#help-17

1 messages · Page 260 of 1

fringe scarab
#

fluid flow like an actual fluid

verbal blaze
#

but also surface area in some cases

fringe scarab
#

or as an adjective

verbal blaze
#

bcs u can have non fluid like vector fields

proper minnow
#

Hn that's sounds interesting

verbal blaze
fringe scarab
#

does "fluid" mean differentiable everywhere?

verbal blaze
#

yeah this makes sense

verbal blaze
#

but not necessarily noncompressible

proper minnow
fringe scarab
#

like i said i took some neutered ass multivariable

verbal blaze
#

I had this result earlier

proper minnow
fringe scarab
#

wait

#

ffs

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that's what they were saying earlier

verbal blaze
#

I proved that
with only one f you can always find where it is

proper minnow
#

Ffgggggggg is always smaller than gggggggff

verbal blaze
#

yeah I see that okay

proper minnow
#

Fffgggggggg will be smaller than ggggggfff

fringe scarab
#

u got it backwards

proper minnow
#

Eh ?

#

No

#

I got it correct

fringe scarab
#

oh there're different numbers of functions

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i thought the strings were the same length

proper minnow
proper minnow
#

I just didn't bother to count

verbal blaze
#

oh hey group theory time

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bcs I see no other way to do it

fringe scarab
#

where's the group

verbal blaze
#

well

#

okay so it's not a group but I mean the whole like

#

equality

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and how we don't know if it's transitive

fringe scarab
#

transitive?

verbal blaze
#

well, the inequality I mean

proper minnow
verbal blaze
#

we know that swaps are necessarily unequal

fringe scarab
#

if they're at the end

verbal blaze
#

uh

#

hm

#

can we prove if h =!= j -> kh=!=kj

fringe scarab
#

what's k

#

another sequence?

verbal blaze
#

arbitrary sequence

gentle sleet
verbal blaze
fringe scarab
gentle sleet
#

I think that's legal

fringe scarab
#

composition is not commutative

gentle sleet
fringe scarab
#

i mean

#

u dont know if h is one to one in the space of functions

verbal blaze
#

u mean k?

fringe scarab
#

yeah k mb

verbal blaze
#

I think it is

fringe scarab
#

im used to the hg != hf example ive been saying

verbal blaze
#

ah

fringe scarab
#

"i think it is"
QED

verbal blaze
gentle sleet
verbal blaze
#

nvm hg != hf is cleaner

#

wait

fringe scarab
#

idk abt in the space of functions tho

verbal blaze
#

hg != hf has to be true

fringe scarab
#

in R -> R yeah i think so

verbal blaze
fringe scarab
#

oh

#

oh yeah

#

are we done then

verbal blaze
#

uh

#

no

fringe scarab
#

let me try

verbal blaze
#

go for it

fringe scarab
#

does fggfgfgff = gfffgfggf

verbal blaze
#

hm

fringe scarab
#

we know
hf != hg
fgh != gfh
fh != gh

verbal blaze
#

we also know
fgg
gfg
ggf
are all unequal

fringe scarab
#

ff != gf, so we have fggfgfgi and gfffgfgj

proper minnow
#

Yes the condition are true but this won't help with other strings

#

Because these conditions start with constant as 0

#

But can't be said same for pattern which appear on different statement

fringe scarab
#

can we say the fgfgi != fgfgj?

proper minnow
#

I and j could be equal

fringe scarab
#

no i = ff and j = gf

verbal blaze
#

I think we have to prove hi != hj iff i != j

verbal blaze
fringe scarab
#

idk abt iff

verbal blaze
#

follows from function numbers

proper minnow
fringe scarab
#

oh shit ur right

#

alr

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fggi and gffj; i = fgfgff, h = fgfggf

verbal blaze
#

graph theory save usss

proper minnow
#

It can't tbh

#

It won't help here

proper minnow
#

You can't tell

gentle sleet
#

you can convert the functions into matricies on a <x, y, 1> vector
also not sure if it's helpful

proper minnow
#

Well ofc without my statements 😉

proper minnow
#

Could be not tbh

#

Eh tbh not

verbal blaze
#

how

gentle sleet
verbal blaze
#

those weren't matrices

proper minnow
gentle sleet
proper minnow
#

Using patterns aren't useful too

verbal blaze
#

or I mean ig they were but not very useful ones. you didn't get linearity or anything

proper minnow
#

Try different method if you want a good proof

verbal blaze
#

babi you haven't proved it either

proper minnow
cosmic cloud
#

bro asked a question and left opencry

proper minnow
#

It should cover all basis

proper minnow
fringe scarab
#

all u did was show gh != fh

proper minnow
#

Using patterns just the worst method

verbal blaze
proper minnow
#

These are functions not some binary digits or pattern

#

You can't use pattern logic here

fringe scarab
#

ok bro

verbal blaze
#

betterert do u kno any number theory

proper minnow
verbal blaze
#

could rlly come in clutch rn

proper minnow
#
  • the distance of f
fringe scarab
#

how could number theory come in clutch

verbal blaze
verbal blaze
#

deciphering the constant term

gentle sleet
proper minnow
gentle sleet
#

or at least you haven't proved that it is transitive

proper minnow
#

Just equate and see it

fringe scarab
#

i mean

proper minnow
#

C will always need to be less than 0 for the pattern to be same

#

But c won't

fringe scarab
#

with the constant term is multiplying by 3/2 and then adding 1/2 and then multiplying by 1/2
the same as multiplying by 1/2, then multiplying by 3/2 and then adding 1/2

