#help-0
1 messages · Page 728 of 1
oh sorry
alright no worries. so when encountering a rational inequality like this one, you can try looking to solve whenever the num=0 and den=0 (undefined), so that those values of x won't yet be our solution but we'll be our x values where our (x²(x-1)³)/(sqrt(x+7)) will touch the x-axis and hence between those x-values, we'll want to test out some values in those intervals to check whether the (x²(x-1)³)/(sqrt(x+7)) is non-negative (so ≥0) or non-positive (so ≤0), which would be our solution, since it's asking whenever ≤0.
as this might be a whole new methodology to you, i will recommend watching a video for you to get kind of used to the method for later to get here and try your problems.
This precalculus video tutorial provides a basic introduction into solving rational inequalitites using a sign chart on a number line and expressing the solution using interval notation and as an inequality. This video contains plenty of examples and practice problems.
My Website: https://www.video-tutor.net
Patreon Donations: https://www....
oh okay, i'll watch it
if i still need help w any of them after the fact should i ask?
of course. feel free to do so
ok thanks
question says:
a bowling ball with radius 10cm rolls in a horizontal V-shaped slot with an opening angle of 60°. The speed of the center of the bowling ball is 18km/h
What is the distance between the centre of the ball and the bottom of the slit
why do they mention the speed
of the bownling ball
or am I just interpreting it wrong
do you need the speed?
I think I know a way to solve it but the speed makes me doubt it
i think the speed is irrelevant
use 30-60-90 triangles to solve it
lines tangent to a circle are perpendicular to the radius
I'll give you the hint that you only need to look at the last digit
You can see a pattern if you write out the first few terms
You can probably try the powers of 2
And see when they repeat
Basically a pattern
And divide 2017 by the number of times after which they repeat
And get the last digit by comparing the index
2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
2^5 = 32
unit digit repeat after every 4 powers you can notice
oh thank you very much
matrices are equal iff all their entries are
I'm confused between α>=2 and α>2 :/
Think about what it means for a function to be strictly increasing
For all x>y f(x)> f(y).
Im assuming this is a calc class?
so answer Lachlan's prompt in terms of calc
yeah, so you'll have strict inequality
So now just solve that inequality for alpha
so isn't x^2 strictly increasing for all x>=0?
I'm confused because of the domain of x...
Because this definition is true even if alpha is greater than equal to 2
Yes, x^2 is strictly increasing for all x >= 0 however in this case was have x(alpha-x)
For instance, this is what the function looks like when alpha = 1
If you apply the f'>0 condition for strictly increasing then you'd have got x>0 but x=0 holds too :/
Yeah
I think I see what you're saying
Here is what I would do
I would say that we want f'>0 for all x in the domain
We know the derivative is alpha-2x
So alpha-2x>0
Right
Yes
This gives us alpha>2x
Now we want alpha to be greater than 2x for all x in (0, 1)
Notice that it doesn't exist at 1
So if alpha = 2
That is greater than 2x
And so I would say that alpha >= 2 is all good
I don't think completing the cube counts as witchcraft
and typically completing the cube is used to reduce from x³+bx²+cx=d to x³+cx=d
what chapter is this in
WHA
WITCHCRAFT
WHAT MATH IS THIS, WHAT LEVEL I MEAN 😭
is this like calculus 3 million
does it talk about uuh
covering spaces
groups
deck transformations
if the book is about riemann surfaces what's the chapter about
ah xD
lol
not sure if they intend it to be solvable
might be worth asking in one of the advanced channels. Check #get-advanced-access first
is any1 here smart at math
Or maybe physics server
no sorry, none of us actually know math
no I just took an L on AP Calc
Jk just ask your question
ill pay someone 25 tom if they can help me in mathe today
it might not but i will
have you considered posting your question
A square of side 1 contains several circles in its interior. The sum of the circumferences of the circles is equal to 10. If you draw a straight line parallel to a side of the square, how many minimum circles will it always intersect?
