#help-26
1 messages · Page 12 of 1
guys is this politically correct
isnt "politically correct" a dogwhistle
are you serious or was this an attempt at a joke
hmmm because it was part of inverse function operation
so i also got confused
as these 2 are not equal
w8 i put whole
🤔
this is solved task btw
Maybe like
is the inverse
ok you've introduced like 5 symbols that we DON'T know the meanings of
has nothing to do with being equal
it dont matter just focus on x , p
those 2 are variables
like
in inverse
ye
from this context it would be correct?
idk what youre saying is equal though
🤔
to the left of P
very nice
no
🫠
@grim swift Has your question been resolved?
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I'm struggling with the pigeonhole principle formal definition in this example
Say I have the set S = {1,2, ... ,10}
And 5 subsets of S, each with 4 elements in it. Let's call them A_1, ... A_5. Let A = {A_1, ..., A_5}
Let R be a relation in AxS such that a set A_i is related to an element n if n is in A_i
R has cardinality 20 because each one of the five sets is related to four elements
Now, this inequality holds
There is some $A_i \in A$ such that $#{n\in S / A_i R n}\geq \frac{#R}{#A}$
casiel368
But #R/#A = 4
Oh hmm I see what is wrong
I want to prove that there is some number in two of the A_i
Using pigeonhole, because this is a toy problem for another one that can't be solved using the non-injectivity of a function
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How many 8-card hands are possible if you want: Two different 3-of-a-kinds and one 2-of-a-kind?
Why is it 13choose2 * 4choose3 * 4choose3 for the first part? Why isn't it 13choose1 * 4choose3 * 13choose1 * 4choose3?
two different 3 of a kinds
if you had 13 choose 1 twice, that would mean that the two 3-of-a-kinds could be the same card value
Oh, in that case could you do 13choose1 * 4choose3 * 12choose1 *4choose3?
in that case you would be saying that order matters
i.e. (three aces) and (three kings) would be treated as a separate case vs. (three kings) and (three aces)
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show that $\frac{\log 12}{\log 18}$ is irrational
bettimsucks
What step are you on?
1. I don't know where to begin
2. I have begun but got stuck midway
3. I got an answer but I'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
1
perhaps?
irrationality proofs usually use contradiction
how does that help?
so i consider it to be rational
?
bettimsucks
aaand $18^{\frac{p}{q}} = 12$
bettimsucks
how do i move forwards?
clear denominators, then factor
yes
write everything as powers of 2s and 3s
you should be able to get a contradiction from that
bettimsucks
@neon iron
yup 
there is only one thing this can be equal to
(you can use fundamental theorem of arithmetic)
p-2q = q -2p =0
?
yeaa
if i add those equations
i somehow get q=0
so it contradicts the fact that log thingy is rational
thus its irrational?]
yes correct 
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you gotta go get another channel
ok
if you delete your msg it will close no matter what
Okay
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Is it possible to take the reciprocal? Or is that not a rule
yeah i know how to solve the problem
just wondering if u can do that
thanks anyways
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partial fraction decomposition
@timid moth Has your question been resolved?
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.open
what do u need help with
my brain isnt braining
everything
b
alr
np
19
oh
12
shouldnt we be doing caitlins one
hers is the tallest
16
the answer is a number
because it wants the frequency
16
alr
I have to answer both first
a and b
7+9+2 is 18
so its 19
thanks!
Yes!
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cya!
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\begin{align*} P(z)&=z^2+1, \ Q(z)&=z^3+2, \ R(z)&=(z+1)^6 + P(z) \cdot Q(z). \end{align*}Note that $R(z)$ has degree $6$ and constant term $3,$ so it satisfies the conditions.
We need to find the solutions to\begin{align*} P(z) \cdot Q(z) &= (z+1)^6 + P(z) \cdot Q(z) \ 0 &= (z+1)^6. \end{align*}Clearly, the only distinct complex root is $-1,$ so our answer is $N=\boxed{\textbf{(B)} : 1}.$
can someone explain
auroraborealis13
can someone explain the last part of the problem
i dont understand the solution
specifically the part where i asked
see the first msg
i dont understand the last 3 lines
the question asks for solutions to P(z)*Q(z)=R(z)
yes
if you plug the definition of R(z) in this is then P(z)Q(z)=(z+1)^6+P(z)Q(z)
the P(z)Q(z) on both sides cancels
leaving just 0=(z+1)^6
which only has one solution
z=-1
why only 1 solution?
how do you know there aren't any complex solutions
its a product of terms that equals 0
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Please don't occupy multiple help channels.
