#help-27
1 messages · Page 373 of 1
,rccw
AB = BC can be proved by congruency of ABP and CBS
Try to prove Congruency
Same with AR = RC, congruency of RAB and RCB
ohh is it asa
Hint : ||ASA||
Yes, ASA for (a) and SAS for (b)
b) part?
the part after AR=RC
Yes, and the perpendicular on B to AR is BR
BR isnt perpendicular tho
I think it means add a new line from point B that will be perpendicular to the surface of AR
and find that oength
It is right angled on AC, but yes, even I'm a bit confused
Oh wait
Do you have the answers?
i dont
I see
We can simply find BR though, IG that's what they meant, the other things would be kindw complicated to find, and this question doesn't seem all that complicated
isnt it more like this
Could be, but that'd be insane to find
if they're congruent ARB and BRC then it would just be 4.5 cuz they are both altitudes
I'm here
You've already done a lot lol
yeah but idk how to find theta
eac
@fringe patio Has your question been resolved?
Try creating an internal angles line or what they use to teach that and bend it.
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Can somebody solve me all of these? I am still trying how it works.
Not for you
Btw this is a past papers
Not an exam
So I basically just try to multiply them based on matrix right
[-1 . 5 2. 1] = [ -5 , 2]

Do you know how to multiply matrices
I see
I will show you how to multiply 2x2 matrices
The process is the same for any size though
So pretty much
You start with the top left element
And multiply it by the top left element of the second matrix
a * e
Then, you move right on the first matrix and down on the second matrix
So b * g
Leading + throughout
And you continue this process until you run out of elements
Then you move to the second row on the first matrix
And repeat the same process
So left most element on the second row, c, times top left element in the second matrix, e.
OOO i see
Then move right -> d and down -> g
Multiply the first row with the first column and add up the elements, first row with the second column, first row with the third column, etc. and when you did everything for the first row you move to the second row and multiply it with the first column, then with the second column, etc.
You have to do this for every row and column
What about this tho, this does not have a 2x2 but a 1x1 horizontally, 2x2 and 1x1 vertically
even easier then
just stop after the first step
It doesn't matter, as long as the amount of rows in the first matrix equals the amount of columns in the second matrix
Otherwise you would run out of elements to multiply somewhere
[
[-1, 2] \cdot
\begin{bmatrix} 3 & -1 \ 2 & 4 \end{bmatrix} \cdot
\begin{bmatrix} 5 \ 1 \end{bmatrix}
]
USS-Enterprise
We start with the first two
[
[-1, 2] \cdot
\begin{bmatrix} 3 & -1 \ 2 & 4 \end{bmatrix}
]
USS-Enterprise
As we said, left most element in the first row of the first matrix TIMES the upper most element in the first column of the second matrix
(-1) * 3
PLUS
The next element in the first row TIMES the one lower element in the first column
2 * 2
And that is our first element of the resulting matrix
(-1) * 3 + 2 * 2 = 1
Get it?
Yes
Okay
Then we move to the second column on the second matrix
And we begin the same way
So it's [-1 . 3 + 2.2 = [1]
(-1) * (-1) + 2* 4
Yes
[
[-1, 2] \cdot
\begin{bmatrix} 3 & -1 \ 2 & 4 \end{bmatrix} = [1, 9]
]
Right?
USS-Enterprise
Yes
If you move columns like here, the next element goes to the right
If you move rows (we didn't because the first matrix only has 1 row) you move down on the resulting matrix
So in the end the result matrix is the size m * n, where m is the number of rows in the first matrix and n the number of columns in the second matrix
Wait what about the (5,1)?
We are getting there
Now we have
[
[1, 9] \cdot \begin{bmatrix} 5 \ 1 \end{bmatrix}
]
USS-Enterprise
How do we do this then
So it's [14] ?
Exactly
That's the final answer?
Yes
TYSM!!
No problem
LOVE YOU BROTHER ( NO HOMO )
🙂
.close
Closed by @fringe olive
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
A and B play the following game: A writes down
either number 1 or number 2, and B must guess
which one. If the number that A has written down
is i and B has guessed correctly, B receives i units
from A. If B makes a wrong guess, B pays 3
4 unit to
A. If B randomizes his decision by guessing 1 with
probability p and 2 with probability 1− p, deter-
mine his expected gain if (a) A has written down
number 1 and (b) A has written down number 2.
