#help-39

1 messages · Page 301 of 1

empty junco
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should be -cos(t) + e^t?

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theres no integrals btw

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calc 1

odd coral
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i think so
double check by substituting

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s(0)

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it mentions s(0) for that one should total to 0

cloud zephyr
empty junco
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cos 0 = -1

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so

odd coral
empty junco
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since V(t) = -cos(t) + e^t

cloud zephyr
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well, it's just polynomials for (b), so um, reverse the power rule

empty junco
#

and e is like 2.7 something

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and -cos(0) is -1

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so it cant be 0

odd coral
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-cos(0) = -1, e^0 = 1

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watch out with the e^t

empty junco
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WAIT WHAT

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i forgot holy

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good catch

odd coral
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yeah now you can remember it
nice

empty junco
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how do i reverse power rule on t^4

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oh

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1/5 t ^4

odd coral
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how do you remember it working for normal power rule

empty junco
#

im dumb mb

empty junco
odd coral
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im asking abt derivative power rule rn btw

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imagine smth like an expression 3x^2
what would the derivative be through power rule

empty junco
#

uhh

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6x

odd coral
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right

odd coral
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think about the power of x in "6x"

empty junco
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yeah i got it, since power is implicit ^1, add 1 to power and divide coefficient by 2

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also, for b i got A(t) = 1/5t^5 - 1/2t^2 + 2x + 3

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but i think its wrong

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since v(0) = 0

odd coral
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or v(t) or s(t)

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also careful with the x you typed

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try getting v(t) first again and lmk what you find

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from scratch
for b)

empty junco
#

oh shi

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mb

empty junco
#

mane i gotta go to bed sorry guys

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popped a melatonin earlier so my study time was limited

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.close

pearl pondBOT
#
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wild fable
#

hello i want to know if im on the right track

wild fable
#

this is what i have so far

random ermine
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hmm not sure about this

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because the entries of your matrix don't directly give you a coordinate chart

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to start, the dimension of SL(2, R) as a manifold is 3

rustic gate
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the lie algebra of SL(2, R) is 3-dimensional

wild fable
random ermine
#

do u know what coordinate charts for this look like

wild fable
#

uh ion think so

rustic gate
#

this is like fine though

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it's not like you have to work with SL(2, R) on its own

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just take it as a subgroup of GL(2, R)

wild fable
rustic gate
#

the tangent space will be a subspace of the one of GL(2, R) with an additional equation

rustic gate
wild fable
#

okay thanks'

rustic gate
#

you've found T_gSL(2, R)

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just calculate T_idSL(2, R) and the derivative map between them

cinder flower
wild fable
wild fable
rustic gate
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uh yeah

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you could also like

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just set g = id in your other calculation

pearl pondBOT
#

@wild fable Has your question been resolved?

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crimson haven
#

question d pls

pearl pondBOT
crimson haven
#

How do I calculate period

still hamlet
crimson haven
#

my teacher said it’s the distance

still hamlet
#

well what effect does cos(x-30°) have to the graph of cosx?

crimson haven
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It moves right?

still hamlet
crimson haven
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idk

dire tapir
#

Well think of the period for cos(x)

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What would that be?

crimson haven
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360?

dire tapir
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Yes

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Now it shifts to the right by 30° degrees

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Does the period stay the same?

crimson haven
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yes?

dire tapir
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Nice

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So its period must be..?

still hamlet
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there's your answer

crimson haven
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360

dire tapir
#

That's correct

crimson haven
#

Oh yay tysm

#

.close

pearl pondBOT
#
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crimson haven
#

.reopen

pearl pondBOT
crimson haven
dire tapir
#

By endpoints I'm assuming they want you to find the point at which the period starts and ends

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Although be careful since they have given us a domain specifically $x \in [-90^{\circ}, 360^{\circ}]$

crimson haven
dire tapir
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Oh whoops

jolly parrotBOT
dire tapir
#

Okay yeah that should be right

crimson haven
#

Bye

#

.close

pearl pondBOT
#
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tiny egret
#

hiya! im really stuck on how to proceed with finding how many elements of R/I there are.. like i just cant think of a strategy here

tiny egret
#

,cw

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,rotate

jolly parrotBOT
pearl pondBOT
#

@tiny egret Has your question been resolved?

tiny egret
#

<@&286206848099549185>

timber cape
#

Hm

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-# out of my domain 😐

pearl pondBOT
#

@tiny egret Has your question been resolved?

