#help-36
1 messages · Page 174 of 1
[brackets?]
(brackets)
(parentheses), if you want to be formal precise and technical
doesnt fucking matter you can use {these} for all i care
anyway
i think i've seen you come here with a question of exactly this type
vertical asymptotes happen when the denom is zero
so when is x(x-1) = 0?
earlier you said you "don't need the logic" and "just want the procedure to get from problem to answer".
i am confused. do you want to know the why behind it all, or not?
make up your mind once and for all.
This algebra video tutorial explains how to find the vertical asymptote of a function. It explains how to distinguish a vertical asymptote from a hole and how to factor rational functions in order to identify all vertical asymptotes in a function. This video contains plenty of examples and practice problems for you to master this concept.
Alg...
i do not care about the why at all
why are you lowkey so passive aggressive😭
its a tutoring server chill out
i am not being passive-aggressive at all.
lmaoo okay wtv
if you don't give a shit about the why, then why this?
those are not the words of somebody who gives no shits about the why.
i do not care about the why i just need to be able to solve the equations
math theory is a waste of my time personally
if you truly didn't give a shit about the why, you would just accept "find VAs => simplify then find zeros of denom" as a given
we are not tutors
you will not be able to reliably solve any of these problems if all you care about is the procedure that may or may not be filled with gaps in logic or explanations
!vol
Helpers are just people volunteering their time to help you. Be polite and patient.
go away politely
ok off i go then
thank you
I think this conversation will take longer than just 11 minutes of a video, that was made for this purpose
example, in the last ticket you made I literally gave you the most dumbed down procedure you could make and you were still struggling to do the exact same type of problem
holy fuck
im just asking where 0 is applicable like hop off
if you think im dumb and you dont want to help then dont say anything
this shit is so toxic
why are you even typing rn
I gave you the explanation right here
you're getting heated at somebody that's been trying to help you for 2 hours
and no I don't think you're stupid
because I used to be almost exactly like you and only wanted to know how to do a problem and not why it works dawg
nah your right i wasted 2 hours with people who just cant help me unfortunately
would have been more effective to watch the video 4 times
not saying its your fault just saying this doesnt work for me apparently
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i suggest a break before trying the problem again
nah the problem is easy asf im just confused as to why sometimes 0 is an answer and sometimes its not
the video will answer
its not easy if youre struggling with it
ive done way harder math than this
in comparison its easy
its just confusing bc everyone here wants to give 20 minute explanations for what should be 2 sentences
but again thats not on them this is just not the answers im looking for
i took stats and ts was SA
you want easy short answers but many times it blocks understanding so you get confused by similar problems
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I have an algebra question
I am trying to work out the 3-term shanks transformation.
I have the solution, but to be honest I'm not sure I could solve this on my own. How do we go about eliminating the dependence on a and q?
jan Niku
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I tried back-substitution or experimenting with some of these products but its not really clear what is supposed to happen, or what process gave this answer
If you sub that in to any of your given equations I don't see how you'd be able to work your way to a true equality in order to verify it is a solution.
Are you sure there isn't more info on what a and q are?
they are general
The idea is that some sum $\sum ^n a_j =: A_n$ has some transient component described by $aq^n$
jan Niku
which vanishes in the limit to infinity along n
if its important
but i dont think it is for the algebra
which is what i dont understand 
If u move A and Aj to one side u get $A_j-A = aq^j$, which tells u the sequence $(A_j-A)_j$ is geometric
Bob the Builder
how does that help for obtaining the given solution for A?
or does it give us access to partial sums
It gets rid of the dependence of a and q
Are they doing that geometric sum trick?
Where you sum all of the equations and do geometric sum memes?
yea but its not a solution in terms of A
i dont know, i got curious because my book doesnt explain
i checked wikipedia
but they cite the page in my book

for some (A_j - A)_j sure
but we want to solve for A
ito not a or q
i guess
maybe im missing your point
jan Niku

my point is that a geometric sequence is only defined by the fact that the quotient btwn consecutive terms is constant
so $\frac{A_{n+1}-A}{A_n-A} = \frac{A_{n}-A}{A_{n-1}-A}$
Bob the Builder
oh, interesting
So, you'd solve for A from this?