#

no

verbal blaze
#

yeah no

fringe scarab
#

i mean that's what makes fg != gf

#

um

verbal blaze
#

g is linear f isn't

fringe scarab
#

f is linear?

gentle sleet
verbal blaze
#

thats what I meant

gentle sleet
fringe scarab
#

what is a linear map

proper minnow
fringe scarab
#

idk any lin alg

gentle sleet
#

here's f

fringe scarab
#

ok bro.

#

what is this.

proper minnow
#

You will get c to be less than 0

verbal blaze
#

thats it

gentle sleet
verbal blaze
fringe scarab
#

is this that x y 1 u were talking about

#

u multiply it by that vector

gentle sleet
#

yea

fringe scarab
#

what does f being linear have to do with this

gentle sleet
fringe scarab
#

owned

gentle sleet
fringe scarab
#

idfk

#

idk any lin alg !!!!

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wait wtf is y

verbal blaze
#

it can't be a linear map they're tweaking

gentle sleet
#

y is the constant term

fringe scarab
#

oh ok

#

can we name it c then

verbal blaze
gentle sleet
verbal blaze
#

wait that works

#

ugh

gentle sleet
verbal blaze
#

linear algebra pls save us

verbal blaze
fringe scarab
#

how does adding help us

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we're doing composition?

verbal blaze
#

they meant add to the constant

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matrices can only scale stuff usually

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also matrices r functions

verbal blaze
#

can u get us g also

gentle sleet
#

now compositions are just matrix multiplication

gentle sleet
fringe scarab
#

i multiplied F by <x,c,1> and got 3x + 1/2 c + 1

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did i do something wrong

gentle sleet
#

did you make it a vertical matrix?

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the x, c, 1

fringe scarab
#

yeah

#

row times column and then you add them all up right

gentle sleet
verbal blaze
#

this one too

proper minnow
verbal blaze
#

this gets us all the properties of matrix multiplication

fringe scarab
#

f isnt linear?

#

f(2) + f(1) gives 11/2
f(3) gives 10/2

gentle sleet
fringe scarab
#

im confused

gentle sleet
proper minnow
#

Even if we get matrix multiplication to work what you can do is just

Show order doesn't matter for 2 of them

verbal blaze
gentle sleet
verbal blaze
#

we're not talking about the inputs/outputs of the functions atp

#

just operations on the slope and constant

proper minnow
proper minnow
fringe scarab
#

what's the +1 for

proper minnow
#

Only can prove for 2 terms

#

You can prove for 3 or more by equating them like I did

gentle sleet
verbal blaze
proper minnow
#

This probably just a induction instead of a proof

verbal blaze
#

guys we got associativity

gentle sleet
#

we already have that, no?

verbal blaze
#

no idea

proper minnow
#

^

fringe scarab
#

yeah composition is associative

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iirc

verbal blaze
#

what

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since when

proper minnow
#

Since ever?

verbal blaze
#

ugh it is nvm

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uhh

proper minnow
#

Hm

#

Just prove by induction fr

verbal blaze
fringe scarab
verbal blaze
#

and the other one too

fringe scarab
#

alr next we need to prove closure and we have a group

#

yes.

verbal blaze
#

inverses are hard

gentle sleet
verbal blaze
#

although

#

wait what

proper minnow
verbal blaze
#

no we don't get closure

fringe scarab
#

the <x,c,1> vector right

#

u cant... square it

verbal blaze
#

what if we just

#

don't think about the vectors at all anymore

gentle sleet
fringe scarab
#

are all linear maps invertible

#

wait

verbal blaze
#

yes

#

no?

fringe scarab
#

idfk

verbal blaze
#

no

proper minnow
gentle sleet
#

and g too is invertable

verbal blaze
#

not all matrices are invertible

#

well

#

okay there we go, inverses

#

we're missing identity

fringe scarab
#

just... add it?

verbal blaze
#

uh

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sure okay

fringe scarab
#

3x3 identity matrix exists

gentle sleet
#

I think you can form these from elementary matricies too

verbal blaze
#

okay we have a group

fringe scarab
#

yes ...

#

i dont think itll be finite though

verbal blaze
#

is that useful at all

verbal blaze
gentle sleet
fringe scarab
#

does it matter?

verbal blaze
#

that said

fringe scarab
#

it doesnt Do anything

verbal blaze
#

prove the group is infinite and you've proved the original statement

gentle sleet
fringe scarab
#

oh no

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i composed my function h with the identity function!