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tiny egret
# jolly parrot

ive reduced the problem to showing that any polynomial of the form $q_3X^3+q_4X^4+\ldots+q_nX^n$ is divisible by $X^3+2X+1$, but im struggling to show it efficiently

jolly parrotBOT
tiny egret
#

tried determining the coefficients of some $A=a_0+a_1X+\ldots+a_mX^m$ by the equation $A\cdot(X^3+2X+1)=q_3X^3+\ldots+q_nX^n$ but its horrific

jolly parrotBOT
tiny egret
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so wondering if anyone can think of another way

tropic saddle
#

and also not relevant for your question

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the key point to realize is that each coset has precisely one polynomial of small degree

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how could you find that?

tiny egret
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ah, well i found using sage that the ring is just the polynomials of degree <=2, so wondered if theyre equivalent by making it a cubic

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guess not

tiny egret
tropic saddle
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lets say we are in Z

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and are doing Z/(13)

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aka mod 13

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what is going on there

tiny egret
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well two integers a,b are equivalent if a-b = 13k for some k

tropic saddle
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ok so the cosets have the form {a+13k}

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lets say I have the number 1073

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its in some coset

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how would you find a smaller representative?

tiny egret
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taking its remainder when dividing by 13

tropic saddle
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good

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have you heard of euclidean rings/domains?

tiny egret
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i havent nah

tropic saddle
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ok then ignore that

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good so for numbers we take the remainder

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can we do something similar for polynomials?

tiny egret
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polynomial long division?

tropic saddle
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yes

tiny egret
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sounds exhausting

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but i can't think of another way so ill try it

tropic saddle
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you dont actually have to do it

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the point is that you could

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did you actually do the division 1073/13? no

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you just saw that you could

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we know that we can get every number 0-12 as a possible remainder

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and they are all in distinct cosets

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what possible remainders can we get for polynomials?

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are they all in distinct cosets?

tiny egret
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oh shittt

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okay yeah ive got you

pearl pondBOT
#

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pearl pondBOT
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zealous moon
#

wanted to ask if x limits after changing the order will be from 0 to y^2/a

pearl pondBOT
#

@zealous moon Has your question been resolved?

zealous moon
#

.close

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fading nexus
#

How do I know which side is b and which side is c ?

proper nova
#

,rccw

jolly parrotBOT
proper nova
#

like $b$ is the opposite of the B angle

jolly parrotBOT
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1 divided by 0 equals Infinity

fading nexus
#

Ah ok

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Does it technically matter or no?

proper nova
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that's how people usually label it

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you should follow that convention so it matches the rule

livid goblet
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at least I think so

fading nexus
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I’m not sure why I got a different answer even tho I did it the same

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Now I just put it fully in my calculator and got another answer that’s 7.4

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Ok I originally did it wrong or put It in wrong but my corrected version is still different

glass meadow
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Do 10 sin(40*pi/180) / sin(60*pi/180)

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(or use degree mode but I personally would stick to one mode so I don't forget to switch every time)

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Wait no it's in degree mode

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Are you doing 60º or 80º

fading nexus
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Wdym

glass meadow
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Yeah you're using 60º

fading nexus
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Yea ?

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is that wrong?

glass meadow
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a/sin(A) = c/sin(C)

fading nexus
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But I’m using angle b

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or should I use x

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C

glass meadow
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But you don't have length b

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You are doing a/sin(A) = c/sin(B)

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That's not the law of sines

fading nexus
#

Ah ok

glass meadow
#

Also it's "law of sines", not "law of signs"

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sine for sine function, aka sin(...)

fading nexus
#

Also why is my teacher sometimes using squiggly =

glass meadow
#

That means "approximately equal"

fading nexus
glass meadow
#

,, \approx

jolly parrotBOT
glass meadow
#

This sign

glass meadow
#

It also just makes the law of sines easy to remember:
a/sin(A) = b/sin(B) = c/sin(C)

pearl pondBOT
#

@fading nexus Has your question been resolved?

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quick venture
pearl pondBOT
quick venture
#

i dont understand how they have applied the boundary conditions

dense jasper
# quick venture

$y(0)=0$ means that $y=0$ when $x=0$. Setting $x=0$ in $y=Ae^x+Be^{-x}+xe^x$ gives
$$y(0)=Ae^0+Be^{-0}+0e^0=A+B$$
and so $A+B=0$. Similar for $y'(0)$.

jolly parrotBOT
#

Civil Service Pigeon

quick venture
#

OH

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okay i see

dense jasper
pearl pondBOT
#

If you are done with this channel, please mark your problem as solved by typing .close

quick venture
#

.close

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quick venture
pearl pondBOT
quick venture
#

im abit confused with this area question

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is it becuase these are the intervals

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and i've calculated the intercepts?

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but we ignore the x=-1

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becuase it isnt in the interval range?

sharp vigil
#

from the problem statement we are asked to calculate $\int_0^2 \abs{x-x^3} \dd x$ (would be different if the interval was not specified), so determining the intersection point is only relevant to finding where the expression inside absolute value changes sign

jolly parrotBOT
#

cloud ☁

quick venture
#

ah okay i see

#

thanks

#

.close

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#
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lethal ruin
#

Fifty students were polled as to what courses they are currently taking. The results are shown below:

24 take Data Management, 17 take Calculus, 22 take Functions.

5 take both Data and Calculus, 7 take both Functions and Calculus, and 13 take both Data and Functions.

3 students are taking all three courses.

