#help-28
1 messages · Page 188 of 1
I got $R_{net}=\frac{3}{2}R,C_{net}=2C$ so the time constant, $\tau=3RC$
kheerii
so we will get $i=i_0e^{-\frac{t}{3RC}}$ where $i_0=\frac{2E}{3R}$
kheerii
here I used i_0 = E/R_net
am I right so far?
for the first part of the equation, finding the current through the battery as a function of time
I don't really get what the key K closing and the switch S opening at t=3RC signifies
doesn't that just short circuit the whole thing
<@&286206848099549185>
did u figure it out?
try asking on electrical engineeing stack exchnage maybe
hmm
here
hmm
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I have a math oral coming up soon and this is a theorem for the formula of the distance between a point and a surface (sorry its written in french on the document), and i dont understand how we go from HP • n to || HP ¦¦•¦¦n¦¦• cos(alpha)
im just guessing but could it be dot product
oui
alpha c'est quel angle ?
je sais pas justement, c'est un théorème que j'ai copié en classe
ah, d'accord
aaaah
une définition du produit scalaire entre 2 vecteurs u et v c'est u•v=||u||*||v||*cos(theta)
thats not the definition but something that is true for the standard scalar product of two vectors
(trahi par le markdown)
I'm aware, a scalar product is bilinear symmetric etc
it doesn't seem relevant here though
où theta c'est l'angle entre les vecteurs u et v
ahh okay, pcq y a un autre théorème qui montre ca aussi mais je croyais que ca fonctionnait pas pour tous les vecteurs peu importe leurs directions
yes but even the standard scalar product is defined as $\sum_i x_i y_i$
Maya
mais ici l'angle entre n et HP c'est 0, donc le cos vaut 1
ooook d'accord
donc c'est juste norme de n * norme de HP
merci bien
j'ai d'autres questions donc je ferme ce salon et en recrée un ?
tu peux continuer je pense
Jsp si c'est trop flou l'image
si c'est flou je me connecte sur discord sur mon ipad
ça va, je te demanderai si j'arrive pas à lire une ligne en particulier
mais en gros j'aimerais savoir comment ou quelles étapes tu dirais pour expliquer la définition de la limite
j'avais fait un oral blanc et je suis tombée sur ca, le prof a pas vraiment aimé comment je le démontrais
oui
par exemple pour le graphique je sais pas vraiment comment l'expliquer
il y a deux choses sur le screen que tu m'as envoyé, la définition de la limite et le théorème d'unicité de la limite
alors juste la définition de la limite avec le tableau
ok
en gros l'idée de f(x) -> L quand x -> a c'est la suivante
tu peux choisir une tolérance quelconque autour de la limite
ça c'est ton epsilon
et c'est ce qui est représenté sur l'axe des ordonnées par L + eps et L - eps
en gros tu veux contraindre f(x) à valoir L, à epsilon près
et si x s'approche suffisamment près de a
dans un intervalle ]a - delta, a + delta[
alors tu sais que f(x) vaudra L à epsilon près
plus tu choisis un epsilon petit, plus le delta correspondant va être petit
mais il y en aura toujours un
okok
ça te semble parlant ?
euhh du coup si on peut pas trouver de x dans cet espace c'est que la limite existe pas ?
je comprends pas la question
la fonction sur le deuxième tableau a un trou ou je sais pas trop comment ca s'appelle, ca veut dire qu'elle existe pas la limite ?
ah
dans ton deuxième dessin, tu peux resserrer delta aussi petit que tu veux
tu n'arriveras jamais à restreindre f entre L+eps et L-eps
(au fait, ça s'appelle une discontinuité ou un point de discontinuité)
et en effet, la limite n'existe pas
mais concrètement, c'est quoi la limite ? j'crois que j'ai toujours pas compris
concrètement, c'est la valeur dont la fonction s'approche
quand tu regardes la fonction autout de a, les valeurs qu'elle prend sont proches de L, sa limite
et elles sont d'autant plus proches que tu regardes près de a
donc quand x tend vers a, sa limite c'est L
mais si x tendait vers b par exemple, L sera à un autre endroit de l'axe y ?
ca marche
d'ailleurs je peux t'ajouter en ami vu que tu parles francais ? (mais vraiment pas obligé c'est juste plus simple pcq j'ai plusieurs questions)
oui, tu peux ^^
ah, je peux pas t'ajouter apparemment
je l'ai fait
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I am stuck on c) for this question. The answer is supposed to be 14.9, I can't see what I am doing wrong or get any other answer. Basically, I solved for y(t) = 20, then solved for x(t), then subtracted 15.
