#help-28
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The question came up in a gcse paper and it doesn't specify
drink water
stay hydrated
Oh
@charred escarp Has your question been resolved?
expected number is not the same as most likely number
you want to keep the fraction
probably
@charred escarp Has your question been resolved?
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How did they get those numbers for CD
as in, the length of CD? you can make a right angled triangle with CD as the hypotenuse
and you know the length of these 2 red sides
well, what's the x coord of D
4 ?
the length of that vertical side is (y coord of C - y coord of D)
the length of the horizontal one is (x coord of c - x coord of d)
If you know distance formula, it's just applying that
If not, you can count the units of each side
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can I just integrate everything here directly?
like the u^3 becomes u^4/4 and the 1 becomes u and the u^2 becomes u^3/3
or do I need to use some sort of substitution or something
no, why?
you have a fraction
how would I approach this problem then?
let x = u^3 - u^2 then find dx and substitute that in?
how are you gonna deal with the u^3 on top then?
$\int_2^3 \frac{u^3+1}{u^2(u-1)}$
artemetra
artemetra
$=\int_2^3 \frac{(u-1)(u^2 + u +1)+2}{u^2(u-1)}$
artemetra
by difference of cubes
I personally would use partial fractions for this problem seems like it’d be slightly easier
$=\int_2^3 \frac{(u^2 + u +1)}{u^2} + \frac{2}{u^2 (u-1)}$
artemetra
but idk feels a bit forced
if I used partial fractions, would I have to long divide first?
You can split up the fraction, and apply the linearity of the integral, you should get something easy to decompose, It will take me a while to type it up nicely on my phone
$\int_2^3 \frac{u^3+1}{u^2(u-1)}=\int_2^3\frac{u^3}{u^2(u-1)}+\int_2^3\frac{1}{u^2(u-1)}$
Then if you simplify the left integral and apply partial fractions to the right I’m pretty sure those should all be relatively easy integrals to do
But it’s 1am and I’m on my phone so I’m not doing the partial fractions myself to check, but I’m like 90% sure it should work out fairly nicely
alright i'll try it out thanks
Nope
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how to find an affine function
what is your definition of affine function
f(a)
- f'(a) * (x-a)
but here i have to variables
So do i take the gradient instead of f'(a)
but
f_x and f_y is just the gradient
cant i insert those without my a and b
just differentiate the function
not sure what you are asking, you need the a and b
alright
Ok
this is what i've done
The question was:
"Here g is the gravitational constant, m is the mass of the pendulum, and ` is the length of the pendulum. The angle θ ∈ R represents the swing of the pendulum (which we allow here to be more than one full revolution), and v ∈ R is the speed of the pendulum's weight. The pendulum rod is assumed to be rigid and massless, and the weight is assumed to have no extension. Energy is assumed to be conserved as the pendulum swings.
Therefore, a pendulum swing (θ(t), v(t)) as a function of time t, with v(t) = `θ0(t), will lie on a level curve for E.
(a) Determine the affine function that tangents the energy function E at a point (θ1, v1)."
looks fine but i dont know what you mean by "we'll insert not" nor what the expression after that is supposed to be
got only one side of an equation there
right but then what happened to this bit
well im following the formula
thats fine yeah but i dont see the need to expand it all out fully
what else should i do
@desert musk Has your question been resolved?
2x2
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I understand how to do the problem but I don't actually understand what the problem actually represents, what would part B be?
One way to think of it, if you're integrating in terms of time, you're multiplying the unit by a time
In other words, if r(t) is gallons per hour, then ∫ r(t) dt is just gallons
∫ r(t) dt is the total amount of liquid that has entered the barrel
oh
so would it just represent
the amount of gallons of watter flown out of the barrel from 9 to 6 hours after 9
would I also include the 1/6 as well
So if ∫ r(t) dt is the total amount, what do we get when we take 1/6 of that? Reminder there's 6 hours here
just one sixth of the total amount right
one sixth of the total amount of water from 9 AM to 3PM
is that right
ohhhhh
wait that makes sense
so it would just be
average flow of water in gallons/hr from 9-3
think so yeah 
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Hi ive been having trouble with this word problem that you'll find below, I just have trouble putting it as a equation to solve
Jess walked for 45 minutes at 3 km/h and then ran for half and hour at x km/h. At the end of that time she was 6km from the starting point. Find the value of x
It may be helpful to split the problem up into two parts: walking trip, and running trip
should with that do i do it as speed x time = distance?
you can use distance = velocity times time
ohh
also be careful with units, maybe convert all the minutes to hours
looks good to me!
alright ill solve it and see if it matches the answer
👍
so from that I got 1.5km/h
althought the answer is apparently 7.5km/h
ohhh
i know where ive went wrong
thank you!
