#help-39
1 messages · Page 327 of 1
chill bro
it is
there we go yea
i will take that
so now 30+a2=b
b is 50
so a2 is 20 degrees
a2=50-30
hold on
now what>
what else do you want help in finding
ok we whole of angle A is80 degrees
no its 50
and 03 would be 50
no
it will be 80
noo
my guy could i just call you and speak
30+50
it will be easier
it looks like youre getting confused with the total measure of angle A and the measure of the two angles that make up A
alright u can just speak
@sacred python i need to verify
you can talk
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doesnt log(e)=2. somethin
but in the question log base 10 is used
where's the original question?
and the log is for sure base 10?
oh. in that case, you are taking the natural logarithm of both sides. that is fine.
wont that give ln(z) instead of log(z)
here
the log here is actually a ln. some syllabi do that.
ah
I would probably check back on the text to see what the default base of your log is.
i did not know that
for us its normally 10
in most calculus courses the default base of a logarithm is e, not 10.
then you may want to approach your lecturer/teacher about this notation.
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,,, this is a test
.close
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,,, amazing
frowny

@minor cloud
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,tex aaa
Let $ABCD$ be a rectangle. Let $K$ be a point on $AD$, let $E,F$ be points on ray AB,DC respectively such that $AE=CK$ and $DF=BK$. Let $P$ be a point between $AB$ and $ CD$ such that $\angle KCD = 2 \angle PAB$ and $\angle KBA = 2 \angle PDC$. Show that $PE = PF$
Copter
uhh from my diagram the lines with the same color are parallel
AP is parallel to the angle bisector of KCD, etc
Let C' be the point on BC such that BC'DK and AC'CK are parallelograms to construct E and F
i dont really have progress on this xd
im guessing this is an angle chasing problem? but idk how id do that
<@&286206848099549185>

bmo?
Did you manage to solve the P3 from Balkan?
is it?
I see
anyway
how'd u make tht
@north talon Has your question been resolved?
question aside how you made ts
@north talon Has your question been resolved?
yea
Try looking at <BAC1 and <DCK
The same for <CDC1 and <ABK
Fun Fact: ||KP perpendicularly bisects EF||
@north talon Has your question been resolved?
<@&268886789983436800>
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Hi
What have you tried so far?
I've tried doing it myself, I gave up after 10 mins so I tried using chat gpt
Even that didn't work
well, the good news is that there are already no negative exponents
True
No matter what I put in, it won't work
do you know basic exponent rules?
Sorta
for example, how would you simplify (27)^(2/3)?
3 to the square root of 27?
Then uh
Idk
try thinking of the exponent 2/3 as (1/3) times 2
Alr
2/6?
I have no clue
okay
now use this
its an exponent identity
(we are only working with 27 right now)
you can try the other 2
its the same thing
got anything?
9a^6b??
OMG
I can't believe it
This is what happens when you're sleep deprived bruh
Lmao
@harsh adder Tysm bro. I still got one more
sure
Alr
if you get stuck anywhere @ me
4^8b^9?
4^8?
what happened to a
nope
write 4 as 2^2
and same thing as last question
<@&268886789983436800> @willow epoch
Ofc
most intelligent discord user:
this has gotten boring now
How hard is it not to fall for those scams bro
Sorry
yea the scam
Oh alr
we need a smth new
maybe they dont need to refer to mrbeast
i guess
@harsh adder I'm lost
which part
can you show your working
if possible
ill tell you where exactly you're going wrong
that will help you better
4^-8 is kinda incorrect
we wrote 4 as 2^2 and then simplified it
to make it 8
so 8 is the first term here
like in the prev q it was 9
I keep forgetting the a
Fuck
@harsh adder Ok I don't know what I'm doing
I think I need to go back to step one
OK
I GOT IT
YES
o
TY!!!
