#help-23
1 messages · Page 378 of 1
ok I think question 2 is true, I'll write some explanation
I take question 2 as:
if B and C are one A* step apart, then is any point on the line from A to C at most one A* step apart from the line from A to B?
The case where the lines are the furthest apart is when A is infinitely far away and the lines are almost parallel, so I will assume that the lines are simply parallel.
Let D be some point on the line from A to C.
Because the lines are parallel, there is a point on the line from A to B that is exactly one A* step apart from D. (the points have the same offset from the center of the tile)
So it is true for the parallel case, and in any other case, the lines are closer so it is true as well.
i have no idea what your talking about but its 1 am
oh hmm
if what you said is right then it proves what your seeing here? i tried to run it with this logic
If the "border strip" is all the tiles that are at most one A* step away from the line A to B, then the property is true. (I think this is the same as what I tried to say)
what is a border strip and what is A* step away
You mentioned it here:
"one A* step in an 8-neighbor direction (up/down/left/right/diagonal by 1 tile)"
and "Is it true that the straight move from A to C can only touch new tiles in a small “border strip” on the side corresponding to the direction B\to C?"
A border strip is generally a line (strip) that is right next to (borders) something, in this case the line from A to B in the question.
I don't know how to explain it besides how you described it at the moment
for example if you are at the black circle, then all gray squares are one A* step away
yes i get it now
i just dont understand your proof its too complicated for me 😭
especially D
il try to get things straight its a bit late, can i get back to you later? i dont want to trouble you @chilly plover
il check your proof tomorrow and get things straightened
thanks
yes, but no guarantees in how fast I respond
(let me know which part you don't understand or if it is just all of it)
<@&268886789983436800> ? ^^
What the hell!?
What
okkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
probably better to open your own help channel else no one's gonna see u fr
what's bro's question?
@cosmic sparrow Has your question been resolved?
!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).
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.
for b.) how did they know f(2) is a minimum
They differentiated f(x) and set it equal to zero in order to find the x-value of the extrema point
ik but that only tells u where the turning point is
it doesn't tell u whether the turning point is a minimum or maximum
well then find $f''(x)$
1 divided by 0 equals Infinity
how does the second derivative tell me whether the value is a minimum or maximum/
sub the x value where f'(x) = 0 into the second derivative
if >0 the graph is concave up
<0 concave down
= 0 inconclusive
local maximum
local minimum
hmm this is a lot of work for a simple question that's worth 3 points only
in the grading scheme, they have made no mention whatsoever of finding a second derivative
p.s differentiating f(x) a second time is a pain in the neck
but i suppose there's no other way
what's the function?
.
oh you already sent it here
nah not allowed in an exam
den no
Calculating the second derivative for exercises like this is very usual tbf
for the record
i dont think we've been taught that
taking second derivative
then pluggin in value
no wait
No!Division by zero does not exist because there is no number that, when multiplied by zero, results in the dividend. 2/0=0 0x0<>2
wrong channel i think
You can also find all f'(x) = 0, which are all candidates for maxima or minima. Then choose values slightly less and slightly greater than those points to determine the sign of f'(x). Then you can interpret sign changes from positive -> negative will be a local maximum, negative -> positive local minimum
No sign change --> neither max or min
But just taking the second derivative is easier imo^
Closed by @river needle
Use .reopen if this was a mistake.
😭
31st bait
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.
Hi I was just wondering if anybody can do these math problems for me
I did a rough translation but and it may not be accurate but I hope it helps
No one is going to do them for you
Someone will help you solve them though if you're having trouble doing so yourself
Well I kinda don't understand the whole subject so yeah
!noans still
The purpose of this server is to help you learn; please don't ask for direct answers. Ask for guidance, explanations, or feedback instead.
@round temple 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.
Is my parabola correct? Why does it seem incomplete
,rcw
you seem to not have taken any negative x-values. that's the only thing I can say
Parabola seems look ok
and that is probably the reason it feels incomplete
but otherwise there's nothing inherently wrong with the parabola itself.
@oak dagger Has your question been resolved?
react to the bot then. the bot cannot read text responses.
(ping)
@oak dagger 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.