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@torpid siren are you comfortable breaking the original integral into three pieces?
I broke it into two, from -1 to 0 and 0 to 1
but it made it more complicated i think.
Every continuous function is integrable, but there are integrable functions which are not continuous. it is your case
oh gotcha, yes I think youre right you dont need three pieces, just two
Ok let me write something down
$\int_{-1}^{1}f(x)dx = \int_{-1}^{0}f(x)dx + \int_{0}^{1}f(x)dx$
pencentre
which "piece" of the piecewise function do we pick for the -1 to 0 part?
well -1 and x
its actually the x^2 bit
$\int{-1}^{1}f(x)dx = \int_{-1}^{0} x^{2} dx + \int_{0}^{1}f(x)dx$
pencentre
since f(x) is defined to be x^2 for values less than zero
let me know if that makes sense
Yes, exactly!
$\int_{-1}^{1}f(x)dx = \int_{-1}^{0} x^{2} dx + \int_{0}^{1} x dx$
pencentre
Once you have this, then you can integrate each piece to find your final answer.
I think I get 5/6, but I just did that mentally
so double check me lol
Ok give me a sec
so are you integrating all of these?
just the x^2 and x integrals
for the x^2, I got 1/3 and for the x integral I got 1/2
adding them together I think gives 5/6
Yea i got it
thank you so much!
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Where dies the 7 come from?
“We notice that we can multiply both sides by 7…”
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so i was doing a job application question assessment thing and its math based but im so confused even tho i do a maths degree
i thought it was simply 19/28 and the rest of the info was just there to try trick you and add info for u to process
but part b makes me doubt my answer to part a (above) and if i need to use the other info
or maybe im just overthinking
in a the graph isnt the number of people who get alerts
its just the average number of alerts a person gets per month
so it wouldnt be 19/28
youll have to use the from the 1000000 and the overall average, you can see there are around 15000000 alerts overall per month
youll have to use the other two averages to work out how many people of the 1000000 are on each method
roughly anyway
just what fraction of the 1000000 is what you need ig
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Ferris Wheel Problem
As you ride the Ferris wheel, your distance from the ground varies sinusoidally with time. Let t be the number of seconds that have elapsed since the Ferris wheel started. You find that it takes you 3 seconds to reach the top, which is 13 meters above the ground, and that the wheel makes a revolution once every 8 seconds. The diameter of the wheel is 12 meters.
a) Write the function equation of this sinusoid.
b) What is the lowest height you go as the Ferris wheel turns?
<@&286206848099549185>
thanks but Question wants sinusoid function
then y = 7-6sin(90-x)
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
when I gave x=3 it gives 12 . but should it give 13? and function will have period like 2π/8 because of the it makes revolution every 8 second. How can I write again function to use period?
<@&286206848099549185>
@queen crater are u available to help me
@shell crane Has your question been resolved?
@shell crane Has your question been resolved?
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@shell crane Has your question been resolved?
But cant you multiplie it with any number? How does one come up with 7?
@shell crane Has your question been resolved?
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Ferris Wheel Problem
As you ride the Ferris wheel, your distance from the ground varies sinusoidally with time. Let t be the number of seconds that have elapsed since the Ferris wheel started. You find that it takes you 3 seconds to reach the top, which is 13 meters above the ground, and that the wheel makes a revolution once every 8 seconds. The diameter of the wheel is 12 meters.
a) Write the function equation of this sinusoid. ( example: f(t) = Asin(B(t-C)) + D )
A is the amplitude (half the diameter of the Ferris wheel, which is 6 meters),
B is the frequency (related to the period T by B= 2π/T)
C is the phase shift (time delay before the motion starts),
D is the vertical shift (the average height).
b) What is the lowest height you go as the Ferris wheel turns?
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How, in my head, should I conceptualize the expectation of a predicted relationship, given an input matrix X and a vector of estimated coefficients Beta-hat?