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help!

gentle sleet
fringe scarab
#

the identity function is like uno, it comes with ur xbox

verbal blaze
#

uh

#

prove u can't divide the group

gentle sleet
verbal blaze
#

then you've proved the original statement

fringe scarab
#

um

#

if u have an element in ur group a
and then an element b
and a third one, c

if ab = ac then b = c

verbal blaze
#

are we

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are we done then

fringe scarab
#

well idk

#

are we in a group

verbal blaze
#

yeah

proper minnow
#

V sauce music intensifies

verbal blaze
#

the identity + the two function matrices + their inverses
generate a group

verbal blaze
fringe scarab
#

it's just True

#

in any group

verbal blaze
#

I mean strong enough to prove our original claim

fringe scarab
#

doesnt prevent like
ab = cd tho

gentle sleet
#

how's that true in every group?

fringe scarab
#

um

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i proved it myself in a little book i own

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i forget the proof

gentle sleet
#

won't f(x) = 2x and g(x) = x/2 also form a group?

verbal blaze
#

yea

fringe scarab
#

idk

#

i think so

verbal blaze
#

it's just z

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it's just the whaitsitcalled

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the boring one

verbal blaze
#

z +

#

cyclic group

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that's just the cyclic group of infinite order

fringe scarab
#

idk what u do with ff and gg

verbal blaze
#

I have some work I need to get done

gentle sleet
verbal blaze
#

idk if we've made any progress in the last two hours except finally saying that hj != hi

verbal blaze
#

just take the number 1 and multiply it by two until infinity

#

then divide it by half and get zero

#

then any of the numbers you've reached can be multiplied amongst themselves w group properties

#

its isomorphic to the integers + addition

gentle sleet
fringe scarab
verbal blaze
#

yeah

gentle sleet
#

ah flob, I read that wrong

verbal blaze
#

that makes sense

gentle sleet
#

mb

verbal blaze
#

I'm gonna go work on something I'm gonna make progress on

#

I've decided math isn't for me and that numbers aren't real

proper minnow
#

This is because you aren't going the right way

#

Groups and matrix aren't the way

#

Induction is

gentle sleet
fringe scarab
#

cute how any function and its inverse generate a group isomorphic to the integers over addition

verbal blaze
#

that's not true

fringe scarab
#

oh

#

why not

verbal blaze
#

uhhhhhhhh

#

seems wrong

#

lemme think abt it

#

no wait it'd have to be its own inverse

fringe scarab
#

yeah that's what i said

#

i mean it makes sense

verbal blaze
#

involutions

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doesn't work with involutions

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I don't think

fringe scarab
#

ok cuz this looks like addition but yeah that would ruin it

gentle sleet
#

won't it be Z/1Z or something

#

Z modulus 1

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or 2

verbal blaze
#

z/2z

fringe scarab
#

would that just be -1, 0, and 1

gentle sleet
#

no, just 0 and 1

verbal blaze
#

uhhh

#

yeah that

fringe scarab
#

oh ok cool

gentle sleet
#

-1 = 1

fringe scarab
#

yeah lol

#

is that the 2 element group

verbal blaze
#

yag

gentle sleet
#

or 1 if f = I
i think

fringe scarab
#

Z/2Z as the function as its own inverse
or as the function and a different inverse

verbal blaze
#

hey wait

#

if we assume two sequences are equal

#

we would be able to wrap them apart w their inverses right

fringe scarab
#

wrap them apart?

verbal blaze
#

yeah

#

like

#

in our group

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fgfg g'f'g'f' or smth

#

however it is

fringe scarab
#

oh

verbal blaze
#

ykwim

fringe scarab
#

u mean invert the sequence?

verbal blaze
#

could we prove that the unwrappings are unique

#

you could mayb prove that f g' or g f' can never occur

fringe scarab
#

well do all the elements we generate have inverses

#

like does fg as a matrix have an inverse

#

if u take the product of 2 invertible matrices do u get an invertible matrix

verbal blaze
gentle sleet
#

so is f'g' = (fg)'?

fringe scarab
#

no, (fg)' is g'f'

#

u reverse the order

gentle sleet
#

oh yea that makes sense

fringe scarab
#

oh

#

then ofc the product of two invertible matrices is invertible

#

it says it right there

#

what are we trying to say in the context of groups then

#

that an element only shows up in 3 places? both products with itself and the identity and then one time in the table?

#

i dont have much experience with infinite groups

verbal blaze
#

inverses are unique

#

so

#

qed gg

fringe scarab
#

im going to bed

verbal blaze
#

I think we did it

#

more or less

gentle sleet
#

nah, we've been running around in circles

verbal blaze
#

well

#

no

gentle sleet
#

but can it be formed by only one sequence of inverses

verbal blaze
#

ugh

gentle sleet
#

yea

verbal blaze
#

wonderful use of3 hours

vast shale
#

that was entertaining so yes

#

good job u lot

vocal sleetBOT
#

@prisma rain Has your question been resolved?

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molten kettle
#

Hello, sorry if my english is bad, i'm not a english native so my spelling in some words could be wrong.
I'm looking for an explanation on how to use the property that something hasn't been completely discovered on a field of mathematics to make use of it and create a new, using bases of maths that we already knows

molten kettle
#

The thing is i don't want to show the work behind to not having someone taking the credits for it, so i'm just looking forward for an explanation on general, because i'm kinda "new" on the fields of maths and all since i'm on physics normally

#

So just looking for an general explanation

trail mesa
#

uhh what

#

if you use progress made by other people, you should credit them

molten kettle
#

I mean, putting references of other people, can this be enough?

trail mesa
#

yeah, ofc

molten kettle
#

So with this i can make a new thing just by citing references of formulas that's already exist? Or there more steps?

