Available help channel!
#help-0
lone heartBOT
Available help channel!
lost folio
do you guys know if is trigonometry in paper 1
lone heartBOT
do you guys know if is trigonometry in paper 1
wary stream
do you guys know if is trigonometry in paper 1
Ask your teacher on the exam structure
worn fox
I've heard the whole of paper 1 is trigonometry
wary stream
How are people in a server suppose to know what the structure of an exam is?
worn fox
rip
worn fox
of course no one has it
wary stream
anyone has the 2023 paper 1 edexcel maths
That's cheating
lost folio
mate imma go review
revise
this is a waste of time
no offence to u
but me just wasting time
worn fox
you've wasted your own time
lost folio
yeap buy
worn fox
.close
lone heartBOT
How do i get help
wary stream
How do i get help
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
Just post your question and wait for help
lone heartBOT
@wanton jacinth Has your question been resolved?
wanton jacinth
Anybody help?
tacit arch
You can ping helpers now if you want
sly mantle
pls dont ping mods for math help
sly mantle
you already pinged helpers, but note that doesnt guarantee someone will come along. theyre volunteers
wanton jacinth
so this might not even be solved?
vapid shuttle
so this might not even be solved?
It most likely will be, but being patient goes a long way in making helpers want to choose your channel to help out in. As was stated above, anyone helping here is just a volunteer, so sometimes it might take some time to get to everyones questions.
tacit needle
I may be interpreting it incorrectly but this seems like a more accurate version of the problem
You don’t actually really need the y I just wrote it because I started drawing your diagram before I read the word problem part
So both triangles should have a base of x
Or rather you don’t need y yet
You do need a calculator for this
Do tan(59°) first to get the estimated value
And then from there you should be able to solve for z and x using tan(62°)
From there it’s just Pythagoras
wanton jacinth
And then from there you should be able to solve for z and x using tan(62°)
wait how?
.close
lone heartBOT
lone heartBOT
Available help channel!
manic thunder
okay so idk how the first number isn’t 1 everywhere i look it’s -0.67 but wouldn’t n-1=0 and anything to the 0 power is just one, so wouldn’t n=1 just be 1?
fervent root
Hello! I would like to join the moderators or the staff. How can I do so?
wary stream
Hello! I would like to join the moderators or the staff. How can I do so?
Pretty sure you can't
Anyways, not the purpose of a help channel
.close
calm gale
hello
calm gale
So for this series
i have to find values of p for which the series converges
ive gotten up to
now heres where I am kind of confused since the denominator will always be less than numerator for very large values of n
thus L > 1
i.e it diverges
no matter p value
unless im misunderstanding something
covert sapphire
im trying to study for my math test i decided to study the day before the test does anyone know how to do this
lone heartBOT
im trying to study for my math test i decided to study the day before the test d...
Please read #❓how-to-get-help
covert sapphire
!help
covert sapphire
did you get to know how to get help?
Yes
lone heartBOT
@calm gale Has your question been resolved?
calm gale
.close
red nest
There is a 4x4 grid of squares, and sally has tiles that are the colors black, white, yellow, and red. How many ways can these tiles be arranged if no 2 colors can have edges or corners touching
red nest
<@&286206848099549185>
chrome salmon
There is a 4x4 grid of squares, and sally has tiles that are the colors black, w...
think about it's cases
tawdry cove
im trying to study for my math test i decided to study the day before the test d...
U need help with this
chrome salmon
how?
red nest
I'm not sure I swear that was the question
it was from a competitive math test
I did
earlier today
chrome salmon
earlier today
think about number of blocks between two colored blocks
woeful pulsar
have you generated any examples
lone heartBOT
@red nest Has your question been resolved?
dark mason
sorry for all the confusion I caused you
I think about it again and I guess I find the solution and here's my thought process (the solution I work out is 4, if this is wrong, please correct me before I mislead this guy)
so let's say we start with
W x y z
B x y z
now what type of tile can W and B occupy?
lone heartBOT
@red nest Has your question been resolved?
snow mirage
I'm stuck on part 1, I can't really find a way to get a constant
snow mirage
I got till here but I think I went wrong somewhere
plain raptor
i believe you went wrong here
snow mirage
Figures, I'm stuck after that portion
plain raptor
try simplifying log 2^n+1 x and log 2^n x seperately
snow mirage
How so? Is there a specific log rule to use
plain raptor
so you would get n/n+1 in place of log2 x
solemn finch
lone heartBOT
solemn finch
Only need the perpendicular length
barren portal
The best way is to draw and picture and calculate
but if you want to do this analytically
are you familiar with finding equation of a line?
solemn finch
Umm yes
But this can be done without finding equation
Because equation of a line is the next chapter
barren portal
I will draw a neat picture and count the length
sharp panther
You can form the equation of the line BC and use the formula for finding the answer
Formula: $\frac{[|Ax_{1}+By_{1}+C|]}{sqrt(A^2+B^2)}$ where $x_{1}$ is the x coordinate and $y_{1}$ is the y coordinate of the point A
solemn finch
I will draw a neat picture and count the length
Ok
barren portal
This will be the analytical way
ocean sealBOT
Beck
crystal crown
lone heartBOT
lone heartBOT
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'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
so at my knowledge K is supposed to be the point where the funtion intercepts Y
crystal crown
```
What step are you on?