Please help
Options are: 2,3,4, can't be determined
I've thought about it a lot but to no avail
You drawn it out?
-25x0 do you right it as -0 or +0 if put in an equation
definitely can't be determined with that much information, trivially you could make a circle of circumference 1 and stack 10 of them on top of each other, then depending on where you line is you either go through 0 or go through 10
you write it as 0, -0 is not a thing
or rather, -0 = 0 and is always written like so
Ok
I did
But wasn't getting anywhere
Since symmetrical orientations didn't work
Also found out the sum of radii of all the interior circles
But that isn't getting me anywhere
I think I found the total number of circles to be in between 9 and 16 but I'm not sure
<@&286206848099549185>
↑
is there something wrong with my answer?
Oh I see
mine seems quite a bit too trivially disprove it, but i don't see a problrm with it
Yep
perhaps they mean non-overlapping circles, but i still suspect you can't determine it
I believe it requires that it always intersects circles
But the wording of it all is a bit dodgy
is this channel free
gonna assume it is
how did they get that as the condition probability
I got $\frac{\frac{79}{98}\cdot \frac{79}{91}}{\frac{79}{91}} = 0.806$
TheMane3
The probability of A, that they have AC, is 79/98, and the probability of C, that they have a companion animal, is 79/91
Would love to look at it but can’t right now 😥
Awh it's okay
Tysm for taking the time :)
why would you only look there
but 79/91 is the probability they have a companion animal @noble sinew
since the amount of people with an animal is the same as the amount of people with ac, i get why they use 79 again, but we're not looking for how many people have an animal right
we're looking for people with ac
so 79/98 is the probability they'll have an ac right
It is the conditional prob that the question asks for
but its also that right
79 people have one, 12 people dont, so theres a 79/91 probability that they have one
No?
what
Both the 79 and 12 are under yes
oh 🤦♂️
what would i do in a future question like this
Hello guys, i am re-learning math because i want to get better at it, and there is one thing i don't understand even now about fraction word problems, why for example here must i multiply the fractions to get the right result? Please help me to understand.
of means multiplication
ok
how do i know if a question is conditional
like what here tells me its a conditional probability
the fact that its in the table?
i mean i remembered the structure but i still would want to understand more in depth if possible, because at first i thought that i have to divide to get the answer
*1/4 is the same as dividing by 4, so yes
nowhere
you just determine the independence of the events
well thats what i did originall i think, the probability of someone having air conditioning is 120/180, and the probability of someone enjoying opera is 120/720, 120/720 * 120/180 = .1111...
since 120/720 * 120/180 does equal .1111, it would be independent
did i do that the right way?
$P(A\cap B)=\frac{120}{1080}=\frac{1}{9} \ P(A)P(B)=(\frac{720}{1080})(\frac{180}{1080})=\frac{1}{9}$
Mosh
so yes they're independent
interesting
why do you do the full thing
like umm
why the totals
720/1080 and 180/1080
howd u know to use those
no
what
dude what
besides, you only want work checked. Use wolfram and show some respect
anyways
there are 1080 people total, so I divided by the total
ohhhh
hold on, if its okay with you im going to write out my steps for one of these questions
and see if i get it right
yeah
ok 1 sec
No
who asked u
You did
(actually what would i search to find questions like these? 😅)
i never pinged u
dude quit it
well same source you're getting your other questions?
u just took my channel
they didnt talk for 15 mins
that was the last question in my book about it lol
you did every single question in a book?
this guy is cheating on his exam
proof
yall are very immature
bozo
ok so ill make the questionnnnnn...."is the probability of liking snowboards and the probability of liking snowmobiles independent?"
would that work
bruh
sure
ok
cool
bye now
bye bye
didnt you say bye just a message ago
Just ignore them, they're just a troll
ye il leaving
cap
this guy is a capper i came for help
i come here for daily help
anyway, yeah just determine if those events are indep. like you chose
@glass lichen so the probability of liking snowmobiles is 80/125, and the prob. of liking skateboards is 80/105, 80/125 * 80/105 = 0.488, so now we look at the totals like we just did in the last question i think, so 125/160 * 105/160 = 0.512, since 0.488 is not equal to 0.512, they're not independent?