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c
,tex .log rules
rie.mann
i know but
this one is a square root @sweet shard
which makes things awkward
if this was a regular natural log, this wouldnt be bad
like, the answer is there but idk how
how do you write a square root as a power?
the onl lead i have is that i should put a square root
square*
square to remove the square root
then youre left with ln Cx(axb)^2
wait a minute
howd the 2 become the denomiator then
recall that $\sqrt{x}=x^{\frac{1}{2}}$
mist9912
,tex .power rules
mist9912
ill google it
see fractional exponent
i think i might get it now
sq root(axb) would be the same as 2sqroot a x b
wait no
what am i even saying
np u shd try to apply the fractional exponent rule again
would 'c' in this question be 'n' in the fractional exponent picture?
hmm no
so would 'n' be 1?
notice how n in the picture is in superscript?
since theres no number on it
so i think itd be 1
and since i add a sqare outside the bracket
$\sqrt[2]{}$ means $\sqrt[]{}$
mist9912
'2' would be 'm'
take note of this
yea no one writes the 2 out
so you shouldnt but the square symbol outside of the bracket to get rid of the sq root?
mist9912
ohh i get it now
u can write sqrt x as x^1/2
but still
howd the 2 go on the denominator
look at power rule
just wondering how did u do the image embed code thingy
mist9912
ive never understood it either
ok anwyays
so after the first step,
it was the error code for my latex, you react to the code
the next step should be ln c(axb)^1/2 right?
press the emergency sign
yea
then c(1/2a x 1/2b) right?
well, since all of it is bracketed, i understand that I have to do the product rule
but which rule do you use to get the 2 on the denominator?
yes we shd now at least have $\ln{c}+\ln{a^{\frac{1}{2}}}+\ln{b^{\frac{1}{2}}}$
mist9912
uh
on the answer?
no this
do u mean sth like in the ans in red?
(ln a)/2 + (ln b)/2?
ik thats the answer but
since the exponent should go in front of the ln
i was wondering why it wouldnt be 1/2ln a + 1/2ln b
yes it is (1/2)lna + (1/2) lnb
waait a sec
OHHHHHHHHHHHHH
1/2 ln a is the same as lna/2 lol
i completely forgot
yea i hope u see it now
since taking the half of something means to divide it by 2
but would (1/2)lna + (1/2)lnb still be correct if I put it on an exam?
yes
np
@analog dome Has your question been resolved?
wait
1 lost question, if anyones still here
in this question, they used a square to get rid of the square root
but the fractional exponent property gave a different answer
wouldnt sqroot(x+2) be (x+2)^1/2?
Yes, you should end up with the same thing
e^1?
Yes, but are you sure it's e^1
yeah
And what happened to the fractional power?
and e is the base, which is 'a'
in the next step
(e^1)^1/2 = (x+2)^1/2
but this is where it gets confusing..
the original way was to just use a square to get rid of the sqroot, but i have to understand the fractional way
hmm let's start again with the fact that we know sqrt(x+2) = (x+2)^(1/2)
so the original equation is $\ln{\sqrt{x+2}}=1$
mist9912
yes
using this, we have $\ln{(x+2)^{\frac{1}{2}}}=1$
mist9912
do u see any log rule we can apply here?
yes, after applying the power rule, we have $\frac{1}{2}\ln{(x+2)}=1$
yeah
mist9912
so we should now multiply both sides by 2 to have $\ln(x+2)=2$
do u see what to do next?
mist9912
wait
just to clarify
we multiply both sides by 2 to get rid of the 1/2 behind the ln right?
yes
ok cool
i think ill probably but this in exponential form now
and try to solve from there
e^2 = x + 2
yes exactly
e^2 -2 = x
so that's your answer here
its the same answer!
nice
so it does work
ill do more practice with this so i can get better
thanks for the help once again
np
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<@&268886789983436800>
yeah mb
i was just stuck on a question but
when i posted it here, thats when i figured it out
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How would you do question 7a
I tried splitting the numerator into x^n-1 and x in order to get the In-2
But there is a log that messes the entire thing up
I also tried by parts with 1 and x^n/(1+x^2)
But then a tan inverse falls out
<@&286206848099549185>
<@&286206848099549185>
Add and subtract x^n-2 from x^n (add 0)
How does that help
You separate the fraction into 2 fractions the x^n + x^n-2 part and the -x^n-2 part
Oh
How did you see that
I tried to make the -I_n-2 part first
Is your first reaction for these questions to immediately apply by parts
Oh wait the question asked for algebraic manipulation
Thanks for the help
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✅
Sorry @thick musk but how would you simplify the x^n and x^n-2 terms
Integrate
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is the determinat e of something transposed the same as if it were not trasnsposed for matrixs
Yes
ok thanks
|A^T| = |A|
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how does simpson's 1/3 rule consider more than 3 points?