#

@trail mesa

#

Which tools do i need to proof to say that something works, even though it hasn't been proved

#

Alright got my answer by someone else, have a good day!

#

.close

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tired dock
#

Can anyone explain the " Multiply to get common denominators " step please?

brittle umbra
#

when ur adding two fractions the denominator has to be the same

#

for ex the first term u multiply by x+2/x+2 which is essentially 1 (multiplicative identity) so it’s not changing the value of the term but we are manipulating its form

#

such that you can now add them tgt

graceful wave
#

uh help

vocal sleetBOT
graceful wave
#

uh

#

mb

#

idk how this works 😭

tired dock
tired dock
tired dock
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.close

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Show your work, and if possible, explain where you are stuck.
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vast shale
vocal sleetBOT
vast shale
#

I am stuck on the first question. The only thing I’ve thought to do is get A+B+C=158

#

I know we need two equations

#

But I am stuck I was thinking of volume but then when taking the partial derivatives I get everything =0

astral pilot
#

what do you think is the formula for volume?

vast shale
#

V=ABC

astral pilot
#

yeah

#

substitute C = 158-A-B

vast shale
#

oh maaa god. Silly me. Thank you.

astral pilot
#

glad, I could be of help

vast shale
#

Ok still stuck sorry

#

This is the working I did. I took partial derivatives and then set =0. Then got two equations

#

Made A the. Subject of one and B the subject of other

#

Then I tried plugging that into v but failed…

astral pilot
#

You get linear equations in two variables

#

158 - 2B - A = 0
158 - 2A - B = 0

#

solve them simultaneously

#

Or, a simpler way, 2B + A =158; 2A + B = 158
Therefore, 2B + A = 2A + B, i.e. A = B

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#

@vast shale Has your question been resolved?

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haughty nexus
#

I have a question about designing LTI-systems. The question is about is making a stabile low pass filter that has a cutoff frequency of 30 Hz by putting 2 poles and 2 zeros on a graph (reel, imaginary as axis). I dont understand the relationship between where the poles and zeros are placed on the graph and the output of the system. How do I know where to place these poles and zeros so that they give me the desired cutoff frequency while having the characteristics of a filter i want?

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@haughty nexus Has your question been resolved?

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@haughty nexus Has your question been resolved?

wet geyser
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@haughty nexus Has your question been resolved?

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@haughty nexus Has your question been resolved?

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bitter holly
#

why f(x) = 2x is injective and not surjective, when defined from N to N

bitter holly
#

oh maybe because on the codomain there are gaps from one step to the other

versed bane
versed bane
#

do you know the definitions

bitter holly
#

like f(1)=2 f(2)=4

#

then there is the element 3 of the codomain

#

ok perfect thanks

versed bane
#

for injectivity 2a=2b means a=b, because you can divide by 2

bitter holly
#

but I am thinking that if we had a function from N to a set defined as {x|x in N, k in N and x=2k} then it would be surjective too

versed bane
bitter holly
#

yeah

versed bane
#

it would be surjective onto that set yeah

bitter holly
#

would the description of the set {2k | k in Z} be better?

versed bane
#

yeah that’s better, k would be in N in this case because we only need positive whole numbers. but yes i would describe even integers that way

bitter holly
#

ok, thanks

haughty nexus
bitter holly
#

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raw coral
#

Help

vocal sleetBOT
raw coral
#

Could anyone help me out solving this

wild ivy
#

all ? one?

raw coral
#

ii) and iv

#

I tried internet but I can't get it

wild ivy
#

$tan(alpha) = sin(alpha)/cos(alpha)

raw coral
#

bruh you know what this stffs is deleted for the latest publishers of the same book but our school still uses the ol

#

...

#

What is alpha here ? Is that theta*

#

i just got the trigonometry table and 3 identities how do solve it using those

#

@wild ivy

wild ivy
#

ya. theta

#

just minute.

raw coral
#

Ok

wild ivy
#

are u clear?

raw coral
#

i got it all

#

can you solve no iv too

wild ivy
#

ok.

raw coral
#

you did it so smoothly the one which my teacher did was kinda long and boring

wild ivy
#

what are u doing?

raw coral
#

i haven't touched it for like weeks

wild ivy
#

talk about that alot.

#

talk in DM.

raw coral
vocal sleetBOT
#

@raw coral Has your question been resolved?