,w (a-x)/(b-x)=(b-x)/(c-x), solve for x
huh
@gleaming niche thats fascinating
i didnt even think to use the fact that the transient part was geometric
Huh wolfram formula looks pretty close.
everyone here is so much more clever than me 
its the formula
for sure
thats really cool 
new trick in the toolbelt
thank you all 
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$ABC$ is a triangle on a plane, with $G$ being its centeroid, if $M$ is a random point on the plane prove that $AM^2+BM^2+CM^2=AG^2+BG^2+CG^2+3MG^2$
skissue.in.a.teacup
i tried cos rule on AGM, BGM, CGM
that gets $AG\cdot MG\cos(AGM)+BG\cdot MG\cos(BGM)+CG\cdot MG\cos(CGM)=0$
skissue.in.a.teacup
Let A, B, C, G, M be vectors. |AG|^2 = |(A-G)|^2 and so on. G = (A+B+C)/3
You can probably do something with this?
vectors 
maybe you can set one of em to be the origin so its cleaner?
M maybe or G?
lets try G
$|a-m|^2+|b-m|^2+|c-m|^2=|a|^2+|b|^2+|c|^2+3|m|^2$
how do you deal with squares of magnitudes
skissue.in.a.teacup
@jagged flare Has your question been resolved?
@jagged flare Has your question been resolved?
@jagged flare any problems you're having here?
dunno how to continue
you're on the right track
got to this but isnt this basically the same as cos rule
do the same for the other two
wdym other two
since you pick G as the origin, a + b + c = 0
why
G is the centroid
yes
G is the centroid if and only if GA + GB + GC = 0
@jagged flare do you want me to prove it?
ill just find a proof online
it's quite an easy proof
ok sure
let M be the midpoint of AB
from the parallelogram rule we have GA + GB = 2GM
but since |GC| = 2|GM| and GM and GC are in opposite directions, 2GM + GC = 0
hence, GA + GB + GC = 0
oh i was thinkung about that but didnt think it will actually work
uhh what do you do with that
repeat this with b-m and c-m
i thought like (a+b+c)-2(ab+ac+bc) but this uses magnitude
see what you get
it should all cancel out to be $|a| |m|+|b| |m|+|c| |m|=0$
skissue.in.a.teacup
wait you're using magnitude?
how can adding 3 of them be 0 unless all three are 0 (which implies degenerate triangle)
it's wrong then
is that not what |a| means?
you don't use magnitude in this case
what you want to use is vec(AM) = vec(GM) - vec(GA)
since you pick G to be the origin then we write vector AM shortly as m - a
and also |AM|^2 = (vec(AM))^2
so |m-a|^2 and (m-a)^2 are the same thing
oh so you can just drop em?
|vector|^2 is a number but vector^2 is another vector is it not?
oh is it some dot product stuff
Dot product
skissue.in.a.teacup
you can think of it as multiplying 2 vectors with same length and angle between them being 0
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just had a question
does it always have to be sinC
no
can it be sinA or sinB, given that they are between two sides
half times two sides, then the angle in between those two sides
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✅
look at how h is formed
Or... sorry that latter part wasn't quite right
The (a*sinC) in the equation comes from h=(a*sinC)
So you could replace it with h=(c*sinA)
But to use sinB you would have to pick a different base value
in other words, you'll need a different height
The three valid combinations are
b*a*sinC, b*c*sinA and *a*c*sinB
Basically, sin of the angle times the lengths of the two neighbouring sides
different height?
So this equation is often read as "Half times base times height"
The "h" in the equation would be the height, and the line it's perpendicular to (90 degree angle) is the base, side "b"
a better way to remember the formula which doesn't rely on specific letters is:
you involve two sides and the angle between them
this way you don't have to tie yourself to specific letters anywhere
but they are in an inclne
"perpendicular height" is a bit of a pleonasm
one dude was saying it cant be perpendicular if its in an incline
and no, seia's diagram is not to scale, but she did mark these things as perpendicular
like you see those little boxes at the ends
those boxes are how you mark a right angle in a diagram
this looks like it's from a completely unrelated context 
how so?
well you're talking about an object on an incline
rather than a geometric diagram with lines making angles of 90° or not
AND trollstar even said "doesn't have to be" but you misread that as "can't"
which there's a big difference between these too...
one dude was saying it cant be perpendicular if its in an incline
this is gross misremembrance
or rather it's an extreme over-generalization that only leads to confusion on your part
so in thhis case, it has to perpendicular
the height from the apex
yes. otherwise your sines won't work
if that bothers you, just turn the triangle around
yup ok
anything else?