Rlly quick question
The mark scheme said 2.2-2.21 so would i still get the mark or no
Bc i basically did what the mark scheme said to do
,w 1.6 / cos(42 deg)
I got 2.15 bc rounded too early so
you rounded too early
O
yeah you should keep 1.6 to like 6 dp
you wouldnt get the mark
So next time just round at the end right
just to be safe
Oh okok
exactly!
you would get M1 but not A1
don't round intermediate steps that much
no worries
Closed by @covert talon
Use .reopen if this was a mistake.
.reopen
✅ Original question: #help-23 message
say 1 = n
how can you write 2 and 3 in terms of n?
2n and 3n
that's correct, but there's another way using addition
5n
no, don't use these
(2+1)
for any general n, can you express the nth term in this sequence
(n+1)?
you know that you always divide by 2
let's look at the numerator for some terms
for 3, it's (3)(4),
for 4 it's (4)(5),
for 5 it's (5)(6)
to find the next number after n, it's n + 1 right
can you see a relation here
so what you need is the next number after the next number
ohhh yes
so how would you express the nth term
don't forget the 2
n(n+1)/2
ohh
yes, so that's correct for (number * next number)/2
how about (next number * next next number)/2
n(n+2)/2?
close
look at this
you were closer with this attempt
what would be the number after n?
yes but put brackets and don't forget 2
oh so its
there we go you have the right idea
(n+1)(n+2)/2
okay now add both the terms
don't expand
you have [ n(n + 1) + (n + 1)(n + 2) ] / 2 if you add both fractions
which term is in common?
right!
so you can factor n(n + 1) + (n + 1)(n + 2)
(n + 1) * (...)
a simpler example is something like $2 \cdot x + x \cdot 3 = x \cdot (2 + 3)$
south
so is that x(3 + 2) = x (2 + 3)
south
well technically 2x+3x=x(2+3), factorisation is the important thing not commutivity
yeah, factoring is the distributive law but you do it backwards
if you've ever seen a(b + c) = ab + ac but never realised what it means
what we're doing here is starting from ab + ca
= ab + ac
= a (b + c)
2 * x + x * 3
= x * 2 + x * 3
= x * (2 + 3)
👍
how's it going with this
no, as I said, don't expand
(2n+2)
right!
yeah cause you just add n and (n + 2)
okay so $\frac{(n + 1)(2n + 2)}{2}$
south
you think you could factor something out of this
south
exponent?
that's not an exponent but yes
so what would be your final expression
(n+1)(n+1)
you want to simplify it
👍
yep
ohh
so annoying wtf and only for 4 marks 😭 legit all the harder higher mark ones r easier than this for me tbh
tysm tho
.close
Closed by @covert talon
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.
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.
Do you know how to solve Raabe Duhamel or Mac Lauren?
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.
we need to differentiate this expression wrt x
please help
Write it y = this
yeah
You will get a differential equation
you will get y² - sin²(x) = y
2yy' - 2sin(x)cos(x) = y'
y = this
Then square both sides
Differentiate both sides wrt x
Solve the DE
Assuming x belong to an interval where y is actually differentiable also
Closed by @granite dove
Use .reopen if this was a mistake.
.reopen
✅ Original question: #help-23 message
I am sorry but I needed to ask one thing that how did you write that entire infinity series just as sin sq (x)
-# y^2 - sin(x)^2 = y requires differential equations...?
idk how they got this but
you could just do quadratic equation if u wanted to
when y = this
square both sides
y^2 = sin(x)^2 + that infinite series which is just y again
yeah but even if i square what about the rest of the roots in there
so y^2 = sin(x)^2 + y
there are no roots left the equation simplifies, see what car did!
ohh wait i think i get it now... yeah
it's y all over again
thank you so much everyone
elligant
anyways, can i dm you?
.close
Closed by @granite dove
Use .reopen if this was a mistake.
sure? about...
or.. nvm i can ask about the differential equation part in hlounge
about the requiring differnetial equations
bc you ?'ed
I dont see how this requires differnetial equations
it is just an implicit function... no?
.oh- so why did you ? me 😭
y^2= sin^2 x + y
.and why did they say this
.yeah that was confusing, "solve the de" doesnt make sense
Maye she meant Differential equation.. maybe she confused it with integration by any chance
2y dy/dx = 2sin(x)cos(x) + dy/dx
this is very easy.... not a differential equation- i hope..?
.(sorry i got confused by what you meant
.its okay!