it doesnt seem ok to assume they lie on a parabola
what exactly do you mean? do you mean the composite version? you split up the interval [a,b] into several smaller ones and then use simpsons on each of those, then add stuff up
so each three consecutive terms get to be their own parabola?
like y0 y1 y2 and then y3 y4 y5
are two parabolas
basically
ok thanks
although you would let them overlap
hmm?
y0 y1 y2 is the first parabola and then y2 y3 y4 the next
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y=x-2
it is very simple
you draw a line between D and D'
and the perpendicular bisector of DD' is the line of reflection
close enough
with acurate measures
you can see that this line should have points (0,-2) and (2,0) on it
therefore the equation is y=x-2
first draw a line connecting D and D'
Then bisect this line perpendicularly
and then you get the equation
bisect
great
when a line is bisected
it means to split it into two half with the same measure
for exxample when you have a 10 meter line
to bisect it
you have to cut it into two 5 meter parts
yep
i think so
unless your teacher wants you to put your work in words
otherwise i think you are fine
yep
that is the line of reflection
Pythagorean theorem?
this question doesn't need that
it just asks you to find the equation that represents the line
long
the line of reflection
that is the long one
yep
sorry quick question
what grade are you?
oh me too
I am becomig 10th this year
extra studies + pain
good luck
you are welcome
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how can you find the time, when you are only given displacement equal to 250.8 m and a acceleration of 9.81meter per second squared?
,rccw
ah
so the object drops from rest. that's important info.
btw you should not have put those vector-arrows there
tbh just d = at^2/2
so that would be my equation?
i'll remove the vector arrows
and how did get that equation?
.close
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I just had two quick questions about the problem
- what does (n,m) = 1 mean?
- what does the dot next to the n mean?
(n,m) probably means gcd. So (n,m)=1 means n,m coprime
dunno what the dot means (probably some sort of typo)
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Why is the „3” equal to 1/3? https://media.discordapp.net/attachments/903430332324405288/1126138890688929854/307914411648090113.png
And how would you eliminate the 3?
You need to take the number 27 outside of the sqrt?
I am not sure what he is asking really tbh.
$\sqrt[3]{27} = 27^{\frac{1}{3}}$
redstoneplayz09
oh, that's what's he is asking xD
@stuck jay Has your question been resolved?
@stuck jay Has your question been resolved?
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rie.mann
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hiii sorry for the mess, I just started trig today and was given this question to do, I could solve the single triangle ones but this question has two triangles and I'm so lost and have no idea what i'm doing, can someone explain or guide me? I'm basically bullshitting my way through this question I have no idea what's going on
start by finding angle RPS
my goal is to find distance between p and q, I was going to use the adj of the entire triangle, and find the hyp, then find the opp of the entire triangle then subtract it by r-p to find p-q
based on already having the other two angles, and knowing the angles of a triangle sum to 180
okay :)
we have 31 already and the triangle is a right angle so 31+90 = 121-180 and I get 59
180 - 59 = 121 for spq
you already have the length of the hypotenuse, and now all 3 angles in the triangle
the other two side lengths should follow from law of sines / law of cosines
these angles are what I put next to the sin cos tan stuff? in the calculator?
not exactly
I don't understand how the inside of the triangle/angles are supposed to help me find the length of the triangle outside
I'm like so clueless
how do i find b and a ?
$\frac{11.45}{\sin{(125)}} = \frac{PQ}{\sin{(12)}}$
austinu
see how that works from your triangle?
then multiply both sides by sin(12)
and you will find the length of PQ
Where do I get 125 from ?
and also if I divide 11.45 by answer of sin (125)
how does that help me with anything for Pq/sin(12)?
I've never done this before
@weak estuary Has your question been resolved?
I just tried again and got p-q = 2cm
@weak estuary Has your question been resolved?
@weak estuary Has your question been resolved?
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Rest of the problems looks complicated ;-;
mostly just angle chasing
remember things like the sum of all angles of a quadrilateral is 360°, sum of angles of a triangle is 180°, straight line is 180°, right angle is 90°
Am trying to do problem e right now
When I tried to find x
I got 90
But then the answer page saids it’s 95
Why is that?
I’m soo confused
Okay so I found the answer for problem e
Just by imagining them as being co-interior angles
(Although it doesn’t seem like that)
How to do problem F exactly?