Yea but you helped me so much
I was stuck on that god awful question for over half an hour
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Pairwise distinct points A, B, C, D, E, F, G, W1, W2, W3, W4, W5, X1, X2, X3, X4, X5, Y1, Y2, Y3, Y4, Y5, Z1, Z2, Z3, Z4, and Z5 on a plane satisfy AW1⟂W1X1⟂X1Y1⟂Y1Z1⟂Z1G, AW2⟂W2X2⟂X2Y2⟂Y2Z2⟂Z2G, AW3⟂W3X3⟂X3Y3⟂Y3Z3⟂Z3G, AW4⟂W4X4⟂X4Y4⟂Y4Z4⟂Z4G, AW5⟂W5X5⟂X5Y5⟂Y5Z5⟂Z5G, BW1⟂CX1⟂DY1⟂EZ1⟂FG, BW2⟂CX2⟂DY2⟂EZ2⟂FG, BW3⟂CX3⟂DY3⟂EZ3⟂FG, BW4⟂CX4⟂DY4⟂EZ4⟂FG, BW5⟂CX5⟂DY5⟂EZ5⟂FG, and AG=2026. Find the product of the lengths of AW1, AW2, AW3, AW4, and AW5.
Just send a picture.
And what have you done?
@viscid dew Has your question been resolved?
give the actual problem in a pic.
and ofc, a diagram.
there's no picture / diagram
Hlo guys
wha, what?
Please provide a screenshot of original question.
ok so from here we can tell that E, Z2, Z5 are collinear
I can't read all that
no, not yet
i did realize what this meant B, W1, W2, ..., W5 are collinear, and similarly for the others
weull uh, since B, C, D, and E don't change as it goes through W X Y Z 1-5 and are perpendicular to FG, we can assume W1-5, X1-5, Y1-5, and Z1-5 are linear
now what do the lines W1X1, X1Y1, Y1Z1 tell us
W1X1 and Y1Z1 are parallel?
ignore this
the lines are perpendicular with common points
so they're kind of either zigzags or squares or smth like that
the lines specifically
also nvm they are
mhm, right
assume W1-5, X1-5, Y1-5 and Z1-5 are arranged like in a square grid
like 5 by 5
4 by 5 woops
draw them out
well, but actually the W's would be on a horizontal line, and then the X's would be on a vertical line, right?
honestly
dunno
my brain fried
u can ask sum1 else mopre imaginative than me I'm out of ideaas
yep the Z would also be on there
would it look something like this
so like draw 2 columns and 2 rows W1-5&B Y1-5&D and X1-5&C Z1-5&E
yeah prolly
swap the W1-W5/mirror it and the bottom
and you should get what ur prolly looking for
this?
yes
so now wait
W1X1, X1Y1 yeah that should be riht
right
what it looks like
now place A hey wait a minute
A is like, non-existent 😭
wouldn't A be in line with the Ws and G in line with the Zs?
i mean, AW1 is perpendicular to W1X1
what if you shift W5-2 lower kinda forming like a diagonal thing
do the same with Y- yeah no that doesn't wok
work
@viscid dew Has your question been resolved?
@viscid dew Has your question been resolved?
@viscid dew Has your question been resolved?
Are you still stuck?
yah
Where?
i mean, i haven't really tried more, since i don't know what to do
basically just labelled the points
the W points, X points, Y points, Z points are colinear (in each set), and are like perpendicular
Well, I read from the question.
For any index i = 1,2,3,4,5, the conditions described that 2 orthogonal paths.
What if we identifying these 2 parts?
Maybe try from vertical - horizontal chain.
oh, i forgot to include the given information that AB=1
.close
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I need assistance with doing 10-20 questions really fast, they are very basic, but neither me nor my friends can do them fast enough. I am not completely sure how I would get assistance with them in this channel as I would need to screenshare them to you though.
just screenshot one problem at a time and send your work with them
like it says here
The issue is that this is an interesting scenario.
this still applies
Sounds suspiciously like a test😭😭
There is a boss that has its health attached to math problems, I am doing a strat with friends, I can do the math fast enough, but they cannot.
The math problems are split across 3 people and its been an issue.
One of them is on console so they cannot send images of the math problems.
He can only screenshare them.
where is the actual math question
This image is only used to display that I am not taking a test.
then just follow this
I can't, they are extremely basic and are during a time constraint. If we were to type them out, we would lose by the time we get the answers.
can't help if you can't ask the math question ¯_(ツ)_/¯
That is why I wished to screenshare them to you.
I have already explained as to why that is not an option.
Just give a couple examples so we know what kind of problem we deal with
Not even a screenshot
Just state an example
Here is one taken from the pool. (This is the most difficult type of question that it gives.) with a 4-7 second time limit. The rest can be as easy as 4+5+8.
I do not have an issue with them, but my friends do, and they need assistance.
practice
Actually that makes the game rly good cuz if you do this over and over again you get better
This game has absolutely nothing to do with math, It is a random throw in enemy that has no reason to be here other than this singular boss.
