#help-27
1 messages · Page 69 of 1
,rccw
btw your proof for 1d is not correct
you’re meant to show it for every odd function (i would assume)
nope its correct, i confirmed with teacher. i just had to show one example
can you do the same for 1e?
shes not responding
wait
u mean try prooving with an example?
yes
uh not sure. it just doesnt make sense to me
if it was allowed for 1d then why not for 1e?
thats why i asked for help lol
she could help me. shes just not responding
probably sleeping 
the actual proof for this would use limits and the limit definition of a derivative
i don’t know how rigorous you’re meant to write it
just a simple proof
nothing complex
a proof or an example
maximo
since both derivatives on the right exists, the one of the left does as well
that’s not rigorous at all but the idea is there
alright
so how would i explain it
i just write it
oh this part
hmm
i feel like my professor would want more, but ig i can make sense of it
maximo
and do the chain rule
alright
done thanks
can u help me with another question please
How would i do 4c and question 5
i think ik how to do question 5 but im not sure what its asking for
and question 4c, im just lost af 
find a general pattern for the derivatives
in particular, for the first, third, fifth, seventh,…
thats what im not understanding how to do lol
we were never taught that
it’s just basic pattern recognition
look at the first derivative and the third and the fifth and so on
all i see is beta increasing by 1 power
and the derivative of the trig function (sin or cos) is taken
you’re looking at every derivative
i’m saying look at the first and third
and think about what the fifth should be
- beta ^6 (sin(beta x))
write it in terms of k
but i dont know how to integrate it into a formula
try something
first
how can you write the power
of beta
in terms of the derivative
note that we were just talking about the odd derivatives
so f^1 f^3 f^5 ...
so in general, we can write this derivative as f^(2k+1)
we want a genreal formula for f^(2k+1)
in terms of k
for example, when k = 0
we get
f^(1), the first derivative
which is just beta * cos(beta * x)
when k = 1, we get f^(3) = - beta^3 * cos(beta * x)
k=2, f^(5) = beta^5 * cos(beta * x)
is that for the even one?
i think thats odd
you're missing one thing
yes
so would it be
- beta ^(2k) sin (beta x)
would it be
(-1)^k beta ^(2k) sin (beta x)
and for the odd function it is:
(-1)^(k-1) * beta^(2k-1) * cos(betax)
you're saying that's for f^(2k-1) right?
ah the quesiton used minus
yeah i think that's fine
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is there any way to find out the equation of this line without trial and error?
like actually using maths to figure out, the only have 2 points, 1 being x-intercept
He means green line
😑
no cyan line is 0.016x^2-0.233x+12.5
you can't determine the equation of the line if it's curved from 2 points
unless you know more information
like what type of function it is
what if i say
it can be any type of function
quadratic, cubic, sin, anything you can think of
only a line can be uniquely defined by 2 points
so you want to find a curve that lies inside this region?
you can try a quadratic first
just the equation
if you say quadratic then
is it all trial and error?
is there a way to mathematically figure it out
there are mathematical ways to find quadratics
so what you do is you plot more points along the curve
and find the interpolating polynomial
all you need is 1 more point along the curve
YO
that sounds good
can you tell me more
i have not learnt interpolating polynomial yet
Wtf will I learn these things😪
but the purpose of this investigation is for me to learn new maths
however, the shape might be wrong, so you can consider maybe adding different number of points to make a different degree polynomial
,w lagrange interpolation
that's the general formula for it, but there's ways to gain intuition on how that works
Let's say I give you the problem "given a bunch of points, find a polynomial passing through them"
Let's consider a special case. Say all of them except 1 are on the x-axis
can you solve this special case?
so you have $(a_0,y),(a_1,0),(a_2,0),\dots,(a_n,0)$
Element118
i have not learnt this-
do you have time to explain me the steps?
or you have like a youtube video
hmm let me check
A basic introduction to Lagrange Interpolation.
