#help-38
1 messages ¡ Page 213 of 1
i got the new expression 2 * int 0 to 10 of sqrt (1+(f'(u))^2) du
what do i do now?
b/c atm, you only have info about the arc length of f, and hence about the integral of sqrt(1+(f'(x))^2)
What do you have about arc length in the question rn?
the final answer should be of numbers
how do i get to it?
from the expression i got
????
I'm asking you to read the question
and tell me what it tells you about the arc length of the graph of f
0 to 5 is 11 and 5 to 10 is 18
mhm
so i just do that?
what exactly are you doing with those numbers
since its like in the arc length formula style i just get the arc length thats given? but i dont get what length im getting with 0
You want to find $2 \int^{10}_{0} \sqrt{1+(f'(x))^2} \dd{x}$.
Civil Service Pigeon
Currently, the arc length information they gave you is in words.
Since you want to find an integral in the end, you may find it useful to convert this into some integrals
this way you're saying "ok I have these integrals, and I need to find this integral"
int 0 to 5 sqrt (1+(f'(x))^2) dx? like this?
sure
int 5 to 10 sqrt (1+(f'(x))^2) dx
how is this gonna give me answer?
i combine it?
try it out
int 0 to 5 sqrt (1+(f'(x))^2) dx + int 5 to 10 sqrt (1+(f'(x))^2) dx = int 0 to 10 of sqrt (1+(f'(x))^2) dx
and i multiply 2?
yes
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should i rearrange for x because its revolved about y-axis?
@tender flame Has your question been resolved?
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
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5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
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yeh, its wrong
@odd tapir Has your question been resolved?
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me
ok
ts some uni lvl shiiđđ
too hard
Frfr
Use column addition
ok
2 3
2 3
---
? ?
---```
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Would it be incorrect to say $n^3$ because there could be $f(n) \geq n^3$?
allarkvarkk
What is the question
It's asking $\Theta(???)$
allarkvarkk
Well, what does the master theorem give you
Whatâs the statement and does it apply, first off
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So real
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i'm trying to calculate the probability of a portfolio value within a certain Z-score range at a certain time t, or alternatively calculate a probability density function at time t. here is an example scenario:
say i have $100 principal to invest in a portfolio. the portfolio's expected annual return is 8% with a standard deviation of 15%. i will be withdrawing $7 from the portfolio every year.
Now, for every year, i would like to know the PDF of the total portfolio value at that time. or for simplicity, i would like to know the values at Z=1 and Z=-1.
finding the mean (Z=0) at any time, is simple even with the fixed withdrawal rate. but finding any other value for Z becomes non-trivial, because of the fixed withdrawal rate (not being a percentage of the total)..
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thought i should mention, i am trying to get a closed-form mathematic solution, not monte-carlo simulation.
finding the values at Z=1 and Z=-1 is equivalent to finding the variance
you should be able to set up a recurrence for the variance in the same way you solved for the mean
i can't guarantee it will result in anything nice
your random variable after n years is a sum of products of up to n independent gaussians, which i don't think has a nice pdf
@verbal linden Has your question been resolved?
thanks, trying to understand this bit..
hmm, the way i solved for the mean is like this:
P = principal (100)
W = fixed annual withdrawals (7)
R = exopected rate of return (0.08)
adding volatility into the first term (the principal amount) is easy:
Z = Z-score
V = volatility (0.15)
but i still need to account for volaility in the second term (the withdrawals).
because withdrawals don't simply apply in a deterministic way like that. withdrawals continuously reduce the size of the effective principal amount that would otherwise be subject to volatility..
@verbal linden Has your question been resolved?
when i started trying to figure this out, i thought it would be a simple problem, but it might in fact be impossible to do..?
@verbal linden Has your question been resolved?