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vestal fractal
#

is there a way to make desmos show work in square-wave "quantized" steps

vestal fractal
#

it should be stepping, non-continuous

flat whale
#

google is your friend

#

non-continuous is "discrete"

vestal fractal
#

would appreciate you not assume i haven't googled before i type here :)

flat whale
#

nah

flat whale
vestal fractal
#

I am one of those "practical men" as described by Mao. Very little formal education in mathmatics

#

less than highschool lol

flat whale
#

¯_(ツ)_/¯

#

googling isn't a skill taught specific to math

vestal fractal
#

to know the term "discrete" to refer to a "square wave step" is

flat whale
#

great i told you

vestal fractal
#

yeah so just using the floor function does what i wanted

#

thank u

#

.close

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craggy imp
#

I need help with this problem. I have no idea where to start.

junior notch
#

!15m

vocal sleetBOT
#

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.

junior notch
#

Sorry

craggy imp
#

!15m

vocal sleetBOT
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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.

craggy imp
#

<@&286206848099549185>

tawny sorrel
#

is this for calc?

vocal sleetBOT
#

@craggy imp Has your question been resolved?

craggy imp
tawny sorrel
#

ok start with the equation for the length of the ladder

craggy imp
#

i dont know how to do that

#

i think i need to use pythagoras

tawny sorrel
#

you basically have two triangles, the sum of their hyptonuse is the length of the ladder

#

you see what two triangles im talking about?

#

your writing the equation for the length of the ladder in terms of the angle the ladder makes with the ground

craggy imp
#

i see the 2 triangles but I dont know how to make the equations in term of the angles

tawny sorrel
#

using trig functions

#

if x is the angle the ladder makes with the ground

#

you have opposite side is 8ft for the the first triangle

#

so what is the hypo for the first triangle

craggy imp
#

how would i find that if i dont have the other side

#

the angle isnt given either

tawny sorrel
#

you aren't finding the length right now

#

you are just setting up the general equation

craggy imp
#

just in terms of x?

tawny sorrel
#

yes

craggy imp
#

sin(x) = 8/y

tawny sorrel
#

yeah but you want it in terms of y, length of ladder

#

so rearrange it

craggy imp
#

y = 8/sin(x)?

tawny sorrel
#

yes

#

now do the same thing for the second triangle

craggy imp
#

cos(x) = 4/y

#

y = 4/cos(x)

tawny sorrel
#

yeah so the sum of the two equations is the length of the ladder

#

write the full equation

craggy imp
#

8/sin(x) + 4/cos(x) = hyp

tawny sorrel
#

ok good

#

now use the first and second derivative to find the minimum

craggy imp
#

so find f'(x) of f(x) = 8/sin(x) + 4/cos(x)

tawny sorrel
#

yeah

craggy imp
#

f'(x) = -8cos(x)/sin^2(x) + 4sin(x)/cos^2(x)

tawny sorrel
#

yea set that equal to 0 and solve for x

craggy imp
#

from what domain would i do it from

tawny sorrel
#

what do you mean

craggy imp
#

theres a lot of values that would fit

#

i tried it on desmos and theres a lot of x intercepts

tawny sorrel
#

just find one for now

#

simplify the equation first and you'll see it doesn't matter

craggy imp
#

i have no idea how to simply from there

tawny sorrel
#

$\frac{8\cos x}{\sin^2x}=\frac{4\sin x}{\cos^2x}$

twin meteorBOT
tawny sorrel
#

get rid of the denominators

craggy imp
#

cos^2(x)(8cos(x)) = sin^2(x)(4sin(x))

tawny sorrel
#

yea which is just 8cos^3(x) = ...

craggy imp
#

4sin^3(x)

#

2cos^3(x) = sin^3(x)

tawny sorrel
#

yeah one more step

craggy imp
#

2cos(x) = sin(x)

#

?

tawny sorrel
#

no

craggy imp
#

i cant take 3rd root?

tawny sorrel
#

well you gotta root the 2 as well

craggy imp
#

oh yeah

tawny sorrel
#

you can

craggy imp
#

3rdroot(2)cos(x) = sin(x)

#

sin^-1(3rdroot(2)cos(x)) = x

tawny sorrel
#

no youre trying to get it to one trig function

#

you have sinx one side and cosx the other

#

how you get it to be 1 trig func

craggy imp
#

is it the trig identity for sin?

tawny sorrel
#

remember tan = sin/cos

craggy imp
#

tan(x) = 3rdroot(2)

tawny sorrel
#

yeah last step

craggy imp
#

now do i inverse tan?

tawny sorrel
#

yes

craggy imp
#

x = tan^-1(2^1/3)

tawny sorrel
#

that should be the answer but you have to verify if its a minimum

craggy imp
#

i have to take second derivative?

tawny sorrel
#

yeah

#

or idk if youre teacher is fine with it just pick a value just to the right of x and see if its larger

craggy imp
#

in the first derivative?

tawny sorrel
#

and to the left of it see its larger as well

#

in the original function

#

you should probably just do the second derivative

craggy imp
#

ok

#

im just getting 0 because its a constant

tawny sorrel
#

whats 0

craggy imp
#

a min or max?