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Im having difficulties with this question it reads, angle A is 90°, ADEF is a square, AB=6 and AC=10, what's the length of AD?
I LITERALLY don't know where to start
I mean is this question even possible with pre highschool knowledge or is it just flat out impossible.
,rccw
Bruh help me😭
similar triangles
Hold on bot don't autoclose it yet
,rccw
DE=EF?
yes
when 2 triangles are similar and one of each their lengths are the same that means they are congruent am i wrong?
but in those two similar triangles DE does NOT correspond to EF
Correspond?? What does that mean? Are you sayin that DE corresponds to FC but we have the info that ADEF is a square (maybe a language barrier but in Indonesia square means that all 4 sides have the same lengths)
But wha bruh🥀
DE/FC=BD/EF?
correct
DE is still equal to EF btw
so?
DE is in the numerator while EF is in the denominator
you can not say FC = BD from there
Ok it makes DE²
Yeah true😔
Bru🥀
DE=AB btw so BA=AD🥀🥀🥀🥀
Look at that bs😭😭😭
what is BD and CF?
there are 2 ways to calculate BD, one is to use BA-BD which gives 6-x. And hint for the other way: look at the triangle BDE
BA-x?
yes
dude we already know BA=AD
And we KNOW what BA is and it's 6🥀
Literally the last image we just saw
BA includes the segment AD
its cant be equal
you missed the term DE*BA
My ass is somehow autistic to day bruh🥀
Alr i got it
Also how do you fight against the fact that BDE and EFC is congruent
I mean they're similar and they one side with same length?
Idk ts is fucking with me
☝️
here triangle BHA and BAC are similar
and they share the side BA
but they are NOT congruent
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Q 22 I have no idea what I'm doing
I got p=qtanA
in Q22 you should draw a right angled triangle it would help
no but sin^2A+cos^2A would
22a?
what did you find for the hypotenuse ?
1
no
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Q22b I'm not sure the triangle is
still the same triangle just use the double angle identities to write sin(2A) and cos(2A) in terms of sin(A) and cos(A)
you didn't tell what was the hypotenuse still cuz it is not 1
what answer did you get ?
seems right
What was ur hyp
sqrt(p^2+q^2)
Wanna know how I got 1
i don't know about that :3
not really
sinA might be kp and cosA=kq
at least there isn't but sinA and cosA could be any multiple of p and q
So how'd u get the answer
same idea just now i know the hypotenuse is sqrt(p^2+q^2) i'd write it as R for simplicity
sinA=p/R and cosA=q/R and then things would work out after adding the fractions and some factoring
Wouldn't u get to P(q^2 + p^2)
/p^2+q^2
which would simplify to p for 22a
But how can u just divide
$q({\frac{p}{R})(\frac{q}{R}})+p(\frac{p}{R})^2$
qimmah
$\frac{pq^2+p^3}{R}$
qimmah
Ye
Factor p and then it’s just R/R
O ic
Same idea for the other question
Alr thanks
Btw @nocturne lagoon
The reason p^2+q^2=1 happens to work it’s because it simplifies in both questions leaving you with just the other expression
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Q24 I'm not sure what to do
Ye
ok, can you state all the double-angle identities you know
Sin2A=2sinAcosA
Cos2A=Cos^2(A)-Sin^2(A)
Tan2A=(2TanA)/(1-tan^2A) tan(A) cannot equal to + or - 1
missing brackets on that one...
also lots of missing brackets around trig functions but that one's more of a whatever
anyway
have you seen this one? $\cos(2A) = 1 - 2\sin^2(A)$
Ann
Ye
???
I did Cos(A)=1-Sin(A) idk what I was thinking
I think I was thinking complementary but don’t know where the 1 came from
Thanks for helping sometimes I can’t spot where to use some identities
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Here is what I tried
how about starting with expanding cos(theta+x) and the negative one too
Ye middle right
yes
divide the whole numerator and denom. by costheta cosx
what'd ya get ?