😓
lol he just ghosted you.
You didnt use the total sample space
wdym?
you divided by 105 and 125 for some steps
yes
ahhh ok
$P(A\cap B)=\frac{80}{160}=0.5$
Mosh
you're using channel 1...
no
Like is this a really hard concept to understand or are you just being needlessly petty
Stop being such a karen
stop being such a dick
Like all you've said is "is this right" when any calculator/CAS can answer that for you.
why do even need this channel anymore, your question has been answered?
how old are u, like 10?
no u need to stop the cap cause it dosent answer every ques
And then you opt to constantly break rules and present yourself as a superior
so what
@gaunt magnet we're still doing this?
okk
sure
yes
how would i determine if that bit of info is independent 😅
then find probability of each and multiply them
each what
we pop at ur party
P(senior) and P(working part time)
Hello kind people, anyone of u help me in Math
channel in use
👍
you wont get any help from that karen mosh
Or just.. use any of the other channels
channel in use
Oh sorry
so P(senior) = 80/160, and P(part time work) = 51/59, multiplying both, I got 0.432, 51/160 = 0.319, so that means its not independent?
or was i supposed to do 51/160
compare
0.318 isnt 0.159.....soooooo not independent
yes
oh they want you to use conditional
the first one is saying 59/160 isnt equal to 51/160, and the second one is saying 80/160 isnt equal to 51/160
they're both true
yeah not sure, but they shouldnt be independent
independent if P(A|B)=P(A) so the one you picked is wrong
so not independent if P(A|B) != P(A)
but they're both true arent they
the first one says 59/160 doesnt equal 51/160
and the second one says 80/160 doesnt equal to 59/160
yes but first one has nothing to do with independence
How does the second one do?
because it shows P(A) doesnt equal P(B given A)
which is the formula for independence with a conditional probability
the first one shows P(B) doesnt equal P(B given A) which doesnt follow the formula
so while theyre both true, one has something to do with independence and the other is random i believe
Ah I see
Can anyone help me solve this problem?
help me in the problem pls
Yeah so just add up the probabilities when D is 1 and when D is 2 unless I’m oversimplifying it
So you mean only add D1 (0.301) and D2 (0.176)?
Yep bc it’s 2 or below
But the only thing that’s lower than a 2, as an outcome is 1
Circumference: [2πr] 2 x (3.14) x (radius)
Area: [r^2π] (radius squared) x (3.14)
oh okay thanks
I do not understand;c
Do you know the equation for circumference and area of a circle?
yes
Apply that concept to that problem
but I don't know how to find it
What's the equation for circumference and area?
i wonder how well google translate works for translating math words to other languages
Google 번역이 수학 단어를 다른 언어로 번역하는 데 얼마나 잘 작동하는지 궁금합니다.
I'm Korean
circumference is twice the radius times pi
둘레는 반지름 곱하기 파이의 두 배입니다.
yeah but im not korean
im just curious how well it works
I would guess since math words are niche that translate would do fine with it
I think the issue usually occurs when the sentences become complicated
the radius is half the line the circumference the bottom line of the circle
Or colloquial stuff is used
몰라서 물어본거 아니였어요?
how do i solve this ? i dk how they got 62%
Ah for the area just do πr² for the area
For the perimeter do 2πr
Didnt know people still play roblox lol
Sometimes it works sometimes it's terrible lmao
Ywah it's prwtty accurate
Does anyone know how to "solve" this>
it seems wrong... but maybe im missing someting
I don't see any reason to think so
This is basically saying "all 2×2 matricies have non-real eigenvalues"
Of?
can someone explain why the inequality is important for the limit not existing, if it was = 0 there, an asymptote wouldnt be there?
