#help-27
1 messages · Page 337 of 1
Uhh welp, I dont understand that part myself, since I guess its asking for one cycle for f(sin x)
And not sin x
Any reasons on why...?
its still sin x
not sin 2x or anything
the cycle doesnt change just because you cubed it
its sin x but cubic now
Ooh, didnt knew that
thnx
but still
what after that?
integrate it?
Welp its a cubic function over a full period? So I didnt even need to do it? I gues?
So sorry for that but I got no phone with me rn
I am on PC
,w integrate sin^3 x - 6 sin^2 x - 15 sin x - 1 from x=0 to 2pi
,w integrate | sin^3 x - 6 sin^2 x - 15 sin x - 1 | from x=0 to pi
whatcha trying to do?
is it asking for unsigned area ?? what does cycle mean 😭
cycle means when the sin x completes one rotation and then repeats itself
,w integrate | sin^3 x - 6 sin^2 x - 15 sin x - 1 | from x=0 to 2pi
how do i make it show the answer in terms of pi?
,w 57.4692/pi
ok so this is the correct answer, according to gemini
but i dont understand how
Because that's how you calculate the area 🤷♂️
The absolute value is there for taking into account that a normal integral would give you the signed area
What was the original question
Ah so the problem is that the answer doesn't match the given ones
Yep
Well only problem could be somewhere forming the correct polynomial,maybe smth went wrong
Wow nice one
It goes through (2, -47)
@restive elk Has your question been resolved?
ye?
We found your mistake
Your plinomial goes trough the point 2;-47 and not 2;47
Didn't I mention that in the question itself?
GPT had a hard time doing OCR... the inflection points are (2,-47)
Ah ok
I'll try to solve it when I'm home from the gym, I'll DM you when I find smth
If you spot it before me, pls tell me
pls do, tysm sirrrrr
will do, tysmmmmmmmmmm
@restive elk Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Guys it says 72 is wrong but me and all the LLMs say it’s right? Help
I solved the first formula for T and plugged into the second. Using 11.8 as delta X
i can see right through your hand
3 sig figs
well im out of chances but thank you
alright
.close
Closed by @oblique mulch
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
for this i know the first part, but am stuck on finding the parametic
Okay, do you have the line?
Or any info about it?
thats all that was given
can't you turn 2x-y+3z =0 to <2,-1,3> and -x+2y+z=0 to <1,2,1>
then i found normal vector by doing cross multiplication
there's a very easy trick for this involving the normal vectors
please elaborate 🙏
the angle between the planes is the same as the angle between the normal vectors
also I think you meant <-1,2,1> here
correct, but i'm not confused about the angle part
the tricky part is the parametric
my teacher did this weird thing, am this is where I am confused at
to find the line of intersection, you need to solve the system of equations formed by the planes, which is what your teacher did
they solved for x and y in terms of z, and then they said z = k (usually I see z = t but k works too i guess)
this part is actually unnecessary
the question says to solve for the equation though.
saying x = (-7/3)t, y = (-5/3)t, and z = t is sufficient
the intersection of two planes forms a line, so you need the parametric equation of a line
which is technically 3 equations
thank you, i think this helped me better understand it
👍
since you're here could you please help me with this as well?
@somber dawn Has your question been resolved?
Ah, this is an application of $\frac{|Ax_0+By_0+Cz_0+D|}{\sqrt{A^2+B^2+C^2}}$, for $Ax+By+Cz+D=0$ a plane and $(x_0, y_0, z_0)$ a point
;(
The proof behind this used the normal vector to the plane going through the point
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
yo yo yo
@lyric hornet pov my teacher is a piece of shit and gives me a 90% even tho i got everything correct for smalls mistakes
Closed by @supple knot
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
1help
!help
To ask for mathematics help on this server, please open your own help channel or help thread. See #❓how-to-get-help for instructions.
question if y= a sin x + b cos x then (dy/dx)^2 + y^2 is a) a function of z or b) a constant
what is z here
its was x
btw just for future reference
you're supposed to just send your question directly
anyway, have you worked out what y'^2 + y^2 simplifies to?
for a start, ^ for exponents...
but also you could post a screenshot or picture of the thing
(dydx)^2+y^2=(acosx−bsinx)^-2+(asinx+bcosx)2
to the power of -2 ?
ok no
write this shit out on paper and send it here
also simplify it fully
wait what
dx/dy ??
did you not say dy/dx before?
why is dx/dy happening?
also $(a \sin(x) + b \cos(x))^2 \neq a^2 \sin^2(x) + b^2 \cos^2(x)$
Ann
Closed by @tough vigil
Use .reopen if this was a mistake.
since when was a^2 + b^2 equal to 1
dear lord you only stated like 1% of the problem to us 😭
[
\left( \frac{dy}{dx} \right)^2 + y^2 = a^2 + b^2
\quad \Leftarrow \quad \text{This is constant because it has no } x.