Chapters
0:00 Introduction
01:07 Lagrange Polynomials
03:58 The Lagrange Interpolation formula
05:10 The Resulting Polynomials
The product links below are Amazon affiliate links. If you buy certain products on Amazon soon after clicking them, I may receive a commission. The price is the same for...
this is probably good
@sonic ravine Has your question been resolved?
well another way which might be more successful would be to formulate it as part of a circular arc
what is this way?
here i tried to copy the larange interpolation method to find the y-intercept
but the result is -67.9
its so far off
I don't think that's a problem
because -67.9 is not within the range we are interested anyway
but why does it give that value
is my working wrong?
i simply copy, i have no idea what i am doing
try finding a circle (x-a)^2+(y-b)^2=r^2 that looks like the curve you are interested in
we don't care what the polynomial does beyond the range [5.5, 8]
okay
i am testing things out
also
the "r" in the equation
what do you call this type of function
i always do functions with only x and y, never touched on r
@craggy dagger
i found a pretty accurate one
r is just an arbitrary constant (radius of the circle)
since your k is positive this would mean it would break apart into 2 functions
when you solve for y in terms of x
ok
how do i say i come up with these numbers
trial and error..?
like the numbers -17, 0.8 and 25
the work that i am doing is for an essay, where i model the shape of that thing
i need to explain what i have done to get a certain function that fits
@craggy dagger how should i explain the method i used for the circle equation
<@&268886789983436800>
is there a way to prove it mathematically..or do i just say i use trial and error..
basically just trial and error
though the circle might not pass through the points of interest in your diagram
which are (5.5, 11.7) and (8, 0), it you want it to pass through those points then you need to use math stuff
oh ok
one more thing
lets assume i will stick with that circle
how do i find the area here
is there a separate way to integrate a part of a circle?
that looks like half of a segment to me..maybe i am wrong
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In a function, f(x)=[x-1][x+5]
Solve for f(1/a)
sub in 1/a for x
,rcw
Show work.
Actually.
It's right.
And it's the same as what they wrote.
Notice how they've the answer in the factored form. While you distributed the expression.
You might every well sub 1/a in the originally factored expression.
To get the same form.
I don't entirely understand could you show me what you mean?
How'd they keep it in factored form?
Like
[1/a-1][1/a+5]
How'd they simplify it?
LCM
Least common multiple?
What the hell am I doing here?
Oops, forget that extra (
Ah
Makes sense now yes
The book also has these other problems
Which are simple but idk how they calculated it without a calculator and idk if they're suggesting something by showing these problems or they're done by like actual rote math
So like in #4
Ugh idk why it rotates like that
And #5 it also gives the value of sqrt(2) as a solution and idk if I'm just supposed to know that or use a calculator
Is there are easier way to find those values that I don't know of?
I'm just curious
,rcw
by definition of fractional exponents
What's the definition of fractional exponents?
Oh wait are you talking abt the sqrt of 2
Oh yeah I understand that
I meant like knowing what the value of sqrt 2 actually is
Being 1.414..
Idk why the book put that instead of sqrt of 2 I thought they wanted me to know the value or somethg
sqrt(2) is the exact value
$a^{\frac{b}c}=\sqrt[c]{a^b}$
A Lonely Bean
1.414...whatever is only a decimal approximation
Yeah ik idk why they didn't just write sqrt 2 in the solutions
i thought you said they did
Oh I meant the opposite idk what I said
And for #4 idk how to do it without rote math or a calculator, I just did it with a calculator
But I'm wondering if there's some sort of shortcut mathematically
$(a+b)^2=a^2+2ab+b^2$
Element118
might help with squaring those things by hand
Oh yaa thinking of it that way does help me do it in my head
Yeah ik idk why they didn't just write sqrt 2 in the solutions
nfi
9+.6+.01
Makes it a lot easier
I also don't know how they simplify number 8 after plugging it in
Oh ok
9 + 0.6 + 0.01
Also I wanna learn to use latex it'd be nice
Also to make stuff easier to read over this
dots may be hard to see, makes it easier to read too
there's an introduction in #latex-help
Or you learn vicariously like me. Stalk channels and see how others use latex
Because why would you read a whole document when you can watch Ramonov's every step 24/7/365
Oh cool I didn't know that was a thing
if you already understand basic function notation,
that's already most of the basics done already
i replied to the wrong thing i meant latex help .-.