1. I don't know where to begin
2. I have begun but got...
2
terse panther
Yeah thats correct
crystal crown
but also
the area is BxH/2
where base is 2R and height is R?
so r² is 64 and r is 8?
K is equal to R?
but the awnser key says K=16
terse panther
so r² is 64 and r is 8?
Wait, how come you got r^2 as 64. The area is given not r^2
Hmmmm Ohh wait
terse panther
Yeah yea, hold on a sec
crystal crown
okay
terse panther
The area of semicircle is pir^2/2
rain trench
Uh can someone please help me 🙂🙂🙏
lone heartBOT
Uh can someone please help me 🙂🙂🙏
vague coral
just ask tho
rain trench
This is what I need help with 😞
vague coral
what have you tried ?
rain trench
I’m not even sure where to start so if you could help me I would gladly appreciate that 🫶
vague coral
they are asking you to find the total resistance of the circuit
what formula do you know ?
subtle birch
This is what I need help with 😞
you aware of equivalent resistance in parallel and series?
rain trench
you aware of equivalent resistance in parallel and series?
Yes but this is confusing me
rain trench
they are asking you to find the total resistance of the circuit
Let me send a picture of what I know
subtle birch
Yes but this is confusing me
First consider 3 and 6 ohm resistors
find their equivalent
rain trench
rain trench
consider only resistors
Oh okay so 6 and 3 and 4
If I add those all up I get 13…
But that’s if it’s a series circuit
subtle birch
If I add those all up I get 13…
do not do that
consider only 3 and 6 ohm resistors now
find the equivalent
using (1/r1+1/r2)^(-1)
subtle birch
yes
rain trench
So would the the total resistance be 6 ohms?
<@&286206848099549185> can I please get some help please 🙏
untold forge
rain trench
Can you send me the invite privately?
lone heartBOT
@rain trench Has your question been resolved?
jade prawn
lone heartBOT
jade prawn
Can someone help me with this?
lone heartBOT
@jade prawn Has your question been resolved?
jade prawn
lone heartBOT
marsh rapids
let S(N) be the sum of the first N cubes of odd numbers.
You're given S(N+10) - S(N) = 99800
Find N. Deduce the answer to b)
jade prawn
how tho
marsh rapids
a) gives the formula for S(N)
marsh rapids
You already have N ?
jade prawn
yeah
jade prawn
(2n-1)^3
if r=1
wait no idk bro just you put it into the formula then make a cubic
Then you solve the cubic and get N
jade prawn
ye
marsh rapids
So the first term of S(N+10) - S(N) is (2N+1)^3
So the answer is 2N+1
marsh rapids
There should only be one strictly positive integer solution
There can several ways to find it, but there should only be one result
jade prawn
What the MS says
I don't understand how they would deduce the second and third results tho
How do they get 11 from the other two
marsh rapids
They write it differently each time
Look at the sums at the start
They're 3 different ways of indexing 10 consecutive odd numbers
Leading to 3 different values of N
And 3 different formulas for the first term as a function of N
And they all coincide to give 11
jade prawn
Yeah but idk how they get the smallest value from 5 and 15
How to get 11?
I think I see it now
Actually
marsh rapids
Find the 2nd are 3rd expressions first terms as a function of n by looking at the way the sum is made
jade prawn
Because the smallest number would be the smaller series top sum + 1
Then you just plug it into the (2r -1)
jade prawn
Yeah i got it now
marsh rapids
You can do the same for 3)
jade prawn
Thanks
half pulsar
Question regarding syndrome decoding: Given your parity matrix, decoding table, modulo m = 3 and vectors of messages, how would you decode this?
half pulsar
The answer is the matrix beneath, I've already looked up a lot about it but couldn't find anything useful so far
lone heartBOT
@half pulsar Has your question been resolved?
lone heartBOT
@half pulsar Has your question been resolved?
lone heartBOT
@half pulsar Has your question been resolved?
verbal bear
Hello can someone help me find the explicit formula for the arithmetico-geometric series in the form:
$u_{n+1} = q*u_{n} + r$
ocean sealBOT
Blissful
verbal bear
i thought about splitting it in two different series but that doesnt work
vale wigeon
the name "arithmetico-geometric series" is doubtful
vale wigeon
i thought about splitting it in two different series but that doesnt work
wdym by "splitting it into two different series"?
vale wigeon
this feels unhelpfully vague.
proven leaf
consider $u_{n}=q\cdot u_{n-1}+r$ and substitute
ocean sealBOT
XxMrFancyu2xX
proven leaf
this exercise can be repeated $u_{n-1}=q\cdot u_{n-2}+r$ and so on
ocean sealBOT
XxMrFancyu2xX
vale wigeon
consider $u_{n}=q\cdot u_{n-1}+r$ and substitute
this feels unhelpful unless you are very confident in algebra
i will suggest this:
pull out of your ass the idea that it might help to define the sequence $v_n := u_n - c$, where $c$ is a constant, in hopes that this new sequence satisfies $$v_{n+1} = qv_n.$$
find $c$ that makes that happen.