.this is called a differential equation but yeah we dont need to "solve" it , if we did we would get the question 🥀
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.
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.
.close
the channel is already closed. you also cant close other people's channels if they're claimed.
Sorry
no dont worry 😭
ty! we should stop talking here
or... some pink person might...
us
well- not ban but warn
so lets avoid the hustle
and stay silent!!!
❤️
Or send a 
-# oh no!!!!! its a pink person!!!!!
-# that can only be done by one pink person 
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.
yes, 3/8 is correct, and your reasoning is correct
however you stated it wrong at the end:
that probability of that event is 1/8
but that's only one of the three ways to get two heads and one tail
if you had said P(two heads and one tail) = 3/8, that would be correct
yw
Yeah, whatever its tail or head they play a symetric role
.close
Closed by @halcyon light
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 dont really understand what theyre saying in the solution here
I think this means the derivative is negative between 0 and 2pi
But idk how they got that or what to do with this information
Wait I see now that tells us its a local max at 0 and min at 2pi
But I still dont see how they got that its negative between 0 and 2pi
if theta varies between 0 and 2pi, what interval is theta/2 over?
What do you mean by interval sry
like lower and upper bound
$0 \le \theta \le 2\pi$ therefore $? \le \frac{\theta}{2} \le ?$
cloud ☁
Positive?
Negative
Ok makes sense, but how do we then know that it becomes positive when theta < 0 or theta > 2pi
you can do a similar analysis
Closed by @steep magnet
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.
matrix multiplication:
i have
A =
(1 # 2 # 2
1 # 2 # 1)
and B =
(1 # 2
3 # 1
1 # 1)
C = A * B; my solution: C=
(5 # 10
12 # 4)
I did
(B0,0 * (A0,0 + A0,1 + A0,2) # B00,1 * (A0,0 + A0,1 + A0,2)
B1,0 * (A1,0 + A1,1 + A1,2) # B1,1 * (A1,0 + A1,1 + A1,2))
is it correct?
ok, that s what i exepted, i did some of these tasks, and all of my solutions were wrong
i though it should result in a 2x2 matrix so, why should i use Bi,2
well you have to get a 2x2 matrix
well you still used all entries of A
and use all elements
why did you use that
with the same flawed logic you shouldnt need all entries of A either
wait, i think i got it, let me retry
i will send the solution
(25 # 20
20 # 16)
no
i did A0 row times B0 column -> A0 row times B1 column
same for A1
you need to take the rows of A and the columns of B
i did A0,i times Bj,0
(5+10+10 # 4+8+8
5+10+5 # 4+8+8)
thats how i got to that result
from where are those 5 and 10 and 10
wait
did you use your wrong result for C?
A0,0 * (B0,0 + B1,0 + B2,0) + A0,1 * (B0,0 + B1,0 + B2,0) + A0,2 * (B0,0 + B1,0 + B2,0)
1 * (1 + 3+ 1) + 2 * (1 + 3+ 1) + 2 * (1 + 3+ 1) = 5 + 10 + 10
= C0,0 (in my solution)
ah ok
that would result into C0,0?
yes
ok, so my result would be
(9 # 6
8 # 5)
yes
Closed by @acoustic zealot
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.
The question:
Kenny is thinking of two numbers greater then 10.
He says: "The highest common factor (HCF) of my two numbers is 7"
"The lowest common multiple (LCM) of my two numbers is 84"
Write down the two numbers Kenny is thinking of.
What I want to know:
Short way to answer the question quickly and correctly using a venn diagram.
I'd start by fatorizing 84 into primes
Wait gonna do it
2, 2, 3, 7
okay, now the venn diagrams
each circle will represent one of the numbers and it will contains its prime factors
the intersection is gonna contain HCF
and the union is gonna contain factors of lcm
Whats gcd?