oh ok cool
facts 😂
real stalker that's crazy
So for #8 I have (x+∆x)^2 + 2(x+∆x) + 1
Idk if there's an easier way of simplifying it than distributing jt
there isn't
I feel like I'm always doing extra work and the book is trying to teach me to do less
Oh ok
omg that's why it's wrong 😂
i definitely forgot the - f(x)
makes sense now 😂
alr no more issues I finished that problem set
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helo
yes yes agree
now cos(arccos(x)) = x
but wait
maybe i dont understant tthe way is it written
also this is from x between -1 and 1
dont i need firstly calciulate arccos(2/3)?
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As part of our homework we have this question "simplify tanx/(1-sinx)" and I'm kind of stuck.
i dont think we can simplify that
was that the exact wording of the question?
Yeah
Just the word "simplify"
did you copy down the question correctly
as there isn't really something thats objectively simpler
The teacher sent it to us through telegram
So I'm pretty sure that I did
through telegram? the sus app?
The app doesn't matter, what matters is that he sent us a pic
check the pic again
are you 100% sure these are "simplify" questions?
100%
because there's not much that can be done with Q4,
and 5,7 are clearly already in the simplest form
We asked him today where did you get these questions since we searched in the textbook and these weren't in it.
He said they aren't from the textbook
some of these can be objectively simplified,
8 isn't one of them
Well
I tried the others
In some programs
And no answer
But when I tried them myself I was able to simplify
So that's why I ask here because maybe people know something that solvers don't
Anyhow I'll go eat something
And I'll ask him about this particular point next time
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Can someone tel me how I show this
,rccw
cos(180n°) = ?
What? Ann
"I'm very bad with sigma notation"
in response to a question that doesnt concern sigma notation at all
ok lets see here
what is cos(180°)?
-1
and cos(2*180°)?
1?
and cos(3*180°)?
yes, so how else can you write down a sequence that goes 1, -1, 1, -1, 1, -1, ... alternating between 1 and -1 forever
-1^(n-1)
parentheses
,rccw
!help
Please read #❓how-to-get-help
@restive river can you explain why the geometric sequence isn’t -1^(n-1)
-1^n = -(1^n)
(-1)^n
overattachment to form
oh @restive river sorry about the !help thing, i thought you were asking a question
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help
@pure grotto Has your question been resolved?
It's correct
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thank you boss
iloveyoumwa
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It cant equal -5
then why write = and not ≠
I just don't have the symbol on keyboard
you can substitute with !=
oh
also i would not be so sure the range actually is R \ {-5}
i have a suspicion about that
but how do you find the domain?
how do you normally find the domain of a fraction like this?
make the denominator 0?
you find all points where the denominator is zero, and exclude those.
does x = sqrt(3) make the denominator zero?
you should get that the equation x^2 + 3 = 0 has no real solutions!
oh
wait
so
it can't be less than 0
no,
I mean
it has to be less than or equal to 0
I'm not sure
what's "it"
x
why does x have to be less than or equal to 0?
then why say it does...
in this case, since you have no complications other than the fraction,
you find all points where the denominator is zero, and exclude those.
I can't get the denominator to be 0 though
you have found that the denominator is never equal to 0, yes.
so there is nothing to exclude.
yes...
I know for the range one of the values is y=-5
oh wait
I got it
already
no, you know that one of the excluded values is y=-5...
Yeah
confusion between "i know this value belongs to the <domain/range>" and "i know this value DOESN'T belong to the <domain/range>" is HIGHLY DANGEROUS.
and the other one is anything greater than 3
yeah
thanks for your help!