How many students are ONLY taking Calculus?

flat hornet
#

can you draw a venn diagram and post it?

lethal ruin
#

Yeah an incomplete one give me a second

flat hornet
#

np

flat hornet
#

perfect

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so how many people take only calculus and funcation but not Data management

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like this area

lethal ruin
#

7

flat hornet
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7 is for this area

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because that would be C and F

lethal ruin
#

I'm not sure actually. I have trouble understanding what to subtract. Could you give me a hint?

flat hornet
# flat hornet 7 is for this area

the area here contains C and F, but also people that take all 3 courses. We would only like the people that take C and F but NOT D

lethal ruin
#

Yes I know but I'm having trouble figuring that out

flat hornet
#

so we would subtract the amount of people that take all 3 courses froom the number of people that take C and F

lethal ruin
#

Wait is my venn diagram inaccurate then?

flat hornet
#

slightly

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but its ok

#

it works

lethal ruin
#

so $C \cap F = 7-3=4$

jolly parrotBOT
#

Elliot Pixel

flat hornet
#

basically

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but notice that it should be CnF/D

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/ for not including

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n for intersetion

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but the number you got is right

lethal ruin
#

so $C \cap F \cap D'= 7-3=4$

jolly parrotBOT
#

Elliot Pixel

lethal ruin
#

I think that's right

flat hornet
#

so D' is not including D right? to be sure?

lethal ruin
#

@flat hornet

lethal ruin
flat hornet
#

that perfect

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so do u think you can finish the problem now?

lethal ruin
#

Yes I think it's

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$17-2-3-4=8$

jolly parrotBOT
#

Elliot Pixel

flat hornet
#

yes that right

#

perfecto

lethal ruin
#

thanks a lot

odd coral
#

nice

lethal ruin
#

AI was not able to help with that lol

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cuz it's easier with a venn diagram

odd coral
#

that taught me another approach too

lethal ruin
odd coral
#

i just drew rows of numbers with letters

flat hornet
lethal ruin
odd coral
#

i do subtracting from certain sections in order

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the drawing skips a lot of the details though

flat hornet
#

its pretty cool

odd coral
#

i started getting rid of the 3 students that share all 3 courses

lethal ruin
odd coral
#

and affect all other groups

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and apply smth similar in stages

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if you can call them stages

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separating different steps in the process with those horizontal lines i drew

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i like the venn diagram approach it's pretty swag

lethal ruin
#

yeah fr

flat hornet
#

its rly cool

flat hornet
#

type ".close"

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have a nice day!

lethal ruin
#

I'm working on the same question rn and I may close it if I figure this out

#

ty

#

thanks for your help

flat hornet
#

ok np

#

ig u could just leave it open for a bit then

lethal ruin
#

@flat hornet @odd coral

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Yea I got it awesome

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thanks again

#

.close

pearl pondBOT
#
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crimson haven
#

can I get help with calculating coordinates

crimson haven
proper nova
#

,rccw

jolly parrotBOT
proper nova
#

Only the endpoints tho

#

So that's just the coordinates where x is at the bounds

crimson haven
proper nova
crimson haven
#

No

proper nova
#

Your exercise asked for the coordinates of the endpoints in these graphs

crimson haven
#

how do Ik which to do

proper nova
#

They specified what are the ranges of $x$ in each of the graphs

jolly parrotBOT
#

1 divided by 0 equals Infinity

crimson haven
#

So we use the range

proper nova
#

Yea

#

The endpoints usually lie on the boundaries

crimson haven
#

what’s boundaries

proper nova
#

For instance $[-90^\circ; 360^\circ]$ then the boundaries are at $-90^\circ$ and $360^\circ$

jolly parrotBOT
#

1 divided by 0 equals Infinity

crimson haven
#

Wait could u help me

proper nova
#

I don't really do trig much but yours is a common sense question so I might be able to help

crimson haven
#

How do I do this coordinate

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Actually how do I do them in general

proper nova
#

-# derivatives opencry

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I think that's called a turning point

crimson haven
#

Huh

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Oh

proper nova
#

With calculus, you could do this using derivatives

crimson haven
#

Will it be (45,0.9)?

proper nova
#

But without calculus

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You should remember the ranges for each function

crimson haven
#

Huh

proper nova
proper nova
crimson haven
#

Cos

proper nova
crimson haven
#

I’m asking for how I do and know which parts to find the coordinates

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Yes

proper nova
#

I thought you asked for the maximum of the function

crimson haven
#

The book and what ur saying is confusing

#

It’s d

proper nova
#

,rccw

jolly parrotBOT
pearl pondBOT
#

@crimson haven Has your question been resolved?

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south ice
#

Hello, can someone walk me through this problem? I’m new to vector function derivative btw

unborn abyss
#

velocity is the derivative of position (which is r)

south ice
unborn abyss
#

well, velocity (at a given t) is a vector and so is position

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take your position vector and differentiate it with respect to t

south ice
#

Sure but the general velocity is just a curve no?