Oh k
okay so we will start like this
now we gotta put those somewhere
both 2's must be in the same circle, because if they were in different circles, then we would have to put them to the intersection part
but the intersection part has to be only 7
okay, this almost works. But both numbers have to be > 10
your left circle number is just 7
so you gotta move the 3 to the left circle
But the only factors of 7 is 7 and 1 its prime
i think you misunderstood what i meant
lcm is the all the factors in both circles
hcf consists of the factors in the intersection
first num consists of factors in left circle, 2nd num consists of factors in the second circle
so we start by placing 7 in the intersection (this part is obvious, 7 is in the HCF and HCF must be in the intersection)
Im just wondering how the 3 came to the first number?
in this case, your first number would be just 7
but the question wants both numbers to be greater than 10
so you must move 3 to the first circle, to make the first number 7*3 = 21
So we place it in left circle due to that.
yep
Ahh
if there wasnt the >10 condition, this would be also vaid solution
So we got 21 and what would be the other how to work it out
corresponding to the numbers (7, 84)
yep
np
Shall I close now then?
hmm, @frozen veldt seems to be typing sth
Yh rlly long
let's wait for a while
there is some caveats to this method, so i think he is going to point them out
sorry
.
I have nothing worthwhile to add
Right thats the caveats
I just wrote my own solution
here it was
HCF = take the factors that are in both
LCM = take all the factors that are in both, with the highest power winning if they contain the same prime factor
we need both numbers to contain 7
we need both numbers combined to produce precisely 2, 2, 3 and 7
7 alone is not enough because it's not greater than 10
so maybe 7*2 works
now the second number has to have a 7 and a 3 but can't have a 2 so as to not contaminate the HCF
does 7*3 work? yes
but now the LCM doesn't work because we don't have enough twos, so we need
7*2*2 and 7*3 and that works because both are greater than 10
oh ic
Its good gng
ill add the caveats myself then
Firstly, you must be careful not to do sth like this
do you know why this is wrong?
Why cant the 2 go there?
Because if there is a 2 in both circles, then they actually belongs in their intersection
but they cant be in the intersection, since that would make the HCF 7 * 2 * 2 instead
Ohhhhhh!
I think a venn diagram is a weird way to visualize this
I need this for test Im revising currently
It kinda is, but it works if you think of it as multisets instead
so for example we cant draw a diagram like this
2 on both intersections
the corrected version would look like this
Yes, but note that the other 2 stays there. You always take them in pairs
we take one 2 from the left circle and one 2 from the right and bring them to the middle as a single 2
and repeat this process until there are no 2 same factors
nevermind I think a venn diagram is a good way to visualize this
Yea
Coprime way and those other ways dont like them
I guess for this reason I don't really like it so much though
because it's very easy to draw the diagram wrong
If you have a sharp eye you good
the only reason it feels weird to see the venn diagram for the first time is that we arent used to dealing with multisets
and thats exactly the same reason why the normal method may feel weird
I don't know what the normal method is but if you just eyeball the gcd and the lcm then there's no way you'd get them wrong because reading the gcd and the lcm out of a prime factorization is something even a toddler can do
because reading the gcd and the lcm out of a prime factorization is something even a toddler can do
This is what i meant by the normal method lol
I generally prefer guessing and checking in mathematics, works in a lot of cases like simple integrals
sure, but you gotta have intutition to guess effectively. and that intuition needs to be built somehow
Intution is technically a gamble
I wouldn't call it intuition that the gcd is easier to visualize than the lcm
but your chances are improving after every round 🔥
that's pretty much the first observation you make when you learn these things
so it makes sense to start with the gcd
and after that it's pretty straightforward to fill in whatever you need to satisfy the lcm
Well, I've seen a lot of interesting observations from my classmates
the only problem was 90% of them were wrong
but ig this is offtopic now
If you have no other questions, I think you can close this now @charred trench
Closed by @charred trench
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.
AES-Cryption:
could you correct my solution?
I mean, not if i there are misstakes, more if i generally did the correct steps
the green arrow are notes, i did while i was in the lecture. they have no connection to the current task
if the green highlighted number looks weird. i just did write 2B as a byte and bitshifted it.
@acoustic zealot Has your question been resolved?
Closed by @acoustic zealot
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.
@noble spindle Has your question been resolved?
?

.close
Closed by @median vigil
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• 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.
[This is a test]
Hallo can someone halp me with fractions they're very hard
Sure, How can we help you
.close
Closed by @exotic anvil
Use .reopen if this was a mistake.
have u tried putting them in a blender that should soften them up
@exotic anvil why do you have three channels?

I was doing a test
@mods acadishon
blud
do you think obsidian counts the same as help channels
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.
No
blud
.close
.close
Closed by @tight nova
Use .reopen if this was a mistake.
Closed by @median vigil
Use .reopen if this was a mistake.