That shape looks like a triangle
Wait nvm
It’s not
<@&286206848099549185>
I’m not sure what my working out should look like
110?
not quite
90?
150?
yep
Wait
yes?
Okay ;-;
all angles tht mke up a line adds up to 180 degrees
yea
the 30 degree angle and the y degree angle = the line = 180 degree
make sense?
so 30 + y = 180
and y = 150
make sense?
Apparently y = 50 though
Oh right right
All good
anyway, that do the angles in a quadrilateral add up to
yea
The entire angles I have?
yea
Got it
r u done with f?
Mhm
Vertical angles
I don’t think I have learnt that yet
Other than
Knowing what vert. opp. Means
(Aka vertically opposite)
do they add up to 180 degree?
110 then?
70
okay
is thst all?
still have problem h and i
alr
;-;
isoceles
so
the idea is that base angles are always congruent for these types of triangle
got it?
got it
second image
sure
thanks so much
65 degree?
mhm
yeah thats kinda how it works
use the fact that the triangle is isosceles
the triangle is not equilateral
see you
hmmm
the angle next to 138 is 42 degrees right?
if that's the case...
2x + 42 = 180
you could also use exterior angles to get 2x = 138 directly
that's definitely not how i'd do it lol
he got a point though
since 180 - 42 is 138 anyway
if you want to do it that way go ahead yea
and then I just had to divided that by 2
which is
69
x = 69
:D
me finished now
thank you for the help!
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hello! sorry for the bother, can I get a second opinion on this, I'm really paranoid that this might be wrong because I have no idea what I'm doing, so the question is that I have to determine which pet of Hilary's is closer to catch, and my answer was dog, thank you very much : )
Greater angle=shorter distance
wait HWAT>???
only in this case
i mean im pretty sure it always applies if the angle is 90 or lower
for both sides I mean
looks right ?
okay thank you both very very much
hope you guys have a great night
appreciate the help : D
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I need help showing that the set of all functions f from N to N such that f is increasing is uncountable. I’ve made a list of functions f1, f2, … fn and i’ve listed out fi(0) fi(1) … fi(n) for all my functions. Is it sufficient to sum the diagonal (f0(0) + f1(1) + f2(2) … fn(n)) and call it a function f and say that it’s not in the list?
you seem to have a good idea but I can't quite tell what you mean. What would g(2) be?
i don’t have g?
g being the new function, sorry
oh it would just be f0(2) + f1(2) + f2(2) which isn’t listed?
so your g(0) would equal f0(0)?
you need to show that it's different than all of the f's
@craggy haven
yeah
like that
that seems like an okay pattern except again, what's g(0)?
how would i avoid this
same pattern but add 1 at the end?
simpler than yours
actually wait yeah fn(n) + 1 wouldn't always be increasing
because my first function could be f0(0) = graham's number
and my second function could be f1(1) = 1
but f1(1) has to be greater than f0(0) no? so that’s not possible
no, my second function is the identity function, which is increasing
hmm what should i do then
I think something like what you had with the f0(n) + f1(n) + f2(n) + ... + fn(n)
but add 1 to it?
okay how do i show that it’s increasing and not in the list tho
well not in the list is pretty straightforward
increasing you'll need to use the fact that each of the input functions are increasing
also, don't be afraid to dream big, if it's convenient to multiply things by 1000, or take their factorial, or whatever, go ahead and do that - there are plenty of natural numbers to work with
Okay got it how do i go about showing that the set of decreasing functions N->N is countable
cuz you sound like a bot lol
why does this feel so much harder than the increasing one 
i can't multiply literally everything together
oh countable
what does "decreasing" mean here? strictly or less-than-or-equal?
<=
ok because if it was strictly it'd be very very finite lmao
How would i go about this
essentially you need to make a list of all of them 
i would start by deciding whether 0 is a natural number or not
it is in my class
ok
if you kinda think about what it means to be a decreasing function on N, it's pretty restrictive, right?
yeah f(0) would be the largest value
so the range is kinda finite
yep
but, that doesn't mean that it'll always be 0 at a certain point, we could have f(x) = 3 for instance
hmm how would we go about listing
can't you ditch the increasing without loss of generality by using the cumulative sum of a sequence
we're on decreasing now
there's one function in particular that's especially stupid interesting
which is where i'd start my list
well, there's no largest natural number
i’m not sure then
what's the simplest function that would satisfy this?
what are you referring to by “this”
oh, that would be from N to N and decreasing
f(x)=-x
natural numbers aren't negative
hmmm f(x)=0 then
yeah, that one's kinda... baseline? like everything else seems to fall down to it
yeah that’s true
what i was thinking about was like, how does the choice of f(0) influence the rest of the function?
so in this case if f(0) = 0 how many decreasing functions are there?