ocean sealBOT
Ann
verbal bear
**XxMrFancyu2xX**
wdym by substitute here
proven leaf
$a_{n+1}=q\cdot a_{n}+r$\
$a_{n}=q\cdot a_{n-1}+r$\
\fbox{$a_{n+1}=q^2\cdot a_{n-1}+(q+1)r$}\
ocean sealBOT
XxMrFancyu2xX
proven leaf
with that, one can define the term a_(n+1) in terms of a_(n-1) instead of a_n
verbal bear
so we repeat until u_0?
proven leaf
you repeat it k times then you have $a_{n-k}$ for this to be considered "explicit" it needs to be in terms $a_{1}$ so $n-k=1$ see below for a derivation of the arithmetic explicit formula:\
\begin{equation}
a_n=a_{n-1}+d
\end{equation}
\begin{equation}
a_{n-1}=a_{n-2}+d
\end{equation}
By plugging equation 2 into 1, we get:
\begin{equation}
a_n=a_{n-2}+d+d \Rightarrow a_n=a_{n-2}+2 \cdot d
\end{equation}
This can be generalized as the following:
$$a_n=a_{n-k}+k \cdot d$$
For such an equation to be dependent upon $a_1$ we need $n-k=1$. Solving for $k$ yields $k=n-1$ and plugging back into the generalized formula yields.\~\
\centerline{\fbox{$a_n=a_1+(n-1)d$}}\~\
ocean sealBOT
XxMrFancyu2xX
marsh rapids
Well no
verbal bear
u forgot the "q*a_n"
marsh rapids
https://fr.m.wikipedia.org/wiki/Suite_arithmético-géométrique
It's meant to be an offset geometric sequence
marsh rapids
the name "arithmetico-geometric series" is doubtful
It works in French but not in English
proven leaf
u forgot the "q*a_n"
this is the arithmetic sequence not yours 
verbal bear
It works in French but not in English
ye im french
verbal bear
this is the arithmetic sequence not yours <:glassescat:1037770587235434567>
yeah but my question is arithmetico-geometric
proven leaf
yeah but my question is arithmetico-geometric
I was showing an example
verbal bear
oh wait
proven leaf
if you read me message lol
proven leaf
aight do whatever their doing cause not 2-1 and with the advanced persons ;-;
verbal bear
$u_{4} = qu_{3} + r$\
$u_{4} = q(qu_{2} + r) + r$\
$u_{4} = q(q*(qu_{1} + r) + r) + r$\
$u_{4} = q(q*(q*(q*u_{0} + r) + r) + r) + r$\
$u_{4} = q^4u + q^3r + q^2r +qr +r$\
$u_{n} = q^nu + \sum_{i=0}^{n-1}q^ir$
ocean sealBOT
Blissful
proven leaf
that's what I did but i'm doubting my result now
ocean sealBOT
Blissful
proven leaf
$\displaystyle a_{n}=q^{k}a_{n-k}+r\sum_{i=0}^{k-1}q^i$\
ocean sealBOT
XxMrFancyu2xX
proven leaf
rewrite using the formula for a geometric sum
proven leaf
some integer
proven leaf
because n is already used
verbal bear
k is more general
proven leaf
k is more general
no.... because n is already used
verbal bear
so what
proven leaf
I could've used big sigma for my variable
verbal bear
$u_{n} = q^nu_0 + r\sum_{i=0}^{n-1}q^i$
ocean sealBOT
Blissful
proven leaf
$u_{n} = q^nu_0 + r\sum_{i=0}^{n-1}q^i$
1 is the first term not 0
verbal bear
explicit is right hand side only has n and no series term
proven leaf
this is math not computer science 
proven leaf
i see
verbal bear
this is math not computer science <:kekw:752021756650455061>
lol
can we rewrite the sum
proven leaf
yes using $\sum_{k=0}^{n-1}ar^k=\frac{a(1-r^{n})}{1-r}$
verbal bear
ohyes i saw this formula in class
ocean sealBOT
XxMrFancyu2xX
verbal bear
i saw $\sum_{i=0}^{n-1}q^i = \frac{q^n-1}{q-1}$
ocean sealBOT
Blissful
proven leaf
**Blissful**
well this is the formula
now we get
$\displaystyle a_{n}=q^{k}a_{n-k}+r\frac{q^k-1}{q-1}$\
$n-k=1\implies$\fbox{$k=n-1$}\
ocean sealBOT
XxMrFancyu2xX
marsh rapids
that's what I did but i'm doubting my result now
It's also fine to intuit/prove it from the geometric sum formula
verbal bear
$u_{n} = q^nu_0 + r\frac{q^n-1}{q-1}$
ocean sealBOT
Blissful
proven leaf
$a_{n+1}=q\cdot a_{n}+r$\
$a_{n}=q\cdot a_{n-1}+r$\
\fbox{$a_{n+1}=q^2\cdot a_{n-1}+(q+1)r$}\
$a_{n-1}=q\cdot a_{n-2}+r$\
$a_{n+1}=q^3\cdot a_{n-2}+(q^2+q+1)r$\
$a_{n}=q^3\cdot a_{n-3}+(q^2+q+1)r$\
$\displaystyle a_{n}=q^{k}a_{n-k}+r\sum_{i=0}^{k-1}q^i$\
$\displaystyle a_{n}=q^{k}a_{n-k}+r\frac{q^k-1}{q-1}$\
$n-k=1\implies$\fbox{$k=n-1$}\
\fbox{$\displaystyle a_{n}=q^{n-1}a_{1}+r\frac{q^{n-1}-1}{q-1}$}
ocean sealBOT
XxMrFancyu2xX
proven leaf
that was my work and I'm assuming a_1 is the first term not a_0
proven leaf
It's also fine to intuit/prove it from the geometric sum formula
cool thx for letting me know I'm not being dumb 😂
verbal bear
that was my work and I'm assuming a_1 is the first term not a_0
its the same work i did
u just replace a_1 with q*u_0 + r
.close
rocky atlas
If f(x) is a bounded function and g(x) is an unbounded function, and h(x)=f(x)*g(x).