Closed by @keen tulip
Use .reopen if this was a mistake.
wtf
beautiful
@rustic goblet hello!
anyhow, you can open two channels if you do it in quick succession
but you can't open three
and the second will tell you off if you don't close the first one
I meant lance has three channels with his name in them
^
obsidian doesn't count as a help channel 
why 25 specifically?
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.
Look at my name 
.close
Closed by @tight nova
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 understand that the max value is (1,2) and no points of inflection. Should the min value be (3,-2)? The answer key doesn't have any min value so I was wondering if it is a mistake or there really is no min value
f is continuous on [0,3]. Reconsider your graph
If f is only defined on [0,3], then you're correct about the min
would it look smth like this?
Yeah that looks good!
Closed by @still grove
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.
So, some say dozenal is a better way to count, others seximal! Those who dare even more say binary is the best way to count. But, what if we've got it all wrong, and there's a better way to maths (maths as a verb like in Toki Pona) that isn't counting? Even if there isn't a better way than what we have now, what might alternatives look like? What I'm circling around, if the above wasn't a good enough description, is the primitive system. Not foundational/axioms. If there is no alternative either, or if this is just too hard to answer, then that's an answer too.
I've thought about this a lot myself and personally have settled on binary though I'm not really asking about bases or looking to debate, sorry.
Two line summary
so wait hold on, what are you looking for a better way to do, exactly?
- Human: base 10
- Computers: base 2
Is counting the only way to primitively represent math?
^^^
not a numeration system, and not axioms, but what
what do you mean by "primitively represent math"
no one counts after learning algebra
Apart when $\frac{n(n + 1)}{2}$ exists
1 divided by 0 equals Infinity
This isn't my question sry.
your question is a bit vague
Prety much is there an alternative to counting.
?? multiplication??
an alternative to what end
There's a lot of debate about how to count with bases and stuff but I'm just asking if the idea which this is based on is wrong.
Answers too could just be that no there isn't an alternative or this question can't be answered.
i think that nobody here understands what you're talking about or what kind of "alternative" you are even envisioning.
and when i say "nobody here", i mean "maybe not even yourself".
Yeah
I will take that as there is no alternative
By this I meant like primitive in daily life. For example, price tags and such use counting numbers.
ok and how are you going to get any sort of economic task done if numbers in any way, shape or form are out of the picture?
"This is a stupid question" is a good answer and I'm leaning on this based of of what I'm hearing.
Good point, ty. I can't quite think of something else, so, yeah I suppose that answers my question.
!done?
If you are done with this channel, please mark your problem as solved by typing .close
Just one minute
I have something which I'm evaluating real quick
I can think of ranges but those still rely on counting numbers to a degree even if they're quantized. Order can't be done either without in some way representing the value that ties back to coutning numbers. Geometry could be used but it's just a roundabout way of replacing counting numbers while sitll having the same fundemental idea. Permutations like in group theory honestly maybe could contend but that's for me to look into and would answer the question, though not sure about this once since I am not familiar with group theory really.
At most I can think of parity (valid contender!), but parity alone is way too basic to get any modern maths done.
Tysm.
:3
!done
If you are done with this channel, please mark your problem as solved by typing .close
.close
Closed by @long galleon
Use .reopen if this was a mistake.
This was probably the dumbest interaction you've had all day, though if you were curious, the question which I was trying to ask (I have poor skills with articulating myself after the brain damage /srs) is if an alternative day to day representation of logic and all stuff math is regularly needed for existed or could meaningfully be conceived of. The answer is no, not really unless you want something extremely cumbersome. This has been in my head for several weeks.
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.
@halcyon light 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.
Prove through Induction:
Am I missing something.
How do i prove this
proof.
You basically, showed this
-
P(0) is true.
-
P(n) is true => P(n+1) is true.
so, since P(0) is shown to be true, it follows by (2), P(1) is true,
i.e., you get a chain of true statements, P(0), P(1), P(2),..., where the truthness is implied as follows,
P(0) => P(1) => P(2) => ....
Closed by @acoustic zealot
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 think there's something wrong with this problem but I'm not quite sure what is it
@cloud maple Has your question been resolved?
<@&286206848099549185> hi
hi
bc≤1 ?