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How is a curve orthogonal

unborn abyss
#

at a given time, the velocity can be expressed as a vector

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direction, magnitude

south ice
#

Yes but isn’t that when we instantiate a specific time

unborn abyss
#

well... yes, but you can talk about it in terms of t

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and youll find that no matter what you choose for t, the position vector is always orthogonal to the velocity vector

south ice
#

I see your point, but how are you supposed to show that the entire velocity is orthogonal to the position ? And how does that look like

unborn abyss
#

well, how would you normally show that two vectors are orthogonal?

south ice
#

Dot product = 0

unborn abyss
#

great

#

so lets do that here

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lets find the velocity vector in terms of t

south ice
#

Okay

unborn abyss
#

so go ahead and do that :)

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its the derivative of the position vector

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which is this

south ice
#

So is that

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$$ bwsin(wt)i - bwcos(wt)j + C = v(t) $$

unborn abyss
#

signs messed up and youre missing a j

#

i think you attempted to integrate it?

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where did that C come from

jolly parrotBOT
#

warbeast002

south ice
#

Ooops

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Oh no that’s supposed to be the derivative

unborn abyss
#

yes

south ice
#

One sec

unborn abyss
#

you can use \vec i if you want

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or dont bother

sharp vigil
#

or \vb i

south ice
#

Alright

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$$ v(t) = dr/dt = -bw * sin(wt) \vec i + bw * cos(wt) \vec j $$

jolly parrotBOT
#

warbeast002

south ice
#

There we go

unborn abyss
#

ok great

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so now can you find v(t) dot r(t)?

south ice
#

Uh

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Yeah idk how that should work

unborn abyss
#

well... how would you take the dot product of two vectors normally?

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like (4i + 3j) dot (i + 8j)

south ice
#

Oh yeah I see

#

Should I not think of it as a curve for this instance

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Like should I just think of all possible vectors at every t

#

Like infinite velocity vectors orthogonal to infinite position vectors

unborn abyss
#

i think that would be useful yes

icy bluff
#

Is the question solved?

south ice
#

Yessir

#

Thanks a lot, I wanna keep the channel open tho incase I need more help

icy bluff
#

So i can share my solution

south ice
icy bluff
#

Ignore my handwriting

south ice
# icy bluff

My answer was up to the dot product = 0. What was it that you did afterward with the square root? Are you taking the magnitude of all velocity vectors ?

#

I can’t tell

icy bluff
#

That's for question b

#

Speed of particle means magnitude of velocity

#

And it is proportional to omega

south ice
#

So i know speed is absolute value of velocity

#

But I don’t get the rest

icy bluff
#

Part b is asking us to show that the speed is proportional to angular velocity

#

That's it

south ice
#

What does proportional mean

#

And what’s annular velocity

#

Angular *

icy bluff
#

Which is dtheta/dt

icy bluff
#

Then both are directly proportional

#

If one quantity = constant/another quantity

south ice
icy bluff
#

Then both are inversely proportional

south ice
#

What is that supposed to be conceptually

#

The angular velocity

icy bluff
icy bluff
#

In which grade are you in

south ice
#

Undergrad

icy bluff
#

Ok wait

south ice
#

Alright

icy bluff
#

Watch this

south ice
pearl pondBOT
#

@south ice Has your question been resolved?

pearl pondBOT
#

@south ice Has your question been resolved?

pearl pondBOT
#
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pearl pondBOT
#
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quick venture
#

how do we know the limits are 3 and 1?

pearl pondBOT
timber cape
quick venture
#

(1,-1)?

timber cape
#

Exactly!

#

So

#

If

#

You shift the circle

#

By 2 units

#

What would the limits be?

quick venture
#

3 and 1

#

i think im just finding it hard to visualise

timber cape
#

Best way to counter this is shifting of origin

#

Let some big X+2 = x then everything shifts back like if it was at origin

#

And in the end just put the value of X instead of the ones of small x

quick venture
#

so x is the radius here

timber cape
#

x is just coordinates

quick venture
#

thanks

#

.close

pearl pondBOT
#
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pearl pondBOT
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thorny radish
#

use \setminus

prime stream
#

I started as follows. Let $\alpha \in F(c)\setminus F$. Then we can write $\alpha = \dfrac{f(c)}{g(c)}$ for some $f(x), g(x) \in F[x]$. Suppose, there exists $p(x)\in F[x]$ such that $p(\alpha) = 0$. Then $p(f(c)/g(c)) = 0$, implying that $c$ is a root of some polynomial, which is a contradiction.

jolly parrotBOT
#

Dedekind

prime stream
#

However, in order for this to work, I believe, I need to show that $p(f(x)/g(x))$ is not the zero polynomial. And also, it seems that the fact that $\alpha \notin F$ is not used in the proof, so probably I am on a wrong way. Any suggestions?

jolly parrotBOT
#

Dedekind

thorny radish
#

so assume f and g are coprime, then clear the denominator and see if you can conclude f and g are both degree 0

#

but you're on the right track

prime stream
thorny radish
#

like 1/4 + 3/2 + 2 = 0 implies 1 + 3*2 + 2*4 = 0

prime stream
#

ah, I see, thanks

pearl pondBOT
#
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prime stream
#

.reopen

prime stream
jolly parrotBOT
#

Dedekind

cursive wraith
prime stream
cursive wraith
#

ok yes sorry

#

but I don't think showing things about f and g is necessary

#

just show there is a polynomial that cancels c as you were trying to do earlier

#

write p(x) = ax^d + ...