@vagrant tangle Has your question been resolved?
The time you calculated is incorrect. Just use the Quadratic Formula to solve for t.
Also, when you Completed the Square, you solved for when (t - 5sqrt(3)/8))^2 = 0, but it doesn't equal 0, it equals 75/64 - 1.
Did I complete the square incorrectly?
No. The problem is that you solved for the RHS equal to zero, but on the second to last line you can see that it is equal to 75/64 - 1.
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how would i do part a? i did dy/dx=0 which got me x=-2k and then i subbed in x=-2k into the original equation to get y=4k-8k^2+1 but apparently its 1-4k^2
complete the square
(x-4k)^2 - 16k^2 + 1?
remember you have to divide b by 2
you did this wrong: then i subbed in x=-2k into the original equation to get y=4k-8k^2+1
oh ye for some reason i was thinking this and did something different, so (x-2k)^2 - 4k^2 + 1?
is the inside - or +?
why wouldn't the differentiation method work?
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hey! i am really struggling with this one and could use some help. Heres the question: Assuming items a and b, show that there is no rational number α which is the solution for "cos(απ)= 1/3"
hmmm
the questions from the previous items (a and b) are: a) Let β ∈ R , tan(β) = 2√2. Suppose that for every positive integer n, there are An
and Bn integers, with bn ̸= 0, such that
tan(nβ) = An√2 / Bn.
Find formulas for an+1 and bn+1 in terms of an and bn.
(b) Show that, for every positive integer n, an ̸= 0 and bn ̸= 0. Hint: It may be useful to calculate an
and bn for small values of n.
if it helps, i got the answers for a and b
show that there is no rational number α which is the solution for "cos(απ)= 1/3"
is this ur quesiton
question
yess
kind of
?
you are?
kind of
well
yep
is it?
alpha is irrational
ill link it here
https://math.stackexchange.com/questions/398687/how-do-i-prove-that-frac1-pi-arccos1-3-is-irrational
Thank you! Really helped out a lot!
np
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how do i solve this volume question?: find the volume of the solid generated byb the triangle with vertices at (1,1), (4,1) and (4,3), rotated about the x axis
im not too confident on whatevers better, shell or washer
and idk what to do since it gives vertices rather than a function
@orchid shell Has your question been resolved?
<@&286206848099549185> srry for ping, i appreciate any input
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@orchid shell did you get the solution?
not really, i just tried the chatgpt explanation which idk is correct
it says that since its constant at y=1 and x=4, you can plug those into washer method
after trying that i got 35 pi
Well you will get a cone when u rotate about the x-axis
the 3 points on the graph look like this
now rotating this will cause rotation about vertex (4,3) making a cone with radiue 3 units and height 2 units
now you can solve it
@orchid shell
uhhhh
its answer should be 6 pi
using washer method?
I dont exactly know about that i just visualised it
can you explain ur process pls
wouldnt it be a cone kinda with a hole bored through the middle
i am spinning the line (1,1) to (4,1) circularly
yes exactly what i am saying
what was your equation
i didnt get any equation i just visualised rotating the line parallel to x axis which will become the radius and the other perpendicular line as height
@orchid shell before continuing i guess you should reopen this problem
or the help channel will go to the available criteria
.reopen
.reopen
✅
awesome ty
yeah done
...
i found a problem in the textbook thats identical, im gonna try to see what the textbook says
okk
im having a hard time visualizing this srry, im still kinda new to volumes
i appreciate your help though
well you are rotating along the x axis
so the line parallel to x axis is your base
and line perpendicular to x-axis which remains unchanged will become your height
@orchid shell something like this
but what are you plugging these values into
here your BC is line parallel to x-axis
its just an example
i am showing how i am visualising
ohh
like this
so ur radius becomes the length of the parallell line
and height remains const
this actually doesnt require you to make equations
this is a better example i guess
wait so youre finding the area of the triangle and multiplying it by 2pi?