(1-tan theta tanx)/(1+tan theta tanx)
to make our lives easy substitute tantheta and tanx with any variable and try to solve for tanx
seperate ofc
Ok
i reccomend other variables than X
first of tell me your substitution
Or send your work and let me see
Remember that it’s equal to A
I got it
Also you are trying to make
B= some expression in A
Good idea to make it more simpler
What'd you got ?
,rotateccw
Write it in terms of B and A cuz it’ll take some time to write
I saw it dw
The x axis
left to right
Here
As in plane
Could you send the whole question once more
Yeah a plane we could draw a triangle With points P Q R
@nocturne lagoon Has your question been resolved?
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This is just same as a1 divides b1 and a2 divides b2 right
,rccw
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2
Alright, what have you done so far?
The relation is symmetric
So 20 elements so far
I'd like to find an efficient way to solve this problem other than counting every possible solution
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,,\sqrt{1+x^2+y^2+x^2 y^2}+xy\frac{dy}{dx}=0
!
do you know how to factorise the expression inside the sqrt
I sent the xy dy/dx to rhs then squared on both sides
On factoring lhs, we get (1+x^2)(1+y^2)
,,\sqrt{1+x^2+y^2+x^2 y^2}=-xy\frac{dy}{dx}
!
,,1+x^2+y^2+x^2 y^2=(xy\frac{dy}{dx})^2
!
this might not help a lot
it is better to keep it in this form
as suggested, try to factor what's inside the square root
and it will inspire you a function sub
Oh whats that
you just sub something like u = .... in terms of y (possibly x)
,,\sqrt{(1+x^2)(y^2+1)}=-xy\frac{dy}{dx}
!
What now
yes
so now we can technically distribute the square root
$\sqrt{1+x^2}\sqrt{y^2+1}=-xy\frac{dy}{dx}$
Raphaelisius Maximus MMIII
this is just to make the substitution more obvious
Oh
make a new function out of y, that will be more interesting to focus on
Like y2+1=v?
Then diff v then get dy/dx?
i think collect dx and x terms and y and dy terms then integrate
and we would like to make the equation as easy as possible
that's another possibility
some f(y)dy = g(x)dx
I did i couldnt the final in proper form given by book
root(1+x^2)/x dx= - y/root(1+y^2) dy
whats ur
!
I got smth like this
this
I didnt get negative cuz i squared here
we didn't square in the end remember
^
we kept the sqrts
But i got back the roots
then that's maybe why you got an incorrect answer xdd
How😭
you went from a = -b to a^2 = b^2 to a = b
Wanna listen to how i approached this?
do you get what I'm saying
yes
Idk whay u r saying
u wrote "root of something = negative" - complex ????
when you sqrt, you have to consider that there are TWO possible stuff
so thats actually wrong
Oh
this
so get rid of the "squaring then taking the root", which just adds possibly unwanted solutions
and just stick with the original roots
,,\frac{\sqrt{1+x^2}}{x},dx=- \frac{y}{\sqrt{y^2+1}}, dy
!
Ok well on integrating b/s
$LHS=-\frac{1}{2}, \log (y^2+1)$
!
Les add c later
yeah
not quite?
,,\sec \theta + \log (\csc \theta - \cot \theta)
!
-y/(y^2+1)
so
that's better
!
!
Can u see the img
?
K nvm
Then on integrating i got
,,\sec \theta + \log (\csc \theta - \cot \theta)
!
After subbing $\theta$ in terms of x
!
that seems like a tiresome sub
yeah, so try sqrt(1+x^2) = u
Oh k
mmmmh I don't see the point
RHS =$\frac{(\sqrt{1+x^2})^3}{3}$
!
no?
lol
How
show me your u sub
put x=tan theta
not sure this works
,,u=\sqrt{1+x^2}
!
it does
I'll show mine and then you can show yours
i find trig substitution easier
Then $du=\frac{x}{\sqrt{1+x^2}}, dx$
for some others it may vary
close the frac
!