#

and transform p(f(c)/g(c)) = 0 into (polynomial in c = 0)

#

by multiplying by g(c)^d (which takes care of every denominator)

prime stream
#

ok, thanks, let me try

cursive wraith
#

If you need to argue why the resulting polynomial isn't 0, just compare the degrees of each term

#

||one of the terms should have a degree higher than any other||

thorny radish
thorny radish
#

i suggested assuming f and g coprime earlier

prime stream
#

So let $p(x) = a_0 + a_1 x + ... + a_nx^n$. Then $p(f(c)/g(c)) = a_0 + a_1\dfrac{f(x)}{g(x)} + ... + a_n \dfrac{f^n(x)}{g^n(x)} = \dfrac{1}{g^n(x)}[a_0g^n(x) + a_1 f(x) g^{n-1}(x) + ... + a_n f^n(x)]$.

Hence have $a_0g^n(c) + a_1 f(c) g^{n-1}(c) + ... + a_n f^n(c) = 0$. Now, it looks like, for example, $a_0g^n(c)$ will be the only one that have the highest order, but only if we assume that the degree of f is less than the degree of g. It's not the same as to assume that f and g coprime, or I am wrong?

jolly parrotBOT
#

Dedekind

cursive wraith
#

Yeah I made a mistake in the degree argument which doesn't always work

#

the point is backwards that this polynomial, p(f(x)/g(x)) * g^n(x), has to be 0 (as only the 0 polynomial cancels c), and so p(f(x)/g(x)) is also the 0 fraction, as g^n(x) is not 0 and F(x) is integral

prime stream
jolly parrotBOT
#

Dedekind

prime stream
#

I mean, apparently it does, but I don't see how

thorny radish
#

no, for example f could be 0

prime stream
#

this I believe we can rule out, since $\alpha \notin F$

jolly parrotBOT
#

Dedekind

cursive wraith
#

f/g can also be constant

#

and p = x - that constant

#

the point is that you need to show those are the only cases

#

which is not trivial

cursive wraith
# jolly parrot **Dedekind**

maybe the degree idea can work when f and g have different degrees
when deg(f)= deg(g) you need to use their coprimeness

thorny radish
#

f and g coprime just solves for all cases though

prime stream
# thorny radish f and g coprime just solves for all cases though

Let me try this. Since $a_0g^n(x) + a_1 f(x) g^{n-1}(x) + ... + a_n f^n(x) = 0$ (as polynomial), this implies that $g^n(x)$ is divisible by $f(x)$ and $f^n(x)$ is divisible by $g(x)$. But since $f$ and $g$ have no common factors, this is impossible, unless $f$ and $g$ are constant. But then $\alpha \in F$, a contradiction

jolly parrotBOT
#

Dedekind

thorny radish
#

that's right

prime stream
#

@thorny radish @cursive wraith thank you!

#

.close

pearl pondBOT
#
Channel closed

Closed by @prime stream

Use .reopen if this was a mistake.

cursive wraith
#

for the other way around, consider the first coefficient a_k that is non zero

#

and you can obtain a similar reasoning

rustic gate
#

the minimal polynomial is irreducible

cursive wraith
#

p isn't supposed to be the minimal polynomial

#

but that's another way

rustic gate
#

assume it is then ig

cursive wraith
#

yes, that's what I agree with

prime stream
rustic gate
#

i think it was rafilou that caught it

pearl pondBOT
#
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sharp smelt
pearl pondBOT
sharp smelt
#

(a) $\sigma^2,\sigma^2, \sigma^2, \frac{4}{3} \sigma^2$
\
SO
\ Y,Y,Y,N

balmy monolith
jolly parrotBOT
sharp smelt
#

the first 3 have 0 MSE

#

How woul T_5 be unbiased for any multiple though

#

the MSE is sigma^2

pearl pondBOT
#

@sharp smelt Has your question been resolved?

brisk scarab
#

It's been a while since I did stats, but I'm pretty sure T4 is unbiased

#

those MSEs look very wrong as well

#

(on average, they're bang on? I think not)

pearl pondBOT
#

@sharp smelt Has your question been resolved?

pearl pondBOT
#
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south ice
#

Hello need help on this

pearl pondBOT
eager jewel
#

b part?