base 3 * 2 height / 2 * 2pi
6pi
1/3 * pi * r^2 * h
r will become the line parallel to x axis
h will become the line perpendicular to it
because the perpendicular line has no changes while rotating and stays const
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hey so i talked with my prof
okk
sorry 😭
???
he said that the slope of the triangle is found with the point/slope formula
and you subtract that by the inner radius
the correct value is 10 pi
ill send my work in a sec leme get a pic
how is there a inner radius in a single sheet cone?
.
the outer radius is the slant and the inner radius is y=1
oh i see so you are rotating up and down
i was rotating left and right
i was visualising along the wrong axis mb
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why the answer is 1/sqrt(x²+1) and no -1/sqrt(x²+1)
notice that arctan gives you an angle corresponding to a particular tangent value
so we can say arctan(x) = theta
then tan(arctan(x)) = tan(theta) so x = tan(theta)
this means that there is a right triangle with an angle theta so that the opposite is x and the adjacent is 1
since the tangent is x and tangent is opposite over adjacent
by the pythagorean theorem, the hypotenuse would be sqrt(x^2 + 1)
and since cosine is adjacent / hypotenuse, you'd get 1/sqrt(x^2 + 1)
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What is a Euclidean triangle?
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How do you do b)
Ik the first two terms are 0, 1
but I dont understand the actual formula itself

if you know the first terms are 0 and 1, this tells you t1=0 and t2=1 yes?
yes
well how do i plug it in....
think of it like a function
is it just 2(3-1) + (3-2)
im confused why the n-2 and n-2 r like small at the bottom..
t(n)=2t(n-1)+t(n-2)
this is equivalent
its just notation for sequences
so you know t(1)=0, and t(2)=1
so plugging in n=3
what happens :3
RAHHHH IGET 5
IDK
ummmmmmmmmm
(they're small because they represent the (n - 1)th and (n - 2)th term of the sequence, respectively)
9
16
mhm
now we know t(1)=0 and t(2)=1
and we have an expression for the function t
the sequence
t(n)=2t(n-1)+t(n-2)
what happens if n is 3
just replace n with 3
in this
t(3)=2t(3-1)+t(3-2)
t(3)=2t(2)+t(1)
and you KNOW t(2) and t(1)
can u show me 
so $t_3=2t_{3-1}+t_{3-2}=2t_{2}+t_{1}$
🫎 Chmoosey 🫎
ok
yeah
do you see how you would get t_4 and t_5?
yea
awesome :3
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when x is large and negative how did they get a negative answer bec i got positive
oh
wait
hruh
negatives cancel
omg
😭
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Y’all is my answer correct? It’s the only one that makes sense to me but it’s still weird because logically, just because you are wearing a scarf that doesn’t mean it is snowing!!!!
This is geometry class 🥲
not quite
if conditional (given) is true, only the contrapositive is true
inverse and converse are not necessarily true
Oh right yes
Would it be “if I’m not wearing a scarf then it is not snowing”?
👍
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ik this question you need to use composite functions to answer it.... but idk how to start
@upper silo Has your question been resolved?
@upper silo Has your question been resolved?
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help
what do you know about corresponding and adjacent angles and stuff
for parallel lines intersected by a transversal
notice that if you look at the four angles produced by the intersection of the diagonal line with L, each of the four angles kind of "matches up" with the four angles made by the intersection of the diagonal line with M
for example, the angle labelled 6x + 3 degrees matches up with the top right angle for L
another useful fact here is that opposite angles are congruent, and adjacent angles are supplementary
that's actually everything you need to solve the problem, then this just turns into middle school algebra
so whats the equation??
this is the only q i need everything else is done for that quiz
i understand you're in a rush but maybe when you do problems with the only motivation of getting them done, you don't learn much in the process
the point of the server is to get help, not answers
alr
notice that if that angle is 6x + 3, the angle opposite it is also 6x + 3 since opposite angles are congruent
yea
that angle corresponds to an angle associated with the line L
what equation does that give you?