1 ≥ b^2c^2(b^2-bc+c^2) ≥ b^3c^3
1 ≥ b^3c^3 với mọi b,c dương
okay ill leave this to an english helper
minimise question
?
backread
I can't read
.
I don't know that lauguge
that is english bro wtf
lmao what 😭💔
Wait nvm
My inequality is wrong
The equivalent inequality is not actually equivalent 😭
.close
Closed by @cloud maple
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.
\lm this is kind of a weird question but what do the coordinates entail here? Like, do we say [
s_1: (\varphi_1(t), \varphi_2(t)) = (-\alpha, \alpha)?
]
that don't make much sense tho idk
\lm $\varphi_1$ and $\varphi_2$ are meant to be basis functions that you can construct any function in that system with. So in the above case you would have [
s_1(t) = -\alpha\varphi_1(t) +\alpha\varphi_2(t)
]
but obviously in that case this wouldnt make sense
@opaque fern Has your question been resolved?
We have $f:\mathbb{R}^{2}\mapsto \text{Set of some functions}$ defined by
$$f((x,y))=x\varphi_{1}(t)+y\varphi_{2}(t)$$
If we let $p_{1}=(-\alpha,\alpha)$, we get:
$$f(p_{1})=s_{1}$$
Closed due to timeout
Use .reopen if this was a mistake.
BBMaths
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 would say yes
Closed by @thin lion
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.
Hello! Im back again
I feel like with other parts of real analsyis, it all feels very rigorosu when writng but idk with series
like is this wht someone marking wants me to realise?
You could even make the first one less rigorous 😉 Notice the geometric series with 8/25 < 1
wdym here
Well it's obviously not wrong, just unnecessary to use the root test once you've reduced it to a geometric series already
Is that fine? Just as a rough idea here, I’ll put the series in after
Oh yea true 😭
Could have just evaluated the geometric series tbh
Wait no Idt this is correct either 😅
wait i do use root test for this right?
just cause of the 2^n
Have you learned ratio test (d'Alembert)
ah i see
It's like 4 lines to prove its convergence
yea i overthought it
not sure why i decided to randomly do comparison test in the middle of ratio test
alr tysm
.close
Closed by @thin lion
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 need someone help me explain this really fast
when loga(b)=x, why a has to be greater than 0
if a was say -2, then the equation would be
(-2)^x = b
just started logarithm so kinda confused
it would be the inverse of (-2)^x
Because it means ln(b)/ln(a) = x
are u familiar with exponentials?
i havent learnt about ln
yea
the main issue is that exponentials with negative bases behave very badly,
for example (-2)^1/3 would be -cbrt(2)
but (-2)^1/2 isnt even defined (you cant have square root of negative numbers)
who knows what (-2)^pi would be
oh yeahhh, but some work, while some dont, why we have to conclude that a>0
(-2)^(28/81), which is very close to 1/3 would be around cbrt(2), which has opposite sign to (-2)^(1/3)
Yep
(-2)^x behaves so weirdly that we dont really want an inverse of that
im still very confused 😵💫
my point is that $\log_{-2}{x}$ would be an inverse of $(-2)^x$
MathIsAlwaysRight
Result:
1.4142135623731i
okay ignore this, its wrong
i thought that log-2(x) is that (-2)^n=x, why it is an inverse of (-2)^x
thats what inverse function means essentially
new to me
dont worry about it then
its just the fact that log_(-2)(x) depends on (-2)^x, which behaves very badly
so if we defined log_(-2)(x), it would also behave very badly
so we dont even bother defining it
this is how badly it behaves
undefined, a little bit further around -1.4 and another bit further its around 1.47
how can i write like this
its called latex, you can try it in #latex-testing
oh coollll
it works by putting $ $ around your equations
and the equations have to be written in special syntax
for example fractions are done using $\frac{1}{2}$, logs with $\log{x}$, $\sqrt{\text{or u can do square roots}}$
MathIsAlwaysRight
ohhhhh complicated
thanks for your timeee, im going to try it out, appreciate it a lot
np
Closed by @topaz furnace
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 got the right formula but I was just kinda guessing
I kinda knew that s = ln(t) and t = 1 and t = 2 would be bounds, not really sure why tho
isn't $\int_0^{\ln t}$ going to get you the region below the curve $s = \ln t$?