]
BVB999
im sry its not 1 its aconstant beacuse no x and no trig function are left
not 1 im dumb i figured it out
\documentclass{article}
\usepackage{amsmath}
\begin{document}
Given:
[
y = a \sin x + b \cos x
]
Differentiate:
[
\frac{dy}{dx} = a \cos x - b \sin x
]
Square both:
[
\left( \frac{dy}{dx} \right)^2 = a^2 \cos^2 x - 2ab \sin x \cos x + b^2 \sin^2 x
]
[
y^2 = a^2 \sin^2 x + 2ab \sin x \cos x + b^2 \cos^2 x
]
Now, add them:
[
\left( \frac{dy}{dx} \right)^2 + y^2 =
(a^2 \cos^2 x - 2
BVB999
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Given:
[
y = a \sin x + b \cos x
]
Differentiate:
[
\frac{dy}{dx} = a \cos x - b \sin x
]
Square both:
[
\left( \frac{dy}{dx} \right)^2 = a^2 \cos^2 x - 2ab \sin x \cos x + b^2 \sin^2 x
]
[
y^2 = a^2 \sin^2 x + 2ab \sin x \cos x + b^2 \cos^2 x
]
Now, add them:
[
\left( \frac{dy}{dx} \right)^2 + y^2 =
(a^2 \cos^2 x - 2
BVB999
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
[
y = a \sin x + b \cos x
]
[
\frac{dy}{dx} = a \cos x - b \sin x
]
[
\left( \frac{dy}{dx} \right)^2 = a^2 \cos^2 x - 2ab \sin x \cos x + b^2 \sin^2 x
]
[
y^2 = a^2 \sin^2 x + 2ab \sin x \cos x + b^2 \cos^2 x
]
[
\left( \frac{dy}{dx} \right)^2 + y^2 =
(a^2 \cos^2 x - 2
BVB999
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
[
\left( \frac{dy}{dx} \right)^2 + y^2
= (a^2 \cos^2 x - 2ab \sin x \cos x + b^2 \sin^2 x)
- (a^2 \sin^2 x + 2ab \sin x \cos x + b^2 \cos^2 x)
]
BVB999
.reopen
[
\left( \frac{dy}{dx} \right)^2 + y^2 = a^2 + b^2
\quad \Leftarrow \quad \text{This is constant because it has no } x.
]
✅
[
\left( \frac{dy}{dx} \right)^2 + y^2 = a^2 + b^2
\quad \Leftarrow \quad \text{This is constant because it has no } x.
]
well, for what it's worth, you're right in that $y'^2 + y^2 = a^2 + b^2$
Ann
so its a constat cause there is no x
is it my textbook answer says so???
???????????????????
Correct
Actually, not because there are no x's
1 last question
yeah
But rather because a and b are constants, hence a² + b² is a constant
With this I mean that you could have had some y or y' (not in this exercise, though) on the RHS
the position of a particle in a straight line is given by y=3t^3 + t^2 +5 find the accelration at t=2
Next time post different questions in different channels
So that we don't have too many messages to read through
Do you know the definition of the acceleration?
Awesome
because y defines the positon
So you have all the ingredients to calculate the acceleration
You don't in fact
Acceleration is in m/s²
[
\text{Velocity: } v = \frac{dy}{dt} = 9t^2 + 2t
]
[
\text{Acceleration: } a = \frac{dv}{dt} = \frac{d^2y}{dt^2} = 18t + 2
]
BVB999
[
\text{At } t = 2: \quad a = 18 \times 2 + 2 = 36 + 2 = \boxed{38 \ \text{m/s}^2}
]
BVB999
it is given in cm
Yep correct
is it beacuse its the area under a triangle of accelration
The positiony you mean?
yeah
answer this
im confused beacuse of s^2
It's a ratio of velocity over time
you can think of dimensions right? its velocity/time
but why time is squared?
yeah
This is meaningless, though
velocity is m/s and you're dividing by another second. so m/s^2
oooooooo
yes
thnx
bye chat
.close
Closed by @tough vigil
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
c
yes
over n over
i got height 5
got the midpoint
everything
what do i do for c
no way u do some
5 distance
hence
3,4,5 triangle
cos that gives u 4
or u could check all 4 on the line from part b
but thats way too long
for 5 marks
aight hold up
you did parts a and b right
can you give the equation for line l that you got
yes
just for reference
reverse polish notation?
yes
do we have an equation for AB as well
no
we dont need it
just grad
gradient
well ok
we can do a different route: CM = 5 defines a circle
take the eq of line l and that circle's equation and solve them as a system
what
whyd we do that
to find every point 5 units away midpoint
bit far fetched no
i mean you did get that the height of the triangle is 5 right
so we gotta do it one way or another
use that info
@restive river Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
any help
with what
what’s ur question
this
i dont get their method
person above suggested a circle
but thats a bit long
send the question again please
theres actually a formula for area of triangle
c
well yh
bro ive never seen this IN MY LFIE
ok then leave it
stop crying
No worries.
everyone somehow has some unique genius simplified method
@restive river Has your question been resolved?