yes
you can solve that for x to figure out the exact measure of that angle
and notice that that angle and the angle (5y + 35) are supplementary, so they add to 180 degrees
x=17
there's another equation which you can solve for y
looks right so far
so what's the angle
how do i find the equation for solving y
find the angle measure first
of either 6x + 3 or 8x - 31
they're the same angle
and you've found x
105
okay
now notice how that angle is adjacent to the (5y + 35) angle
together the two angles make up 180 degrees
no
hmm
what's the equation you get
the angle on the left is 105, you found that
and notice that the two angles, 105 and (5y + 35), are adjacent on this line
the angles add up to make that big angle, 180 degrees
we say the two angles are "supplementary"
8??
yes
so the answer is 8
yes
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i need help solving the derivative of this
these are examples my professor gave me
we’re solving it the short way with the equations
@woeful basalt Has your question been resolved?
@woeful basalt Has your question been resolved?
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By using the linearizations at the other critical points we find that (2,−1) is a saddle point
and (−2,−1), (−2, −1) is an unstable node. Furthermore you have to use the properties of the other two critical points as found above. The following picture shows the direction fields on squares of length 2 centered around the four critical points.
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I have no idea what I did wrong with this question
When i plug the values into my calculator
I cant find my lambda because the answer I got was with decimals
Which is not the answer
wait why is it wrong?
-(3-x)(4) ≠ -12-4x
its cause of the infront
[(-3)(-4) - (3-x)(4)}
(-3)(-4) = 12
(3-x)(4) = 12 - 4x
12 - 12 - 4x
am i wrong?
im stupid im so sorry hahaha which part
It would be 12 - (12-4x)
but i still have to subtract it no?
Because (3-x)(4) are a product
12 - 12
12 - (12-4x) = 12 - 12 + 4x
No, its 4x, but you have it down as -4x
OH
THERE IT IS
okayokay thank u man
i failed my final because of this question
now i can resit peacefully
thanks man i really love u
no homo
Be careful with signs, long as fuck when you mess up a question because you miss a single sign
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have I done question 4 right?
your answer is correct but it seems like you just guessed 16 and checked it
which is totally valid as long as you know how you would solve it if you couldnt guess that
what is it
im not following your work here tbh
none of the above
and what did you get for your answer
I didn't work out an answer
Does this server have a VC?
A and R are paralell
now that youre left with the little slice down the middle, observe that you can drag the bottom part over to the top to form a rectangle
Could you explain me how to do number 4
you can set up an equation this way in terms of x, the length of a side
get your own help channel
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How? i am new here can you assist me a bit?
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if i throw a ball from 3.05 m and it lands 18m ahead how do i find the angle it falls under just inverse of tan(3.05/18)?
but some1 told me I have to to the inverse tan of vy/vx
and idk which one is right
they both seem logical
but u get 2 diff answers
it is
its pararel
to the ground
the throw of the ball
no it was on a test today and im calculating my points lmfao
but it just asked the angle
and the throw is directly straight
the throw doesnt really matter the ball is on the ground so it's a triangle and what you said works 👍🏼
yh thats what I did by my nerds said i need to do the inverse tan of final vy/vx
ik lmfao but wait ill sketch it rq
final velocities
the bottom triangle is the final velocities
yes you need to use final velocity, if i throw a ball up really high, it'll likely come down nearly straight, so you're expecting an angle of nearly 90. but this isnt the same angle as in the triangle like you've drawn
damnn
just depressing
ggz then
ending it all
tysm
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How can I prove that lim x->0 (sen(x) ÷ x) = 0
do you mean lim x-> 0 sin(x)/x
it’s not 0 tho
yeah, sen is spanish / portugal
L'hopital's rule?
i mean if he wants to prove L'hopital's rule
it’s kinda hard to explain it all out here
the reason why lhopital is bad for this is because this limit is required in finding the derivative of sin(x)
Well this limit is used for finding the derivative of sin(x)
using lhopital’s rule for this kinda creates a loophole
Anyway, the proof usually relies on squeeze theorem
🥪
Using the squeeze theorem to prove that the limit as x approaches 0 of (sin x)/x =1
Watch the next lesson: https://www.khanacademy.org/math/differential-calculus/limits_topic/epsilon_delta/v/limit-intuition-review?utm_source=YT&utm_medium=Desc&utm_campaign=DifferentialCalculus
Missed the previous lesson?
https://www.khanacademy.org/math/diffe...