Ye mb
yes that's correct
well x doesn't cancel, so what do you get instead
1/x^2 du
U^2/x^2 du
alright
yes
U-1/2 log blah blah 😭
we're now at $\int \left(1-\frac{1}{u^2-1}\right),du$
Raphaelisius Maximus MMIII
Ye
well "log blah blah" is a bit more complicated than that
you gotta split fractions first
and then you can blah blah
Split what
you know
U+a/u-a
1/(u^2-1) = A/(u-1) + B/(u+1)
what would that be?
alright
We have direct formula instead of actually expanding and solving
if you've been taught about that formula then yes use it
idk what is the idea behind tan sub
but knowing the answer it wouldn't have been pretty
.
What does ur name mean
how much can a tan sub can help us if there's no tan in the final answer xd
just pompous form of my original nickname
Forget abt the sub, but we can convert the theta terms of x using right angle triangle
Ye sure sounds
Ok thanks
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lol 12th class?
Yes 😭
Me just boards🗿
🫡
some places dont have direct formula
i use a sec sub here, some use partial frac
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what does he mean by rearrangement
moving numbers around
In mathematics, the Riemann series theorem, also called the Riemann rearrangement theorem, named after 19th-century German mathematician Bernhard Riemann, says that if an infinite series of real numbers is conditionally convergent, then its terms can be arranged in a permutation so that the new series converges to an arbitrary real number, and r...
wdym moving numbers around
adding up the same sequence of numbers but in a different order.
how can that be different
here it says this
but this isnt really a rearrangement its a completely new sequence
You're taking about two different things
This is a definition of conditional convergence
Read alternating harmonic series
oh
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. @dim robin
need to find the exact value , and where do i get help there are like MANY channels
This is your channel now
oh okay
You pick the ones, where there is no name, else it's occupied already
okay
how do i solve this
i tried to write the first term which is 1/sin(pie/4) . sin (5pie/12)
i tried multiplying 2 numerator and denominator
I was thinking of applying maybe sine addition theorem first
,, \sin(a+b) = \sin(a)\cos(b)+\cos(a)\sin(b)
,, \sum_{k=1}^{13} \textstyle \f{1}{\sin(\pi/4-\pi/6+k\pi /6) \sin(\pi/4 + k \pi/6)}
?
okay let me search it up
you will need to make use of this
sin(x - y) = sin(x)cos(y) - cos(x)sin(y)
Multiply and divide by sin(pi/6)
B is the latter angle and A is former
Yes
B-A*
sin(A-B)/ sin A sin B , and does it matter B-A because if we take A first it can come minus but we are also dividing by the same , so minus is gone
and everytime it is -pie/6 or pie/6
the difference*
Yeah it works
I was telling you wrt my assumption
whats sin(A-B) /sina sinb simplify to
like
cot?
ya
Yes
so its eaier to sum
Just solve and use angle minimization
easier*
And see the magic
oh there is symmetry
i tried it on k=1 and k=2
i took 2 out
and the terms cancelling
would it continue till 13th?
All terms would cancel out except
Mb
This is the correct sum
29pie/12 = 2pie + 5pie/12
It’s done
No
thanks
huh?
It’s a standard submultiple
I MESSED UP AT FINAL PART 💀
yes 2root3 -2 is 100% ans
lets goo thanks
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The number of distinct real roots of x4 - 4x3 + 12x2 + x - 1 = 0 is
Is this class 11 - 12 standard math?
12th yes
Oh, I am from class 10 nevermind
||rolles theorem?||
i havent learnt that properly yet..is that the way to do this? if yes then ill leave it for later
What did differentiating tell you
Descartes's rule of signs
nothing
Dyk cubic determinant
No it always tells you something
i dont know that
nope
That's the easiest way to get roots
4x^3-12x^2+24x+1=0 what does this tell
huh i need to get the roots?
That tells you where the critical points of the original quartic are
but i cant find any values of x for which the eqn satisfies
In particular, since the coefficient of x⁴ is positive, the starts at inf and ends at inf (on the -inf and +inf part of the x axis)
yeah i noticed that
Okay well, you just wanna find out how many local minimas there are
Well, look at the 2nd derivative and see where the inflection points are
The inflection points give you some more info on where the critical values of the cubic might be
Which in turn tells you where the roots of the cubic might be
Which in turn tells you if there are local minimas and where they are
second derivative is
x^2-2x+2=0
b² - 4ac seems negative
No roots
No inflection points for the quartic
What does that mean
no points in which concavity changes?