Closed by @lone scaffold
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I am not sure where to start with this...
we have to find Sn here
euler?
yes
Well, I would simply do it with area = 1/2 base × height 🤷♂️
how should i deal with the n power on cos
like de morvie had something to do with powers but im not familirized with it yet...
wait i think i got it
is the answer 0
no
you need the identity
$\cos^n\theta
=\frac1{2^n}\sum_{j=0}^n\binom nj,e^{,i(n-2j)\theta}$
mia
stems from de moivre
plug this into the sum so you get a nested sum
then you will realize inner sums are either 0 or n depending on j
im not sure why you would attempt this question if you werent too familiar with de moivre
@valid iron Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Is there a way to bound $\frac{e^z}{z^2 + 1}$ on $|z| < 2$
dyxn
Cant seem to get anything to work
dyxn
:/ doesn't work
oh wait
uh
the function isn't bounded on the disc
whoops 💀
.close
Closed by @storm raptor
Use .reopen if this was a mistake.
.reopen
✅
The constraint is on |z| = 2 mb
is this part of a bigger complex analysis question
|z^2 + 1| >= |z|^2 - 1 = 3
I don't agree with the second equality - where did you get that from?
@storm raptor Has your question been resolved?
yeah I figured this out lol, thanks
bound an integral
but that's all I needed, so thanks
.close
Closed by @storm raptor
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Okay. So. I just randomly thought of this problem, and I genuinely do not know what the answer is, so I can't validate it by anything other than a proof. Also I barely understand what I'm asking, and no this is not for homework, this is purely for casual/fun interest.
So, I am standing somewhere in multi-planar space - somewhere which can be located on a complex plane. North of the origin is the positive imaginary, south of the origin is negative imaginary, east of the origin is positive real, west is negative real.
I'm trying to figure out where I'm standing in relation to the origin. North of me is positive imaginary, but... to my east is negative imaginary, to my south is negative real, and to my west is positive real. How is this possible, and where am I standing?
Valid answers are:
- That's not fking possible bro
- It IS possible and here is your position relative to the origin
I don't think that's possible
Why not, can you prove it
Idk
I'm just saying it based off of common sense, I'm neither good with proofs nor with graphs
I mean that there could be multiple planes in this space, and that my position may** not be** on the complex plane. I’m actually not sure how many planes there are, but there are definitely at least three (X, Y, Z)
Yes
Probably… sorry I’m a baby at math so my terminology may not be very precise 😄 Would visuals help?
I guess what I’m imagining is it’s possible that maybe the planes have been wrapped around to form a sphere, making the planes no longer infinite
Oof well give me a second because I have to redraw my visual, apparently I merged all the layers and failed to save a copy of the unmerged drawing...
For a little more context by the way, I'm describing metaphysical objects in a little project I'm working on. So the rules definitely are a tiny bit permissive, mostly because I'm still trying to figure out what all the rules are 😄 But there are some rules that I know for sure are fixed
Okay here we go
look at them colors
So, the black dot is the origin right, and the colors represent the planes. Obviously we know that imaginary and real numbers can overlap each other and stuff, but the general point is the yellow is the positive imaginary, red is positive real, green is negative real, blue is negative imaginary
So somewhere along the way while I'm God or whatever making these fancy numeric systems, I dropped my universe making tool down some mysterious wormhole
And it landed somewhere where the planes look like this
yes
I'm trying to figure out how to explain without giving more context than necessary lemme think
It's actually really hard to explain without sounding really mythological, so I'll just do that lmao
So we start with the first image here right
#help-27 message
The "origin" is a location, actually. It's a mythological location that only a bunch of aliens know how to access.
The second image is a compass, which points towards the origin. You only know what the colors mean, and that when the compass points in that color space, it means that's the direction you have to go in to get closer to the origin. So if the compass points to the yellow, you need to move along the positive imaginary line to get closer.
But as you can see, the cardinality is twisted in a weird way. Does that suggest that the compass is oriented wrong, or that you are oriented in a strange way in relation to the origin?
There are project related reasons that they are specifically the real and imaginary plane, which I could explain but idk if it would help make the solving of it any easier
Hmm
I suppose the one contextual detail that may possibly help is: the aliens specifically do not want you to find the origin. They know that if you find where North, South, East, and West is of the origin (aka if you have the first image) you'd be able to find it. There is an alien guarding one of these paths and hiding it from plain sight so that you never find it.