Am I supposed to conceive of the input matrix as a random variable?
The professor for this course has stated that X*Beta (without the hat, and not the expected value, just the multiplication) is a constant, though. So the input matrix X isn't a random variable?
Oh, wait, is it because Beta-hat is found by doing a least-squares regression of Y on X, and since it's an estimate there are always errors (i.e. noise) that mean(s) that Y doesn't fully correspond to X, and the error term is a random variable, so because our estimate of Beta-hat depends on whatever errors get thrown at us, Beta-hat is actually a random variable?
(Holy run-on sentence, Batman)
@heavy nimbus Has your question been resolved?
more simply put
Y is a rv
your estimator β^ depends on Y
so β^ is also a rv
Oh because Y is a function of the X inputs, which are known, but also an error term, which is a random variable?
yes
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since it is oriented clockwise, we have to flip the result, is there some place to do this typically or would I just flip the end result?
also im getting $\int\int_D 1 dA$ so would it just be the area of the circle?
Clarkie
Yeah you can just flip it at the end if you'd like
i would probably just flip the bounds personally
It's really up to you as long as you know what's going on
alright nice,
oh
im getting -3 inside, ;-;
can I take it out and just multiply the area of the circle in that case?
trying to save time 
Not sure what this means but you can always take constants out of your integral
so when I swap through green's theorem
I get (3x^2-3(x^2+1))
which just results in (-3)
niceee
so -3 times (oriented) area
good job!
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I know this relates to trigonometry and would require the use of sin, cos, and tan, but am stuck on how to solve the problem.
Note that angle Q is 90°
yea i dont understand that
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THEY GIVE YOU THE AREA OF THE TRIANGLE
WHAT FORMULAS DO U KNOW FOR AREA OF A TRIANGLE
bh/2
ANY OTHERS
not that i can think of...
ALRIGHT
SO, HOW WOULD YOU FIND THE AREA OF THIS TRIANGLE
WHAT SIDES WOULD YOU WANT
THE POINT IS, YOU WANT TO MAKE EQUATIONS OUT OF THESE GUYS TO STEP CLOSER TO FINDING PR
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3.42 3.43 and also
4.34
for 3.42, factor a -1 out of the denominator of 9/(2-t) and then solve
for 3.43, square it and then it should solve pretty easy
for 4.34, you kinda just take out common factors until you cant anymore
Oh tyy
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this is literally 5987 digits
how are they expecting us to calculate this in a math contest for 1 and a half hours 😭
Also it's 2019!-3
Idk why
so the roots are x=1, 2, ..., 2018? right
Yep
And since the leading coefficient is 1, it can be written as this
so it's basically (-1)^2018*(2019)!-3
Ohhhhh
I'm dumb
Thanks
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What is this called?
I am doing differentiation , but struggling with this last step , i cant find any questions like it
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Can you show what the example looks like from the beginning?
@compact widget
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@compact widget Has your question been resolved?
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1/4 of 7/8 forgot how to work theese out
of means times
cool thnks

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$|3x+1| = 4x$\newline
$3x+1 = 4x \vee -3x-1=4x$\newline
$1 = x \vee -1 = 7x$
Tomasz#5153
its not correct i dont know why
i suppose thats not how i should write absolute value
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✅
pls help
.
are you looking to solve for x?
Tomasz#5153
So how I always approached it was that the equation that is in the absolute value stays the same and the other portion of the problem becomes negative.
IE:
3x+1=4x and 3x+1=-4x
You would technically get the same thing, but that is how I would approach it.
So the x=1 is correct, but you need to finish solving for x in the second equation
i mean it says there is only one solution x = 1
i dont know why
its tragic dfont look at this ^
So the x=1 would be correct.
If you were to go through the process of solving for the other x, you would get that x=-1/7.
Which when you go to check the answer, will not compute to equal one another.
I will write it down. It took me a second too but I forgot that we should check work to double check, especially when it comes to absolute values
You have to take both of the x's and plug them into the original equation. If it works, then the answer is correct. If it does not work, then the x is incorrect.
Therefore the x=1 would be the only possible solution
there must be a better way than to plug values for x
It's one of the sure fire ways to always check your work.