Is h(x) an unbounded function?
rocky atlas
If not give counter example
rocky atlas
Maybe let g(x) = 0 for x bigger the some a
That's constant function
Oh
You're right
That's the best example
Thankyou!
.close
lone heartBOT
golden canyon
e^-2x and e^x also work
rocky atlas
.reopen
lone heartBOT
✅
rocky atlas
e^-2x and e^x also work
No that doesn't work
their product is e^(-x)
Ok I'll close channel then
pearl dagger
Trying to solve y’+2y’’= sin(x) I’ve tried 3 different ways and I can’t figure it out
lone heartBOT
Trying to solve y’+2y’’= sin(x) I’ve tried 3 different ways and I can’t figure i...
Show your work, and if possible, explain where you are stuck.
pearl dagger
Well first method is I tried to convert it to dy/dx then multiply by dx but then when I get to here I’m stuck on the next steps here as I think I’m not doing it correctly
I also tried to brute force the answer and converting the primes to exponentials and solving for the integration factor but that didn’t work
alpine sable
how did you get that?
pearl dagger
Converting the derivatives to exponentials
alpine sable
so you solving it as a second order ODE using the char poly?
pearl dagger
Yes I believe so
This method I know it works I just don’t fully understand how to do it yet
So this is basically practice
alpine sable
follow the process outlined in your notes
alternatively, look here: https://math.libretexts.org/@go/page/2626
pearl dagger
Notes are a love hate relationship lol
I just need some guidance through this one and I should be good to solve the rest
alpine sable
there's a worked example in the book I linked
first find a solution to the homogeneous ode
then find a particular
pearl dagger
So for this would it be y’ + y’’ = 0 for the set up?
alpine sable
y'+2y''=0
pearl dagger
Oh right
Forgot the 2
So then you convert it to P to solve for integration factor?
alpine sable
?
there is no integration factor if you want to follow the second order solving process
pearl dagger
Oh I confused that with something else
So then what was the idea behind setting it to 0
That’s what I’m confused one
alpine sable
alternatively, look here: <https://math.libretexts.org/@go/page/2626>
motivation is given in this book ^
pearl dagger
Yeah so -1/2 would be it’s roots
alpine sable
there are two roots
alpine sable
yes
pearl dagger
Ah I found 0 but canceled out because yknow it’s 0
Then I used -1/2 as the integration factor which was part of my notes
I think that’s where I made a mistake
pearl dagger
I ended up with e^(-x/2)
This is how I ended up with this
pearl dagger
Isn’t 2 the constant
pearl dagger
Ohhh
alpine sable
we don't know what it is without more info
pearl dagger
I thought we knew what it was
alpine sable
not with the question you've stated
pearl dagger
So you get c_1(1)+c_2(2(e^(-x/2)))?
alpine sable
anyways, you have found a homogeneous solution $y(x)=c_1+c_2e^{-\frac{x}{2}}$
ocean sealBOT
Toby
alpine sable
no
pearl dagger
So what happened to the 2 in y’+2y’’
alpine sable
c_2 can be anything, so we dont need anything else
alpine sable
sure
pearl dagger
Makes sense
Ok to find the particular solution don’t we plug it back in the to original equation
alpine sable
yeah
just y_p
forget about the homogeneous solution for now. we dont need it till later
pearl dagger
Ok
alpine sable
pearl dagger
Well -sin(x) + 2sin(x) = sin(x) so I was thinking of something like that
Oh wait that’s cos
Are a and b here similar to the variables in euler rotations?