If x approach 3 from the right, the limit goes to positive infinity and if it goes to left it goes to negative infinity
x - 3 > 0, if and only if, x > 3, so the limit from the right goes to positive infinity. If the limit was approaching 3 from the left it would be negative, because x-3<0
what does the 16 > 0 signify?
That 16 > 0? If the limit of the numerator was negative, then the whole limit would approach negative infinity
cuz it's done the same way for approaching from the left
If num approached 0 then you had 0/0 expression which you can’t say what value it is just like that
Hence the important part is num doesn’t approach 0
ah, so its saying part of the reason that the func is approaching inf is that the numerator is more than 0?
That it isn’t 0
Because then you can just apply product rule and find limit which is what they did (without saying)
in this are they just making the 5 have the same denominator by multiplying the denominator of the left side
Yes
wow
If u look at the part with the five u can see that the numerator and denominator would cancel out leaving u with 5 meaning same as multiplying by 1
His question was a quick answer
got it, i overthink this sorta stuff too much
It’s all good I did too
Just make sure u get this stuff down ull use it later down the math line
for sure
What math class/grade is this?
its an online intro into calc
Precalc?
yea
Ya these algebra skills will start to become more important def work on it
i'll try
U can also hmu if u need help with that kinda stuff btw
I’m kinda studying math in college rn just a more specialized degree than standard math degree
if you're cool with that, thanks, thats a bit reassuring
Yah np might be a little busier come the end of august when classes come up but for now 🤷♂️
yea im just trying to get through my course before august ends, gotta get through a mid term, two units, one assignment and a final before then
College or high school?
college ye, its a online one
Completely online college or just this course?
its a completely online one, im planning on transferring the credits from this into my actual uni
What year/what are you going for?
finished my second semester, going for business but i need this credit to try and transfer from law
That’s cool which business degree or just general business?
haven't really put much thought into that so im not too sure
maybe accounting or finance
Both not bad choices tbh
I found accounting kind of boring and liked finance but I have friends who thought opposite
hope i dont find whatever i get into too boring
If u do switch 🤷♂️
Better to waste some money than rest of ur life
I just finished my freshman year back in April my sophomore year starts end of august btw
nice, just stressful to think about but true
how do i create a right left arrow in latex
$\rightarrow$?
cgodfrey
??
cgodfrey
there we go
oh lol
or $\longleftrightarrow$
cgodfrey
$\iff$
Mosh
$\longlongleftrightarrow$
$\Longleftrightarrow$
cgodfrey
JeffTheRef
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
$69x^4+420x^3+69x^2+420x=69$
JeffTheRef
$e^{\pi i}+1=0$
JeffTheRef
$ x{\leftrightarrow}x$ and $\iff$ and $ x{\longleftrightarrow}$
JeffTheRef
There's a latex help channel and testing channels
So i'm not very good at math but i was wondering how to use this function to squish a number between 0 and 1, i'm trying to figure out what to set x and e to.
e is e...
and that would be what XD
like 2.71828... irrational garbage
$e=\lim_{n\to\infty}\left(1+\frac{1}{n}\right)^n$
Mosh
thanks. the first time i searched it i thought it was exponent, not eulers num
I mean you could've guessed from the function notation it was the number e
since S was only a function of x
But yes, $S:\mathbb{R}\to (0,1)$
Mosh
<@&286206848099549185>
is l4 the left riemann sum with 4 rectangles
If z= a-ib, then mod z will still be, root(a^2+b^2)?