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hello i seem to forgotten how to get the x in the picture i got the <A=180-50-90=40 so i have all of the corner sizes <A=40 <B=50 <C=90 but how do i get the x
x + 40 = 180
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Hi guys this is a definiton from my script
Please don't occupy multiple help channels.
in a ring R(+,*)
thats the proof
i dont get how they even start
from where comes the part after the plus?
do you mean 0∗a + 0∗a = (0+0)∗a
Well as for what's happening, that's the distributive property, (a+b)∗c = a∗c + b∗c
although I don't remember if it's actually true for all rings, it's been awhile since I studied rings
We know 0 = 0 + 0
So 0∗a = (0+0)∗a = 0∗a + 0∗a is where the first part comes from, then, we have that by the distributive property this is equal to (0+0)∗a which equals 0∗a
So, we know that 0∗a + 0∗a = 0∗a
This can only be true if 0∗a = 0
I don't see where they prove a∗0 = 0 though
Oh, well the argument doesn't really depend on the order, so you can just the above argument but start with a∗0 = a∗(0+0) = a∗0 + a∗0 -> a∗0 = 0
All of this assumes that (a+b)∗c = a∗c + b∗c, and the second case, c∗(a+b) = c∗a + c∗b
Which I don't know if that's true or not for all rings, you'll have to figure that one out
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I'm so tired
idk how to find the intervals
I'm trying to work backwards with the example problem and nothing is making sense
why can't this just be straight forward
why does everything have to have some complicated formula and 6 different steps to find
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let $\theta = y/2$
ταυταυ
yeah
what's y in terms of theta ?
yeah
now replace y with 2 theta
so the 2 cancels out :)
see theorem 6 they say
sure
what's the triangle OAP ?
yeah
well
it's the definition of the sector using radians
you've learnt that the area of the circle is 2pi r^2, but it's only because the angle is 2pi
yeah
my bad, it's pi not 2pi
because you have to devide by two lol, using calculus you can get why but idk if you're gonna get it
area is pi r^2
yeah
you divide by two
well
there's a calculus thing
but it's calc3 level
and you're doing precal which means you won't get it
idk the geometry of it
The reagion of the area is $$R = {(x, y) \mid x = \rho \cos{\varphi}, y = \rho \sin{\varphi} \mid 0 \leq \rho \leq r, 0 \leq \varphi \leq \theta }:.$$ So the area is the following double integral
$$\int_0^\theta \int_0^r \rho ,\mathrm{d}\rho, \mathrm{d}\varphi= \frac{\theta r^2}{2} :.$$
took me too long to write LOL
but you wouldn't get it anyway so i did it for no reason
ταυταυ
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Hello, nice to meet you. I would be very grateful if you could help me with this problem because I am having difficulty solving it.
What I have been able to deduce is that:
0.05*30=1.5mg/kg
30+1.5=31.5 mg/kg
so the legislation says that you can indeed add 1.5mg/kg of zinc per kg of soil per 100 years, right?
which means you can add X kg of sewage sludge per kg of soil, where X is the amount of kgs of sludge that has 1.5mg of zinc. follow?
@stuck surge
Yes
and 1kg of sludge contains ???? mg of zinc
which means in ????kg of sludge, there is 30mg of zinc
two different ????s to work out
But if that's the case, I can simply make the rule of three
Or am I making a mistake?
not too sure what the rule of three is
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,tex \begin{theorem}
Let (X = (X_t){t \geq 0}) be a continuous local martingale with respect to a filtration ((\mathcal{F}t){t \geq 0}). If
[
\mathbb{E}\left[\sup{0 \leq s \leq t} |X_s|\right] < \infty \quad \forall t \geq 0,
]
then (X) is a martingale.
\end{theorem}
Ive shown the family $({|X_{t \wedge T_n}|})$ is uniformly integrable, using boundedness of the E(sup) and doob's inequality.
But Im a bit stuck on how to show it's a full martingale. I'll probably need the Dominated Convergence Theorem for taking limits but not really sure how to construct the proof.
Pure
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this is so ugly wth
Pure
Don't you just need that $\mathbb{E}[X_t | \mathcal{F}s}] = \mathbb{E}[\lim{n\to \infty} X_{t\wedge T_n} |\mathcal{F}{s}] = X{s}$ by applying the dominated convergence theorem.