The compass has been constructed by humans, and absolutely definitely works - and we can assume that it always does reliably point to the origin - but because of this alien and its "mysterious ability to relate to the metaphysical world", what will be unclear is whether we are in fact getting any closer to the origin, or if we're just going in circles forever
lore reasons
(I do have a more satisfactory answer, but basically lore reasons)
Well, that is actually helpful, because basically what I could conclude from this is one of two (possibly one in the same) thing:
- If and only if the compass always does point to the origin reliably, then the way the real world relates to the origin makes the compass very deceptive. This is because the aforementioned "guardian alien" is manipulating the real world so that humans with the tools available literally cannot physically find the origin, it would be impossible
- The compass is mapped the way it is because that directionality maps to something concrete in the real world - orienting it any differently would make the compass not work in the real world. That suggests the compass needs to be able to map something almost "super real" in order to arrive at the origin, another deception this alien would be capable of
So to explain a little more fully: there are three worlds in this project I'm making, one is "reality", one is sorta like a super-reality, platonic, metaphysical place. "Heaven" basically. It's assumed that math rules over all the worlds - so anything that can be calculated with math is true for both Heaven and Reality, but just because it's not true in reality doesn't mean it's not true in Heaven
There is a reason I'm using the complex plane in this specific example, but I won't go into that 😄
This?
oh wow i didn't expect that to be invisible
It almost feels like the compass has to be sort of clock-ish to actually work correctly
Basically two different hands, one which cares about imaginary, one which cares about real - but they still might have some challenges pointing any particular way
I'll give it more thought and see what I can do with it
Thanks for the help ❤️
(do I have to mark this channel's discussion as finished or something)
.close
Closed by @queen narwhal
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hi I need help with 2ii using the hence method
hence method?
Hence means like therefore
.
@dark dawn Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hi, I'm a little unsure why this is wrong. I was assuming to be independent you needed to sum to 0
And dependent was if it didn't so I interpreted it as "if same direction, then dependent and if it has a counteracting direction then independent"
@broken wagon Has your question been resolved?
Oh that reminds me, it's been 15 minutes
<@&286206848099549185> It's not a rush so please help others if needed and assist at your connivence, thanks in advance
Just ping me when you do
@broken wagon Has your question been resolved?
@broken wagon Has your question been resolved?
@broken wagon Has your question been resolved?
Need help?
Well if possible yeah, I'm just unsure what I did wrong
Top row (left to right):
1. First field: Uniform field pointing right no rotation
Answer: Path independent
2. Second field: Diagonal lines, consistent direction no curl
Answer: Path independent
3. Third field: Vertical vectors only, evenly spaced no curl
Answer: Path independent
Bottom row (left to right):
4. First field: Clear circular flow rotation present
Answer: Path dependent
5. Second field: Another rotational/circular field rotation present
Answer: Path dependent
6. Third field: All vectors horizontal, uniform no rotation
Answer: Path independent
7. Fourth field: Horizontal field again, uniform no rotation
Answer: Path independent
@broken wagon
Oh I see, sorry my eyes aren't too good but I can't recall a 7th field
Unless you mean the 7 attempts lol
???
What
As in, there are only 6 graphs there
Alright, thanks
I got I
U*
- Path independent
2. Path independent
3. Path independent
4. Path dependent
5. Path dependent
6. Path independent
Okay, I apreciiate this, thank you
Did that help
Top row (left to right):
1. Graph 1: Vectors point uniformly to the right → no curl
Answer: Path independent
2. Graph 2: Vectors diagonally increasing → no visible circulation
Answer: Path independent
3. Graph 3: Vectors point straight up → uniform, no rotation
Answer: Path independent
⸻
Bottom row (left to right):
4. Graph 4: Obvious circular rotation (counterclockwise) → has curl
Answer: Path dependent
5. Graph 5: Also shows a rotating pattern → curl present
Answer: Path dependent
6. Graph 6: Horizontal vectors, no swirl or circulation → straight and uniform
Answer: Path independent
So tell me how the 5th graph has any rotation
I really think this is ai
It did
Just help him i can’t rn
If you can't answer somebodies question don't spam llm junk at them.
chatgpt is not a cheat code for reality, and we do not need you to run it for us.
do not post output from chatgpt in this server ever again (unless specifically requested).
did you uhh get it right?
Well I was trying to be polite but that's what I put it initially
So at least one of it was wrong anyway unfortunatly
here is what i think it is
That wasn't it unfortunatly but I really appreciate the assistance
.close
Closed by @broken wagon
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello
When distributing union or intersection why doesn't it switch like from like 4th line to the 5th line?
Comparing it to the 3rd to the 4th line
.close
Closed by @stark shuttle
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Use a double integral to find the area of :
so from the wording of the question it is clear that 3cosθ=<r=<1+cosθ and not the reverse order
my main problem is with determining the bounds of θ
the bounds of theta can be found by finding theta such that (1+\cos\theta=3\cos\theta)
PajamaMamaLlama
$1+\cos\theta=3\cos\theta\implies\cos\theta=\frac 12\implies\theta=\frac{\pi}3+2k\pi,\ k\in\mathbb{Z}$
pirateking0723
i guess that i am fine if i just consider 0=<θ=<2π so that the solution of this equation is θ=π/3 right ?
but then what about the other bound
there's another solution to cos(theta)=1/2 👀
ah -π/3
PajamaMamaLlama
so $\int_{\frac{\pi}3}^{\frac{5\pi}3}\int_{3\cos\theta}^{1+\cos\theta}r\dd r\dd\theta$?