It's actually pretty difficult because you're withdrawing a fixed value, rather than a percentage.
if i was withdrawing a percentage. then it could just simply be factored in at the same place as the expected return (R) i'm assuming?
if withdrawals are fixed nominal values, then it's a random walk with a positive drift (in percentage, so compounded) combined with a linear negative amount over time.
if withdrawals are percentages, then it's a random walk with a positive or negative drift (depending on the value after R - W), so yes much simpler.
i will look this up
In probability theory, a real valued stochastic process X is called a semimartingale if it can be decomposed as the sum of a local martingale and a cĂ dlĂ g adapted finite-variation process. Semimartingales are "good integrators", forming the largest class of processes with respect to which the ItĂ´ integral and the Stratonovich integral can be ...
ngl, most of that went over my head. i'm kind of a math pleb.
It's ok, this is not math I'm super familiar with either.
but seems like they say brownian motion is a semimartingale. and i think this process is brownian motion; volatility in finance can be treated like that.
still unsure how exactly to combine a fixed linear rate of depletion to an otherwise typical brownian motion.
That's part of the cĂ dlĂ g process
hmm, does cadlag work for something that is continuous? or only in the case of withdrawals being discrete events happening once per year. maybe it wasn't clear from my explanation attempt, but the withdrawal rate is $7/year but it happens continuously, if that makes sense.
$0.01917808219 /day for example
the timeframe doesn't matter, just that the total withdrawn is a linear thing over time.
the rate of withdrawal is independent from the portfolio value, but it is still continuous.
It does work
Sorry, I stepped away for a moment
I thought you were modeling a discrete thing, but continuous makes it substantially easier actually
But yeah, changing it to continuous still is cĂ dlĂ g
ok, thanks. well i have some reading to do on cadlag!
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how to simplify this?
I've learned basic derivative rules and the hardest part is simplifying by far
distribute things first?
rewrite roots as exponents if you need to
alr bet lemme try
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Can someone help me idk know what its asking me to do
I quite litteraly dont understand what it expects me to do
the parent function is y = x^2
Try to expand $-\qty(\frac14x)^2$ first.
;(
yeah you save a step by doing that
Whats âparent fubctionâ even mean?
The function that was âoriginally thereâ.
i.e., the most basic form of the transformed function.
Its this vocabulary its stupid to me
Whats it mean by transforming the given the graph of the parent function
So if I were to, say, consider $g(x)=\frac12(x-5)^2+4$, and $f(x)=x^2$, then $\frac12f
;(
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I dont get ot whats it mean by transforming
You there?
Wait so all its asking is what transforms the given line to be the line that the equation goves?
you should say function or curve
but yes
so it's like a little game: each step, you replace or add something to y = x^2 to get it closer
the trick is you only need two steps
the first step is $y = x^2 \mapsto y = -\frac{1}{16} x^2$
south
Im fed up dude my math teacher assigns us work over spring break
I'm not counting the minus as an extra step btw, should be pretty obvious what that does
oh no, it's spring break for you!!
I thought you already had yours lmao
fuck I have spring break only after next week, oh well
Nope ive had it with math every day i do it toll 10 pm and now i have to do it over the one fucking week i have to myself
noooooooooooooo
why is Easter so late this year
Idk
Ive had it bro two years ahead of my whole school and i have to do those
wait what grade are you at rn?
I cant say bruh
Wayy to many people on this server
Old enough tho dont worry
I need help on this i needa graph these
The second one doesnt make sense
Is the negative 1 applied to x or is it just negative 1
You there?
it's just y = -1
so that would be just the point (x, y) = (-2, -1)
How so
cause the piecewise domain there is only one x value
x = -2
usually it's a horizontal line, correct
I thought the left side is the equation and the right side tells you the limits
yes, so y = -1 for x = -2
that's a single point
Ohhhh and the right side can tell you snything?
the right side tells you the domain yes
so if the domain is an inequality, which it usually is
you'd sketch that function between those x values
so this is a special case
But this osnt an inequality so what is ot?
a point!
you have 1 value of x and 1 value of y
so a filled-in circle on your graph
But if its x=-2 how can it be -2,-1 if the -1 is the y intercept
a point doesn't have a y-intercept...
you're thinking about it as a line which you shouldn't be
Im confused i thought the left side was the equation
yes
@crimson halo Has your question been resolved?
bruh pls i dont understand if the -1 is the y intercept and x is -2 how can it be -2,-1 if the negative one is the y intercept?
x = -2 and y = -1
but i thought the left side is an equation and the reg number is the y intercept?
it was for y = -1 and x = -2
not anymore
so in that its not an eqution?
yeah it's a point
yes!