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For this question we can use the ideal gas law. PV=nRT
P is pressure
V is volume
n is moles(quantity of gas)
R is a constant(ideal gas constant)
T is the temperature of the room
Since the gas is in a sealed vessel, n cannot change. And T can be ignored since we can assume that the gas will reach the same room temp after some time as in the initial conditions. And since R is a constant, it can be ignored as well.
Enlargement factor, that is for volume right?
ya
Alright. And you say T is to be assumed constant?
Again, you're changing problems. Which one do you need help with?
idk
...
it just says enlargement factor
Didn't ask that. Do you need help with 3 or 4.
4
Alright.
If nRT is completely constant then you have PV = constant.
Meaning P is inversely proportional to V.
ok
Do you know how to do it from there?
no
And if V changes by a factor of x. Then P should change by a factor of 1/x.
So that their product is always a constant.
.
That is it.
It tells you the enlargement factor is F.
So you should get the factor by which P changes as well.
ok thanks
so can i write the x here as F
like
And if V changes by a factor of F. Then P should change by a factor of 1/F
It should.
one last quesion
does P being inversly proportional to V mean the same as V being inversely proportional to P
?
Yes.
then cant it also mean that if P is enlarged by a factor of F then V is enlarged by a factor of 1/F
?
.
It can. All of it is the same thing.
But your question doesn't say that.
ok
and what if the enlargment factor was for pressure?
then would it be that if P is enlarged by a factor of F then V is enlarged by a factor of 1/F
?
Yes, just now you asked the same and I said yes.
Whatever the enlargement factor for either of them is, for the other it is 1/that quantity.
Makes sense?
Obviously it matters.
Since they've told you volume is the quantity that enlarges by F. Then you can surely comment on pressure.
but the question just says the enlargement factor is F. not the enlargement factor for volume
Well, clearly volume is the one changing. And that is also what I asked you in the first place.
Besides by "enlarge" you'd assume the volume is the one that changes.
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can someone help me with this problem?
trig integration
I think I have some of it down...this is what I have so far, can you tell me if im on right track:
Number 4
I used trig identity tan^2(x)+1=sec^2(x) to solve problem
but now im stuck
I think I would get more tans instead
Hm, but the powers are odd
I have integral tan(x) *(sec^2-1)sec^7(x)dx . I then multiply the sec^7x by sec^2 and -1 respectively, right?
hold on
You could then factor out a sec(x)tan(x)
Wouldn’t I do u substitution or something?
Second term should be tan(x)sec^7(x) (or you're missing
), and yes you would
Maybe I misunderstood a step. Wouldn't we just keep the tan(x), multiply the sec^7(x) by sec^2(x) and -1 and get tan(x)*sec^9(x)-sec^7(x)dx
Here you said you had
[
\int \tan(x) \cdot (\sec^2(x)-1) \sec^7(x) \dd x
]
right?
yes
@upper schooner
yeah, tan^2(x) turns into (sec^2(x)-1)
You then multiplied out the brackets here, right?
I only multiplied sec^7(x) by sec^2(x) and -1
@upper schooner
[note the
in the first one]
So this would get us this:
Almost
I canceled the sec(x) with the sec^9(x) though..
You can't do it with only one, you need to do it for both
Thank you.
See here 
if you factored out another sec(x) you'd see how it cancels for both
@jaunty gazelle Has your question been resolved?
Okay, so assuming this is right, I've learned that everything comes down to trying to apply a trig identity, factoring and/or multiplying, some sort of integration technique like u substitution, and simplification?
The following above was another problem I attempted just now (problem above):
This is correct.
Is my thought process and steps right to?
Yep.
Is this statement also true: "Okay, so assuming this is right, I've learned that everything comes down to trying to apply a trig identity, factoring and/or multiplying, some sort of integration technique like u substitution, and simplification?"