#

critical number

tawny sorrel
#

no what do you mean you are just getting 0

craggy imp
#

the tan^-1(2^1/3) derivative

#

im getting 0

#

should i do (tan^-1(2^1/3))/x

#

derivative of that?

tawny sorrel
#

you shouldn't be getting 0

#

im getting 51.56

craggy imp
#

can you show me how

tawny sorrel
#

like just put it in your calculator what is tan^-1(2^1/3)

#

oh hold on you mean second derivative

craggy imp
#

yeah

tawny sorrel
#

you wanna find the derivative for the general formula

craggy imp
#

oh ok

tawny sorrel
#

tan^-1(2^1/3) is not the function that is the answer for f'(0) =

craggy imp
#

im getting 51.52 degrees when i plug it in calculator

tawny sorrel
#

yea that should be the answer for where the minimum is but you got to verify that it is a minimum with the second derivative test

craggy imp
#

what equation should i take the second derivative from

#

x = tan^-1(2^1/3)

this?

tawny sorrel
#

no the original equation for the derivative

#

x = tan^-1(2^1/3)
this equation came from when you were solving f'(x) = 0

craggy imp
#

cos^2(x)(8cos(x)) = sin^2(x)(4sin(x))
this?

tawny sorrel
#

yeah that

#

no

#

not that

#

that is still f'(x) = 0

craggy imp
#

8/sin(x) + 4/cos(x) = hyp

this one?

tawny sorrel
craggy imp
#

ok

tawny sorrel
#

its gonna get really ugly

craggy imp
#

(8sin^3(x)+16sin(x)cos^2(x))/sin^4(x) + (4sin^3(x) + 8sin^2(x)cos(x))/cos^4(x)

tawny sorrel
#

i'd just put it into wolfram alpha to check i didn't calculate it

craggy imp
#

eyah i did

#

some solver

tawny sorrel
#

k now you gotta check if it is positive 51.56

craggy imp
#

how

tawny sorrel
#

you just plug in that value for x in the second derivative

craggy imp
#

ok

#

i got 49.80 using 51.52 degrees

tawny sorrel
#

so its a min

craggy imp
#

how did you know that

tawny sorrel
#

first derivative is 0

#

first derivative 0 means it is a turning point happens at the original f(x)

#

second derivative is positive which verifies its a min

#

if it was negative its a max

craggy imp
#

ok so now would i plug this into the original equation

#

the x value that i have

tawny sorrel
#

yes

craggy imp
#

8/sin(x) + 4/cos(x) = hyp
in this one right

tawny sorrel
#

yes

craggy imp
#

THANK YOU SO MUCH

#

ive been stuck forver

tawny sorrel
#

youre welcome

craggy imp
#

if you have time can you help me with one more?

tawny sorrel
#

i dont really have time but jost post the question ill tell you what to look for

craggy imp
#

im pretty sure i use similar triangles

tawny sorrel
#

this is gonna take me too long i cant help close this channel and open snd ask in a new one

craggy imp
#

howdo i close it

tawny sorrel
#

.close

craggy imp
#

.close

vocal sleetBOT
#
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mighty jackal
#

I would like to know what part I was wrong about. In the module it says the answer should be (e-1)

mighty jackal
#

The topic is Areas in the Plane, Calculus

marsh charm
#

not 0

#

prob one reason why u got it wrong

outer warren
#

draw a graph and you should see what you missed

outer warren
mighty jackal
marsh charm
#

i could be wrong

#

cause i actually dont know

#

but

#

this shit never lies

mighty jackal
#

yea but e(1)-e is e-e which is 0

marsh charm
#

i see

#

i didnt see

mighty jackal
#

but i think i didnt miss anything

marsh charm
#

e1 anywehre

mighty jackal
#

Maybe the module is weong

outer warren
#

the module is fine

muted plaza
#

yeah i think it is, factor out an e

mighty jackal
#

Ok

muted plaza
#

e(lne-1)

#

e(0)

#

=0

outer warren
#

the integration work you've done is fine
you just missed a component for the total area

mighty jackal
#

Oh

outer warren
#

draw a graph and you should see what you missed

mighty jackal
#

idk what i missed

#

Ok

#

I still dont get it

outer warren
#

can you show what you drew

mighty jackal
#

i didn't draw anything

#

hmm

#

Ok wait

outer warren
#

note that the integral you have doesn't give the area of the whole desired region

#

only part of it

#

specifically the part from x=1 to e

mighty jackal
#

Yea the area doesnt make sense

#

Hmm

#

So the 1x1 area was not included in the e-2?

outer warren
#

i.e. you've only calculated the area of this part

mighty jackal
#

Yea

#

Okay i got it

#

how do i write it in my solution

outer warren
#

at the start, A = 1 * 1 + (your integral)

#

leading to
A = 1 + e - 2
= e - 1

mighty jackal
#

Okay thank you so much

outer warren
#

and provide a rough sketch as well

mighty jackal
#

ok ok

#

oh and can i ask a question

#

Check the final part of the solution of my other problem

#

Was what i did correct?

#

I changed it to positive 8/3 cause.. the area cant be negative?