5pi/6?? 👀
pirateking0723
now that can be evaluated using Calc II knowledge :)
well i checked wolfram to get a number quickly so that i can compare it with the given solution
although it is relatively easy to evaluate it by hand
but then it turns out that the answer is different

ah wait, bounds on theta should be from pi/3 to 5pi/3
did you mean to swap them by any chance ?
oh wait yeah lol
because what you wrote here is the same as what you wrote to wolfram 
so the integral now would give 2π
but yeah that's weird
which is positive but still not the desired answer
how did the answer sheet get pi/4?
I am actually so confused what ur prof is doing here
actually this is from stewart's book
well to me it seems that he reached these bounds just after drawing the figure
and didnt figure them out beforehand

really? huh
yea
yeah idk man im sorry I may have overlooked something but I have no clue what I did wrong 
dw man no need to be sorry
instead , tysm for your help
For the first part of the cardioud and the circle
in the upper right quadrant
then taking the area betwen the two ends up just as the normal integral
however, not the the upper right quadrant
as the r = 3cos(Theta) ends up going negative at that point
wdym by the 2 ends
ill send a picture
the ones in red ?
alright
what is solution please
Malika, ce forum est pris, il faut en ouvrir un nouveau
If we take the inegral to be the same as before, then the 2nd part ends up encompassing not just the small bit between the cardioud and the circle, but because the circle has a negativbe radius, we end up counting that negative area as well
its easier to translate into regular graph form
We want the area between the green line, and the circle. That would be whatever area is greater than the black line and less than the green curve for the first part. But when the black line goes below 0 after pi/2. Then the integral ends up counting all that negative area
so i want the area between the green and the black curves but then i will need to split into 2 integrals before and after θ=π/2 and flip the sign of the integral after π/2?
You will have to modify the lower bound of the inner integral to go to the origin instead of the circle
ah wait
after π/2 the area is no longer between the 2 curves but instead between the black curve and the x-axis, ie y=0
yep
thats why the second integral will have lower bound 0 and upper bound 3cosθ (flipped the bounds so that the integral is positive)
the upp bound will still be the 1+cos(theta) as the outer edge is the heart and not the circle
?
well, the idea is clear as the figure is in front of me rn
but i need to figure everything out without any reference to the figure
so that i can solve a question like this without needing a diagram
ik but i think it is troublesome to draw sometimes thats why i usually avoid it
but well maybe i understand a bit without referring to the figure too
the need to split is that 3cosθ<0 for π/2<θ<π
but we dont want to have 3cosθ<0 since this is a radius
is this the correct reason or does this just happen to lead to the result of splitting by chance
For pi/2 < theta < pi, A line from 1 + cos theta to 3 cos theta ends up crossin the circle at 2 points and not just 1 like before
And for pi/2 < theta < pi, the second point that the line crosses is the one at the origin
So any line in between the origin and the heart (1+costheta) is going to be the area instead
@zenith spoke Has your question been resolved?
We want the area between the heart and the circle. So we can think of adding up infinitely many boxes between them. However, because 3cos pi/2 ends up at the origin, that means that the box between 3cos and 1 + cos only needs to go as far as the origin, r = 0 for that point
if r = 0 at pi/2 in this case. Then that means the box used for area will only ever need to go down to that r = 0 for any radius
If I instead took the box from 1+ cos theta down to 3cos theta, then the box will go past the the point at the origin and go through the circle to the other side of it, counting both the area we want as well as the area of the circle as well
as the point of the origin is also a point on the circle
ohhhh i see. This helped me get the idea too
but why does he just stop at θ=π
is it because he only wants to find the area of only one of the 2 bounded regions
and then use symmetry ?
when theta = pi, then the heart thing radius is 0
the 2 small areas are the same, so rather than setting up a second integral that would be almost the same, we can just multiply by 2
yea i agree with this
take your time
I got the integrals, Also I made the ones for if I didn't use symmstry
$A = 2(\int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\int_{3\cos\theta}^{1+\cos\theta}rdrd\theta} + \int_{\frac{\pi}{2}}^{\pi}\int_{0}^{1+\cos\theta}rdrd\theta}) = \int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\int_{3\cos\theta}^{1+\cos\theta}rdrd\theta} + \int_{\frac{\pi}{2}}^{\pi}\int_{0}^{1+\cos\theta}rdrd\theta + \int_{\pi}^{\frac{3\pi}{2}}\int_{0}^{1+\cos\theta}rdrd\theta + \int_{\frac{3\pi}{2}}^{\frac{5\pi}{3}}\int_{3\cos\theta}^{1+\cos\theta}rdrd\theta$
oop
Yeatte
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
lowkey, I do not want to really calculate 4 double integrals
no you dont need to
yea sure
1 + cos(pi) = 1 + -1 = 0
you dont even need to evaluate that
i only wanted to know how to set up the integral
the calculation is left as an exercise to the author 

i still want to know how to set up the integral purely algebraicly (idk if this is a word lol), ie without depending on the figure in any way
but i will try that alone
i wont take more of your time and i now understand why the integral was set up like this thanks to you

Closed by @zenith spoke
Use .reopen if this was a mistake.