$\frac{4}{6}=\frac{22}{23}=\frac{2}{3}$
Omfish
Ok thanks Omfish 😅
how to do part (a) and (b)
for part a
i solved $P'(x)=0$ and got $x=0, -\frac{2B}{3A}$
abe
but how do i rule out x=0 as a solution
what reason should i state
also for part b, should the 2nd term on the LHS be -4B^3?
because i get 8B^3=0 when i simplify part B
and the quesiton stated B cannot be 0
if x = 0 then A(0) + B(0) + D = 0 or D = 0 but according to the question A, B, D are non-zero so 0 isn't a solution
ty for part a
Hey, um idk if you have already solved it yet. But if not, just substitute the value of X you got from the part a (That is -2B/3A) in the original equation.
That is it
yes
and i get 8B^3=0
which means B=0
but B cannot be 0
as the question had imposed ccertain restrictions earlier
soooo
idk whats going on
see, if you substitute $\frac{-2B}{3A}$ in the original equation, you get:
$$A\cdot \frac{-8B^3}{27A^3} + B\cdot \frac{4B^2}{9A^2} + D$$
$$= \frac{-8B^3}{27A^2} + \frac{4B^3}{9A^2} + D$$
$$= \frac{-8B^3+12B^3}{27A^2} + D$$
$$= \frac{4B^3}{27A^2} + D$$
$$= \frac{4B^3+27A^2 D}{27A^2}$$
But since our equation equals $0$, we get that:
$$4B^3 + 27A^2 D = 0$$
Hence, proved
Schrödinger's Smile
does my solution help?
for what?
ohk np
yehh
hi
does the logical statement “either a or b” mean “a xor b”
so yes
yes
lol brilliant is wrong
@covert agate
XOR is a precise mathematical function
"either a or b" is imprecise.
Sometimes they're the same, sometimes not.
huh
"either a or b" does not unambiguously mean "but not both"
statement: “either you or me is math major”
reality: both math majors
conclusion: statement false?
why are you pinging helpers on gansta's behalf 
it say u can ping helper after 15 mins
so i help him
and ping for him
@vale wigeon helper he no understand
never heard 😛
that's what the tilde means that you circled
essentially, we say $f(x) \sim g(x)$ if $\lim \frac{f(x)}{g(x)} = 1$ (as $x$ approaches whatever we need it to approach)
Ann
asymptotic equivalence means, roughly, that one function can be replaced with another in a product
this can be accomplished without explicitly mentioning it by multiplying your fraction by x^2/x^2 and grouping the x^2/tan^2(x) together (and acknowledging it approaches 1)
ok...
but if so can we substitute tanx = x on the numerator so that the limit equals 0?
no
one function can be replaced with another in a product
this means that if f ~ g then we have lim h*f = lim h*g
asymptotic equivalence is also preserved if raising both functions to a constant power, which covers doing this in the denom of a fraction
so it is product only...
thanks @vale wigeon
i think i get it
although i just read the definition 😛
technically you can use equivalences in sums, but you'd have to prove that you don't miss anything behind that o(x), or whatever you'd be left with, when you do that. With multiplication it's guaranteed(can be proven in general) that you'd be fine.
that's not how it works. You first post a question, then ask for help.
Use subtraction
just apply the subtraction algortithm
you can do it with small numbers, you can do it to large numbers
can you do it if the numbers are smaller?
then can you follow the same steps to subtract?
You will get banned or muted if you act uncivilised
if you want you can show your rough work as you go along
sounds quite inappropriate
now try doing that, but instead of milk use numbers you were given and instead of pouring it out, subtract them
also aren't you asking for help on subtraction
kaden, what are you doing?