alpine sable
I'm not sure what that is
pearl dagger
I'm not sure what that is
Basically like the introduction to using e^ipi to rotate an equation around and go from the real plane to the complex
alpine sable
there's no complex numbers here
pearl dagger
Yeah but that equation just looks very similar so I was wondering if there was a connection there
Anyways ima start with 1 and 2 just to see how they change if it’s not correct
alpine sable
the only connection I see is differentiating gives a similar pattern
alpine sable
Anyways ima start with 1 and 2 just to see how they change if it’s not correct
let A and B vary, then you can figure them out later
alpine sable
dont use the homogeneous solution yet
pearl dagger
Ah ok
alpine sable
differentiate the particular solution twice
then check what A and B are by equating coefficients
pearl dagger
So solving for the primes?
alpine sable
I'm not sure what you mean by that
pearl dagger
Like solving for y’ and y’’ to substitute them in?
alpine sable
yes
pearl dagger
Do we include the beta symbol in the derivative
alpine sable
r(x)=sin(x)
alpine sable
then look at this
pearl dagger
r is your initial guess
alpine sable
r(x) is the rhs of the ode
pearl dagger
According to that table
pearl dagger
r(x) is the rhs of the ode
I get that
alpine sable
According to that table
initial guess is the second column y_p(x)
pearl dagger
so how did we end up with 1 from that
alpine sable
r(x)=sin(1x)
alpine sable
yes
pearl dagger
Then -Bsin(x)-Acos(x)
Then you plug those into the original equation?
And equate the coefficients?
alpine sable
yes
pearl dagger
I ended up with (B-2A)cos(x)-(A+2B)sin(x)
alpine sable
now equate coefficients
pearl dagger
Not entirely sure how with the trig functions being different
alpine sable
sin and cos form a basis
so equate the coefficients in front of sin
then separately equate the cos coefficients
alpine sable
I ended up with (B-2A)cos(x)-(A+2B)sin(x)
using the ode, what does this equal?
pearl dagger
r(x)?
alpine sable
yes
pearl dagger
So sin(x)
alpine sable
yes
pearl dagger
So we have y(x) now?
pearl dagger
B=-2/5?
alpine sable
,w B-2A=0, -(A+2B)=1
ocean sealBOT
alpine sable
yup
then add with the homogeneous solution
then you are done
,w y’+2y’’= sin(x)
ocean sealBOT
pearl dagger
Wait where did the 1/5 come from in c_1
alpine sable
yw
pearl dagger
.close
spring galleon
This the answer I got from math away
lone heartBOT
This the answer I got from math away
wary stream
This is the answer I got
Multiplication is commutative
spring galleon
Multiplication is commutative
I know that, but the fact that the minus sign is in a different place made me doubt
wary stream
Show your full work
wary stream
Your mistake happened here
You factored out -1 from -7m + 2
But you only changed the sign of 7m, and not 2
Basically $(-7m + 2) \neq -(7m + 2)$
ocean sealBOT
dldh06
wary stream
Yes
spring galleon
Alright, thank you so much
lone heartBOT
@spring galleon Has your question been resolved?
torpid magnet
find big O of f(n) = (x + 1) ln(x^2 + 1) + 3x^2
would f(n) = O(n^2) since 3x^2 is the dominant term. and if so, does that mean no matter what f(n) is, the dominant term always signifies the order of Big O?
tacit arch
find big O of f(n) = (x + 1) ln(x^2 + 1) + 3x^2
would f(n) = O(n^2) since 3x^...
yes
although you're mixing x and n willy-nilly
lone heartBOT
@torpid magnet Has your question been resolved?
torpid magnet
although you're mixing x and n willy-nilly
How would I avoid mixing those in a proof?
tacit arch
when you write f(n)=..., all variables on the right side should be n and not x
torpid magnet
Oh, weird this is how the professor wrote the problem. would the answer be different or would that just be an over sight on his part?
viscid canopy
how to proceed with this question?
lone heartBOT
how to proceed with this question?
viscid canopy
.close
normal patrol
i dont understand what to do
normal patrol
<@&286206848099549185>
remote heron
<@&286206848099549185>
do you know what a fence is
you should google or check in your book
that part should just be using a definition
normal patrol
ah. how do i find them?
remote heron
a formula is given in the article
you need to find the IQR
hope you dont feel like im pawning you off on articles, i just want to prompt you to ask more specific questions or use some resources
normal patrol
hope you dont feel like im pawning you off on articles, i just want to prompt yo...
no worries. im just confused lol
normal patrol
thank you. so i gotta find the iqr?
normal patrol
ohhh okay.
remote heron
normal patrol
what do i need to calculate? like i dont get the formula
normal patrol
ok thanks
remote heron
you need the range between Q3 and Q1
this is like....
data between Q1 and Q3 is the most 'normal' of the data, since its closest to the mean
or the median i guess
so the range is important since it tells you how much the really 'normal' data is spread
normal patrol
so correct me if im wrong but the iqr is 2.5?
normal patrol
okay
remote heron
. next step
normal patrol
pretty sure what I got is wrong, i got -363 for "lower fence"
remote heron
what is Q1
normal patrol
12?
remote heron
whats the IQR
remote heron
and whats the formula again?
remote heron
,calc 12-1.5(2.5)
ocean sealBOT
Result:
8.25
,calc 14.5+1.5(2.5)
ocean sealBOT
Result:
18.25
okay i think i got it. thanks!