.reopen?
ah no i was asking if you wanted to add something 
I just wanted to say, that you should be totally fien with drawing things. At some point you will be drawing things in your head or on paper, especially more geometric arguments like these
I can go through my recent notes, and it's not just equations
its a few drawings as well
the thing is that i am not used to draw these sorts of shapes so i definitely need a bit of time to draw a figure like that
which i dont have in exams for example
yea sometimes i imagine the figure
Here's an exmple of something I drew, even if vague
you dont need to care about the other math, but drawing that pentagon really ends up important intuitively
but i am not sure how to draw a graph of the sort given in this question (r=1+cosθ in this case)
ah I see, that would come down to kinda already knowing what 1+costheta looks like
yea i get what you mean
exactly
it is much easier to imagine it if you already know what it looks like
drawing it in x,y plot and then transferring it to polar or vice versa is a great way to change the perspective and gain insight
like, If I only looked at the xy plot and not the r theta version, there's a chance I might not have caught the trick with the origin
isnt r=1+cosθ something painful in crtesian coordinates
sqrt(xx+yy) = 1 + x/sqrt(xx+yy)
It ends up being somewhat okay, not but pretty
what i mean is
giogn from
y = 1 + cos(x), to r = 1 + cos(theta)
yea exactly
ohhh
you can think of it as taking the xy plot, and wrapping it aroudn the origin
also stretching the higher the y point is
hmmm i see
maybe i have to admit that sometimes a sketch will make life easier when setting up multiple integrals 
but i just hate to draw a figure for some reason
anyway tysm again
.reopen
✅
i reopened it so that we can continue leisurely without being concerned about the channel closing suddenly
you flipped 2π and 0 so that you get the same exact figure as that above instead of a reflection of it right ?
but why does just rotating one half like that give the desired figure
and why does it give a reflection of the desired figure if you just rotate without flipping first
It's not really rotating, but rather stretching around in a circle
And If I stretched first without flipping, then the part on the right side of the graph, the 2pi, would end up on the x axis. But instead of the theta increasing when going counter clock wise, it would be decreasing
If I draw at line at x = 2pi, then its originally vertical, however, after the stretching, it would end up horizontal. So both the left and right parts end up stretching, its just that the left half is stretching and rotated by 3pi/2 while the right part is stretched and rotated by -pi/2
but i dont see any difference, because if you look at it as stretching around in a circle then you wont be changing the radius that you are going in from the original radius right ? at least thats what you are doing here as far as i can see
I say stretching because although it would be the same radius from the origin, if we take a y=1 line and a y= 2 line. the distance between (0,1) and (pi,1) aroudn the circle ends up being pi. whereas if I took the points (0,2) and (pi,2) from the y = 2 line and stretched it around the circle, then the distance around the circle of radius 2 would be 2pi for and not pi like the first line
If I instead took the graph y = 0, and looked at the points (0,0) and (pi,0), the distance between them is pi. And then when stretched around the origin, they end up at the same point
so the distance between (0,0) and (pi,0) -> (r = 0, theta = 0) and (r = 0, theta = pi) ends up being 0. so compresssed
,rccw
the distance gets distorted when transforming functions from a y = f(x) to a r = f(theta) setup
lowkey really interesting math that goes on behind the scenes here
consider 2 points a, and b on the y = 2 graph
And we consider the distance between them along that y = 2 line
Let a = (0,0), and let b = (pi,0).
Then the distance between them along that line is just pi
However, If we then move that to the r = 2 space.
And take the distance along the r = 2 line. we end up with something else
As these 2 points are halfway across the circle. and we are only allowed to move along the r = 2 function. Then we calculate half the circimcfrance. So D' = C/2 = 2pir / 2. And as r = 2. that means that the new distance between these two points along the line r = 2 is D' = 2pi, where as D = pi
So as distance is not the same in this transformation. I would say stretching rather than just rotation
You can alternatively think of this as calculating the length of the line from A to B
u there?
by this sentence you mean to take the "usual" distance between (0,2) and (pi,2)
yep
it might be better to think of it in terms of a line between those 2 points ctually lel
ohhh i see your point
yea if you look at it like this then it is reasonable to call that stretching
well you can consider the arc between these 2 points in the r=2 space as a line between them
because that is actually what a line in this space look like right ?
yep
i suppose that such transformations are studied in topology ?
idk maybe i am wrong since i am not familiar with topology
i barely have a vague idea of it
I haven't done topo yet, but I know this sort of thing is doen in differential geometry
ohhh
which was what the formula from before was a part of
i see thats nice
The idea of distance, and how that changes is a pretty big part of it
what are you studying these days
I think I've put it on the back burner for now, as my source material and most source materials online don't really have a great answer for my question on it
It ended up being a question of "why am I using the numbers in this way? what does this intuitively mean?"