He's struggling with subtracting
what is all this about?
or just trolling
asters?
asters?
what's an asater?
sounds like troll
^
okay probably troll
okay you are definitely a troll
<@&268886789983436800>
that is an obscene gif that you definitely did not need to post either
gross
what first grade subtraction exercise does to mf
banned
can anyone explain how they got 1/k(k+1) = a/k - b/k+1
partial fractions
can i get some help understanding what this means
f is a function from A to B
g is a function from the powerset of B to the powerset of A which sends each D ⊆ B to its preimage by f
Hello I was doing a worksheet and this question popped up, can anyone help me?
do you know about eulers formula for polyhedrons
v-e+f=2 for any polyhedron
v being the number of vertices, e the number of edges and f the number of faces
another Euler's formula? didn't even know about that one
that one is pretty neat and generalizes to any finite dimension
? <@&286206848099549185>
I don’t know the answer but I will say that the helpers in this discord tend to help people more when there’s a demonstration at an attempt at solving a problem when posting
help, ping me when u get solution, thanks
,rotate
I simply will not
the question is missing information
oh
nvm im retarded
its c)
i thought it was a question itself
was tryna help my friend find ans
𝑎 is directly proportional to the square of 𝑏 and inversely proportional to 𝑐. Find the effect of 𝑎 when 𝑏 is increased by 10% and 𝑐 is increased by 20%
imma need some help
with this question
have you tried anything at all?
𝑎
how did u type these special characters
a𝑎
i copy pasted
please ask in another channel
yeah but i got stuck at one point, there's an explanation for it but i don't know how they went from one step to another
channel is occupied
all of them are open but this one atm lol
we dont help with exams here
you will straight up be banned from the server if you ask for help on an exam
mods offline rn tho
okay...
whered you get stuck
this is the explanation
and i don't know how they did this
from the first one to the second
wdym by effect
so like how much it changes from the original value
what happens to a when you increase b by ten percent
oh
so multiplying b by 1.1 has the effect of increasing b by ten percent. same with multiplying c by 1.2; it has the effect of increasing c by 20 percent
i think i got it
k is just some proportionality constant
yeah
the increased/decrease of a will be in %?
yeah
and after carrying out some computations, the effect of increasing b by 10 percent and c by 20 percent has the effect of scaling a by a ratio of 1.21/1.44
there are some typos in the solution, mainly just that they forgot to write b^2 in a couple places
i still don't how they inputted kb/c
a_new is given by k(1.1 b)^2/(1.2 c) which is in turn equal to (1.21/1.2) kb^2/c
is that what you were asking
cool
they shouldnt have because thats wrong. good catch
this "solution" is riddled with errors
Guys is there a formula to finding a general sequence from a recursive sequence? Like for example how do we get from a[1] = 1; a[n] = a[n-1] + n to a[n] = (n(n+1))/2 ?
no
there is no formula in general
it can be very hard if the recurrence relation is nasty enough
Ah I see. So the only way is just to like... get something by the slope of the sequence or something?
there are a lot of techniques for solving recurrence equations
i took a class that almost exclusively focused on solving them
I see. So there are actual ways other than just trial and error?
the real moral of the story is that you can just plug it into wolfram and not learn how it works
Hm right
absolutely, but I'm not going to go into detail here
Yea it's okay
it's kinda like differential equations, different types need different solutions
not all of them are easy
if your recurrence relation has a certain form there are techniques which let you solve it
^
master theorem go brrr
In the analysis of algorithms, the master theorem for divide-and-conquer recurrences provides an asymptotic analysis (using Big O notation) for recurrence relations of types that occur in the analysis of many divide and conquer algorithms. The approach was first presented by Jon Bentley, Dorothea Haken, and James B. Saxe in 1980, where it was de...
Oooo
this is a way to solve some subset of them
this isn't quite what i was thinking it was, but there's something in here that gives you the exact forms
yes
,rotate
can you post the other pic again?
if a line makes a 45 degree with the positive x-axis then the slope of the line is tan(45) or 1
yeah
which is y=x
oh
it sais coordinateS
so all i have to do is x=x^3-x^2
and get all x coordinates
no y=x is just one of the line that has slope 1
there are infinitely many lines with slope 1
all of those make a 45 degree angle with the positive x-axis
you have the general equation of the tangent
and you also have the slope
which is also?