A good way to practice then might just be to spit out examples to each other and get them to answer as quickly as possible maybe
You can also definitely automate making these kinds of problems
An issue is they also have to focus on micro-managing their units while doing problems which is an issue
Well it is clear I am not getting assistance here.
.close
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i know that the number must be odd and not divisible by any primes up to 7, but i cant figure out anything more than that
ive set up a series of representations of these divisions and remainders using modular arithmetic but i dont know where to go from there
my first instinct is to do something about the system of congruences using CRT.
please show what you have tried so far for other helpers to know where to start :)
well obviously the integer in question is odd since it has a remainder of 1 when divided by 2
and ive basically written
n ≡ 9 (mod 10)
n ≡ 8 (mod 9)
n ≡ 7 (mod 8)
etc.
also i tried thinking about like
doing 2^2 * 3 * 5 * 7
and then that minus 1
thats what my intuition told me but it didnt work
hint: this system can be written another way such that the congruences end up having the same remainder mod each divisor.
only works for the division by 10 case
-# Chiaki you are green!
ohhhh do you mean like writing n+1 divides 10, n+1 divides 9, n+1 divides 8, etc.
close!
you are indeed going to have to do something with 1. but it might not be a +1 that you're looking for.
well I sense another helper is about to come in and take over, so I'll leave this to the other helper.
another way you can think of this is since n+1 has to be divisible by all numbers 2-10, what's the smallest number thats divisible by all of those?
yeah thats what i was saying sorry i mixed up n+1 divides 10 and 10 divides n+1
can someone help me understand how to solve this? its on my test tomorrow morning
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
and how would you go about getting that number?
ig its just 2^3 * 3^2 * 5 * 7 right? since that covers all factors
-# crossing out this if you're following Krish's method.
yeah that works perfectly i think
2519?
was just going to say n+1 equals that number but you got it!
yep
imo thats the most simple way to do it but if you want to try to learn chiaki's method you can go ahead and do that
learning this actually helps with a problem i got stuck on before that which i think is another system
so imma go do that one rq and see if the same method works
yep works with that too
!done?
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I have a desire to know what every math symbol means. (I am running short on time but will return in the near future).
In which field?
Sets, or..?
can you send some examples of ones you don't know?
Sure thing.
One sec
it would be much a better usage of your time to just learn the math you want to learn
there is nothing deep about the symbols
you'll learn the symbols as you go
gamma isn't really a "symbol"
Yes... but I am unable to work the math currently (I can mentally) but not on paper. So DOING the math becomes more difficult.
just a variable name that's used for a function mostly
well for the E, it says what it is in the title: "is an element of" and it refers to sets.
The first one is just an element that belongs to a set.
Ok... what does an 'element' mean. Or 'set'?
The Pi one is for products, right?
the capital pi is similar to sigma notation, except instead of summing it means a product
not sure what you mean
what math have you learned so far?
I have no paper nor pencil at this moment. Not any surface where I can work complex problems out.
you can just read actual math texts and try some of the problems
and of course, lowercase pi is just the ratio of a circle's circumference to its diameter
Hmm. For the Gamma one, I don't think it is used much in math, but logically it's stand for basis.
thats gonna take forever
It might, but an edge is an edge.
Which is "already knew some conditions".
doesnt gamma(x) = (x-1)!
an edge?
To get ahead of others.
Never heard of that unfortunately.
brother
for only x belongs to positive integer
😭
ive heard of it once or twice but never really used it
Well Gamma mostly used in CS.
It does if we see them...
,w gamma function
Or in Lambda Calculus.
that really won't help you if you don't do any problems involving it to understand it
oh yeah true
people that have "an edge" over you in math aren't wasting their times stroking their egos thinking that learning symbols makes them smart
Well, I see it commonly displayed on papers that I aspire to be able to write
they are doing problems and learn whatever symbols show up
For, example: $\Gamma \vdash B: C$.
Mercury (ヤフォダ)
right, but you won't be able to write a paper if you don't know how to use the symbols
damn i completely forgor all of lambda calc now 😭
That's why I am trying to learn.
knowing the definition is one thing and knowing its application is another
You want things to be clear, not too confusing by applying symbols.
They avoid using too much symbols for some reasons.
more symbols in a math problem =/= more knowledge on the topic
or complexity
Can we start with Element for now?