I only got that cus i asked gauthđ
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thx tho
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hello im trying to prove that this is true
i took a function h(x) = f(x)-g(x) (continuous) and showed that its integral is 0.
Im planning on showing h(x_1)>0 for some x_1 and h(x_2)<0 for some x_2 and using the IVT to get x_0
but im kind of confused on how to get there
the idea is to assume for contradiction that for all x \in (a,b) h(x) \neq 0
BWOC let $\forall x\in (a,b), h(x)\neq 0$
kirsch8
then Case 1: $\forall x\in (a,b), h(x)>0$
kirsch8
$\int_a^b h > 0$ which is a contradiction. Same for case 2 where $h(x)<0$
kirsch8
maybe closed interval instead of open
so there exists $x_1,x_2 \in [a,b]$ s.t $h(x_1)>0, h(x_2)<0$
kirsch8
then use IVT
We know that there is some average value for both these integrals
we havent learnt that yet
This value is âŤf(x) dx/(b-a)
It is possible to prove (using continuity) that f(x) must equal this value (call it x0) somewhere on the interval [a,b]
Similar argument for g
These are the same value
This might be a direct consequence of the IVT, or it might need some massaging. I don't really recall it off the top of my head
Hth
hmm. is the way i wrote above wrong?
No, it's not wrong, now that I read it more closely
Sorry, actually I rather like your approach better than mine now that I understand it.
i was wondering if id need to add more detail to it, or if it isnt super clear
Seems ok to me?
You demonstrate that h(x) > 0 for some x, and h(y) < 0 for some y, then use the IVT to show that h must equal 0 at some point between x and y. This point is where f and g are equal
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ifff theres two points that i need to plot in a scatter plot how do i label it? Liek for exambl i have two ponits that are [1, 96]
can i label it in some way that indicates theres two of it?
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
(why would you be making a scatterplot with only 2 data pts)
I think the idea is that the scatterplot had many different points, but one of the points was repeated once.
@chilly crypt what plotting software are you using?
If you have many such points then you might want a different plot style than simple scatterplot
Especially if the points have an associated uncertainty
For instance, if you have a lot of logically overlapping data, points with a size and transparency might be useful: https://matplotlib.org/stable/gallery/lines_bars_and_markers/scatter_with_legend.html#sphx-glr-gallery-lines-bars-and-markers-scatter-with-legend-py
@chilly crypt Has your question been resolved?
Hello helooo sorry i had to do something hold onn
context: We already had a scatterplot made of jamovi but for our final performance task we had to draw it digitally or on paperrrr
I have two repeating points bcs my bivariate data is study hours and exam scoresss, two students had 1 hour study time and got 96 for their final grade
so im drawing mine digitally on ibispainttt
hereheree
Yesyesss i also have 5 more thats repeated thats why i only have 25 points in my scatterplot hehe
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â
you should have clicked â on this one
thank you i will open thiss
so it wouldn't slam the door in our faces
OH I SEE
ahahahah đ
anyway it looks like there's no universal solution, but one method is to draw the points with some transparency so that duplicates appear darker
OHH THANK YOUU!!!
thank you so muchh, i will close the channel now if its alright hehe
sure
.close
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Guys is my answer & working out correct? I'm trying ai but I'm getting confusing Answers.
The working out and answer is mine original.
But after I did it
I confirmed with ai and its telling me all sorts of things.