Uh, I wouldn't say everything because there are a lot of identities and I don't know if you know them all, I don't know if you know when to apply which identity
But in this case you certainly did apply the right one, however there's almost always more than one way to integrate something
Just keep practicing
I for one certainly don't know everything when it comes to applying a trig identity and simplifying
Okay. Let me ask, I also tried doing it the other way, as in, applying the trig identity to sin^2(x) to get (1-cos^2(x))*(cos^3)dx. I gave up eventually. Would that not work for a problem like this?
It can but it's lengthy
Gotta use some angle identities I think
Your way is the shortest I believe
Okay. Another final question, would I have to use a reduction formula on this:
it's not uploading..
Btw Idk if it'll work but you can also try using u = cosx or u = sinx and see what happens
What do you think?
I know I have to factor the 5 out, maybe take the antiderivative of x^3...but idk if it this is meant to be used with reduction formula
A simple u-sub
let me check hold on.
with our u sub being cos?
I am getting tis as an answer, and this is my work:
I don't think I'm getting this correct.
Can anyone help? <@&286206848099549185>
use an integral calculator
Any you recommend? Can't see the steps using symbolab..
@jaunty gazelle Derivative of x^4 is 4x^3 and 5x^3 is already given.
This implies a u-sub, u = x^4
Is there another way of seeing that x^4 is u sub...
Other than seeing that its derivative x^3 is given, no
doing u substitution i get 5/4* integral of cos^2(x^4)..
do I apply trig integration on cos^2(x^4)?
Should be $\int \cos^{2} (u) \dd{u}$
Sup?
5/4 outside too
okay so err...
we do something with the cos^2, right?
trig identity!
Yes
1-sin^2?
Nope
wait
? I thought the trig identity was cos^2(x)+sin^2(x)=1..
There are more
that wouldn't apply here?
I see...this is my work for it:
so we apply double angle identity 1+cos(2pheta)/2 du
and then we simplify to get 5/8 (u+1/2sin(2u))
at the end it should be sin(2u)/4
All good otherwise
chain rule, you divide by the derivative of 2u
Oh wait
Nvm
You factored out the 2
Okay
All good.
Thanks so much, Sup. 🙂
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how is this wrong?
You forgot to plug in 0
@indigo abyss Has your question been resolved?
cos(0) = 1
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Simple question:
Why can one not construct confidence interval of beta_0?
this is what we have
<@&286206848099549185>
yo
@mild summit Has your question been resolved?
@mild summit Has your question been resolved?
you can
its done in exactly the same way
its just not especially useful
or statistically meaningful
unless you have a really specific research question
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can anyone help me with this error if they have ever used mathematica?
nvm i found the problem
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,rotate
(x-y)^2 is bigger or equal to 0
this is all you need
yes so do you see why the - signs don't matter
yes ye
so i can just move on to the conclusion right
no need for further explanation
like for the answer
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anyone who can help me on the right path with this integral?https://gyazo.com/6d8e5975fa5827996ba4b1532f250672
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just making sure the possibilities of sitting in a round table is (n-1)! and like a class with normal tables is n! ? or not.
@restive river Has your question been resolved?
m8 what
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@restive river Has your question been resolved?
Yes
@restive river Has your question been resolved?
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Collatz conjecture
are you asking what it is?
The Collatz Conjecture is the simplest math problem no one can solve — it is easy enough for almost anyone to understand but notoriously difficult to solve. This video is sponsored by Brilliant. The first 200 people to sign up via https://brilliant.org/veritasium get 20% off a yearly subscription.
Special thanks to Prof. Alex Kontorovich for in...
nope sorry should have been more clear i have a proof but am having a hard time wording it
looking for people to chat about with it
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how to find the derivative of this function
chain rule
dont use someone elses channel
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Something like this?
yh
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Hi can someone explain this question and answer? I'm stuck thanks!
its asking you to expand that
and compare terms
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Even though that force is acting up, the particle moves down the slope?