Just help the guy already
in what context? we don't know what you have covered and what you haven't
-# except the lagrangian model for particle physics
Ouch
Assume I have never seen this symbol in my life... (Because I have no idea its application nor definition)
But do you need it yet?
well, have you seen any sets before?
No, I have not.
But, I have seen it
have you taken algebra?
have you ever seen any of these?
youtube video?
I have seen R, N, and X.
or anything in notation {x1, x2, x3, ...}

I am unsure I am well versed enough to distinguish a 'set'.
fahhh
insert the who is he gif
Ok, so what is a 'set'?
In mathematics, a set is a collection of different things; the things are called elements or members of the set and are typically mathematical objects: numbers, symbols, points in space, lines, other geometric shapes, variables, functions, or even other sets.
Mathematics typically does not define precisely what constitutes a "set" or "collection...
I mean U is legit for some cases.
Ok, how would I notice this or apply it?
apply it to what?
You know more than I do...🥀💔
I don't know. When do we use this?
well its used in a variety of classes in different ways. discrete math, calc, linear algebra, stats, computer science
Alright, would it be better for me to ask: How do we use it in algebra?
uhh well you would probably see it in like a set of solutions to a given function, or domains of a function
for example if you had a function:
$f(x) = \frac{1}{x-2}$
Krish
the domain of this would be ${x \in \mathbb{R} : x \neq 2}$
Krish
and this reads as follows: x is in the set of Real Numbers, such that x is not equal to 2.
or "x is an element of the set of Real Numbers, ..."
Ok, I see now.
i guess you could also make a solution set for solving an equation for a variable
$x^2 = 9 \implies x \in {-3, 3}$
Krish
Oh, so Element refers to (in this case) what the 'x' could be?
Krish
Krish
which would evaluate to false.
theres also an "opposite" of this symbol, which means "is not an element of"
$4 \notin {1, 2, 3}$ evaluates to true.
Krish
Impossible
So, how does $4\in {1, 2, 3, }$ evaluate to true but the other not?
because this is saying "4 is an element in the set {1, 2, 3}"
Kira1sJustice
this is saying "4 is not an element in the set {1, 2, 3}"
because 2 is in the set {1, 2, 3}
Ok, I understand now.❤️
simply its asking:
you have the set {1, 2, 3}. do you see a 2 in there? yes? then its true.
And, in the instance with a variable all it requires is solving, and then finding that number to the variable in the set. Right?
yes that is usually the idea
however like i said that's not the only way sets are used, there's different uses depending on what class.
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ofc!
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Not really sure how to attempt the inductive step
for future helpers, please show your current progress.
you're good so far.
now, you have to show that the RHS of your current inequality is \geq the RHS of the original inequality given n = k+1.
so would be have to compare them?
mhm.
and subtract
subtraction is the right move here, but depends on what you subtract. best to continue your work and we'll see.
sure.
Thank you!!!
quick question tho
is this like the method i should always use for these type of inductive questions? (proving inequalities)
hmmif u can could u like explain maybe a case where it could be different
if not its fine dw
I can't think of one off the top of my head, but I also don't want to nail it down completely lest there is an edge case I never thought of. I'd rather not spread misinformation.
sorry.
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so this is what i have so far
$\sum_{k=2}^{\infty}k\left(k-1\right)a_{k}x^{k-2}+\left(1-2x^{2}+\frac{2x^{4}}{3}\right)\left(\sum_{k=0}^{\infty}a_{k}x^{k}\right)$
so im not sure what to do next im supposed to mulply 1 - 2x^2 + 4/3 x^4 by the terms from a_k x^k up to k=4?
water beam
@wild fable Has your question been resolved?
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<@&268886789983436800>
List to make 20 biscuits
260g of butter
500g of sugar
650g of flour
425g of rice
How to find the mass of rice as the percentage of the mass of sugar
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You gotta make a new channel, sorry
This one will close
he a mathematician 😢
No mathematicians in my server 
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hey how can i solve for every $c_k$ the system of equation $c_1 + c_2 x_k + \cdots + c_n x_k^{n} = 0 $
akbar_m3gaz
Given the value of roots?
Using vector and matrix?
Like solve for c(k) using what info?
I think he is asking for a general solution of any polynomial ☠️
the polynom $$P(x) = \prod_{i=0}^{n} (x - X_i) = \sum_{i=0}^{n} a_k x^k$$ i want every $a_k$ expressed with all the $X_k$'s
Ohhhhh
akbar_m3gaz
Vietas relation
thanks
Ye just find it on Google there's many sources explaining it
Yeah it is very interesting and long
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What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
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
1
A translate would be much appreciated.