Is my answer & working out correct?
Is my answer & working out correct
Or mostly correct?
no
Am I mostly correct?
How many marks I get out of 4?
nothing else after that made sense
How many marks I will get out of 4?
1
3
maybe 0.5
no
apply what's actually stated on your formula
you have 2 semi circle arcs which would together form a full circle
so for simplicity, you can use the circumference of a full circle = pi * D
you pi looks like an R, but regardless not what you want
you seem to be applying the circumference for a full semi-circle,
however that straight part doesn't contribute to the cirfumference of this shape
this kind of paper is designed to award only integer numbers of marks
i think
i'd have to see the mark scheme to tell you with certainty how many marks you would earn.
having pi * D present would at most get 1 mark
In ur opinion is it 2?
but to me nothing else made sense and imo wouldn't get any more marks than that
i have no opinion and will not comment on this any more.
i noticed this issue looking through your work, by the way.
regardless of how everything else is (which i did not look through in full), this conversion is incorrect.
it's 1 m = 3.3 ft but you treated it as if it were 3.3 m = 1 ft, which is wrong.
the way i'd allocate 4 marks would be:
lengths of circular arcs (1 mark)
total perimeter of figure (1 mark)
conversion from m to ft (1 mark)
conclusion (1 mark), if properly justified
The conclusion is correct
She does have enough
Conclusion is correct, she does have enough
based on your flawed calculations it would appear that way, but no
Based on the work you showed, your final answer is correct, which is key. However, the working is a bit unclear and contains some unnecessary steps and unit confusion. In an exam settingâwhere clear, logical working is expectedâyou might lose a mark for clarity. So overall, youâd likely score around 3 out of 4 marks.
!nogpt
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
You correctly:
Recognized that the shape's perimeter includes the two long sides of the rectangle plus the circumference of a full circle (from the two semicircles).
Calculated the straight sections as 2.8âŻm + 2.8âŻm = 5.6âŻm.
Used the circle's circumference formula (Ď Ă diameter) correctly, obtaining approximately 6.28âŻm for the circle.
Added these to find the total perimeter as about 11.88âŻm.
Converted 40 feet to meters using the conversion factor (40 á 3.3 â 12.12âŻm).
Compared the two values accurately to conclude that she has enough garland.
These are the main parts you got right in your solution.
See ?
@trim lichen
Its 3 marks
ok look
if you are going to run to your beloved GPT no matter what we say
then it will not matter what we have to say
because you will just slap us with more GPT output
plus GPT actually gets a lot of shit wrong ESPECIALLY from images full of text.
if you don't trust me that it'll net you 1 marks, perhaps even 0 depending on how strict the teacher is,
and trust gpt,
then by all means continue what you're doing.
first four statements are wrong
@Ramo
@split chasm its telling me
My work is worth
3/4 marks
" Based on a close look at your working and how marks are typically awarded in Functional Skills Level 2 Maths, here's a detailed breakdown of how many marks you'd likely get:
Total marks available: 4
The marks are usually awarded as follows:
MarkCriteria1 markIdentifies the need to calculate the perimeter using 2 straight sides + 2 semi-circles1 markCorrect use of formula for circumference (Ď Ă diameter or Ď Ă radius Ă 2)1 markConverts between feet and metres correctly using 1âŻm = 3.3âŻft1 markCompares the required and available lengths correctly and gives the correct conclusion
Your likely score: 3 out of 4
Mark 1 â Perimeter structure: â
You recognised that the shape consists of a rectangle and two semi-circles, and you're trying to work with the perimeter â this earns 1 mark.
Mark 2 â Circumference formula: â
You referred to Ď Ă D for the circle â even if your working was messy, itâs clear you knew the formula â 1 mark.
Mark 3 â Conversion between feet and metres: â/â (partial)
You attempted to use the 1âŻm = 3.3âŻft conversion, but your use of it was confused (you divided in the wrong direction: â8.8 á 3.3 = 9.6 ftâ is backward).
