gets the right answer, memorise it as well as i can (i still forget though unless i keep practicing the steps), and then i move on
this is painful to read
|x| = x if x >= 0 and |x| = -x if x < 0
i can barely understand what this says
|a| = b, means a = b or a = -b is easy to memorise
so then maybe if my memory allows me to i will use this when appropriate
but i dont really understand it
you're just stripping the sign
i will probably use it inappropiately as well
so if you plot y = |x| on a graph
i do know what that graph looks like
note that the left hand side looks like y=-x
the right hand side looks like y=x
that's gives you it as a piecewise function
i just dont get how that turns into a bunch of other knowledge
now your question was |x-3|=5?
yes
how familiar are you with complex numbers?
only a little bit, i have been looking at them recently
ok
i know there are cartesian and polar forms for them
okay
i will just do that on paper right now
with x=3 as the centre
ok cool
ok i dont understand why we are drawing the circle
where does the circle cross the line
what were your solutions before?
but like does this count as motivating that answer
like i dont have to motivate the circle
are you trying to understand this for yourself or for your teacher?
for myself so i can start actually trying to understand math and not just memorise an algorithm to solve problems
ok
this is an example from an online pdf i found that is more complicated for me, i asked about help with it earlier but only got like half way
|x| = 2|x − 1| − |x + 1|
i was told that you can see the critical points straight up
like i dont even have to factorise or anything
remember that a circle is all the points a distance of 5 away from the centre
i dont understand that at all
ok let me think of a way to make this makes sense
are you trying to get me into thinking of the imaginary axis too?
no not at all
oh ok
although it might help in the future
i thought maybe that had something to do with compelx roots or something
like 3 + 5i or something
in this case
but maybe that's not a root since it is on a different axis
roots are on the x axis always right?
no tbh i dont really know how to handle |x| still, but r is just the distance between origo and a complex number, like a point on a graph with an imaginary axis and a real axis?
like it is almost like a hypotenuse
(I'm also trying to figure out what you know and don't know)
that's okay with me thanks for asking
given a complex number z, |z| is the distance from the origin
gives the set of points where it is a distance of r from the origin
idk what that means
sorry
i understand some of it maybe
yeah i can do that
oh i did it anyway but yeah i can do that
i can do it for decimals to most of the time
if they are nice
like 0.25 or 0.5
maybe 0.1, 0.2
0.1 uses up a lot of the page
the decimals being the coefficient to x
ok that's fine
you understand how any point on this line satisfies y is x multiplied by m
(where m is your decimal)
sry this might be a language barrier thing but what do you mean by satisifies
sweden
were you on CE server a few days ago?
CE server?
Chinese English
ooooh, that's interesting, i'm in one right now, but i haven't really chatted much in there at all i think
i checked and yeah i havent sent any messages there
but im in a chinese english server
no worries, I thought I chatted to a swede the other day
ok funny coincidence but it was not me
i dont understand this question
I just want you to picture it
yes i can do that
the general shape
what happens if i increase m
and sometimes steep or less steep
big m steep
increasing steep
and low m steep, but decreasing
sorry
that is wrong
if m is above zero
see this is like really basic stuff but im already slowing down trying to follow along with what you're explaining
it's not that i haven't seen it before i just have never understood it well
i agree there are an infintie number of points along the slope of y = mx
but i didnt know they could all be described by (x, y)
i dont really know what that part means
i understand a point has a y value and x value
(3.141, 3.141)?
ok
and negative as well, like in the third quadrant
yeah i agree with that
y=x is your rule for this line
it would be a different line if i changed the m value from 1 to something else
yes
is there a way to tie this back to |x| = 2|x − 1| − |x + 1|? sry if im being rude, i appreciate you taking the time to try to understand what i know, i just dont feel like know is the right word, i just memorised most of it
like when you asked me about this i have never really memorised this even if it is true
it is never really something i use when i solve problems
at least not actively
and frankly i dont think at all
something that would help me would be to hear what goes through your mind when you see a problem like this
|x| = 2|x − 1| − |x + 1|
for me i see absolute values and yeah i dont understand them very well yet
i understand now that they are a distance from to 0 on the number line
to some place else
on the number line in this case i think, but apparently (maybe) it can like crossover to the complex points as well
dont really get that very well
|x| = 2|x − 1| − |x + 1|
like more things pop up in my head but i cant use them because i dont understand them
there is a definition for |x|
that is somehow useful i think
but i dont understand how to apply it and i dont understand the definition
then apparently you can find critical points by just looking at |x| = 2|x − 1| − |x + 1|
like |1 − 1| = 0
so one critical point would be at x = 1
i dont understand how that becomes a critical point though
previously whenever i encountered critical points it has been with mostly fractions
like (x+1)/(x-1)
one critical point is -1, where it is defined
and another is 1, where it isn't
|x| = 2|x − 1| − |x + 1| this is a mess to me
apparently i can remove the absolute value sign by splitting something up into two cases
x = 2|x − 1| − |x + 1| or -x = 2|x − 1| − |x + 1|
i dont know if i did that right
but it doesnt feel like it helps me, because i still have two absolute value signs left
and from what i understand there is some kind of utility to leaving them there
i dont understand why it is useful to leave them there
can i just keep going like a mad man?