#

can anyone answer me? just a quick simple question pandaohno

#

<@&286206848099549185>

vocal sleetBOT
#

@mighty jackal Has your question been resolved?

vocal sleetBOT
#

@mighty jackal Has your question been resolved?

mighty jackal
#

.close

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errant sigil
vocal sleetBOT
errant sigil
#

Not sure where to go from here

#

Solution

#

Not sure how this arises

#

Partial derivatives btw

mighty nacelle
#

for dA/dr, you forgot to use the chain rule for v

#

for partial derivatives, you have to treat the other variable like a constant

#

imagine its pi or something

#

so you dont need product rule for dA/dtheta

errant sigil
#

I thought we did that at the end

#

Hmm

#

Lemme try that again

errant sigil
# errant sigil

@mighty nacelle when u derive A with respect to r, you also take account of what’s inside the bracket since its chain rule

#

But

#

Fourth line

#

It’s the same thing, minus the R ofc

#

So does that just mean u can’t derive tan theta or..

#

I hope I’m making sense

mighty nacelle
#

im not really understanding

errant sigil
#

Ignore all of that

errant sigil
#

Basically is what I’m asking @mighty nacelle

mighty nacelle
#

you have r*arctan(r tan(theta)) right

#

left term is the first part of the product rule

#

right term is r*derivative of arctan(r tan(theta))

#

outer function is arctan

#

inner function is r*tan(theta)

#

do the chain rule

errant sigil
#

Essentially when u derive tan theta, is it just tan theta then?

mighty nacelle
#

differentiate r*tan(theta)

#

what type of function is that?

#

remember that theta is a constant

errant sigil
#

Can u write it down 😭

#

Sorry

mighty nacelle
#

take a second and think about it

errant sigil
#

I’m js confused cus ur saying u don’t need the product rule,, what I’m also confused about is why it’s multiplying tan theta at the end

errant sigil
mighty nacelle
#

ok lets try this

#

differentiate arctan(2r)

errant sigil
#

1/1+(2r)^2 ?

mighty nacelle
#

f(x) = arctan(x) and
g(x) = 2x
what is f(g(x))?

errant sigil
#

arctan(2x)

mighty nacelle
#

ok, whats the derivative of f(g(x))

errant sigil
mighty nacelle
#

no, use the function notation first

errant sigil
#

Okay one sec

#

f’(g(x))= 2/1+4x^2

#

#

Right?

mighty nacelle
#

derivative of f(g(x)) is f'(g(x))g'(x)

#

this is important

errant sigil
#

Oo

#

So

mighty nacelle
#

if i replace the g(x) with x*tan(y), what is g'?

errant sigil
#

x/1+tany^2

#

sorry i’m so exhausted but if that’s wrong ill pick it up tomorrow morning

vocal sleetBOT
#

@errant sigil Has your question been resolved?

vocal sleetBOT
#
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junior brook
#

you can do isolation of variables technique since the left and right sides are both products of x and y

#

the right side is correct, 2xdx, but the left side is going to be dy divided by: (e^-tan(y) cos^2(y) )

#

so that will turn into e^tan(y) *sec^2(y) dy

#

since 1/e^(-x) is e^x

#

and 1/cos is sec

#

ye

#

then afterwards its an easy u sub to complete the integral on the left side

#

you got this!

vocal sleetBOT
#
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torn prawn
#

how do i find the nth degree of this? i've tried like 20 different things and they're all wrong, including stuff like x^4 or 4. i'm not really sure what the second part is asking.

meager shoal
#

what is the mclaurin series in e^x

junior brook
#

find a pattern that changes for each recurring term of the sequence

meager shoal
#

as summation symbol

torn prawn
junior brook
#

the question is asking for a general term of the series, not something specific like 4

torn prawn
#

ohh okay

meager shoal
#

note that series is just a sum of sequence 👀

torn prawn
#

.close

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#
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acoustic turtle
#

Hey there I'd like to understand how we get the fraction -2/7 I simply know the steps but I don't understand why it works.

junior brook
#

Hi! So first you want to substitute the value 1/2 in for x. the denominator becomes 1/2 - 4, which can be rewritten to 1/2 - 8/2. doing this subtraction you will get -7/2 in the denominator.

#

1/(-7/2) just flip the bottom fraction and you will get -2/7

acoustic turtle
#

thank you owoLight for responding so quickly

#

I apologize I'm not seeing the connection "rewritten to 1/2 - 8/2."

junior brook
#

so you can change it to 8/2 in order to make the math easier

acoustic turtle
#

yes that's true

junior brook
#

1/2 - 8/2 they have similar denominators so you can just subtract the numerators

acoustic turtle
#

gonna write this down real quick if that's fine I think I'm understanding you.

junior brook
#

of course. take your time

acoustic turtle
#

you got finals week as well lol

junior brook
#

yeah bro 😓 not looking forward to it

acoustic turtle
#

I think you'll be fine!

junior brook
#

thank you for the support! im sure your finals will be awesome as well (if you have them)

acoustic turtle
#

so I've got 1/2 - 8/2 that'll be -7/2 right?

junior brook
acoustic turtle
#

and then to get rid of the bottom

#

I simply multiply the reciprocal with 1 so that'll be -2/7

junior brook
#

yep

acoustic turtle
#

damn lol

#

I missed a lot of this stuff when I was younger.

#

thank you for the help man.

#

!close

junior brook
#

any time

acoustic turtle
#

.close

vocal sleetBOT
#
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white tusk
#

$89.95 cm^{2} = \frac {23.5*h}{2}$

vocal sleetBOT
twin meteorBOT
#

Beata Szydło

white tusk
#

How do I find h?