dusty jungle
#

use the fact that the velocity function is the time derivative of the position

south ice
#

I don’t understand angular velocity

eager jewel
#

What did u get as velocity

south ice
#

I got it right

eager jewel
south ice
jolly parrotBOT
#

warbeast002

eager jewel
#

Yea correct

#

Now speed is absolute value of velocity

south ice
#

Yes

eager jewel
south ice
#

$$ speed = | v(t)| = | - bw * sin(wt) \vec i + bw * cos(wt) \vec j | $$

eager jewel
#

No

#

U can't remove the - sign for when the expression is added

eager jewel
#

And take w common

south ice
#

I don’t understand what you’re saying tbh

eager jewel
eager jewel
south ice
midnight haven
jolly parrotBOT
#

warbeast002

eager jewel
south ice
#

You mean this

eager jewel
south ice
#

Whatever the command is

eager jewel
pearl pondBOT
# midnight haven

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).

eager jewel
south ice
#

w is not with ?

midnight haven
# south ice ,taken

i was suggesting that this is how you find the magnitude and not asking a question but nvm

south ice
#

With what

eager jewel
#

Take omega common from that expression

south ice
#

What’s omega common

#

😭

eager jewel
#

Bruh ka + kb = k( a+b )

south ice
#

Oh just factor out omega

eager jewel
#

Just do this with omega in that expression

#

Yes 😭

south ice
#

😭😂

midnight haven
#

$\omega(-b * sin(\omega ,t) \vec i + b * cos(\omega ,t) \vec j)$

jolly parrotBOT
#

atlanta

south ice
#

$$ speed = | v(t)| = | w(- b * sin(wt) \vec i + b* cos(wt) \vec j) | $$

jolly parrotBOT
#

warbeast002

eager jewel
#

Yes now do u see that we proved speed directly proportional to omega

south ice
#

No bro because I don’t understand what angular velocity even is conceptually and that’s what I’ve been trying to understand

eager jewel
#

Angular velocity is the rate at which an object rotates or revolves around an axis, measured as the change in angle per unit of time

toxic goblet
#

wsp guy

#

wsp guys

#

typo

#

im new

south ice
eager jewel
#

Omega=d(theta)/dt

#

Just like velocity=dr/dt

south ice
#

For example position has a function that you differentiate

#

Or does it not have one

#

Hope I’m not asking a stupid question

eager jewel
#

Position may not always be a function of something

eager jewel
south ice
south ice
eager jewel
south ice
eager jewel
south ice
eager jewel
#

for example we may just have r(t) = 7

south ice
#

So time isn’t really completely absent here

#

But man I’m still not understanding the speed being proportional to the angular velocity

eager jewel
#

why not..we proved it mathematically..

south ice
#

Because essentially that’s what we’re quantifying with algebra

eager jewel
#

graphically? how do u understand proportionality graphically

south ice
#

I don’t know broooooo

eager jewel
#

well i dont know then

south ice
eager jewel
#

yes

#

as given in the question

south ice
eager jewel
#

its not expressed on that graph..the particle is rotating in a circle with angular velocity omega

pearl pondBOT
#

@south ice Has your question been resolved?

eager jewel
#

no its constant with time

south ice
#

Is w angular velocity ?

eager jewel
#

why are u asking the same questions

south ice
south ice
#

w ⇒ angular velocity

angular velocity ⇒ function

∴ w ⇒ function

#

<@&286206848099549185>

pearl pondBOT
#

@south ice Has your question been resolved?

pearl pondBOT
#

@south ice Has your question been resolved?

south ice
#

<@&286206848099549185> can anyone help me out with this ?

lavish bay
west ether
#

What's up

south ice
# lavish bay ya whats up

Thank you, I’ve been trying to understand part b conceptually for a while now, can you please help me out

lavish bay
#

sure no problem

south ice
#

What does it mean to have angular velocity and how does that even look like in relationship to the position function we started with and the graph???

south ice
lavish bay
#

angular velocity essentially tells you how fast the angle is changing

#

in this problem its within the the coswt and sinwt meaning it rotates around the circle at rate w

#

so larger w maskes it go around faaster

south ice
lavish bay
#

its always measured relative to a chosen center of rotation

south ice
#

So w is a constant right ?

lavish bay
#

yes w is a constant

lavish bay
south ice
#

How does this differ here

lavish bay
#

thats a great point you make

#

i think ur thinking about velocity in terms of linear velocity

#

or the actual speed of an object along a path

#

in the case of circular motion you still have a velocity function but it's a bit different due to the motion being on a circle

south ice
lavish bay
#

yes

south ice
#

So where is our angular velocity function

lavish bay
#

the angular velocity is constant so there is no angular velocity functio

#

it simply describes the constant rate at which the angle ,tex θ(t)=ωt changes with time

stone egret
#

But how do we show it

south ice
#

Yeah im trying to use similar logic to linear velocity

stone egret
#

Tryna understand with u lmao

south ice
#

No worries

south ice
stone egret
#

Theta(t) means angular velocity in most case

south ice
#

<@&286206848099549185> anyone?

south ice
#

.

south ice
#

<@&286206848099549185>

warm swan
#

What's the question

south ice
#

I really wanna understand what angular velocity is man

#

Like I know it’s how fast an angle changes of some particular relative to the origin