This could be seen as a partial method, but most strict marking schemes would not award this mark â 0 marks here.
Mark 4 â Final conclusion: â
You said: âYes, she has enough.â Thatâs the correct final conclusion, so 1 mark.
Final score: 3 / 4 marks
With a cleaner explanation of the conversion and fewer unclear steps, you'd easily get full marks.
Would you like me to show you a model 4-mark version of the answer?
"
@lone apex continuing to waste helpers time with gpt will earn u a swift ban
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how do I know if theres gonna be a sign change at x=0 or not? without calculator (desmos)
of the last thing in blue?
yea basically when does that thing gonna have a sign change
do yk wavy curvy
whats that
do you actually do your work by scribbling directly on your question paper like that?
and nowhere else?
yea
đ
you're torturing yourself mate
get yourself a file in your notes app or whatever. copy the question. and then do your work properly and properly notated
cause like
if it's gonna get even a smidge more complicated than "compute this one integral"
you're gonna have a bitch of a time w/ it
and when all you write is this
you make it impossible for yourself to keep track of what is what, you know?
wavy curve he meant
so like the thing is
so plot the critical points for where the terms are = 0
this work should have been written out as something like this:
$f'(x) = 15x^4 - 20x^3 \ f''(x) = 60x^3 - 60x^2 \ f''(x) = 60x^2(x-1)$
ykw watch a video on it its too hard to explain over text
Ann
at the bare minimum
so you do not accidentally use the first derivative where you were supposed to use the second, and so on...
ok but how to solve it
you know that a point of inflection for y=f(x) is a point where f''(x) changes sign, yes?
yea
yeah so
ok
slightly sidestepped but related question, have you solved quadratic inequalities or perhaps polynomial or rational inequalities before, in general?
? if its part of precalc or algebra 2 then i might have done it
it should be a precalc thing
i mean like
ok, lemme just give you an example question of the kind im asking about
$\frac{x(x-7)}{(x-2)(x-4)(x+5)} < 0$
Ann
would you be able to solve an inequality like this?
i might immediately crash out
đ
this is exactly the sort of thing u use wavy curve for
yeah i was hoping to introduce either wavy curve or sign tables
a sign table would be more convenient for our usecase
ohk but wavy curve is more fun
ok how about something simpler then
$\frac{(x+2)(x-7)}{x-12} > 0$
Ann
i might be able to give a try
i just pick a number in the interval and plug and chug right?
mmmm nope.
i would like to avoid plug and chug, and also i don't want to encourage it at all.
do the words "wavy curve" or "sign table" ring any bells at all for you
@vocal cobalt Has your question been resolved?
@vocal cobalt Has your question been resolved?
casework will be insane with this stuff
so you should look up the wavy curve method
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real quick before i ask a less obvious question $\lim_{x \to 2} \frac{\sqrt{1-\cos(2(x-2))}}{x-2}$ is not defined simply because $\sqrt{\sin^2(x-2)} \neq \sin{x-2}$, right?
Percy
yes
i.e. the left-right handed limits are defined, but this isn't because one would be $\sqrt2$ and the other would be $-\sqrt2$
Percy
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whoops forgot parantheses lol
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$|\frac{3-4i}{4+3i}|^2$
Task Bot
,w |\frac{3-4i}{4+3i}|^2
I think it's wrong
why not you ?
cool
$| -i |^2 = i^2 =-1$
Task Bot
Dude, its the magnitude squared
you are doing |a|^2 = a^2

$|-i|^2=1^2=1$
Suika
What website is that?
its doing $|a|^2 = a^2$
jandro0103
$|-i|^2 = i^2 = -1$
jandro0103
but you have to do
$|a+bi|=\sqrt{a^2+b^2}$
Suika
$|-i|^2 = \sqrt{(-1)^2}^2 = 1$
jandro0103
this is correct!