What value of p maximizes the minimum pos-
sible value of B’s expected gain, and what is
this maximin value?
i thought of first saying P(1) = P(1|B guess)P(B guess) + P(1|B not guess)P(B not guess)
is it a right move?
are you doing a) or b)
also just to clarify... how much is B supposed to pay A on a wrong guess?
B pays 34 units to what?
3 , or 4 or 34
a
ok so B gains €1 if he guesses correctly and the number was 1, €2 if he guesses correctly and the number was 2, and on any wrong guess he loses €0.75
yes
so a) is the scenario in which A's number is 1. which means that B's payouts are:
- +€1 with probability p
- -€0.75 with probability (1-p)
find B's expected payout in this case
no probability or anything but expectation aka expected value
lemme use event G_B as gain of B
p×1 + (1-p)×(-0.75) more like
ye lol same thing
q = (1-p) btw
oh lemme just say 1-p to simplify
it'd be like (7/4)p - 3/4
E[G_B | A=2] = (p)(-.75) + (1-p)(2)
2 - 11/4p it'd be
yes now you need to find the value of p which equalizes these
Closed by @low parrot
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
hey can someone help me understand optimal linear prediction?
i know you have to draw a line in the graph, but no idea how you know how to draw said line
can u give an example problem
the book doesn't have like excersises but i can show an example that i'm trying to figure out how they did that?
sure
is it machine learning
i don't think so? no idea what you mean by that tbh
it's like you got data for all these points and then you need to predict what a new point will have when it only has the X known, based on what all the other points are
it could be, but machine learning is not mentioned anywhere in the book
oh zlr thanks
.close
Closed by @dry harbor
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Prove $\int_{0}^{\pi} \frac {1}{\sqrt[3]{\sin x}} ,dx$ is convergent
Carbonara
$\int_{0}^{\pi} \frac {1}{\sqrt[3]{\sin x}} dx$ = 2 $\int_{0}^{\frac {\pi}{2}} \frac {1}{\sqrt[3]{\sin x}} ,dx$ < 2$\int_{0}^{\frac {\pi}{2}} \frac {1}{\sqrt[3]{x-\frac{x^3}{3}}} ,dx$
Carbonara
what should i do next
i feel like you are overcomplicating it a bit
hint: utilise the fact that sinx \approx x for small x and use the limit comparison test
if you want something exact ig you can use sin(x)>=2x/pi for x in [0,pi/2]
oh
that's it
thanks
.close
Closed by @pure stone
Use .reopen if this was a mistake.
how do you use LCT for integrals
the same way you use them for infinite sums
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
.close
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Closed by @floral lodge
Use .reopen if this was a mistake.
Gotta claim another one
Since you’ve deleted the original message
aww 🙁
^^
I deleted as it was badly formatted
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
help 🥺
dont remember 🥺
what's the limit of $\lim_{x \to -\infty} \frac{5x^2 + 2x + 1}{x^2 + x + 2}$ for example?
south
lim 5x^2 / x^2 ?
yep!
so lim f(x) / x^2 = 3?
yes
I see.
importantly, if $\lim \frac{f(x)}{g(x)}$ is not $0, \infty, -\infty$
south
that means $f(x)$ and $g(x)$ must be of the same degree
south
@verbal comet Has your question been resolved?
Closed by @verbal comet
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Yo I got a doubt
!da2a
No need to ask “Can I ask…?” or “Does anyone know about…?”—it’s faster for everyone if you just ask your question!
just ask
,rotate
Will have 3 coincident normals
Right?
Lemme explain this
Parabola normal equation
Got relationship btw m values so that the cubic has 3 roots
Hence 3 normals pass from a pt
Got this graph
That shows number of normals that can pass through a pt in each region
Caught up?
Well the question is what is the equation of 3 coincident normals that pass through pt 2a,0
Like tell me how to get it
Also the 3 coincident normals are supposed to pass through vertex of parabola and pt 2a,0
But not any other pt on axis
Like only 1 of those 3 will pass through rest of em
How's that happening
Please help needed

!original
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
Ye no there was no problem given
Just explanation
And I had doubt in that
And I sent the related theory that was given
Like a parabola assumed y2=4ax I think
At the pt 2a,0
Will have 3 normals passing through it
Which will be coincident
As a rule
explanation of what problem
Only theory was taught about no. Of normals passing through diff pts on parabola
Like I think the only pre required info was the parabola is y2=4ax I think
I don't think any other assumptions were taken
Do you want me to give a rundown on what is going on in the image?