normal patrol
gotcha! 
is it okay if i use this chat to use the calculator to calculate one thing?
remote heron
yea
ocean sealBOT
Result:
2
,calc 15-1.5(2)
ocean sealBOT
Result:
12
,calc 17+1.5(2)
ocean sealBOT
Result:
20
dark pelican
lone heartBOT
dark pelican
Can someone help explain this
primal tartan
!show
lone heartBOT
Show your work, and if possible, explain where you are stuck.
remote heron
try a usub?
lone heartBOT
@dark pelican Has your question been resolved?
finite estuary
lone heartBOT
finite estuary
<@&286206848099549185>
lone heartBOT
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'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
@finite estuary Has your question been resolved?
finite estuary
No
finite estuary
```
What step are you on?
1. I don't know where to begin
2. I have begun but got...
1
alpine sable
use this right angle triangle
lone heartBOT
@finite estuary Has your question been resolved?
lone heartBOT
@finite estuary Has your question been resolved?
signal trellis
The important thing to notice is that all the angles are corresponding, so the coordinates will be the same except for their signs. 11pi/12 is a lot like pi/12 except it's in Q2, so the x-component should be made negative while y stays positive. The next question can be done similarly
lone heartBOT
@tacit island Has your question been resolved?
foggy current
first, what equations can you deduce from the conditions?
let the number of envelopes be E
and let the number of paper be P
yes
foggy current
yes
notice that for every envelope Sue uses 3 sheets
I just noticed the first equation should actually be S-E=50
can you think of the next step?
for the second equation the number of paper used is 3 times the number of envelopes used
and the number of envelopes used is equal to E-50
and Sue used S sheets of paper
what do you mean?
no, because Sue uses 3 sheets of paper per envelope, as stated in the question
instead of one paper per envelope
foggy current
because she's using 3 sheets per envelope
therefore the equation should be S=3(E-50)
wise lodge
The quantitative data set under consideration has roughly a bell-shaped distribution. Apply the empirical rule to answer the following question.
A quantitative data set has mean 20 and standard deviation 4 . Approximately what percentage of the observations lie between 12 and 28 ?
Ive tried reading the book and I have no clue what its even asking of me or where to begin. I have several of these to try and get through
fervent river
The quantitative data set under consideration has roughly a bell-shaped distrib...
I don't know a lot of distribution but i can give you a start.
How much standart deviations are 12 from 20?
wise lodge
I have no clue. I ended up figuring this out with a calculator online, but then when i applied the same logic to the next question it was wrong so now im going back to this one
its the 68-95-99.7 rule thing.
so it was 12-28 was 95%
because 68% fall under x-s (20-4)= 16 and x+s (20+4)= 24 , 95% falls under x-2s and x+2s which is 12 and 28, and then 99.7% falls under x-3s and x+3s which was 8 and 32
fervent river
I have no clue. I ended up figuring this out with a calculator online, but then ...
Maybe the next question does not fall in the 68-95-99.7 rule.
wise lodge
It tells me to use the empirical rule
the second set of info has a mean of 30 and a standard deviation of 2 and it wants to know the number of observations between 26 and 34
which it should also be 95 but its not
fervent river
which it should also be 95 but its not
You used the same 68-95-99.7 rule in that question. Right?
wise lodge
Correct
fervent river
Now i ask: what the number that the 68-95-99.7 rule gives means?
wise lodge
the x-2s and x+2s gives me 26 and 34. which is what is used for 95
The Empirical Rule states that 99.7% of data observed following a normal distribution lies within 3 standard deviations of the mean.
Under this rule, 68% of the data falls within one standard deviation, 95% percent within two standard deviations, and 99.7% within three standard deviations from the mean.
fervent river
the x-2s and x+2s gives me 26 and 34. which is what is used for 95
Yes. It gives 95%. This 95% is the probability that a given sample falls in that range and not the amount of samples that aproximatily falls.
wise lodge
So if it gave me a sample size of 80, i need to do 95% of 80?
fervent river
Yes. I think so.
wise lodge
I figured they threw that in to mess with me because hte previous one didnt have it and it worked correctly both written and in an online calculator
fervent river
Sorry for any errors. It has been a while since i studied this.
wise lodge
No worries at all
okay so it was 76 so i guess i misunderstood what that question was asking and how it was different from the first-
fervent river
I figured they threw that in to mess with me because hte previous one didnt have...
The second question asks for number of observations which i believe is another way of saying the size of a sample.
wise lodge
I see
fervent river
I believe 95% of 76 means the avarege numbers of things whitin two standart deviations and this will do the job.
wise lodge
Can you claify what this one is asking then? :
fervent river
Can you claify what this one is asking then? :
I am here to help.
wise lodge
The area under a particular normal curve between 13 and 19 is 0.9732 . A normally distributed variable has the same mean and standard deviation as the parameters for this normal curve. What percentage of all possible observations of the variable lie between 13 and 19?
fervent river
@wise lodge, i recomend you watch this video: https://youtu.be/zeJD6dqJ5lo.