JessicaK
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why do we have the second equality?
oh
[
\lim_{n \to \infty} \mathbb{E}[X_{t \wedge T_n} | \mathcal{F}s] = \lim{n \to \infty} X_{s \wedge T_n} = X_s.
]
Pure
its just this isnt it
I think so, but it's been a little while since I've used any stochastic calculus
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@layla 
:waves:


oh u dont ahve niitro lmao
T_T

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hello
pi radians = 180 degrees
so 180 divided by whatever under?
huh
if x is in degrees then x*pi/180 is the radian equivalent
can you solve the first one for an example
pi/3 * 180/pi = 180/3=60 degrees
not = no
you could maybe get away if you wrote rad on the left one
but i still wouldnt write it like that
$\frac{\pi}{3}\cdot \frac{180}{\pi}$
then =...
AℤØ
HUH
what?
its just what i wrote here
i dont see the issue
oops wrong one
this one
why is it multiplying
it comes from here
why is there an A
because im multiplying by the ratio of degree to radians
i really dont know what you want me to say
thats just how you convert it
sorry for not understanding 😢💔
If x is in degrees, then:
$$x\cdot \frac{\pi}{180}$$ is the radian equivalent angle. \newline
If x is in radians, then:
$$x\cdot \frac{180}{\pi}$$
is the degree equivalent angle.
so basically the thing is cross multiplying
AℤØ
^
just use this
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I’m confused what to do from here after factoring 7/4 out
Might have helped to have factored out the 7/4 before deciding to make a substitution 
Like this?
Yep, and then rerarrange that $\frac{ \pqty{x - \frac12 }^2 }{ \pqty{\frac74} }$ a tiny bit, which then should make another substitution that should make your life easier!
@devout valley
I get this
But I’m just confused with the substitution for arc tan because I need u^2 alone but I can’t do that when I have (4u^2)/7
You can "absorb" everything inside the square root 
I’m not sure I totally understand
You know, for example, that $4 = 2^2$, so $4\pqty{x - \frac12}^2 = (2x - 1)^2$
@devout valley
Can you think of something similar for that 7? 
wait wat 4(x-1/2)^2 = (2x-1)^2?
Did you expand that out
to find that
Or was there some sort of cancellation I didn’t see
Cause you have $2^2 \pqty{x -\frac12 }^2 = \pqty{ 2\pqty{x - \frac12} }^2$
@devout valley
Hm I have never seen this algebra manipulation trick before
You haven't? 
Damn, it's basically a consequence of rules of exponents though, that $(ab)^n = a^n b^n$
@devout valley
I need to stop changing my mind to use tex halfway through a message 
@twin wolf Has your question been resolved?
Well I’ve seen that but I haven’t seen it applied in like quadratics here
Awww, well the aim of doing it here is that you just need to make only one substitution
That then makes your life easier 
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Any idea whats wrong?
Im supposed to just divide so i dont know how my answer is wrong
$3a^2+2a+5-\frac{19}{a+2}$
Joanna Angel
you did it
$3a^2+2a+5\text{ is a quotient}\\-19\text{ is a remainder}\\a+2\text{ is a divisor}\\3a^3+8a^2+9a-9\text{ is a dividend}\\\text{in same way you do in next problem}$
Joanna Angel
-19 is a remainder
But 1 is the remainder of this equation?
remainder of the division
The expression is -5x^2 + 1, when you do the division, you should add placeholders. Because there is 0x, you should have written -5 0 1
Not -5 1
And that's what I'm saying, put place holders for the 0 terms
So -5x^2 + 1 would look like -5x^2 + 0x + 1
So that way you write -5 0 1
Then that just gives me 10x+0+1
You should have something like this
The arrow with -2 is to indicate that it got multiplied by -2
Oh wait
I multiplied 10 by 0
instead of adding
Ok well i see now thank you
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I know the first one uses sine rule but the second one how ?
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i sense calculator
There's isn't any way?
you use a calculator
and you can leave the answer as tan invese
since this isnt a special case or anything
IT ASKED FOR BETA?
where calculator was not allowed?
some countries idk
thats crazy tho..