x + |x + 1| = 2|x − 1| or -x + |x + 1| = 2|x − 1|
x + |x + 1| = 2(x − 1) or -x + |x + 1| = -2(x − 1)
|x + 1| = 2(x − 1) - x or |x + 1| = -2(x − 1) + x
(x + 1) = 2(x − 1) - x or -(x + 1) = -2(x − 1) + x
0 = 2(x − 1) - x - (x + 1) or 0 = -2(x − 1) + x + (x + 1)
nah that doesnt make any sense
plug in at -1, 0 and 1
why?
because that's what your x's need to be to make the inside of one of the absolute values 0
i was told that, and it was supposed to make sense but i still dont understand why
like again, if im given a something like this (x^2 + 2x + 1)/(x-1)
can you agree that if you add linear terms, you get linear results?
that's a completely different matter
but why dont i have to factor first here
to determine the critical points
|x| = 2|x − 1| − |x + 1| i 100% agree that
if i put in x = 0 for |x|
that it returns a 0
and that for 2|x-1|, if i plug in 1, it returns a 0
and for -|x+1|, i plug in -1, it returns a 0
but that's individually
like if i plug in 0
for x
then i get 0 = 2 - 1
and that doesn't make any sense
if i plug in 1 i get
1 = 0 - 2
if i plug in -1 i get
-1 = -4 - 0
sry
but how can there be multiple different edges
because that's what your function is
|x| = 2|x − 1| − |x + 1|
but i dont get it like
if i plug in a critical point fo rx
for x*
the function doesnt return anything that makes sense
or
no i dont get it at all
is this even a function
$f(x) = 2|x-1| - |x+1| - |x| = 0$
Xetrov
i heard || is a function but
,w graph 2|x-1| - |x+1| - |x|
i dont understand how it looks like that at all
when everything is above 1, all of those absolute values take positive form
campus is closing in 15
i wish i understood more but im just so extremely lost
i dont understand this at all
|x| = 2|x − 1| − |x + 1|
can i add you? i wont spam you a bunch
this is so weird to me
the middle part i assume is made out of the 2|x-1| and |x+1| bit
and the steeper half of the graph
is made out of the 2|x-1|
but i dont understand why that is or how it works
but yeah i really gotta get going unfortunately
campus used to be open past midnight but apparently homeless people and drug addicts would come here at nighttime
so they stopped keeping open during those times
ty for trying to help it was very much appreciated im gonna ask a lot of these questions to the student-lead tutors on monday-thursday next week
.close
Closed by @fickle flume
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.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
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.
!help
To ask for mathematics help on this server, please open your own help channel or help thread. See #❓how-to-get-help for instructions.
need help transforming 6 = a(x+1)^2 +8 into factorised form
which is f(x) = a(x-x1)(x-x2)
What have you tried
That's the freshman's dream unfortunately
wait what 6-8 is -2 so ull have complex solutions
$(x+1)^2=x^2+2x+1$
depression
not necessarily bc a could be negative
ok look
that form is
canonique
canonic
the one i just said
thats canonic
f(x) = a(x-h)^2 + k
f(x) which is 6
a i dont know
x neither
h is -1
k is 8
Sure
No x is a variable
If you're trying to factorise it then that gives you possible solutions for x
So sort of
ok look
So what have you tried to factorise it?
oh bruh show the grpah then
nothing
ight
Okay
Okay
make sure to give any relevant diagrams to the Qs along with the Question next time
So you've almost got it
alr
It looks like you've found that the equation is of the form $y = a(x+3)(x-1)$
depression
yes exactly
To solve for a you can just substitute in values for x and y
what is x tho
but theres 2
ye but theres 2 x
the x1 an x2 are roots
the values of x for which the function is 0