#

But I don’t understand the math behind that

#

Like the w and it being inside the cos and sin functions

warm swan
#

That's the equation of a circle

#

In parametrized form

#

You use that and the fact that angular velocity is the rate of change of angle

south ice
#

I’m trying to understand whew that comes from how do we obtain it what is it

real arrow
#

They just replaced it with the angular velocity formula

#

Angle theta = w*t

#

So instead of theta, they write wt

#

If ur asking why they do thay

#

I'll just use 0 as theta

#

Its because the angle is changing with time

#

So instead of just 0

#

U have 0(t)

#

And 0(t) = wt

proper nova
pearl pondBOT
# south ice <@&286206848099549185>

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.

proper nova
#

don't ping twice

south ice
ashen mauve
#

thats the only relationship you need

south ice
#

can you please help me out on this

#

so im trying to think of it the same way you think of normal velocity

#

for example

#

i know velocity of some position function is the limit of the difference quotient as h approaches 0

#

So i know the logic that makes up this velocity

ashen mauve
#

same thing for omega

south ice
#

whats the logic that makes this one up

south ice
ashen mauve
#

omega can be a differentiable function

#

it doesn’t have to be

#

think angle as position

#

it’s a unique type of position measurement in the fact it’s dimensionless

#

but it’s used similarly in the calculation of angular velocity

#

simply the rate of change of an angle

#

if i turn 1pi radians every second

#

then my angular velocity is just omega=pi/t

#

similarly you can have angular acceleration too if the velocity function is of degree 2 or higher

south ice
#

what would the positon function equivalence be

ashen mauve
#

your angle at time t

#

theta(t) = …

south ice
#

Like the function

ashen mauve
#

i’m sorry wdym

#

the function is dependent on the scenario

#

if i’m not rotating then it’s constant

#

if i’m rotating at a constant rate then it’s linear

#

you could have theta(t) = t^3+t+4

#

or you could have theta(t)=pi

ashen mauve
ashen mauve
south ice
#

According to what you explained above such that it could either be linear or not

#

Like in this example

#

How do I know what my angular function is

ashen mauve
#

if it’s provided

#

or you measure it

#

or you derive it from other given functions

#

if you’re given an angular velocity you can integrate to get your angular position +c

#

c can be found if you know the starting position

#

ex, omega=7, i started at theta = pi

#

integral of that with respect to time is 7t+c

#

my starting position was pi, so c=pi

#

my position function is 7t+pi

ashen mauve
south ice
#

In our example what is our angular position function ?

#

They’re just saying dθ/dt

#

But then also w is supposedly dθ/dt

#

So w = dθ/dt?

ashen mauve
#

you keep saying angular function but that could refer to anything

#

angular position, velocity, acceleration, jolt

#

omega = d(theta)/dt is the definition for angular velocity

ashen mauve
south ice
ashen mauve
#

angular position or just position?

ashen mauve
south ice
ashen mauve
#

they are

#

refer to what i asked in my previous comment

south ice
#

Yes the one where when you differentiate it you get your angular velocity

#

I’m asking so I know the root of the angular velocity and how to obtain it

ashen mauve
#

then that’s angular position

#

here denoted by simply theta

#

since its in derivative form

#

the function would look like theta(t) = …

south ice
# ashen mauve the function would look like theta(t) = …

Yes but what im asking is:

Is there anything related to angular motion (such as the position function for θ or its angular velocity?)
And where is it? They’re saying d θ/dt but where is the function itself ? Am I supposed to solve for it somehow?

ashen mauve
#

why do you need angular position

ashen mauve
#

you aren’t given info about omega so you cannot solve for it here

ashen mauve
#

as that’s not the intent of the problem

south ice
ashen mauve
#

yeah

#

particles moving in a circle

#

cos tells you x coordinates sin tells you y

south ice
#

So I’m asking because angular velocity here is expressed inside the cosine and sine functions, can that differ based off of the position function itself ?

ashen mauve
#

it’s there bc it tells you how fast theta changes with respect to time

#

multiply it by time, you get position

#

that’s why it’s (omega)t inside

#

that just tells you what angle it’s at

#

thus giving position

#

it’s just inside the cos and sin because that’s how we can make circular motion

south ice
ashen mauve
#

yes

#

think of it how you can multiply velocity by time to get position

south ice
ashen mauve
#

i move at 10m/s multiply that by 2 seconds i’ll get 20m

#

technically that’s change in position

#

this assuming p(0) = 0

south ice
ashen mauve
#

?