Yes
Yea
so ig we just have to like kinda guese which is closest
One is 15 not 35
Yea
i cant think of any way other than extreme aproximation , which is again kinda wild to ask
damn
cool gl
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For the fifth part i tried looking for some pattern
Made sets like
When the sum is 5
(1,4) (2,3) (3,2) (4,1), 4 sets
likewise when 10
(1,9) (2,8) (3,7) (4,6) (5,5) (6,4) then repeating so ,9 sets
now did 4+9+14...99 which is 1030 but the no of favourable cases is 520 whats wrong in this
@patent sierra Has your question been resolved?
when you get to 55 the number of cases starts decreasing
you start from 4 + 51, 5 + 50, 6 + 49, ...., 51 + 4
there are 51 - 4 + 1 = 48 cases here
i seee
continuing that pattern does give 520
so its decreasing in the same apttern
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help pls
what do i do now
what kind of triangle is ABC?
looks equalatrieral
those segments are congruent
no i mean about the ABC triangle
those sides are equal
yes triangle with 2 congruent sides
so is this also a isosceles trinagle?
yes
what can you say about angle A and C now?
they are equal
lol
angle GBC equal to angle GCB gives you GB=GC
just the converse of what ive told
you
above
no i mean it wants me to reorder it
to be in the logical ordere
but idk what the logical order is
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Is there another way to find G? This is for reflection angles of light rays defined as a vector field of V. The reflected vector is R, the T is the surface tangent, and n is the surface normal. X is the X-axis. I got the table from just logically thinking about what the reflection angles would be when the light ray hits a surface at specified angles just to get a sense of what the graph would look like for G. I can only find the reflection angle defined as 360-G which G is some function of a angle. Such a angle I will call XZ. XZ is between the surface normal to the X-axis. The reflection angle is also taking in the input of such angle, but I am having trouble finding the G function. I feel like what I have is correct to a sense, given that three of the values match what I expect G to be at the given angle XZ as shown by the table.
Though I highly doubt its a coincidence that two or three of the values I got for a calculated G, match what I expect G to output at three XZ angles. If that makes sense?
Basically I have doubt its a coincidence that the G function I calculated, isn't in some way, related to the expected G function. This is because three of the 5 values it gives me, match
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Back
Is there another way to find G? This is for reflection angles of light rays defined as a vector field of V. The reflected vector is R, the T is the surface tangent, and n is the surface normal. X is the X-axis. I got the table from just logically thinking about what the reflection angles would be when the light ray hits a surface at specified angles just to get a sense of what the graph would look like for G. I can only find the reflection angle defined as 360-G which G is some function of a angle. Such a angle I will call XZ. XZ is between the surface normal to the X-axis. The reflection angle is also taking in the input of such angle, but I am having trouble finding the G function. I feel like what I have is correct to a sense, given that three of the values match what I expect G to be at the given angle XZ as shown by the table.
Basically I have doubt its a coincidence that the G function I calculated, isn't in some way, related to the expected G function. This is because three of the 5 values it gives me, match
@heavy gulch Has your question been resolved?
@heavy gulch Has your question been resolved?
@heavy gulch Has your question been resolved?
@heavy gulch Has your question been resolved?
@heavy gulch Has your question been resolved?
@heavy gulch Has your question been resolved?
Thanks @quaint prawn and @torn jolt
@heavy gulch Has your question been resolved?
I think I may have solved it
By analysis and two lines of mathematical manipulation, θR = 270+2*θxz
There is a weird thing where the reflection angle will go past 360 but I don't think the math in the future will care
@austere cove
Hi, is this the same problem from before?
Yes
I never really took the time to understand how your system of variables worked, so I can't speak to how correct it is, but it looks reasonable assuming that you are having to add 90 to the degrees in order to take it from a normal vector to a plane.