U can't get equation of 3 normals from 1 pt
Well
We got it other way around I think
We first got the equation of normal
Then gave condition for 3 solution
U can get the slopes of the normals
Could u explain ur question again? Ur typing in so many lines I xcant understand
From the pt 2a,0 3 coincident normals of parabola y2=4ax pass through,
Somehow the 3 coindent normals do not satisfy any point on the axis other then 2a,0
Like it's there but it aint
And why do u think they will satisfy any other point on the axis?
Cuz well they pass through the axis
One of the normal is the axis
And if they are coindent
Then others must be same no?
Huh coincident
Uh yea
Why will the parabola have 3 coincident normals..
Is there an original question
How is that an equation
The image I sent is all
Ye well I think there was something there but it got simplified to this
I know I am not being helpful at all
All I can say is that the h>2a condition is correct for 3 normals of a parabola to exist
Well lemme tell what I understood from class
After doing that
M1 m2 when put in orignal function and multiplied
Will give negative result
So we did that and put inequality less than. 0
So we got more accurate discription of when 3 normals
Yes
Like when that condition follows we get 3 distinct normals
Why h=2a?
No like if we take h=2a
There are supposed to be 3 normals
Just not distinct
Like just tell me this
Where did tangents come from
Yo mb
We are using equation of normal right
Tell me this
Like give me example of a coincident line
Like x2=0 that's a line right
Coincident?
U can say that I guess but if they are coincident then how can u classify them as different normals?
Yes obviously it won't.. the condition is for 3 distinct normals we are not getting 3 distinct normals
I don't think I can recall exactly what the teacher said
So I'll just ask in general way
X2=0
Btw are u preparing for an exam
Is equation of lines right
What is x2
Like it's far away
Yo
I think I have a way to explain
But I gotta restart it's all too cluttered I don't wanna waste another age explaining to someone again
.close
Closed by @nimble turret
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Why is the answer to this no? The answer sheet gives one contradiction but the question asks if there is some linear transformation given $x_1,x_2\in V$and $y_1,y_2 \in W$ such that $T(x_1) = y_1 $ and $T(x_2) = y_2$
Pen
If V is a subspace of W, then surerly I can map the vectors to themselves?
or if V and W are of the same cardinality (is that the right term here?), mapping each x_i to y_i
Why are you making these assumptions?
Because there is no restriction on V and W
and it asks if there is some linear transformation and not for all transformations
Yeah but you're not the one choosing
Then how else am I supposed to answer it?
If it said for all linear transformations given V and W, then sure
but that does not seem to be the case
Maybe there's more context you're not showing here, but this reads as "for all x_1, x_2 in V and [...], there exists [...]"
I mean, just take V = W = R
x_1 = 1, x_2 = 2, y_1 = 1, y_2 = 3
T(0) must be 0, and T(1) = 1, so T(x) = x
But then T(2) =/= 3
Okay, that is a counterexample to those values
if V = W = R I can let x_1 = 1, y_1 = 1,x_2 = 2, y_2 = 2
It's a counterexample to the statement
My bad, yes
Hmm
Why is it a counterexample to the whole statement and not just those values?
What you don't get is that you cannot just pick the values you want for it to work
Why is $x_i = y_i$ not a valid choice here?
Pen
The statement is "for all [...], then there exists [...]"
It is a valid choice, but not the only choice
right, it is not the only choice but it is a choice
wait
Nel, do you mean that for ALL values in the set
If all valid choices made it work, then the statement would be true
My counterexample is a valid choice, yet it doesn't work
so any random $x_1, x_2$ in V has to satisfy the conditions given any random $y_1,.y_2$ in W
Pen
If the statement said "affine transformation" instead of linear, then it would be true
Or if it only had one value x and one value y
(the transformation being linear means there's already an implicit pair (x,y) that must work, namely (0,0))
Yep
I need to take a step back and re-tackle the phrasing of some of the questions, I am not reading it correctly
Thank you so much, Nel!