Renato
You should have a formula for the average value of a function in a region in your notes.
What’s causing you trouble then?
Have you sketched the region?
its a disc and x >= -y and y >= 0
Umm i have a doubt regarding math and mind
Can I ask?
!occupied
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It is. If you draw it you should see that it’s just a sector of the disk
help please
Polar coordinates 🥀
care to elaborate?
Youll have to solve w/ polar coordinates
why
mostly cause this is a slice of a circle.
why
Polar coordinates just behave really well with circular regions
It makes the actual computation more manageable (and sometimes possible in the first place).
So this is why you should draw the region and figure out how you’d express it in terms of r and theta (instead of x and y)
how
Draw the boundary curves of the region
x = -y
y=0
Then shade the appropriate region. It should make it clearer that it is a sector of a circle.
Then you can either try to delimit it in r and theta visually, or you can use the equations x=rcos(theta) and y=rsin(theta) for polar coordinates and see what the inequalities for your region translate to.
this?
That’s not the portion with x >= -y.
You can check that (-1,0) doesn’t satisfy that.
yeah
Why is x=0 delimiting anything ?
Try graphing the 3 conditions as regions, and find the intersection of all three.
easy to say
pretty easy to do too
Careful with signs and inequalities
Not quite
You need y>= 0 though.
You want the region which is above the line y = -x, above the x axis, inside the circle.
I CANT
Well just draw the three inequalities and take their intersection like laplace said then.
If anything just indicate with an arrow the side of the lines you’re keeping
can u help
Can you graph the region x² + y² =< 1?
If you just take the time to do it instead of trial and error you;ll understand.
Draw the three inequalities y >= -x, y >= 0 and x^2 + y^2 <= 1
i have trouble with y >= - x
help
i can draw y = -x
but idk y >= -x
You can usually consider that the line y = -x divides the region which doesnt belong to that criteria from the one which does
So, try a value above the line and one below
Just test a point on one side of the line to see if it satisfies the inequality
Any point that isn’t on the line.
0-1 and 10
Right so which one of those satisfies the inequality
10
So that indicates which side of the line your inequality is describing
The side which contains the point (1,0)
It should be easy to graph inequalities if you’re doing multivar calculus
Anyways
So now you have your region.
If you can guess right away from the graph the way you would express this with r and theta, then you should do that.
If not, then consider the inequalities y>= 0, x >= -y and x^2 + y^2 <= 1 along with the polar coordinate equations x = rcos(theta), y= sin(theta).
don't bully I'm new to calc
how?
sin(t) >=0, cos(t) >= -sin(t), r <= 1
It was not a dig at you. I'm just saying that this will come up a lot, first with 2D regions, then with 3D regions, and you should either be already comfortable with dealing with them, or get used to them urgently.
r is less than or equal to 1 and angle is 90 + 45 deg
Yep
what about it
anal is hard
Yes
unsure
Well that's it. sin(t) >= 0 just means your angle should be in [0,pi].
sin(t) >= -cos(t) just means your angle should be in [-3pi/4, 3pi/4]
r <= 1 tells you r is in [0,1].
So taking the intersection for the angles you need it to be in [0, 3pi/4].
how?
trig scary
They're the same equations as your region. It should make sense that the angle in the disk is restricted to [0,pi] by y >= 0 and that it's also restricted to [-3pi/4, 3pi/4] by y>=-x.
yep
nice
now what
?????
@summer imp
If youre tasked with using polar coordinates you should start practicing for trig.
You're looking for the average value of f(x,y) = x+y in this region.
don't bully
So now you need the area of the region first.
Can you compute that (without an integral)?
2/3?
angle is [0, 3pi/4]
r is [0,1]
Do you remember the formula for the area of a sector?
3pi/4 is A(R)
To get the area of a sector you multiply the area of the disk by (sector angle)/2pi.
Idk why you would expect this to be the area
,, A_s = \frac\theta2 r^2
lets just use integrals please..
You don't need integrals to find the area of the sector of a disk (not that it's particularly hard)
Can you set up the integral to calculate the area?
yes
Can you write down the general double integral for the area of any region?