I recomend the entire the chanell but... focus.
fervent river
The area under a particular normal curve between 13 and 19 is 0.9732 . A normal...
"Area under a curve". This does not ring a bell?
fervent river
The area under a particular normal curve between 13 and 19 is 0.9732 . A normal...
It is asking about the fraction (porcentage) of everything that lies between 13 and 19.
wise lodge
okay i think i understand. One sec
So im essentially working backwards right?
Maybe?
fervent river
So im essentially working backwards right?
Could you show what you did?
I don't i understand tbe question.
wise lodge
Uhhh im not even sure either. I was assuming there was a way to figure out what th mean and standard deviation was in order to find the percentage
fervent river
Uhhh im not even sure either. I was assuming there was a way to figure out what ...
Area under the curve.
What we use to discover areas under curves?
wise lodge
Im super rusty at all things math. Its been 5 years since ive done any type of math course ( this is elemantary statistics) and this is only my second homework assignment so its probably something super obvious that isnt clicking for me.
wary stream
So im essentially working backwards right?
No, I think it's much easier than you think. The area under a normal distribution relates to the percentage. So if you take the percentage between x and x - S, you understand that's 34%, correct?
wise lodge
whats M. like what does it represent
wise lodge
thanks. okay so yes. Kinda. SO far ive only been familiar with the 68-95-99.7
wary stream
Anyways, 34% relates to an area of 0.34 under the normal distribution curve, x - S and x - 2S
area under a particular normal curve between 13 and 19 is 0.9732
Here, it gives the area under the curve, it wants the percentage
wise lodge
so it just wants what 0.9732 is as a percent? Thats it?
wary stream
If I understood the question, yes
wary stream
wary stream
No, I think it's much easier than you think. The area under a normal distributio...
Mistyped this
I meant between x and m - S
wise lodge
Oh i see
wary stream
If you notice, it's 34% of the area under the curve
wary stream
Do you understand this?
wise lodge
I do
wary stream
Z score is related to that. The 68 - 95 - 99.7 rule is based from the mean to 1S, 2S, etc
wise lodge
right
wary stream
Z score is a value that relates to the percentage under the curve from the left end to that z value
So for example, this orange part, you want to find the percent, it's not easy with the 68 - 95 - 99.7 rule so we use z score
There's a formula, $\z = \frac{x - \mu}{\sigma}$ where mu is the mean, sigma is the SD, and x is the value you are using
ocean sealBOT
dldh06
wise lodge
oka. So if i have a question phrased like this, where amd i plugging what or what steps am i taking to solve this
wary stream
So for example, this orange part, you want to find the percent, it's not easy wi...
I forgot the picture
wise lodge
wise lodge
I have 3 questions phrased like this. One thats left of, one thats right of. and one thats between
wary stream
Do you have a z table?
wary stream
Google is your friend
wary stream
Send a screenshot of the table you have
wise lodge
wary stream
So the left most column, as you notice, is the ones digit and the tenths place
The top row, is the second decimal place
So for example, if you wanted -3.45, you look at -3.4 on the column then go to 0.05 in the row
What is that value?
wise lodge
.00028
wary stream
Yes exactly
Now to mention, that chart represents the area under the curve from the left end
wary stream
Meaning that this table represents this shaded area on the left side of the z score
wary stream
it would be -0.0 then .04?
Yes
wary stream
The question says to round to 4 dp
wary stream
Try it
wise lodge
Its wrong
wary stream
Does it tell you what is wrong?
wise lodge
No, it just told me to remember what im calculationg for which was phrased super closely to how you described it
and it mntioned using a z table but...yeah
wise lodge
It was correct that time
wise lodge
Technically yes, but if i get a certain part of the question wrong and its a 4 part question i have to repeat the whole question again with another set of numbers/answers to get full credit
wary stream
Hopefully you can figure out the rest of that problem
wary stream
Not quite
wise lodge
Okay. How do i figure out the right and the in between
wary stream
The normal distribution curve, from the left end to the right end, the total area is 1
From the left end to the z score, you use the table
Do you know how you can relate that info to find the area to the right?
wise lodge
is it the difference between the left value and 1?
wary stream
Exactly
wise lodge
okay sweet
and if i have a question like this?
im going to swing back to B of that last photo i sent. I assumed it was .948 based on how we got A to work. But it was incorrect. It was also incorrect as .9485
wary stream
im going to swing back to B of that last photo i sent. I assumed it was .948 bas...
Which picture?
wise lodge
whoops. the one before th z table. the area left of the z curve where it has a through d
this one
wary stream
To answer this, you want to find the shaded area, if the z table represents area from the left end to the z score, do you see how you can find the area in between?
wary stream
Try a different table, like this
wise lodge
find the area of both z scores and then find the difference from the furthest right to the left one?
wary stream
find the area of both z scores and then find the difference from the furthest ri...
Yes exactly
wise lodge
oooh i see. okay.
wary stream
All good @wise lodge ?
wise lodge
WIth that stuff yes. Im finishing up the 3rd 4 part question. I think i only have 1 or 2 other questions left i need you to help me logic through and im all set
or rather, would appreciate if you were able to help me logic through them*
wary stream
Sure
wise lodge
Okay, grabbing the last of the screenshots.