.close
Closed by @floral lodge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
In Exercises 121–124, determine whether the sequence is monotonic and whether it is bounded.
well, what do you think? 
why what part?
which part of the solution is the confusing part?
In order for it to converge, it needs to be increasing and have an upper bound, right?
sure
But its not increasing right?
why not?
Cause its negative
write out a few terms of the sequence
So its getting smaller as n increases
1 - 1/2 = 1/2
1 - 1/3 = 2/3
Oh
😅
Ok I see your point
Thank you!
❤️
.close

Closed by @viral lynx
Use .reopen if this was a mistake.
Also wow help from higher, I am honoured
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
How do I make a help channel bruh
Guys
Can someone help me with discrete mathematics sets and relations
send any mathematical questions you have here
No need to ask — there’s always going to be someone that can help.
which question do you have a problem with?
all 
!status
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
How do I factorize a polynomial of 4?
Do you know how one proves a biimplication?
Biimplication= if and only if statement
yes
Okay, can u tell me
A biimplication is really the and of two implications
So you have to prove two statements
p => q and q => p
So for 6-8
You have to prove that
- If power set A is a subset of power set B then A is subset of B
- If A is subset of B then power set A is subset powerset B
How will you go about proving 1.
idk
If you take any element in A
And make a singleton set with it
It will be in P(A)
Makes sense?
And this P(A) is a subset of P(B)
Which means that singleton set is also in P(B)
Which means that element must be present in B
So any element in A is present in B
=> A is subset of B
Tell me if this makes sense
What do you mean where
like how will I prove that if I dont have the sets
like set a and b
@silk terrace
@azure sleet Has your question been resolved?
I mean assuming that A and B are not empty sets
They will contain some element x
Rest of the argument follows
For any arbitrary set
@azure sleet Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Im confusingmyself here
I don't think i really understand what im looking for?
i think i dont really understand the question
depth is referring to height correct?
yes, your diameter looks correct
ahhhh
this seems pretty similar to the cylindrical one you did. how about tracing what you did in that problem, so you can figure out what is confusing you here?
I think im confused with depth
i know how to do it in theory but like the terms are confusing me a little
let me try it once more
@woven vale radius isn't a constant for this right?
so i do need dr/dt
this is fair, and i honestly think its kinda mean that they used depth and height in the same problem
think of depth as the height of the cup, or how "tall" the liquid will look inside the cup
if this helps
radius is not constant, correct. if you imagine looking from above at this cone, you will see a circle of water that gets smaller and smaller, right?
thus the radius of this circle is changing
i like to start by identifying whats going to change and what's not, within the formula for volume or w/e
then taking derivatives is a little easier
yes thats what i was assuming aswell
im so confused still with what depth is
can i ijust assume that its height
yes
okay let me try to solve it now then
also just wanted to point out that this isn't correct :(
oh no
h = (v/pi(r^2)3)
idk i dont think i can solve thid question rn
im very confused
okay, don't worry about isolating variables right now
focus on taking the derivative properly, then you can rearrange
what is the "rest"?
okay let me try and solve it again
okay sounds good
if you're not sure what part of the word problem means, or how to apply it, you can circle it and send that too
is dh/dv right so far
@woven vale
im loset
this is one hard question
so lonely
😭
@potent pike Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
have u heard of geometric series
Yes we learned them today but i dont fully understand them
do you know what a geometric sequence is
Same thing
no
I mean same like we learned it today but i dont fully understand it
it's when you get the next term by multiplying that with the previous one by a common ratioo
Ah ok
1, 2, 4, 8, 16...
all terms are multiplied with the common term 2
that is a geometric sequence
and now if you were to add up all these numbers, you get now a geometric series
But adding them would get infinity no?
not necessarily
Cause the sequence is infinite
imagine you have 1 chocolate bar
you can divide it into half, then 4 parts, then 8 parts
etc.
doesnt mean you get infinite chocolate now, does it
have you learnt a formula for geometric series
I have a geometry test in 3 days 🙏🏻
Congrats
!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).
Nope 1 sec ill google it
Oh yeah I remember this from the lecture
this is btw how you may imagine the chocolate bar
Oh
yea it was for finite sum, surely
What is the ratio and how do I get it
write down soem terms
where is the negative come from and it starts at n=2
if you look at the terms what did you do
what does (1/4)^n suggest doing
as n increments
In terms of if its increasing or decreasing?
no, arithmetically
what are you doing in every new step
how does 1/4 differ from 1/16
The denominator is increasing by a factor of 3 then 4 then 5
you are saying that: 1/4, 1/(4x3), 1/(4x3x4), ...