2
think there are slightly more than that 
hold up let me think
yep i'm planning to let you go for at least like ten minutes on that
is this this with the function f(x)=1
that would be an example of a decreasing function that satisfies f(0) = 1
there are others though
wouldn’t the only 3 be f(x)=1 and f(x)=0 and f(x)=1-x
I guess they're allowed to be zero/one after a certain point?
Otherwise you have to change decreasing to nonincreasing, and that means there aren't a finite number
it is non increasing
the set of nonincreasing functions from N to N seems uncountable to me, but not sure
it says to prove that it’s countable so i think it is
hmm maybe it is countable
ah yes
i thought so at first as well
f(x) = 0 doesn't satisfy f(0) = 1 though
it does feel very similar to real numbers with terminating decimal representations though
think about it this way:
0 1 2 3 4 5 6 ...
--------------------------------------
f 1
how to fill in the rest of this table?
ahh damn there’s prob a bunch of functions tho
has to be less than or equal to 1
don't worry about formulas and stuff, a function is just the set of its input-output pairs
right?
ye correct
so what are your choices for f(1)?
okay if it's nonincreasing, I think I have a sketchy ass argument for it:
encode the function as a sequence of binary digits in the following manner:
start with m = 0 (which function value we're currently encoding)
- Add f(m) 1s to the binary sequence
- Add a 0 and increment m.
this thing is guaranteed to eventually repeat all 0s or all 1s, and then you can show that this set is contained within the rational numbers
uhh i think the answer involves showing that it’s part of a countable set or a union of countable sets
without binary digits
nah this is a common technique for various arguments
the binary thing is just an injection
decreasing, with the exception of zero is easier than nonincreasing, because you can guarantee that there are a finite number of functions with f(0) = n
but if it's nonincreasing, then it could go on forever
i'd stay away from the complexity of binary here
is there a way to do it without binary
yeah

so just limiting ourselves to the case where f(1) = 1, can you make a list of decreasing functions?
0 1 2 3 4 5 6 ...
----------------------
f 1 0 0 0 0 0 0 ... (you said this one earlier)
f 1 1 ? ?
but this only works if the problem asks about decreasing functions
if it's nonincreasing, then you can't say the list of functions corresponding to f(0) = n is finite
i can and i will
it can keep going on forever
oh not finite no but countable
you can but isn’t it infinite?
there are no strictly decreasing functions from N to N
yeah, so? as long as it's countably infinite we're good
yeah but maybe they put in an exception for 0 idk
yeah if it's countable you're okay
just appeal to the countability of N x N
but how would i list that 💀
you'd list a pattern
like how you can list the natural numbers 0, 1, 2, 3, 4, 5, ...
well there’s 1000000000000
11000000000000000000
111000000000000 and so on but is there a way to generalize it
i mean, you just said "and so on" so it sounds like you think so 
well the case with the largest possibilities will have a ton of possible values
listing is kinda weird, but you can show that all of the sequences will eventually end up repeating zeroes
except for one of them 👀
which one 🤯
the constant function that always returns 1
oh we were talking about just where f(0) = 1 lol
yeah
basically the idea is the same though
eventually the sequence of numbers you write has to repeat something
it’ll start at some f(0)=m and then keep decreasing from there
I was thinking of listing out the differences, but you could just list out the function values and it's the same thing
showing this as a first result is a good first step in the proof
by the well ordering principle there’s a smallest number so it must repeat eventually?
what dimension did you just pull that out of, yes that's right
you'll want to clearly state the set on which you're applying the WOP
that was honestly kinda unexpected
i mean i didn't expect you to know that theorem
😐
the set N does have a smallest element, it's 0
but functions don't have to repeat 0, they can repeat any other number
we already saw one that repeated 1
it’s a subset of N which is the range of values the function can output
yeah there you go
what should the next step be
||run length encoding||
if we let f(0)=k then there’s k-(smallest number) values before it repeats right
what does that mean
well, no, it could output k for the first 1000, then k-1 for the next million, then k-2 for like a billion
I advocated for something resembling decoding that, but it's kinda weird
you don't need a bijection, injection/surjection (depending on your function direction) is fine
there is no weirdness, ||each function starting at n is encoded by an n-tuple of run lengths, allowing for infinity (and zeroes afterwards possibly), which shows that the set is a countable union of of countable sets||
saccharine originally had some binary thing that I couldn't tell what it was doing and seemed overly complicated