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(Ignore my choice)
I’m not really sure how this works.
The opposite angles of a cyclic quadrilateral add up to 180°
So you can use angle k and l to find their opposite angles
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Isn't this straight up 1/2 x base x height
Pro_Hecker
dont we rationalise it
GCSE Maths goes crazzzyyyy
Rationalise
Do you guys still need help here?
How
faiyrose
uhuh
Do you know how to expand (x+2)(x-3)? Its the same concept as the above
-1 + 9 underrot 3 is answer and
A = - 1 and B = 9
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
~! vil
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
sorry ok
Multiplication method
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Hii sorry if this might sound dumb english isn’t my first language, I was studying for my GAT and I encountered this problem,
It tell us to compare between 2 values:
1 - the area of a rhombus with the diameters of 8m & 10m
2- the area of a square that is equal to 25m^2
I’ll attach a picture to how I solve it, but I’m honestly really bad when it comes to geometric shapes. Please help. 🥲
I guessed since the diameters are 10,8 that the other side would equal to 6, since (10,6,8) is a famous triangle, so I just multiplied it by 4 to get the area
Wouldn’t that still make the area of the rhombus < 24m^2 ?
Yess
The original answer from my tutor stated that the area of the rhombus is greater than 24m^2
Ohh I see, thanks!
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Yess I just now noticed that you mentioned it, I’m getting brainrots from over studying haha
Wouldn’t it be +?
🧌
faiyrose
Thanks a lot!💖
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So regarding (b)
I've done some thinking
Basically the algebraic numbers of "order" 1 require linear equations
order 2 require quadratics
order 3 cubics
and so on
sqrt(3) + sqrt(2) would be order 4, it needs a quartic
So basically any algebraic number can be associated with a certain index, that being a natural number, and thus A_n is countable?
(c) is easy, algebraics are countable, reals aren't, therefore transcendentals aren't
is that index unique for each algebraic number tho?
(By index you mean the least order of a polynomial such that it's the root?)
yeah
The reals could be countable too then
if i just map them to their integer parts
you need to ensure that the mapping is injective
multiple algebraic numbers cant be mapped to the same natural number
that doesnt show that it's countable
e.g. both sqrt(2) and sqrt(3) are associated with the number 2
this is wrong
no its not
to be able to count the algebraics, you need each natural number to correspond to at most one algebraic number
but atleast for the single term ones
they're all gonna be naturals
so you have a union of countable sets
yeah sorry i was away for a bit i didnt elaborate
countable union of countable sets, thats important
but yeah, this explains it
If I have a union of infinite countable sets thats not fine?
I got it then?
Kind of unsure how I'd write this down formally though
Yeah
Form set for each order
there will be countably many of the sets and each will have countably many elements
Right sounds simple enough
mhm
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np
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how do i quickly calulate the eigenvalues of this matrix
i need them for to check if the function is definite or indefinite
i tried going - lambda on the diagonal and use the rule of sarrus
but the solution of that was 3 lambda -8
no idea what to do there further
Show your work
(1-λ) x (1-λ) x (4-λ) +2 +2 - [(1-λ) x (1-λ) x 4(4-λ)]
this is what i get from using sarrus
how do i get the eigenvalues out of this
Like calculating that is 3λ-8
I want to get the 3 eigenvalues
Are you sure you are applying the rule correctly? That's not the characteristic polynomial
oh sec i made a mistake in the second part
they should be +
(1-λ) x (1-λ) x (4-λ) +2 +2 - [(1-λ) + (1-λ) + 4(4-λ)]
like this
hmm
result is still complicated how do i get eigenvalues from that
expand it into a cubic then try factor/remainder theorem to determine linear factors
if it's an exam question o.e. that'll generally work, as long as you're not given non-integer eigenvalues
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if m and n are positive integers ,prove that m root n is either a positive integer or irrational.
i’m sort of confused, because if m=2 and n=8, then we have 2 root 8 (the square root of eight), which is neither a positive integer nor an irrational number.
why is it not irrational?
is it rational?
can you write it as a fraction?
there you go
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I am trying to prove this formula for even powers of cosine. Clearly I am going wrong somewhere, I suspect the issue is where I take the real parts of the equation, but I’m not sure exactly how.