,, \int \int_R f(x,y) dydx
Renato
Thats for the cumulative value of f(x,y) over R
we want the area of R
Notably, theres a really specific """function""" that gives you the area of a region.
just 1
,, \iint_R 1 \ dydx
Now, what happens if you translate this to polar coordinates?
Renato
unsure
Do you have notes on polar coordinates?
r = 1
Mostly, how to move from cartesian -> polar
You should have seen in class how to integrate regions over polar coordinates.
what about it?
You should prob have some notes on |J|, the jacobian determinant of the transformation
So, what happens when you move from dxdy -> dθdr to our previous ""function""
1 -> r
Write down the integral
$\iint_R r \ d \theta dr$
Renato
And what are the bounds for "R"
hard
Its what weve been discussing at the start.
,, \int_0^1 \int_0^{3\pi/4} r \ d\theta dr
Renato
And now solve
how?
As any other double integral?
Go from the inside to the outside, compute the antiderivatives and evaluate, etc...
Good.
Now similarly compute the cummulative value for the function f(x,y) = x+y you were given.
how
use polar coordinate transformations x = rcosθ, y = rsinθ to get the function you wanna integrate alongside with the same bounds
i dont follow
You just did $\iint_{R} \dd{x}\dd{y}$. Now you need to compute $\iint_{R} (x+y) \dd{x}\dd{y}$.
Azyrashacorki
Same method with polar coordinates. x=rcos(theta), y=rsin(theta).
is there any tricks to skip that and go to the result
You forgot the jacobian
Nobody has introduced you to Fubini's Theorem/Rule?
Sign error for -1 here in any case.
wdym
Should be -cos(3pi/4) - (-cos(0))
fuck this shit broo
Ill spoil it to you
,, \int_0^1\int_0^{\frac{3\pi}4}(r\cos\theta + r\sin\theta)\cdot r\ d\theta dr = \int_0^1\int_0^{\frac{3\pi}4} (\cos\theta + \sin\theta)\cdot r^2\ d\theta dr =\ \int_0^1 r^2 dr \cdot \int_0^{\frac{3\pi}4}(\cos\theta + \sin\theta) d\theta
is illegal
It's not. It's just a consequence of Fubini's theorem you've learned about.
care to elaborate
ngl i dont recall what are all the conditions on Fubini's
Big corollary which will prob be corrected:
If a function $f(x,y)$ can be written as the product of two functions, $g(x)\cdot h(y)$, and you have a region $R$ where the bounds are constant\par --- $(a\leq x\leq b) \wedge (c \leq y \leq d)$ --- then:
$$\iint_R f(x,y) dx dy = \int_a^b g(x) dx \cdot \int_c^d h(y) dy$$
There are a few ifs and buts, but in general this is the idea.
In reality Fubini's Theorem is this huge thing that allows you to draw a lot of conclussions for calculus & real analysis.
You should know what sin(3pi/4) and cos(3pi/4) are.
trig scary
.
,w 8 /(3pi) * 1/3 * (sin(3pi/4) - cos(3pi/4) + 1)
.solved
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anyone here
xan anyone help
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
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I keep getting this wrong, where did I mess up ?
Your setup here means that you essentially calculated the integral of -|2-x| instead
Dropped negative
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Hi does anyone have free
simply ask the question
Ok
Two right circular cones with vertices facing down as shown in the figure below contain the same amount of liquid. The radii of the tops of the liquid surfaces are $3$ cm and $6$ cm. Into each cone is dropped a spherical marble of radius $1$ cm, which sinks to the bottom and is completely submerged without spilling any liquid. What is the ratio of the rise of the liquid level in the narrow cone to the rise of the liquid level in the wide cone?