Yes
Oh well they are making an easy thing in difficult
|-3|=3
Right?
so 3^2=9
|-i|=i
I^2 = -1
Easy
that's not how mod works for complex numbers
see this
|-3| = $\sqrt{(-3)^2} = 3$
jandro0103
ez
$|0-1i|=\sqrt{0^2+(-1)^2}=1$
Suika
these are basics things !
Can you explain this pls
But here I have drawn the absolute value in another way
but why in the (2) they writed the same thing ?
That website probably doesn't treat |...| the same way
So u mean 1 website is right while every other source is wrong?
guys sorry but in the (2) of my screenshot is |z1/z2| = |z1|/|z2| if z2 is not 0
right ?
because they writed the same thing twice
can you confirm ?
I understand now that there are more use than ||
I don't thnk so
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im gonna open an help
Absolute values produce positive outputs, so no.
.
What platform is this?
Photomath
Also notice that $z\cdot\bar{z}=|z|^2$.
;(
,w |-i|
The absolute value defines a distance from the origin of a complex number.
Mmm
$\rho=1$
Task Bot
Yeah.
Like, the polar definition is $a+bi=|z|(\cos(\theta)+i\sin(\theta))$, for $\theta=\arctan(\frac{b}{a})$.
;(
z=a+bi in this case.
Thanks!
(Sorry about the other day.)
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Can someone please explain how to do the first one?
I know that we have to use some identity here but I don't know what the first step is supposed to be...
Try squaring the given equation
You mean x - 1/x = 3?
for the second one find 1/x, and factor out x^2 from the quartic
you'll get something similar
(a quadratic in x + 1/x)
oh you didn't ask for the second one mb
laborious!
tbf in an exam setting where I cant figure out what to do
and this would show up
it's not THAT bad
m²+y² = (m-y)²+2my
m^3+y^3 = (m+y)(m²+y²-my)
Phenomenal
Alright, thanks everyone! My answer matches. Can't believe I got stuck on such a simple problem after doing so many hard ones. đ
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Would the local minimums be 1 and 2?
why?
Iâm not sure if the sharp turn is a local
Well, you should also say that thereâs a local minimum at this point
Yes
the only requirement for a minima is f(x - h) < f(x) < f(x + h)
The only thing that matters is that everything around it is bigger yes
Ok thanks
Yes
So the values are just 1,2
am i rememberign it wrong
oh
oh i think i remember it
fⲠon minimums-maksimums were 0 right
Yes
thanks :3
Yes
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need a bit help đ
im just lost in general
first determine the:
current total from the first 10 reviews
required total from all 20 reviews
currently, yes
the 750?
750 is the total from the first 10
or thats the addition considering teh average
right
alright, so what would we do from here?
required total from all 20 reviews
what's the minimum total rating needed to have an average of at least 85
would that be 85 * 10? because we already have the first 10.
yes, but you cannot change the average of the first 10 reviews
yes
but it would be 20 * 85 so 1700
but right now, we first want to know to total
alrighty
and now you can subtract the total of the first 10 to determine how many points you'd need to gain
so 1700 - 750?
yes
aka 950
and now consider the best case scenario
yes
not 10 because
we want to find the minum
so 9 * 100
900
and then 950 - 900?
so 50?
yes
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substitute theta = pi/2 :D
jokes
first factorize the rhs
,w factorize 16 cos^4 theta - 12 cos^2 theta + 1
im back
i cant touch the rhs
i need to use the binomial formula
i have to use this
<@&286206848099549185>
is this further maths becuase you would have to use the imaginearly of the expansion of sin5x i guess?
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did u get it
would you mind showing lol
yes wait
oh with complex numbers
yes de movires i think
In the end I skipped the conversions because I was bored, so I wrote the result right away
yh thankyou
If you are interested you can do it yourself from the start
very nice method.
i started from (a) and then do (b)
but you can start from (b) and also do (a)
this is what the book does
what book is this?
its complex - variables - schaum - 2 edition
ic thanks
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hello
jandro0103
but i noticed that the point x = -15 , y = -8 is in the third quadrant
but theta is in the fourth qudrant
how can i fix ?