(not talking about 1)
huh?
the slope of the tangent is what?
how do you find the slope of the tangent line to a curve at some point (a,b)
rise over run
ehh no
or y2-y1/x2-x1
thats the slope of the secant line
lemme ask you, how did you find the coordinates in question a?
yep
u put f'(x)=0
why?
which then is parallel to x-axis
why do you know f'(x)=0 gives you the coords where the tangent line is parallel to the x-axis?
not the answer im looking for, but yes
the derivative at that point is the slope of that tangent line
yes
what is the slope of the tangent line in part b?
OH I GOT IT
since m=tanx
1=tank45
the gradient of the tagent line must be 1
so therefore
1=dy/dx
yes
yes
BRUHHH
IM CRYING INSIDE
IDK HOW TO DO THIS QUESTION
somebody help me on how to do this
have you made any progress or are you stuck not knowing how to begin?
please do
aha
alright, this is in line with what i was going to suggest
so you see that the two segments in the lower left are equal to each other, yes?
kl
here
yh those
ik
let's call them both z, as i did on the pic
ok
then we have that (x+z)^2 + (y+z)^2 = (x+y)^2, don't we?
what do you get when expanding this?
2z^2 + 2(x+y)z + x^2 + y^2 = x^2 + y^2 + 2xy
indeed
we can simplify this to z^2 + (x+y)z - xy = 0
wait what
oh
or are you asking how to get from your thing to mine?
ok
(x+z)(y+z) = z^2 + (x+y)z + xy
= (z^2 + (x+y)z - xy) + 2xy
does this make sense to you?
yh kinda
well from this we see directly that (x+z)(y+z) = 2xy
we're one step away
exactly!
THX SO MUCH
a little clever algebra goes a long way
lol
i'm serious
sounded funny I guess
it's true though. a lot of problems crack open when all you do is algebraic cleanup without being afraid of what the end result may be
yeah true
are u guys from uk?
A cubic equation $x^3 -5x^2 + 17x - k = 0$ has a root $\alpha$ at $x = 2 - 3i$ \\
a) Find the other complex root and the real root \
b) Hence find the value of k
ZED_118
not me
@alpine sable have you made any progress thus far?
me neither
us?
germany here
russia
bruh u guys are smart
Ann is, im not lol
u guys do alevel?
I did b) first and found k = 13. But I'm not sure how I should find the other roots
how did you find k to be 13?
in 3 years (we should stop this smalltalk)
ah wait, i think i know how you did it
plugging 2-3i into the x
you plugged in alpha
okay yeah
well
the conjugate of 2-3i will be a root as well, bc the coefficients are all real
for the third root you can either get the sum of the roots from the x^2 coefficient, or the product from the constant term
2 + 3i?
yup
could you explain why?
vieta's formulas
If that's not within reach maybe comparison of coefficients would work, but I didn't try this out yet
alternatively, just expand $(x-a)(x-b)(x-c)$ and observe that you get $x^3 - (a+b+c)x^2 + (ab+bc+ca)x - abc$
Ann
^
i was trying to explain why the "read sum & product off coefficients" trick works
yeah i understood that
so i told you to expand a generic cubic in factored form with a, b, c as its roots
how do you know that (x-a)(x-b)(x-c) is a generic cubic?
...
are you asking me why i named the roots a, b and c instead of something else? or what
no
the roots are what i wanted to give names to here
every cubic can be factored completely over the complex numbers
i mean, ok, i'm also setting the leading coefficient to 1, simply to get it out of the way
what do you mean by that?
Before you go further, what would you understand 'the alternative' would be?
you mean what i understand by this?
No, I assume from your question that
You potentially see a cubic polynomial not of the form (x-a)(x-b)(x-c)?
No, I just want to understand how you get to that form
Right so basically an assumption is that a cubic polynomial can have up to 3 roots
These polynomials are factored into the form (x-a)(x-b)(x-c) where a,b,c are the roots
[Anyway I wrote here assumption, but it can be proven]
how would you prove it?