So that last one with the bell curves pictures; i tried ti figure it out before i asked in here. So i dont know why the ones i got right are actually right, or how to find the correct answer for the ones i got wrong/ was unable to answer
wary stream
I hope you realize that you send two of the same question
wary stream
Oh there's a table
wise lodge
yep. the last literal question of the assignment
wary stream
So this is the reverse process of what you did here
wise lodge
I thought so. But arent there multiple numbers that could be right if im only going by 2 decimal places?
wary stream
Same this with this, reverse process of how you found the area on the right side
wary stream
I thought so. But arent there multiple numbers that could be right if im only g...
Pick the closest to it or the one that rounds to it
wary stream
Not sure if it wants the one rounded to it or closest
wise lodge
okay so i thought i had it
but it told me this
when it was wrong
Note that the area given in a standard normal table is the area to the left of the z-score. Use the fact that the total area under the standard normal curve is 1 to determine the required area to the left of the z-score. Find the area in the body of a standard normal table that is the closest to the required area, and then find the corresponding z-score. If two area entries are equally close to the one desired, take the mean of the two corresponding z-scores as an approximation of the required z-score
so maybe i just did it wrong, but -3.27, -3.28 and -3.29 all have .0005 to the left
wary stream
Do you get to see the answers after you get it fully wrong?
wise lodge
Yes
wary stream
Can you do that problem, and purposely get it wrong and post a screenshot of it? I want to see what it says the answer is
wise lodge
it said it was -2.58
wary stream
What was the area under the curve?
wise lodge
oh shoot
i guess i wasnt paying close enough attention
i thought it was .0005
but it was only 0.005
and a -2.58 wouldve gotten me to a .0049
so a .005 rounded
wary stream
That's what it looks like
wise lodge
okay. let me try the new one
okay i got that new one right. So the only one that remains is that multi part spider question
wary stream
Can you send that screenshot again?
wise lodge
i think this one is a 5 part question so there might be another thing that pops up. Ill need to repeat the whole question over since ive missed parts anyway but i had no clue what i was doing at that point and was just guessing
wary stream
Remember this curve, where the middle is the mean, and in each direction it goes by every SD
ocean sealBOT
dldh06
wary stream
Where mu is mean and sigma is SD
wise lodge
yes
wary stream
Do you see how you can do part b based on that?
wise lodge
Yes. Okay. It looked like it made sense like that but i dont think i had seen that referenced yet. But yes. that makes sense
wary stream
Part c looks like it's based on purely SD, so if the middle is the starting point. It's just like the x - S, x - 2S part of the graph but only focuses on the S part
wise lodge
Im a little confused on that one. On that one the s was 1.27.
it just shows a regular bell curve without going to -4 and 4 though. Is that because just said distribution of z with 0 other information? (and the last of 4s is because the graphing of it is so miniscule for that size graph?
wary stream
Remember this curve, where the middle is the mean, and in each direction it goes...
Look at this and part C, compare the x axis, do you see something in common?
wary stream
Do you see how part c only references the SDs?
So if you're in the middle of the curve, you're at 0 SD
Then two to the left, you're a -2 SD?
wise lodge
Ohhhhhhh
wary stream
Do you get that part now?
wise lodge
Yes i see
wary stream
Part d uses everything you did in previously. So you use the equation from part B to find the z score, then you use the table to then find the area in between
The values in part D relates to x in the formula
wise lodge
okay so
i tried it
and i got half of it right
Your first answer is correct. However, your second answer is incorrect. Write 14mm in standardized form using the standardized version of the variable equation found in part (b).
cause i got -1.79 and 1.98
wary stream
Your first answer is correct. However, your second answer is incorrect. Write 1...
Can you post a screen shot?
wise lodge
yeah
i mustve made a mistake when putting it in
oh. i think i did 57 instead of 27
for the top x porton
cause i got 1 this time
mustve accidently hit the wrong one on my phone
well. e is revealed
wary stream
That one is just using the formula and find the area to the right
wise lodge
right
wary stream
Because notice the question is is asking for the area to the right
wise lodge
okay so i tried it
and got 0.016
but it doesnt seem to be right even as 0.01 or 0.02
wary stream
What was the value you got from the table?
wise lodge
unless i had to round the result i had to look for in the table
i got 2.14 (unless i was supposed to round up to 2.15). from the table i got .9838
wary stream
You were suppose to round to 2.15
wise lodge
oof okay
wary stream
Because (18 - 15.27)/1.27 = 2.149606..... which rounds to 2.15
wise lodge
alrighty.gonna attempt a new question over and hopefully thats it!
I got it all. Thank you SO MUCH for taking the time to walk me through this
wary stream
I got it all. Thank you SO MUCH for taking the time to walk me through this
No problem.... so btw I dmed you a bit ago because I wanted to ask you something
wary stream
I got it all. Thank you SO MUCH for taking the time to walk me through this
Don't forget to .close to close the channel if you're done too
wise lodge
.close
proper garnet
lone heartBOT