I also guessed that the missing bound would be 0, not sure why either
Bungo
I have no idea sorry
Heres the full solution
But yeah could someone maybe explain whats going on here
And here
Cause I got lucky with my answer but I want to understand what im actually doing
s is horizontal and t is vertical. You should start out by rewriting the curve to t = ...
Ok but what does s being horizontal and t being vertical tell us sry
I dont know what were doing
Just easier to interpret what 'above the curve' actually means if you rewrite them
Interpret it how sry
Well, it's harder to picture 'above' when the curve is written as s = ln t because 'above' normally refers to the vertical direction
That's why we rewrite to t = e^s
(It's easy to picure that you want t >= e^s)
Im so confused 😭
Ok i think im just going to try and find another video on this topic
.close
Closed by @steep magnet
Use .reopen if this was a mistake.
If anyone has a good video pls ping me and send it
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.
Hi, can someone explain to me how Rodrigues rotation formula works? Thanks
In the theory of three-dimensional rotation, Rodrigues' rotation formula, named after Olinde Rodrigues, is an efficient algorithm for rotating a vector in space, given an axis and angle of rotation. By extension, this can be used to transform all three basis vectors to compute a rotation matrix in SO(3), the group of all rotation matrices, from ...
this one? @eager junco
@eager junco Has your question been resolved?
Yes
Closed by @eager junco
Use .reopen if this was a mistake.
.reopen
✅ Original question: #help-23 message
I know basics operations of vector, but not much after that
did you read the wikipedia article at least
do you understand up to the point where v is decomposed into a component parallel to k and a component perpendicular to k
What’s before that?
I know that the cross product gives one of the two perpendicular vectors
Is v rot the answer we are trying to get?
yes
Ok, what about w?
$\bd{k}$ and $\bd{v}_{\perp}$ are perpendicular (by construction); $\bd{w}$ is perpendicular to them both (also by construction) and completes an orthogonal triad (because we want that to happen)
Ann
Oh so is it v perpendicular cross v parallel?
v_perp crossed with k rather than with v_parallel.
that way $|\bd{w}| = |\bd{v}_{\perp}|$.
Ann
(but crossing with v_parallel would give the same direction)
Oh I see
So v parallel + v perpendicular = v?
I think I understand diagram now
@quasi bison may i know how these vectors are calculated?
yes
thats what it means to decompose v into a perp and parallel component relative to k
Got it
roughly speaking the recipe goes as follows:
\begin{enumerate}
\item calculate $\bd{v}_{\parallel}$ by projecting $\bd{v}$ onto $\bd{k}$ (via dot products)
\item calculate $\bd{v}_{\perp}$ as $\bd{v} - \bd{v}_{\parallel}$ (or via cross-product shenanigans as wikipedia gives)
\item calculate $\bd{w}$ as $\bd{v}_{\perp} \times \bd{k}$ --- a vector of the same length but rotated 90 degrees in the direction of rotation specified by $\bd{k}$
\item rotate $\bd{v}_{\perp}$ by angle $\theta$ in the plane spanned by $\bd{v}_{\perp}$ and $\bd{w}$
\item add $\bd{v}_{\parallel}$ back in
\item ???
\item profit
\end{enumerate}
Ann
Ok, according to the wiki, it says that v parallel = (v dot k)k
May I know which multiplication it is implying here?
Oh, nvm I forgot that do product returned a scalar
I understand now till step four.
dot means it's dot product.
do you mean that step 4 is where you're stuck
or that you understand step 4 and are stuck with 5
Stuck at step 4
Do I use the 2D rotation matrix here?
What does span mean?
do you know how to rotate a vector in R^2 about the origin by a specified angle theta
I think it’s by using matrix multiplication
Do I relate this to polar coordinates?
sure, you can express it in that way.
though maybe it's best that you brush up on your linalg.
Ok, just wondering, is it hard to figure out why Rodrigues rotation formula works after developing a good foundation?
not very, imo
it'll be a bit of a bash/slog but not like... terribly difficult once you grasp rotations in 2d and linear maps in general
Closed by @eager junco
Use .reopen if this was a mistake.
Have a good day 🙂
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.
We know that we can use summation for approximating areas under a curve $\f(x)$ by partitioning the area into rectangles of equal width deltax and the height defined as $\f(x_i)$, where $x_i$ is our endpoint (suppose right endpoint), $i$ is our index, and $i=1$. We do this for $n$ subdivisions, and the evaluation of our sum tends to the true area under the curve as $n$ is set to larger and larger integer values. In fact, we can evaluate the limit as $n\rightarrow\infty$ of this sum to find the exact area under the curve, leading to the integral.