Yeah so it just goes down and up
Only 1 real root to the first derivative
If you wanna be fancy you can even try newton’s method
oh so because it has no roots weve concluded that theres only 1 local minima?
So there’s only 1 local minima and you need to find it
Well if there were other critical points
Namely more than 1 minima
alr alr how do we find it tho? thats an ugly ass cubic
You’d need to change concavity to do that
I’m sure there are tricks for it that I don’t know but you could try newtons method
It works pretty well on a set up like this I believe
i dont know that one sorry 😔
That’s cheating
Ik
yeah
if we were allowed to use desmos then why would i even ask the question
You can't do rational root theorem and derivative 🤷🏿
I'm just suggesting 💔💔
To see how many roots cuh 💔💔
You should know newtons method
It’s very clever
Learn the Newton-Raphson Method in this quick tutorial! 📐 Discover how to solve nonlinear equations efficiently with step-by-step guidance. Perfect for students and math enthusiasts! 🚀
Oh beautiful a yt shorts to teach maths
You guess some number
Anything
Really, anything you’d like
And you iteratively get closer to the answer
okay lets go with 1
I’m pretty sure this isn’t how you’re supposed to do this though
(assuming the function is nice enough 🤓)
But I’m stuck and I haven’t got another idea
but in their case they already knew how the curve looks
We have a cubic with 1 root here
yeah alr
You need only to know the tangent line at the initial guess
Which you can find by putting your initial guess into f’
Then find the x intercept of this tangent line
That’s your next guess
Then repeat
Can you imagine that with some initial guess x = 1 and the given function f(x) you can draw a tangent line at (1, f(1)) with slope f’(1)
wait
newton's method but on the derivative xd
For finding roots of equations
@versed crater f(0) =-1 so we know that the minima will be below the x axis somewhere and graph goes till infinity so from there cant we conclude 2 roots?
so we dont have to actually find the minima
So y - f(1) = f’(1)(x - 1)
ohh
You can also do that
But then you’re guessing where on ℝ will f be negative if at all?
It’s great if you can immediately guess it but it mightn’t be obvious
yeah i agree with ur point..this is actually why i didnt get the answer
But you could argue that looking at the coefficient the minima can’t be that far away from 0
But say you try 0 and it doesn’t work
What might you try next
The newton’s method gives you a way to determine what’s a good next guess
I suppose you can also just use the derivative to tell you where to go
The derivative will go from negative to positive
So pick a number to start at
Then find f’(number)
If it’s positive pick a smaller number
If it’s negative pick a bigger number
u can differentiate and set equal to zero
If your derivative changes sign you know the minima is somewhere in the middle of your last 2 guesses
Well we don’t need to solve for it
We just need to know if the minima is negative or positive
after that use rolle theorem
If it’s negative you have 2 real roots
so we are basically finding where the nature of the curve changes and that is our point?
yeah okay
Yeah you guess a point then use the derivative at that point to help you pick a new guess
i havent learnt that yet..will try once i do tho
Since you know the general shape is like U shape
its pretty simple
u just need to find the local maxima and minima
New theorems are always simple if you already know them
okok i think i got it now thanks a lot
yes that is our problem brother 😭
That’s crazy because this wasn’t easy to do either
i mean
cubic formula?
You’re just being ridiculous now
cubic formula is insane
its actually not
@old quarry despite this probably not being the solution I suppose it works, I’d say ask ur teacher how you were meant to do it and then ping me and tell me as well 😆
depressed cubics can be slved easily
alr alr tomorrows the discussion ill lyk
and x-b/3a can be used to eliminate the x^2 term
Mate if you let someone use cubic formula
You might as well just send the fucking quartic formula nuke on this problem
Like what
I’m pretty sure that’s not the intended solution
i dont know the quartic formula
pretty sure it doesnt exist
idk the cubic formula
it does
.
It’s actually not
that was for cubics
cubics aint TOO hard
like they may be a lil hard
We have formulas for all polynomials up to but not including quintics
So there is a quartic formula
Now you do
thx for telling