Idk I assumed the force would pull it up the slope or something 😭
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is F = ker(f - id) the same thing as F = Im(f)?
because ker(f - id) is the same as the set of f(x) - x = 0
ie f(x) = x
but the set Im(f) is all the x of f(x) so not the same
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that's what i thought
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Am I supposed to have a whole number here?
brackets
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if i have a function that is continuous, differentiable and positive, then would its sum be greater (>=) or its integral? or does it depend?
no, like a finite sum
$$\sum_{x=1}^{n} f(x) \geq \int_{0}^{n} f(x) \textrm{ or } \sum_{x=1}^{n} f(x) \leq \int_{0}^{n} f(x)$$
f(x) when the index variable is i?
oh my bad
ibzi
if the function is increasing
also i think you can remove the differentiable and positive conditions
continuous and increasing or continuous and decreasing should be enough to state inequalities like that
oh okay
integrable and increasing 
okay okay one second
can't tell if you're serious haha
you don't get strict then but I don't see why not
wait is this correct ^
Should be yeah
okay; awesome!
If it's not continuous you can't guarantee they're not equal
Or if it's constant
If it's strictly increasing though then you're good
$\sum_{x=1}^n f(x)$ could be 0 when it doesn't look like it should be at all
💜𝓁𝒶𝓎𝓁𝒶💜
by just making f(1), f(2), etc 0
for increasing functions tho
f(a) = f(b) = 0 implies f([a,b])=0
In that case I'd say it definitely would look like it should be zero
ok true
does it work the other way around, i.e., can i say $\sum_{x=1}^{n} f(x) \leq \int_{0}^{n} f(x) \Longrightarrow$ mono increasing?
ibzi
oh yeah!
again, thank you so much!
that's what i thought was an issue before it wasn't really haha
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was looking through an old classic textbook on Calculus by Courant and i think it contains an error..if h = 0, it's just 1 = 1 so is this lemma supposed to be >= instead of > or what am i missing?
Pretty much everywhere else I’ve seen that stated, it’s been a non strict inequality as well
Seems to be strict whenever h≠0 which is weird
ok thanks, always love finding errors in print 😬
guess they forgot lol
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I'm at a point where I have worked out k-6 = 3x-2y and k+12=4y-x on Q2.3 how can I now prove point P lies on y=x+3 ( I have got this from the knowledge that Q= B*P )
make k the subject of: k-6=3x-2y and 3k+12=4y-x
since k is constant you can then equate those 2 equations and rearrange for y
Okay Imma try that now I'll be 2 secs
Okay so I have y = (2x+9)/3
Which I suppose I can now make 2/3x + 3 ?
how did you come to this?
So I got
k =3x - 2y + 6
and
k = 4y - x - 12
Then equated to each other to get 6y = 4x +18
divided through by 6
k doesnt =4y-x-12
3k does
with brackets, yeah
Okay 2 secs
so y = (7x+30)/10 ?
howd you get 7x?
(4y-x-12)/3 = 3x -2y +6
*3
4y-x-12 = 6x - 4y + 18
+x
4y-12=7x-4y+18
3(3x-2y+6)=9x-6y+18
How did you get this ?
I can see the 3x-2y+6 is from the k = of equation 1
(4y-x-12)/3=3x-2y+6, just multiplied both sides by 3
should be -6y i actually had that written down at least XD
Lemme neaten up my work a sec so I can see where I'm at, theres a lot of scribbles rn
Okay so Just to check
K = 3x-2y+6
and
k = (4y-x-12)/3
yup
(4y-x-12)/3 = 3x-2y+6
4y-x-12 = 9x - 6y +18
10y = 10x+30
y = x + 3
?