#

Do I have to divide 23.5 by 2?

#

And then subtract from 89.95 cm^2?

#

@loud walrus

#

@mellow void

#

@mental falcon

mental falcon
#

don't ping random people

#

for no reason

#

that'll just make people less inclined to help

white tusk
#

Ok, can you help me quickly?

#

Im actually in class.

#

@steep crater

steep crater
#

Wat

#

Y ping

white tusk
white tusk
steep crater
#

Dude stop ping random ppl

#

Anyway is the unit cm^2 on RHS

white tusk
#

Whats rhs

steep crater
#

Right hand side

white tusk
#

Idk what that even is

#

The area of a trapeze is 89.95 cm^2

#

a = 13 cm
b = 10.5 cm

#

and so I used the formula for trapeze

steep crater
#

Then solve ig

#

Multiply 2 divide 23.5

#

Theres h

#

What is this

white tusk
#

$\frac{(a+b)*h}{2}$

twin meteorBOT
#

Beata Szydło

white tusk
#

I move 23,5 cm to the other side?

steep crater
#

What

#

Just divide

white tusk
#

Show me @steep crater

steep crater
#

Times 2 both sides

steep crater
white tusk
#

@steep crater

steep crater
#

What

#

Nono

white tusk
steep crater
#

Times 2 both sides dude

#

89.95 x 2 = 23.5 x h

white tusk
#

Ohhh and the. Divide

#

Ooooohhhhh

#

Ty

steep crater
#

Yess

white tusk
#

It makes sense

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Ooohhh

#

I get it

steep crater
#

Np

white tusk
#

To get rid of 2 you need to divide by 2

steep crater
#

Ya

white tusk
#

.close

vocal sleetBOT
#
Channel closed

Closed by @white tusk

Use .reopen if this was a mistake.

vocal sleetBOT
#
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elder fable
#

Can anyone help me with eliptic curve crypthography ?

elder fable
#

and ElGamal protocol

#

import random

Curve parameters

p = 257
a = 0
b = 7

Operations

Inverse

def inverso(a, p):
return pow(a, -1, p)

Sum

def soma(P, Q):

if P == "O":
    return Q
if Q == "O":
    return P

x1, y1 = P
x2, y2 = Q

if (x1, y1) == (x2, -y2 % p):
    return "O"

if (x1, y1) == (x2, y2):
    u = ((3 * x1 * x1 + a) * inverso(2 * y1, p)) % p
else:
    u = ((y1 - y2) * inverso(x1 - x2, p)) % p

v = (y1 - u * x1) % p
x3 = (u**2 - x1 - x2) % p
y3 = (-u * x3 - v) % p

return [x3, y3]

Multiplication by a scalar

def multiplicacao(k,P):
R = "O"
for i in range(k):
R = soma(R, P)
return R

ElGamal Protocol ECC

Alice public and private key

a = random.randint(2, 255)
A = multiplicacao(a, [109,229])

Bob encript "m"

m = 3
M = multiplicacao(m,[109,229])

r = random.randint(2,255)
c1 = multiplicacao(r, [109,229])
c2 = multiplicacao(r, A)
c2 = soma(c2, M)

Alice desencript

if c1 == "O":
c1_sim = "O"
else:
c1_sim = [c1[0], (-1 * c1[1]) % p]

M_2 = multiplicacao(a, c1_sim)
M_2 = soma(c2,M_2)

print(M,M_2)

#

i have this python code

#

My english is also not the best i apologize for that

#

when Alice desencripts the whole thing she gets the same encripted point that Bob used to encript "m" , so they share a secret which is that point M

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and if she or an "attacker" wants to find out "m" they need to solve the discrete logarithm problem which is "impossible"

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but isnt the whole point of this to make Alice find out "m" ?

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In this specific Protocol ElGamal ? Cause like in Diffie-Hellman if my understanding is correct the goal is to give both parties a "secret" which only they share and with that they can encript messages with other systems using that secret as a key , but here they specifically encript "m" so i thought that the goal should be, Alice getting "m" without other people knowing.

vocal sleetBOT
#

@elder fable Has your question been resolved?

vocal sleetBOT
#

@elder fable Has your question been resolved?

vocal sleetBOT
#

@elder fable Has your question been resolved?

flat whale
elder fable
#

ok ty

vocal sleetBOT
#

@elder fable Has your question been resolved?

blissful sentinel
#

you might also want to try a cs server instead, see #old-network

vocal sleetBOT
#

@elder fable Has your question been resolved?

vocal sleetBOT
#
Channel closed

Closed due to timeout

Use .reopen if this was a mistake.

#
Available help channel!

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Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
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• 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.

rare solar
#

i cant figure out the domain on this bad boy

still mica
#

Is h the length of the base?

rare solar
#

nno

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h is the height

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b is the base

still mica
#

So, $V > 0$ => $\frac{4800b - b^3}{4} > 0}$?

rare solar
#

Yes

still mica
#

Did you solve that inequality?

rare solar
#

wait no

#

i think your function is wrong

still mica
#

4800b mb

twin meteorBOT
#

Adarsh
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