[asy] size(350); defaultpen(linewidth(0.8)); real h1 = 10, r = 3.1, s=0.75; pair P = (r,h1), Q = (-r,h1), Pp = s * P, Qp = s * Q; path e = ellipse((0,h1),r,0.9), ep = ellipse((0,h1s),rs,0.9); draw(ellipse(origin,r*(s-0.1),0.8)); fill(ep,gray(0.8)); fill(origin--Pp--Qp--cycle,gray(0.8)); draw((-r,h1)--(0,0)--(r,h1)^^e); draw(subpath(ep,0,reltime(ep,0.5)),linetype("4 4")); draw(subpath(ep,reltime(ep,0.5),reltime(ep,1))); draw(Qp--(0,Qp.y),Arrows(size=8)); draw(origin--(0,12),linetype("4 4")); draw(origin--(r*(s-0.1),0)); label("$3$",(-0.9,h1s),N,fontsize(10)); real h2 = 7.5, r = 6, s=0.6, d = 14; pair P = (d+r-0.05,h2-0.15), Q = (d-r+0.05,h2-0.15), Pp = s * P + (1-s)(d,0), Qp = s * Q + (1-s)(d,0); path e = ellipse((d,h2),r,1), ep = ellipse((d,h2s+0.09),rs,1); draw(ellipse((d,0),r(s-0.1),0.8)); fill(ep,gray(0.8)); fill((d,0)--Pp--Qp--cycle,gray(0.8)); draw(P--(d,0)--Q^^e); draw(subpath(ep,0,reltime(ep,0.5)),linetype("4 4")); draw(subpath(ep,reltime(ep,0.5),reltime(ep,1))); draw(Qp--(d,Qp.y),Arrows(size=8)); draw((d,0)--(d,10),linetype("4 4")); draw((d,0)--(d+r*(s-0.1),0)); label("$6$",(d-r/4,h2*s-0.06),N,fontsize(10)); [/asy]
$\textbf{(A) }1:1 \qquad \textbf{(B) }47:43 \qquad \textbf{(C) }2:1 \qquad \textbf{(D) }40:13 \qquad \textbf{(E) }4:1$
Solution
Hate
for q12 if all roots are integers they must be factors of 16
and that their product is 16
you also know that they add up to 10
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I dont get where the 3 and 4 come into this equation, its very annoying
can you send the full original expression? it appears to be cut off in this picture
i assume you got the LCD correctly, right
Yeah the lcd is right, then I always get the top part wrong, i dont get where I get it wrong though
can you send your rough work?
Lemmie put it to paper, 1 sec
ah i see i can probably guess what you did
you did 2 ⋅ 12 and 7 ⋅ 9 and got 24 + 63 = 87
Yeah I did that exactly
alright
so you want to have both of the fractions have the same LCD (36) so you can add them directly
right ?
Yeah
lets work on the first fraction. whats the denominator in 2/9 ?
18?
insult
can you work me through how you got to 3?
not sure what this means, exactly
for example, in $\frac{1}{2}$, what would the denominator be?
insult
2?
insult
6?
why 6?
Multiples of 2 are 2, 4, 6
Multiples of 3 are 3, 6, 9
Lowest thats both multiply into
you're getting LCD mixed up with denominator
Ohhh
besides, you shouldn't even be finding the LCD of that fraction ... because 2 is a numerator and 3 is the denominator
how about in this fraction, $\frac{2}{5}$? what is the denominator here?
insult
5
insult
10
okay
so whats the denominator in 2/9, in the previous question
9
alright
so we want to make that denominator into 36, the LCD, so we can add them directly, right
Yes
alright. so we want to turn $\frac{2}{9}$ into some fraction with denominator 36, $\frac{?}{36}$
insult
what do you think should we do?
We find that by also finding the denominator of the fraction we are adding
So the other fraction denominator is 12, so we simply find the lcd of both
And we see its 36?
alright, thats how to find the LCD. but we've already done that
what do you think we should do to get 2/9 to have a denominator 36?
yup, so how much?
alright, four. now since we multiply the bottom by four, we have to multiply the top by four to keep it equal
$\frac{2}{9} \cdot \frac{4}{4}$
insult
what does this equate to?
8 over 36
alright, keep that in your mind for later. now, for the second fraction, we have $\frac{7}{12}$. what do you think we should do here?
insult
Do the same, multiply by the amount needed for lcd, 3 so
7 times 3 is 21
So 21 over 36
So its 8 plus 21 so 29
The answer would be 29 over 36 since the denominator always cancels out
alright, so now we have two fractions with the same denominator (you may have called these like fractions). $\frac{8}{36} + \frac{21}{36}$
insult
what does that equate to?
29 over 36
great, you've added them. before answering however, you should check if you can simplify it further. does 29 and 36 have any common factors?
yes, it is unsimplifiable. however, this is the wrong reasoning
for example, look at fraction $\frac{6}{4}$.
insult
1 and 2 over 4
ah you're using mixed Numbers
Huh
dont mind that. its just that later youll find that its often easier to work with fractions that aren't in this form
anyways, ill just leave off saying that you can simplify $\frac{6}{4}$ as $\frac{3}{2}$.
insult
Ohhhhhh I see what you mean