Answer?
<@&268886789983436800>
@edgy yarrow Has your question been resolved?
<@&286206848099549185> please help
You have it right so far. You need to keep going
Try n=2 and n=4 to see what you need to do next
Okay, will do. I assumed it was wrong because the LHS is the same but the RHS isn’t
Nah, so far you been right
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.reopen
✅
I've tried substituting in n=2,3,4,5 and all of them work. So now I'm wondering why I can't find my version of the formula online anywhere, especially because it's so simple compared to the one I was trying to prove. And the one I was trying to prove is for even n, but my equation seems to work for all n.
Surely I'm missing something
Have I invented a formula here? <@&286206848099549185>
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can sm1 explain what func g(x) i use for the fixed point method
im kind've lost
i tried g(x) = 25/x^3
not sure waht else i can do can any1 help?
@round plank Has your question been resolved?
Your g would be 25/x^2 since x = 25/x^2 is equivalent to x^3 = 25 not your g. However the derivative of this new g is likely too big to converge nicely. Can you think of other functions such that x = g(x)?
Hint: perhaps you can introduce another factor/fixed point
not really
It will work if you add a factor of (x-4) so you are solving (x^3-25)(x-4)=0 between 2 and 4
25/x - x^2? idk
Does this have the same solution and bring g’ below 1 in your area of interest?
what?
how r u getting x-4
I worked backwards
Start by adding a linear factor x - a and write out the expression for g
Then pick your starting point (3 is good), and try some values to get g’ as low as possible
In this case it is clear a=4 ensures |g’(3)=0| which is as good as you can get
Starting with a guess of a linear factor makes sence since it is the simplest modification to f you can make
what are u saying
the way i get g was just solving for x
whats the easiest way to do it
I’m trying to paste a screenshot
The first 3 steps transform a function that has 25^(1/3) as a solution into x = g(x) form
Then g has a fixed point ar the solution by definition of fixed points
And you can iteratively apply g to some close starting value (in this case 3) to get your approximation
3 steps should be enough for your desired accuracy
I chose x-4 by first doing the first 3 steps with x-a and writing the formula for g’
Then a=4 minimizes |g’(3)| so it will converge fastest
And since the derivative is 0 which is less than 1 it will not diverge
So your idea to solve for x is correct but you need to solve a function that yields a g’ with low absolute value to ensure convergence
Introducing another factor is a good way to do this
why r u randomly adding x-4
i dont understand this
is there not an easier way to do this
It’s the same method as yours. Take a function f with root 25^(1/3) and solve for x to get g
no
However your f(x) = 25 - x^3 does not work
Because the resulting g has too large a derivative to convergw
i see
but where r u getting (x-4) from
We need to modify f to keep the root but add some other root(s) to minimize |g’|
I guessed that adding a linear factor (1 root) should do the trick
So I solved for g with an extra x-a factor
Then solved for the a that minimizes |g’| which 4 does
There are plenty of other modifications that work, x-4 is just the one I chose
A good hint that 4 as a root will work is that we can tell the value is between 2 and 3 and hence can use 3 as the starting value. Then 4 is further from the starting value than the solution so the fixed point we find will be the desired solution and not the fixed we added at 4
or i can just use newtons method as an equation
That should work
x - f(x)/f`(x)
Newtons method is just a special case of fixed point iteration
what is f(x)
that i use
x=25/x^2?
Assuming you meant to place parenthesis around the numerator then yes
how did this person get 1/2(x+25/x^2)
then
doesnt amtter
wtv
how would i determine the interveral
to tell if it converged i just take derviative of f(x) and plug in something to see if it is less than 1 right?