We turn our attention now to the product. What can we do to find geometric purpose with the product?
You may find this interesting: https://en.wikipedia.org/wiki/Product_integral
A product integral is any product-based counterpart of the usual sum-based integral of calculus. The product integral was developed by the mathematician Vito Volterra in 1887 to solve systems of linear differential equations.
Ah I do see the product with expression 1+f(x_i)deltax. My problem arises from the idea of geometrically drawing this. I understand that this is not an expression of area, but that’s where my capacity of grasping the expression stops. How would I go about drawing this, as is possible with drawing Riemann sums?
It would be one thing to just accept the expression, but I want a geometric motive for it that I can see on paper.
<@&286206848099549185>
<@&286206848099549185>
<@&286206848099549185>
@fervent granite Has your question been resolved?
If no-one gives a good answer there is this: https://math.stackexchange.com/questions/1140507/is-there-a-geometric-interpretation-of-the-product-integral
If you have questions about it, I think more people might help
@fervent granite Has your question been resolved?
@fervent granite Has your question been resolved?
@fervent granite Has your question been resolved?
!15mins
Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.
stop spamming helpers
.close
Closed by @fervent granite
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.
From the top of a 12m high building, the angle of elevation of the top
of a cable tower is 60° and the angle of depression of its foot is 45°.
Determine the height of the tower
Guys I'm having problems visualising this and making a diagram which is important to do in the exam I need help in how you visualise this and also how to solve it
Are you confused about angle of elevation and depression?
Right and how to visualise it as well
Elevation would be when you're looking up
Found on Google from nagwa.com
If i were to make a diagram of this question how will i?
Start with a vertical line for the building
🎯NEET 2024 Paper Solutions with NEET Answer Key: https://www.youtube.com/watch?v=fwXYZUBp4m0&list=PLmdFyQYShrjc4OSwBsTiCoyPgl0TJTgon&index=1
📅🆓NEET Rank & College Predictor 2024: https://infinitylearn.com/neet-rank-predictor?utm_source=YouTube&utm_medium=NEETYT&utm_campaign=LIVE What do we mean by Angle of Elevation and Angle of Depress...
Try this
Closed by @trim lion
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.
What next
you didnt divide the 7
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.
The original post of this help channel has been deleted, and it will abruptly close and possibly lock. (This is irreversible.) Please claim a new channel, and don't delete the first message of any future channel you claim.
its cus im doing it on my apple pencil but for some reason it has some like autowrite thing
like it changes what i write
go open a new channel
Looks like a test.
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.
(Given a,b,c be non-negative real numbers such that ab+bc+ca > 0, prove the above inequality)
I instantly thought of using pqr method when looking at this, and the inequality also allows me to consider p = 1
But I still can't think of a way to work it out, especially the (1+√2)^2
What’s the pqr method?
Let p = a+b+c, q = ab+bc+ca and r = abc
Substituting (ka,kb,kc) into the inequality and it still holds, so we just need to consider p = a+b+c = 1
Yea
Where is this problem from?
https://www.scribd.com/document/472238275/a-b-2-b-c-2-c-a-2-pdf
A pdf that studies the term (a-b)^2(b-c)^2(c-a)^2 when using pqr
I dont think its possible lul
No way you can pull out the (1+√2) just using known inequalities

Maybe you define a function and then find that its minimum value is (1+sqrt2)^2
Well there's this inequality which can help in defining a function
except its
too long
Also one more note: the equality is attained if a = b = c, yes, but there's one more case and thats the main reason (1+√2) appears
[ \frac{(a^2+b^2+c^2)\left[(a-b)^2+(b-c)^2+(c-a)^2\right]}{2(ab+bc+ca)(a+b+c)^2} \ge \frac{(1+\sqrt{2})^2(a-b)^2(b-c)^2(c-a)^2}{(a+b)^2(b+c)^2(c+a)^2} ]
kheer257
Yes so discount the case where any two are equal and then divide through by the numerator on the left
@cloud maple Has your question been resolved?
@cloud maple Has your question been resolved?
@cloud maple 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.