The denominator is 2^(n+1) every time
it's literally here what it is
Like each time it adds 1 to n
1/4
I still dont understand why its 1/4 sry
Like if the equation was (1^n)/4 would the ratio still be 1/4
Or (1/4)^n
you are multiplying by 1/4 everytime not (1/4)^n
as n increments, you always multiply by an additional 1/4
Fr i was watching all the time
so since z=1/4 we have 1/4 < 1 so it converges
Ahhh ok
I dont think we learned this today
Or maybe we did lol idk
But im gonna try some examples
you can derive it by taking the limit of the formula
I will just learn it instead 😅
But thanks again!
❤️
.close
Closed by @viral lynx
Use .reopen if this was a mistake.
Guys
learning by proving 
Is the 80-20 rule work
I had a question
Wait
you are free to open a help channel
Ok
.reopen
✅ Original question: #help-27 message
show the formula and then compare it to your sum and start index
Oh
n goes to inf
So n isnt the n = 2 under the sigma?
Thats confusing
But I see what you mean
So (1/4)^infinity tends to 0
yes
Closed by @viral lynx
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
how can i demonstrate the commutativity of the multiplication? a times b being equal to b times a
you could always use rectangles (width 𝑎 and height 𝑏) and rotate the rectangle by 90º (width 𝑏 and height 𝑎). The area of the rectangle wouldn’t change just because you rotated it.
If you want a rigorous proof, you’d probably need peano axioms and induction.
i thought about that but i can't think of a way to demonstrate that the area of any rectangle is width times height, like why the dimension meter multplicates with another one and we assume meter squared represents an area
ik these are the basics but i can't find demonstrations for this type of stuff lol
@zenith owl Has your question been resolved?
Consider two numbers $a,b$ WLOG $a\geq b$
We assume they are not equal
$$a + a + a + ...\text{b times} \neq b + b + b+ ... \text{a times}$$
Since $a>b$, we write ($a=b$ case is trivial)
$$(a-b) + ... \text{b times} \neq b+b+... \text{a-b times} $$
We repeat the procedure finitely many times till the two numbers are equal, and then it becomes trivial $c\times c=c\times c$
Adhi
@zenith owl is this satisfactory?
This is the best I could think of using the least vague axioms
we only used equals subtracted from equals are equals and also we have to repeat the procedure for whichever is lesser than the other
i didn't understand it quite well
i got lost on the second step
@zenith owl Has your question been resolved?
@zenith owl Has your question been resolved?
if you consider commutativity for natural numbers as @celest frigate showed above, then you can show it for rational numbers if you consider them as ordered pairs $(p,q) \in \mathbb{Z}\cdot\mathbb{Z^*}$
Annie Maqionde
And define equivalence relations etc on them
for real numbers, dedekind cuts might be useful
@zenith owl Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Q 10 im not sure if the way i am answering the question answers it, if u know what i mean
It says algebraically, right? Also, it seems cut.
There's no need to involve gradients, I believe.
You can just make use of the equation of the line, substituting it to the eq of the circle
Aren't you able to get the value of y in terms of x? Use it
think about how it may manifest algebraically that the line and circle would be tangent (ie have exactly one point in common)
So i should find the contact point first?
You have to prove it first that it's tangent before finding the contact point.
O well i found the contact point
Something ti do with right angles?
Perpendicular
ok i feel like there has been a "missed forest for the trees" moment
can you show your work
Ill quickly rewrite it
Is it ok if i hold this channel while i eat shouldnt be too long
ok so you reduced the thing to a quadratic in x
and you solved it, and -- importantly -- you found that its discriminant is zero and that it has only one solution.
@spiral plover Has your question been resolved?
Sorry im back
Is this enough evidence to prove that its a tangent
Yes
Closed by @spiral plover
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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 don't. get this
what don't you get?
@lost laurel Has your question been resolved?