Yes
Depends on g. If g’ is 2-x^2 for instance, that reasoning won’t work
It is better to calculate the derivative for g and check when it is less than 1 in magnitude
how
Differentiate g and find an interval by looking at the inequalities
Solving g’(x) < 1 can be done by finding the zeros of g’(x) - 1
bro
can u explain it better
like not complicated
i dont understand what your trying to say
and also
for this someone did this isntead is this correct?
They are equivalent
They just did some algebra to the same answer (and have a misplaced equality between f and g at the beginning)
Are you familiar with derivatives? If so, find the derivate of your g(x)
Are you familiar with solving inequalities?
i did
Ok, then solve |g’(x)| < 1
u cant i dont think
(2x-e^x)/3
This one works in [-1, 1] for instance. You just have to look at g’ - 1 and see when it crosses 0
how do i solve
for this
-3<2x-e^x < 3
Think about the shape of g’, what does that tell you?
Well, when x is negative, the linear factor dominates
When x is positive e^x dominates
yea
My wifi is not really working rn, messages take many minutes to send. I suggest you put it into an online algebra calculator and look at the steps. It’s just an inequality
,wolf \left|\frac{2x-e^x}{3}\right|<:1
this is so confusing lmao
@round plank Has your question been resolved?
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can someone help with this?
I have the answer key for it but I am not exactly too sure on how they got their answers
like why did they do half cirlces etc
because integrals are just essentially measuring the area under a curve
in (1) for example, you are integrating from 0 to 2, so you are finding the exact area that is shaded between the function and the x axis from x = 0 to x = 2
right but how is a half circles below x axis -pi/2?
because remember, any area under the x axis is considered negative
what is the radius of the semicircle?
the one from x = 0 to 2
I dont remember that rlly but If I had to guess its prolly pi/2 huh
are you sure? the radius?
well think about it this way
it's a half circle, and its centerline is 2 units long because it ranges from x = 0 to x = 2
ok
what is another name for this centerline?
Not sure to be completely honest
ring any bells?
diameter?
yes
so the centerline of the entire semicircle is the diameter, and the diameter has length 2 units
how do you find radius from diameter?
d=2r?
yes; so do you multiply or divide diameter by 2 to get radius?
multiplying
no
oh I see cuz d=2r is finding the diameter so we do d/2=r to find r right?
yes
because remember
radius is defined as the length from the center to the circumference of a circle
yea
so radius will always be less than diameter
so anyway, your diameter is 2, what would your radius be for the semicircle?
pi?
just a wild guess to be honest
well, refer to this equation you just wrote out yourself
your diameter is 2
what is your radius?
d/2?
what is the value??
Idk Im lost
alright, what does the letter d represent in that equation?
diameter
and we just specified what about the diameter?
that it is 2
so, d = ?
2
now, r = d / 2 = ?
are u asking what r is or what d/2 will be?
we just said that r is equal to d/2 no?
yea
then using this information, what is r equal?
2/2 or 1?
ok
the radius is equal to 1 unit because it is half of the diameter which is equal to 2 units
the radius of the semicircle is equal to 1 unit
ok
now that you have the radius of the semicircle, what is the formula for the area of a circle?
A=(pi)r^2?
yes
however, the area is a semicircle, not a circle
a semicircle is a circle that is cut in half
therefore, what is the formula for the area of a semicircle?
A=(pi)r^2/2
1
(pi)*1^2/2= pi/2
there you go
yes
ok that makes more sense
sorry for your trouble
Imma try and do the other ones and see if I get em right @sick karma
alright
@dusky drift Has your question been resolved?
it matches the same answer as the answer key but lmk if its wrong @sick karma
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Can someone explain how to do this??
it wants you to find which is the graph right?
Yeah
notice that the constant infront of x^2 is positive, so the graph will be some sort of u shape
Ok
and you can try to plug in some random value x
like take x=3, tmif you plug it in you get y=3
you can easily see which one is correct
So if x=3, then y=3
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can't simplify like this
yes
degree of numerator is greater than or equal to degree of denominator
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