I wouldn't prove it, but someone smarter than me did prove it
But anyway if you can accept it has 3 roots
Then you should be able to accept the 'decomposition' of ax^3+bx^2+cx+dx^0=(x-q)(x-w)(x-r)
For any (a,b,c,d) to corresponding (q,w,r)
So basically, you're assuming that $ax^3 + bx^2 + cx + d = 0$ with roots $\alpha$, $\beta$ and $\gamma$ can be factored into $(x - \alpha)(x - \beta)(x - \gamma)$ which in turn gives you $x^3 - (\alpha+\beta+\gamma)x^2 + (\alpha\beta+\beta\gamma+\alpha\gamma)x -\alpha\beta\gamma$ \\
however, wouldnt you have to first divide the first equation by a? \
$\frac{ax^3}{a} + \frac{bx^2}{a} + \frac{cx}{a} + \frac{d}{a} = 0$ Meaning that in the last equation, $\alpha+\beta+\gamma$ is actually divided by a??
Oh, right, that's definitely a miss on me
ZED_118
Right, since I messed up, it's x^3+bx^2+cx+d=(x-q)(x-w)(x-r)
a can't fit into the previous cubic polynomial form since it would need to be multiplied with the x-es
The previous form would require a=1 basically
Alright, I think i get it anyways. But Im still curious as to how you prove (x-a)(x-b)(x-c)
@vale wigeon
"prove (x-a)(x-b)(x-c)"?
There are 2 parts to that statement: the existence of 3 roots, and that you can factor polynomials out that way
why is the background white here?
that user must be in light mode ig
how dare you slander me so
yes. prove that a cubic of the form $ax^3 + bx^2 + cx + d = 0$ can be factored into that form
ZED_118
you're essentially asking me to prove FTA for cubic polynomials
dont feel like doing that rn
maybe research Vieta's Formula
@vapid oak no, it's a config option. ,tex --color light
FTA?
fundamental theorem of algebra
Yes
The factor theorem needs to be separately proved too
It's the 2 parts I mentioned
So I should either try understanding how the fundamental theorem of agebra is proven, or I can simply go on with life just assuming that I can do (x-a)(x-b)(x-c)
From what I see, you could probably do it in university math year 1/2?
But before that I don't know how you would get the requisite knowledge (assuming standard curricula)
so
going back to the initial question
I use (sum of the roots) = 5?
2+3i + 2 - 3i + c = 5
this?
hence the real root is 1?
for dependence of a conditional Probability, P(A|B) should not equal P(A), in the example my teacher is doing, she says it's dependent because P(N|B) isnt equal to P(B), how does this make sense? In order for it to be dependent, shouldn't P(N|B) not equal P(N)?? Why does she compare it to P(B)
You can check polynomials quite easily, no?
nowhere in that is that claimed
Hard to read whatever is there tbh
thats what she says
if you mean why she wrote about P(B) and P(N|B)... that's cause those are the givens...
@glass lichen No she wrote it weird but when she talks she said "Because P(B) and P(N|B) are not equal, it is dependent"
thats what im confused about
she wont respond until monday
so wait
i need to get this done today, regardless, how are we supposed to know if it dependent or not, we'd find P(N), right?
idk why 1 thing is gonna nullify everything else you've been taught in class / this discord, so dont make a big deal out of it
yes you need P(N)
can i rewrite in latex to see if i understand right cuz its a bit confusing
$x^6-3x^2\cdot{y^4}=69 \ y^6-3x^4\cdot{y^2}=6969. \ Calculate {x^4+y^4}$
i think u may need ~
$x^6-3x^3y^4=69 \ y^6-3x^4y^2=6969$ Calculate $x^4+y^4$
Mosh
That was hurting my head trying to read that haha
Omfish
whatever sorry im wasting time
hey i just graphed the two equations, it looks like there arent any solutions for x and y
doesnt matter:))
Did you graph the first one as x^6 - 3x^2 * y^4
yep