So I've gone back to doing analysis which I should've done a while ago
yep
real analysis ? or you've already done that?
real analysis, my rigor was really lacking early on in my math, and I'm paying the price for it
-1/12 if you know you know
so I'm building from the ground up to get better at that
i didnt get this ngl lol
do you have any advice for how i should go about the class
ah i see yea math gets too rigorous as get deeper
Read this too: http://www.bradyharanblog.com/blog/2015/1/11/this-blog-probably-wont-help
More links & stuff in full description below ↓↓↓
EXTRA ARTICLE BY TONY: http://bit.ly/TonyResponse
The sum of all natural numbers (from 1 to infinity) produces an "astounding" result.
ANOTHER PROOF & EXTRA FOOTAGE: http://youtu.be/E-d9mgo8FGk
MORE: ht...
i am studying real analysis too
ah yea i know this
rearrangement
nice
you cant play as you like with any infinite sum
fortunately I found this sereis
there have to be some conditions for you to be able to rearrange the terms as you like
(absolute convergence)
$\sum_{n=1}^{\infty}{\frac{1}{n^2+1}}$
Yeatte
this really helped me out
i am not sure if i can say something helpful
^
but i recommend that you go through the proofs of the propositions/theorems by yourself
so pick up the theorems of the course
try to prove them yourself
check if your proofs are correct/ if they dont exactly match that doesnt mean that you are wrong so ask on this server for example or something like that
how did it help
it helped you know when you can rearrange and when you cant?
yeah this server seems like a really good resource
ohh i see
yeah mickey mouse clubhouse university bottom 10 stem school
rn my university is trash too lol but i will try to get into a better one
that being said, it doesnt mean anything for the only thing that matters is your work to understand the topic
before, I though that I could do whatever I wanted with any series, after rearranging, I ended up getting 1/2 + "zeta(-2)" + "zeta(-4)" + .... assuming I could do the things I thought I could and so i would get 0 for each term except the first. But a sanity check told me otherwise. that I needed to be careful
as 1/nn+1 def convergeed to more than 1/2
so I knew the only step that was wrong was assuming finite values for the zeta 'series' and manipulating those without worry
yea it gets tricky with infinite series
I also accidentally foudn the solution to the suum anyway lel
one can easily get something totally wrong just by assuming that usual manipulations for finite sums work just fine for infinite ones

btw are you a math major ?
I am a bakery worker
oh thats nice
I'm not in college for various reasons, so i study on my free time
everyone has their hardships/reasons for not doing something
i hope you can bypass all of your problems
and btw you dont need college to be knowledgable
well you are the best example
you were just teaching me

I took a break from it for a while, but I couldn't stay away
I finished up some ideas from hs for physics and it ended up leading me down a rabbit whole all the way to diff geo
ohhh
electromag is really nice
in my opinion most of physics is really nice
ignore air resistence
this might be happening cuz like infinity kind of wraps around
well not really but
there was a point in time where i was choosing between pure math and theoretical physics
the part that i hate in hs 
you know how in computer science once you get to the end of the signed digits and you keep increasing you actually end up wrapping around
well not too long ago since i just started university some months ago lol
I should prob go back to college hm
well you know whats strange about series like this , you can literally get any number that you want
I heard bout that ye
if you can then i encourage you to
i think that maybe it is better to close this now that we are done from everything (probably) since it is a help channel
nice to meet you yeatte
aye, and to you too
we will probably have more encounters in the future since we are both in this server xD
i am looking forward to it
🙂
Closed by @zenith spoke
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I need help
alright, so you can prove it like this
think about it
anytime you draw a line between two points, what are you doing in terms of their odd/even degrees
@muted sapphire Has your question been resolved?
Closed by @muted sapphire
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
i need help
where's it from?
green is middle
because rule 3 says, you need to do VGB or BGV, so green is not 1 or 5
but if it's 2 or 4, then rule 4 doesn't allow it
hm
so like, PBGVG?
it doesn't make sense, there's only 4 colors, so I don't even have to use pink
alright
.close
Closed by @fathom hound
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
OK, the easiest way will be a Venn diagram.
Have you done this sort of thing with one before?
Hmmm, nah.
I have done probability before, but not question like this where there is incomplete data
OK, draw a Venn diagram with three circles.
One circle for discrete math, one for statistics, one for linear algebra.
Okay, then?
OK, now we work from the center out.
How many take all three? Write that in the middle.
Okay, it's 1
OK, that was the overlap of three circles. Now we do the overlaps of two circles.
How many take statistics and linear algebra?
It's 3
OK, so the overlap of S and L circles has two parts in the Venn diagram.
If you lightly shade it in, you'll see that.
So, we have those two parts of the Venn diagram adding up to 3.