Closed by @lost laurel
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
pretty sure its B..
top right
i didnt see the option markings were removed sry
$\binom{55}{r-1}2^{55-(r-1)}(\frac{1}{3})^{r-1} = \binom{55}{r}2^{55-r}(\frac{1}{3})^{r}$
use calculator to check ur answer
and the other options
coeff of $x^r$ is $\binom{55}{r}2^{55-r}(\frac{1}{3})^{r}$
yeah but i don't want to just trip over on the same mistake in the calculator
its just the off-by-one error thats ticking me off
u can see the formula so it's hard to make a mistake
do u need like a package to use \binom
dont think so
i just wanted extra validation from someone
so
sheaf of stacks
tbh a calculator might have difficulty handling this
@glossy dew Has your question been resolved?
I agree
Closed by @glossy dew
Use .reopen if this was a mistake.
@glossy dew Maple also agrees
You can see the two equal coefficients in the expansion!
That's all that matters
@glossy dew It is 7th and 8th btw, not 8th and 9th
Idk what B is in your picture
no its 8th and 9th in what you showed too
the computer decided to troll me by placing the x term at the start
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello. Suppose we wanna solve the equation: z^6 = -1, and graph the solutions in the complex plane. now, i dont rlly remember the solutions, but my question is: if we find the argument and (i think) the root of unity, can we just write it in the form of re^(i(Arg(z)+2kπ) for k=0,1,2,...,5 and graph it easily like that? I ask this because our professor hasnt taught us the exponential form and we have to evaluate the trig functions and get it down to the form of a+bi. Or is the exponential form missing smth?
I'm quite sure that the solutions are ||evenly spaced out around a circle of unit length||, so I'm not sure how correct that expression is on first inspection.
the idea of using roots of unity might apply but in a slightly different way, I believe?
(do wait for other helpers though. I am not confident in this.)
the good thing about equations of the form z^n = k is that you only need to find one solution
That is correct
Now observe that if points are evenly spaced around a circle, then you can get from one to the next by multiplying a root of unity
we need only find the argument and the absolute value of one of the roots right?
Yes
ohhh i didnt know that
and theta is pi
I can never remember but I think so yea
hmm so we only need to find how many degrees the root of unity rotates smth upon multiplying then right?
That's easy no, the principal nth root of unity rotates it by 360/n degrees
Cuz applying it n times takes you to 360
true
Closed by @modest shadow
Use .reopen if this was a mistake.
im having trouble in class cuz i missed a week lol
Btw just as a general tip
For complex numbers
If it involves multiplication/division you are better off using the polar (exponential) form usually
our prof doesnt allow us to use it in exams lmao
If it involves addition/subtraction you are better off using the rectangular form
I wonder what caused that hmm...
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
why isn't the answer of this the integral of x^2-3 added with the integral of 1
between the bounds of -2 and 2
What do you mean by with
Addition? Subtraction?
unless im interpreting this wrong
it seems intuitive to just add them both
I presume the question asks for area of shaded region?
between the bounds
How?
yes
Youre adding the strip twice
I thought that the integral was just the area of the function relative to the restriction of the x-axis
like how I shaded in the two graphs above
Integral is signed area.
When u take - 2 to 2 bound for g(x) = 1 you are including the unshaded patch which ive outlined with blue
Moreover, integrating -2 to 2 for the parabola will most likely give u a negative answer
Since again, integral is signed area, not just area
You will have to do quite a bit of work if youre integrating wrt x
so the answer is just the integral of g(x)-f(x) between the bounds of [-2,2]?
Take some time to process what ive said
Because you're still wrong
Not tryna demotivate you, just want you to think a bit
I just used the method I just said and it was the correct answer according to the textbook
Yes youre right
Im stupid lol
Thats the correct method
in the example where there isn't the small unshaded patch
am I able to use the method I used before of just adding
because the two functions would just compliment eachother
and not interfere
or no
.close
Closed by @rotund token
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
How are you meant to integrate 1/(k - root x) dx
.close
Closed by @spiral leaf
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Can anyone explain me the Recursive Relations in Sequence and Series?
.close
Closed by @coarse lodge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
is there a faster way to get to the answer or atleast deduce from the multiple choice?