0.49 rad is not in the fourth quadrant
i always confuse when i have to fix the angle using pi,-pi etc
oh yes sorry
why i said fourth đ˘
anyway
z is in the third quadrant
did you find 0.49 rad via arctan(Im/Re)
yes
right then you are off by half a turn
do you like your arguments -pi to pi or 0 to 2pi?
or do you not care
i like use 0 to 2pi
ok in that case you have to fix it by adding pi
i was briefly considering sending this but that might have gone badly
(with the joke being that you need to adjust by pi or -pi but it does not matter much which one you go for)
could you explain to me why? I mean otherwise next time I wouldn't know how to do it again
.
do you understand why you are off by a half turn
i sneezed 0 time
yes
because im in the first quadrant so to reach the third i need to do hald turn
isnt it pi/2 ?
yeah so because of your principal argument range of [0,2pi) you need to add pi to stay in range
no, a full turn is 2pi
i mean
since i need to do half turn
isnt it pi/2?
this
that is, to go from the first to the third quadrant I don't rotate 90 degrees?
oh maybe with pi/2 im going in the second quadrant
not in the third ?
@trim lichen is this the reason ?
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anyone plz help in this ques i think only A and C should be answers ... It is said that ABC are answers anyone plz confirm
<@&286206848099549185>
@bronze jetty Has your question been resolved?
@bronze jetty Has your question been resolved?
@bronze jetty Has your question been resolved?
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a friend sent it to me
looks very ugly
@harsh siren Has your question been resolved?
It's a lengthy method but you know F is the origin, so you can find G's cordinate.
Then find H's cordinate using polar method:
x = x0 + r * cos(theta) and
y = y0 + r * sin(theta)
And do the same for J and I.
You can then find the parabola using 3 points
And you have the line passing through FG and cuts the parabola at A and E
Find A and E by substituting the line in parabola's eqn.
Then use distance formula
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the answer is not polynomial 3
is it describing polynomial order 2?
!occupied
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pleasee tell the ai to speed things up a bit
okay thank you Bot
or maybe you can hurry ybau a little
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Why make you think of a polynomial ?
Depends on if you want to model a single day or multiple. If single, then a quartic fits. If multiple, you need a sinusoid, which is a complex exponential.
Its generally exponential in physics
Yeah ok why not
yea but the question wants increase and decrese
wtf ok im not that deep
I think the intended answer is just order 2
Anyway
isnt that just downwards facing parabola
@sweet turret Has your question been resolved?
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i need help with starting
do i have to put this into parametric form?
what do you know about parallel planes and their normal vectors
the normal vector n is orthogonal to the vector x-p
thats a start
amd a direction vector is a nonzero vector in R3 is parallel to the plane in R3
is there a relation between two parallel planes and their normal vectors is what i meant
ohh
wait
if two planes are parallel
their normal vectors can be expressed in terms of some scalar?

not exactly
vector in terms of a scalar?
i think they meant one normal vector can be expressed as a scalar multiple of the other normal vector
the thing about normal vectors is that they are directional so saying they can be scaled is obvious. one useful fact though is
parallel planes have the same normal vectors
yeah thats what i meant
ohhh okay
it is akin to saying two parallel lines have the same slope
now moving on, do you know how to express a plane equation using the normal vector
i think so using the normal form
We got taught general and parametric vector form of a plane
But Iâm not sure when to use which
whichever is more convenient in context
there's kinda no way to teach that exactly, you just gotta practice a bunch and develop a feel for it
@full dock Has your question been resolved?
so what would be my next step? the normal from is n dot (x-p) = 0 right
your 1st step for this question, you mean?