I didn't realize the equation I got was the correct answer until I tried like, 6 different angles and they all got the same answer I expected, but a few were rotate a full 360° but it still got the same spot
I would recommend just simply trying an angle for each quadrant
I tried more than that
I'll refine the work some time in the future
But for now it's just disorganized chaos in my notebook
Surprisingly
and is not the evil arccos shit you had before 🙂
And your idea of shifting the perspective made it possible
I'm glad to have been of help
Here is the short work I did after my analysis but its a bit difficult to explain. I was getting two different equations that satisfied what the expected reflected angle got. The two equations made up the domain of θxz but each equation had its own subdomain within the domain of θxz. For example, this equation I was trying to get, was apart of 0° <= θxz <= 45° and another equation I got was from 90°<= θxz<=180°. This was just seeming like another dead end to me though it was helping with my analysis of how the reflection angle is effected by θxz. However the first equation I was using, I refined a bit more as shown in the work I sent, and it turned out to solve the entire problem I was having, which was unexpected and it's simple as you said
Sorry for my crappy handwriting for G'(θxz)
But basically G'(θxz) = 90 + 2*θxz
G'(θxz) is prime because it's what I calculated based on your idea of using a perspective shift. G(θxz) is what I expected
Of course you can subtract my equation I got for the reflection angle by 360 and it still doesn't really matter because a negative angle is still mathematically the same when it's calculatrd with different trig functions
I've never struggled for almost a month on a math problem until now that turned out to be so simple but a lot of it was thanks to your help and my intuition
Therefore it definitely was not a coincidence that some of the values matched (G') to what I expected on both the reflection angle and it's complementary angle (G). Of which made up 360° when added together
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@heavy gulch is this channel done?
Yeah
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may i know how to do this?
well how mant digits does this number have to have
4
3?
but then 7 doesn't appear twice
and 9 doesn't appear at all
you need them to appear twice
5577992?
yes
well to me it seems you've correctly identified
that
the 2 must go in the last spot right
so
we can ignore the 2
and then the problem becomes
how many numbers can we form with the digits 5,7,9 appearing exactly twice
do you see how that is true
ok
this is our new problem that gives the same answer
so how to answer this one
well
this is like a similar problem
how many distinct 6 letter words can you form with the letters
AABBCC
do you know how to solve that one?
Yes you're right abt the first part, but all the letters are repeated twice
So if it's just 6!, The word
AACCBB would be counted twice, you see?
6! / 2
it would actually be counted 8 times I believe
yea
But the dividing by 2 is just for one letter
You gotta do it a few more times, why?
No
pretending that each of the letters are different
we have
6!
$A_1A_2B_1B_2C_1C_2$
WOWWA
if we pretend they are different
like this
then there are 6! ways to arrange
but
$A_2A_1B_1B_2C_1C_2$
WOWWA
WOWWA
in terms of what we are actually looking for
and you can see
that for each "word" if we pretend the letters are different
we are overcounting by 8
because the As can be arranged in 2! ways
and the Bs can be arranged in 2! ways
and the Cs can be arranged in 2! ways
for each word
so divide by 8?
so for each word there are 2!*2!*2! copies if we consider each letter different
yes
ooo
The only difference is that instead of 2x3, you do 2³
so its 6! / 8
Nice explanation man
thanks
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hello i got some issues in the first question and i need some help
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any idea on how to solve this
yes
yes
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So this is a solids of revolution problem. I am not sure how to use the washer formula because I can't think of either function for the inner and outer radius to plug in, or the bounds. I think it being rotated around the y-axis is specifically what is throwing me off the most. Here is the problem:
Find the volume of the solid generated by revolving the region defined by the triangle with vertices [(1, 0), (2, 1), (1, 1)] by the y-axis
Please don't occupy multiple help channels.
dang it
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Question 1b
Why is the permanent order label 2 on node B shouldn’t it be of order 3
<@&286206848099549185>
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I took C as 100% then B = 75% and A = 89%
Then A’s income is 11 % less than C’s income
(11/100 * 100)
But the answer is 10%
Where am I going wrong?
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If one section has 10% students who got A+, In approximation how many students in % in 8 sections ?
I know it's 10% but how do I explain someone it is ?
He isn't taking the logic can anyone logically put it for him to understand ?
what does he say instead?
He's confusing amount and percentage
He likely understands that 8 sections will have in total approximatively 8 times more students and 8 times more A+ grades than a single section
What he doesn't realise is that this means the total percentage of students with A+ will remain the same
if one section has 100 people then ten people would have an A+. if we add all the sections together we would have 800 people with and 80 people in each section with an A+ so that is still 10%
If there's 8 times more students and 8 times more A+ grades then the total fraction of A+ grades to students stays the same
There's likely quite a bit more ways to explain this
I don't know which is best
it would be 80/800 which simplifies to 1/10 or 10%
I like Fox's explanation because people tend to be bad at abstract thinking so you often have to provide a concrete example
thanks
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• 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 to check my answer on this question
Proof directly that,
“If m is an even integer and n is an odd integer then m+n is an odd”
Ok