Is this enough to prove that point P lies on that line?
it is, since p is the point (x, y) youve shown that y=x+3, so P lies on that line
Legendaryyyyy
i've been waiting for help since like 2 hours ago you're such a big help here
no worries
any idea on the approach to Q2.4? I've only just learnt invariant lines and I've never done a question like this before is all
its been quite a while since i did this
but the way i learnt it was to create 2 line equations, since you have B here, then we can have:
y=mx+c and y'=mx'+c, so an invariant line is where these 2 are the same, the y' and x' are y and x under the transformation
3x-2y=x' ->3x-2(mx+c)=x' 3x-2mx-2c=x'
-x+4y=y' ->-x+4mx+4c=mx'+c =m(3x-2mx-2c)+c
-x+4mx+4c=m(3x-2mx-2c)+c
x(-1+4m-3m+2m^2)+c(4+2m-1)=0
(2m^2+m-1)x+(2m+3)c=0
so then either m=-1, 0.5 or m=-3/2 or c=0
so since the m values arent consistent , we can have a combination of m=-1, c=0 or m=0.5 c=0
so y=-x or y=0.5x
its been a few years since i did this so forgive me for any errors
It's okay I appreciate the help, so Just the start bit, Is this equivilant to what I did with the last one where I started with Q= B*P but instead I'm doing [x' ; y'] = [3x-2 ; 4y-x ] ?
basically yeah if you wrote it in matrix form its B( x y ) = ( x' y')
pefect okay so that makes sense to me
and then you just sub in y=mx + c to both of them equations
yup
Or sorry do you sub in y'=mx'+c into the y' equation ?
i replaced any y with mx+c and any y' with mx'+c
Rightttt
Then we wanna equate them and arrange to = 0 to find the possible values for m
and possible values for c
when you say equate them, what do you mean?
from the 2 lines that has the first part 3x-2y=x'
first i replaced the y and y' with their respective equations, and then replaced x' in the second line with the equation for x' from the first
but then yes you want to check for possible m and c values
Yeah sorry that's what I meant, you used x' to eliminate the x' in the y' one so the only variables you're left with are x m and c
yup
Okay so im caught up to there, now im confused with the m =-1, c = 0 and m=3/2 c = 0
does this mean that the invariance lines are at y = 3/2x and y =-x?
we have (2m^2+m-1)x+(2m+3)c=0
for that equation to be true, then 2m^2+m-1 has to be 0, AND (2m+3)c=0
the reason i dont use m=-3/2 is because then the quadratic isnt 0 which we need it to be so that m value is discarded, forcing c to be 0
So m has to be -1 or 0.5
yup, for the quadratic to be 0
yes, those are the invariant lines
Love that ! thank you so much for your help XD
no problem
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Why ∫^{y}_{0}∫^{x}_{1}\frac{1}{t}dt dx = ∫^{y}_{0}\frac{\log{x}}{\log{e}}dx
Why $\int^{y}{0}∫^{x}{1}\frac{1}{t}dt dx = \int^{y}_{0}\frac{\log{x}}{log{e}}dy$
doctor99268
Maybe
@valid gale Has your question been resolved?
No it needs to be a dx
I phrased that wierd. I meant, shouldn't that be a dx instead of a dy.
Oh u meant that, yeah
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!nosols
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suppose this is a function f(x)
and i want to find the unsigned area under the graph
when i do ∫f(x) the negative and positive area cancels out
if i want the unsigned area, can i just do ∫ | f(x) | dx?
its my own question, not necessarily from a textbook. so uh chose lets just say 0 to 2pi idk
Sin is positive from 0 to pi and negative from pi to 2pi
So we can split the integral up
Or we can see that the area from 0 to pi is the same as from pi to 2pi, just negative
Therefore we can just get one area and double it
mhm makes sense. i just chose sin(x) arbitrarily, i was thinking about a general function
so ig i'll just do this?
well if you solve the points f(x) = 0, you can see where the function is negative and positive, idk tho which way is faster
Doing that pretty much may require you to split the integral up into the parts where the function is positive and negative to use the piecewise definition of the absolute value
Depending on what you're integrating, of course
ohhh yea i remember doing a question like that now that u mention it
makes sense
alright got it thanks
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Unsure what the method would look like
I understand the question (kinda) but I don't get how I'm supposed to show my working out
the method is stated in the task: "by first factorizing"
use the formula for the difference of two squares
Can't figure that part out for the life of me
a^2 - b^2 = (a-b)(a+b)
using this theorem you can factorise anything of the form a^2 - b^2
Ah I get it now