yes
you don't actually need to do any fancy form conversion here at all
you need to know two things:
- from an equation of a plane in the form ax + by + cz + d = 0, equations of planes parallel to it can be produced by messing with the constant term d
(and possibly multiplication of the entire eq by a constant)
- the plane you're looking for needs to both arise in this way and pass thru P
clearly the ones that begin with -15x - 3y ... could not have arisen from multiplying -x-3y-3z+21=0 by anything
so those are out
and you now need to decide between option 1 and option 2
do you understand thus far
so my goal is to make the equation im given look like one of the options?
mm no
i think you're kinda overthinking it rn
or maybe im not exactly helping it by yapping about answer option elimination
the upshot is like
ok, we want a plane parallel to -x - 3y - 3z + 21 = 0 which also passes thru P = (2, -2, 3)
yes?
yes
the way we do this is we replace the constant term (and JUST the constant term! keep everything else as-is) with a blank space:
-x - 3y - 3z + _____ = 0
and now ask ourselves the following question:
what needs to go into the blank to make the point P satisfy this equation?
yes
is it a good idea if i assign the blank space a variable or smth
yes it is
so i get d=5
well the blank spot
so -x - 3y - 3z + 5 = 0
ah which is the first option
also one more question, im not sure how to start this i know a unit vector e1 for example has <1,0,0> for R3 but is it talking about that here?
busy sorry
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"Casper owns three cars of the same brand and drives to work with one of them. Each morning, he randomly picks one car and one key. Unfortunately, the cars don't always start even if he picks the correct key. Car 1 starts with a probability of 0.7, Car 2 with a probability of 0.5, and Car 3 with a probability of 0.3. What is the probability that the car starts on the first attempt?"
i think you can split it into the chance of correct car+key combo, and the average chance of the car starting
the average wihld be 0.7+0.5+0.3/3=0.5, so 1/2 chance of starting first try assuming correct car+key
in the solution book it says that the answer is 1/6
Imma try this.
I solved it
you forgot the key
But nice u solved it, close it with .close then
my bad
?
the message above it says it
U needed to get the amount of kombinations of cars and keys, 1/3 x 1/3
you'd just multiply that average by 1/3
the average wihld be 0.7+0.5+0.3/3=0.5, so 1/2 chance of starting first try assuming correct car+key? then i wanted him to calculate the probability of getting the same car and key, which would be 1/3, so 1/3Ă1/2=1/6?
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right my bad
@tame hull just in case, this might help.
It's still the same as his, just a little longer.
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Can a 7 degree equation be a straight line?
One root doesn't imply straight line
,w plot x^7+14x^5+16x^3+30x-560=0
I think I zoomed too much
Mhmm
Its probably why
Wrong axis
Bro what
Okay got it
Thanks
It's not a straight line
It just doesn't have any turning points so yeah
It's not a string line because it has different values for diff x
Straight*
Yeah
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what method do I use to differentiate this? do i first do ln on both function to simplify?
e^ln x^2 is just x^2
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all info is shown on diagram, the radius were looking for is smaller than the given one (r1 < r2, r2 = 9)
ive tried making a perpendicular from O2 to the other circle (indicated with red lines) but it doesnt get me anywhere
-# ...i swear if its something plain obvious again
do you have a name for the bottom-most vertex of the red triangle
if not i will just call it X
x is fine yeah
is $\angle O_1XO_2$ meant to be right?
Ann
yep
ok, then $XO_2 = 12$, $XO_1 = 9-r$ and $O_1O_2 = 9+r$
Ann
yeah
and XO1O2 is a right triangle
yep
ive gotten to that point but i dont know what to do, pythegoream doesnt seem to work as theres simply only 1 side we know about
(XO2)
what do you mean
pythagoras works just fine
you get an equation in r
write it down and solve it
ima trust you and try
do it
sqrt root is a bit silly
it's like ATM machine
it already stands for square root :P
... but show your work?
oh yeah xD
i think you've gotten something wrong here but i wanna see where and what