So, something + 1 = 3.
Write that something in the unfilled-in part of the overlap of S and L.
Okay, that's 2
OK, so write that in. Then, we look at the overlap of L and D.
How many people take both linear algebra and discrete math?
I don't know, the data is not included in the question
OK, so there are two parts of the Venn diagram for this, so write x in the unfilled in part.
What about D and S? How many people take discrete math and statistics?
It's also not included...
OK, so write in y for the unfilled in part.
Now let's do the circles themselves.
How many people take statistics?
11
OK, so the four parts of the S circle should add to 11.
So, what will the unfilled in part be?
8 - y?
19 - x
OK, what about D?
28 - x - y
50
OK, so add up all the parts, set it equal to 50, and simplify the equation as much as you can.
I get x = -y + 8
OK, so x + y = 8.
Then, I guess you can simplify the D alone part of the Venn diagram.
I can't see any more simplifications.
Oh, wait.
Let's see.
Never mind.
OK, from here, you can do part a, but I don't see a way to get b and c.
So, does this mean there is no answer for b and c?
There might be a way to get another equation with different coefficients for x and y when you simplify it so that you can solve simultaneous equations, but other than that, I can't see a way.
Right now we have x + y = 8.
From the five statements they give, all except the discrete mathematics one lead to no variables when simplified, and the discrete mathematics just gives us x + y = 8.
I suppose you can replace y with 8 - x.
Hmm.
It might be even worse than that, since the first sentence implies that it might not be all 50 who take at least one of the three courses ("Out of 50 students in a campus, there are several students..."). That can't refer to students that take all three, since the one student who does that isn't several students.
@daring depot Has your question been resolved?
I'd recommend answering b and c with something like: "If we take x as the number of students who take discrete math and linear algebra without taking statistics, the answer is whatever/50."
x could also be written as |D n L n S'|.
Closed by @daring depot
Use .reopen if this was a mistake.
You're welcome.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Oh wait! |(D u L) n S'|.
.close
Closed by @strange nimbus
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Need help with this geometry problem
.close
Closed by @cedar merlin
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Pls only give very subtle hints
I need to use 4k-2 and the factorials in some way, probably by multiplying
@thin geode Has your question been resolved?
i got it
multiply 4k-2 with k-1
factor out the 2 and put it into the k-1
makes 2k-2
@thin geode Has your question been resolved?
look at the factorials
see if you can rearrange(4n-2) * (2n-3)!/(n-2)! to be (2(n+1)-3)!/((n+1)-2)!
if you do that you're done
try expanding the RHS
@thin geode Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Someone please dm me if they are willing to help me with my pre cal hw it’s just 2 questions
Just ask them here?
I’m desperate istg
Just send the questions
ask your question here
Send your question here
set x + 5 = 0 and y = 0, those values of x and y are your centers
this ellipse is basically shifted
I honesylu don’t know what’s going on 😭
all the properties remain the same, but all the points on the ellipse have been shifted 5 points in the negative direction
okay let me graph this
in standard ellipse form
$\frac{(x - h)^2}{a^2} + \frac{(y - k)^2}{b^2} = 1$
the center is (h,k)
mia
this is a normal ellipse, with it's center being (0, 0)
now that is the same ellipse but it's shifted 5 units in the negative x direction
This is a sample question we did in class
all the points, the focii, the end points are just shifted 5 units in the negative x direction
that's all there is to it
I’m still so confused 😭
Learn how to graph vertical ellipse which equation is in general form. A vertical ellipse is an ellipse which major axis is vertical. When the equation of an ellipse is written in the general form, we first rewrite it in standard form using completing the square.
After the equation has been rewritten in the standard form, we then graph the vert...
@final forum Has your question been resolved?
Not yet
It’s not close to the question ☹️
This algebra video tutorial explains how to write the equation of an ellipse in standard form as well as how to graph the ellipse when in standard form. It explains how to find the coordinates of the foci, vertices, and co-vertices. This video contains plenty of examples and practice problems.
Get The Full 1 Hour 55 Minute Video: ...
Ig that's exactly what r u looking for
This guy is the best
Physics, calculus, chemistry 
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I’m really struggling to understand maclaurin and Taylor polynomials does anyone have some resources I could use ?
khan academy is always a good place to start
@winter meadow Has your question been resolved?
Closed by @winter meadow
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
when ur constructing the table
it would be better with a venn diagram tbh
3-way tables are kinda tricky
ah they use a table in the mark scheme
Ok i'll try that
even that sounds kinda tricky
ah
how many bubbles should there be
i mean circles in the venn diagram
idek
@opaque talon Has your question been resolved?
for iv
on the denominator
i get an extra 0.15
cuz not S is 0.35+0.15
and not T is 0.15 + 0.15
idk
look at it in terms of the overall area
this is the part signified by S' union T'
this should rule out the extra 0.15
np
idk if u have any tips for the venn diagram here as well? 😅
oh that wasnt answered yet?