I first did: 2x+2=(3−sqrt(x))^2
then got to the 7−x=6sqrt(x)
then (7−x)^2=36x
x^2−50x+49=0
then used the long ass quadratic formula to find the x
x = 49
x = 1
this process is not ideal for me, cause i have an exam with 50 questions for 30 minutes...
plug everything in
that's the fastest way
ahh
x cant be negative
and 49 would give a negative rhs
yep
yh
when you square an equation you have to check all the roots in the end, by squaring you can sometimes add some extra solutions, which arent sols
in this case, this extra-root was 49
so this is another reason why just plugging everything in is much faster
Closed by @heavy jay
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
are there any tricks to understanding how to do part b?
i know its asking to find the integral of the marginal-cost function between 0 and 25.
the problem im having is with the u-substitution. (its complicated for me) usually i'd just u-sub everything inside the sqrt. here it doesnt seem to work (?)
looking for general advice on what to do in cases like this and what to look for
Well, I'm not sure this could help but you could look at the power of q.
total cost = sum of all marginal cost
But since you have a derivative, it's the integral instead of a sum
when i checked ai it suggested usubbing for just q^3/4. is that what you meant too?
this also means i could solve it by...solving for the sum of all marginal costs by substituting in q=0....25? + fixed costs at the end
yes. try it and see
You can try 🥀
dont have time for it rn, but maybe if im stuck on my exam i will use that trick. it does sound right
maybe a follow up to all this would be how to solve, using words if you (anyone) doesnt want to work out the math fully for me to see 😬
Still part b, I assume?
q^3/2 works like a charm actually, it cancels things nicely.
So, I suggest observing all the possible values you can substitute for u to make the problem look easier. In this case it was: q^3/2
@pulsar relic Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
Closed by @split dirge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• Do not immediately ping people or roles. After 15 minutes, feel free to ping <@&286206848099549185> once.
• 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.
hey, i dont get how to solve this page
oh do you need help on your test?
yeah its a practice test but the test is near the same level as the actual exam im about to do
i get circle theorem and that but im not sure what rule i have to apply here
work out DBA from the internal angles of a quadrilateral
from there you can get DBC = DCB
is that 360 - 90 - 112 - 52?
correct
i got 106 for the last angle in the quadrilateral, not sure what to do now
180-106?
well, if the angle created by DBA + DBC = 180, and DBA = 106, we can see what DBC is
yes
okay
i got 74 for this, i know that two angles in an isocles triangle = eachother, not sure what the next step is, chatgpt is saying i should divide 74/2
bad bot
think about it, which two angles are identical?
within the triangle DBC
DBC = DCB?
and to make sure you understand, why these two?
so would it be 180 - 74 - 74?
they are from the same chord and have the lines to indicate
it's been too long 😂 I forgot what a chord was, but they're the two identical angles in the isoceles triangle because they are not the angle that's sandwiched between the two identical lines
yes, x would be that
okay i understand thank u!
ty
Are you done with the problem? If so, you may want to close the channel. If not, I could help because I just learned this so it's fresh in my memory
i have other problems i need help with if youre free?
Mhm! Ok. I know geometry tho, not functions, although I'm sure I could figure it out
no dont think so
Aw dang it that would be the simplest way to solve it
i bet itd be easy to learn then?
Ah kinda but your teacher may not want you to use it
yeah true
Basically, a secant is a line segment that passes through the circle such that one end is on the other circle and the other end passes through the circle out the other end. Two secants meeting outside the circle form a secant secant angle. The major arc minus the minor arc divided by 2 equals the secant secant angle
You don't need to know that for your class tho lol
lol i kinda get it tho
Its very handy. The proof is relatively simple too. Id recommend checking it out if you're interested
Imma try and figure out a different way to solve your problem tho lol
Well, you know angle DOB
I'm not sure if I'm supposed to intervene since I'm new here so sorry about that but it does say that co = ce
And that makes an isosceles triangle
Oh you can intervene it's fine
So that means finding this angle in red is x
Oh alright
oh i didnt notice yeah ur right
And finding angle DCO is 2x
That's why secant secant angles would be so helpful tho. (69-x)/2=x
Wait I'm dumb 😭
DCO is also isosceles because of the radii
So angle DOC is 180-4x
Its simple from there
Hey Xen have you solved it yet? If not, I can give you hints
The main thing to remember is that triangle DCO is also isosceles
i understand this but im not sure what to do with it
Oh ok
Well, a triangle adds up to 180
So does a line
So angle DCO =angle CEO plus angle COE
Does that make sense?
So angle DCO is 2x
You get why?