#

what second unit

#

theta/t • t

#

t cancels

south ice
#

Does it cancel out with the s in the bottom

south ice
#

I’m trying to understand why it gives you position

ashen mauve
#

i mean it just means you multiplied it by the time it takes

south ice
ashen mauve
south ice
ashen mauve
#

it’s just dimensional analysis

south ice
#

How is it that if you multiply that speed by some time , you magically get a position

ashen mauve
#

because you’re taking a distance per time

#

and multiplying it by the time it took

#

if i travel 60mph

#

how far do i travel in an hour

south ice
#

Ohhhhhhh I think I get it

#

@ashen mauve and in the case of this problem your angular velocity * time gives you the angle of that particular at that time? Or tue position of that particle ?

ashen mauve
#

it gives you the angle theta, then taking the sin and cos of that angle give you the x and y coordinates

south ice
#

Or is it actually there but it’s equal to 1?

#

I’m guessing stuff

ashen mauve
#

assuming thats a position function

#

youll just move in some sinusoidal motion

south ice
# ashen mauve then youre just taking the cos of time

Well then what’s the point of having w in our position function? Whats the deal with having to take the cos of the angular position of some particular , vs taking the cos of the time ? How are these two things related to the position function ?

ashen mauve
#

well bc the original function is circular motiono

#

while cost is a sinusoidal motion

#

which looks very different

ashen mauve
south ice
#

Is that because if you have a circular motion, you can utilize Θ to obtain your position

#

?

ashen mauve
#

yes its the way of obtainning theta in this case

#

since our function is parameterized by t

south ice
#

Interesting

south ice
#

But also aren’t those functions specifically for angles

ashen mauve
#

sin takes a scalar value and outputs a result

#

those outputs correlate to angle ratios

#

but i dont have to use an angle if i dont want to

#

i can just time sine of time

#

and get a perfectly graphable funciton

south ice
#

Also I’m assuming your statement is inclusive to cos as well

ashen mauve
#

yes it is

south ice
#

Or do non circular functions not take θ at all

ashen mauve
#

Hmmmm, i’m not gonna confirm or deny that as i’m not quite sure

pearl pondBOT
#

@south ice Has your question been resolved?

pearl pondBOT
#
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pearl pondBOT
#
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zenith bramble
#

How to do this???

pearl pondBOT
zenith bramble
#

I tried first maximizing the sqrt term (because bigger value subtracting would result in minimum value in result)

#

But after that it becomes like very bad expression

dire tapir
jolly parrotBOT
zenith bramble
#

It's in application of derivatives chapter btw if it helps lol

dire tapir
#

then find the derivative

zenith bramble
#

It's 4th power

dire tapir
#

hmm

zenith bramble
#

But like expressions are different and stuff

#

Wait I think I got smth

midnight haven
#

straight differentiation would be ugly

zenith bramble
#

Holy shi

#

I got it

dire tapir
jolly parrotBOT
zenith bramble
#

Smth like this

#

Then solve it with shortest distance between parabola and point

frank violet
zenith bramble
#

Tysm for insight @dire tapir

tough ore
#

That thing under the root seems to be equation of circle

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With center (15,0) and radius 2

frank violet
#

I think

zenith bramble
#

Yes yes

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One horizontal and one vertical

frank violet
#

exactly

zenith bramble
#

I feel like my brain just opened up lmao

frank violet
#

typical jee problem

dire tapir
# jolly parrot **MxRgD**

yeah I was just gonna say that you can tell from here that $y_1 = \frac{x_1^2}{20}$ and $y_2 = \sqrt{(17-x_2)(x_2-13)}$

jolly parrotBOT
zenith bramble
zenith bramble
frank violet
#

KEK no, but so many people have asked similar problems

tough ore
#

I solved this exact question last year lmao

dire tapir
#

jee is tough, they kinda want you to spot tricks like these

zenith bramble
midnight haven
zenith bramble
#

Wait is tht circle

#

Oh shi

frank violet
#

not sure, just graph it tbh

zenith bramble
#

x square has -ve

midnight haven
#

if its AOD for jee always better to solve graphically 🥀

dire tapir
#

well if you think about my P_2 that i've defined seems to be an upper half of a circle when you simplify and complete the square?

frank violet
#

catcutethink yeah right

midnight haven
#

hmm..

dire tapir
#

plus y ≥ 0 as well

midnight haven
#

one above the x axis

zenith bramble
#

Yea it's actually 2grapgs half circle and half parabola(the first one)

dire tapir
#

the half circle

zenith bramble
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Cuz they said x1 belongs to positive real

zenith bramble
dire tapir
# zenith bramble Yea

Yeah, so i'm thinking it's essentially a minimum distance between a point on a parabola and a point on a circle question

#

that we've reduced it down to

midnight haven
zenith bramble
#

💀💀

dire tapir
#

😭

midnight haven
#

lol smol ass

#

semi circle

zenith bramble
#

Ye ty for the help guys

#

I think I can solve it from here

#

.close

#

.close

pearl pondBOT
#
Channel closed

Closed by @zenith bramble

Use .reopen if this was a mistake.

pearl pondBOT
#
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vernal tinsel
#

hiii guys so i have 2 questions to ask i just came out of a test and im just asking the questions i wasnt sure of to see whether i guessed them right or wrong lmao. theyre not in english so pls let me know if theres anything that ishould translate

dire tapir
#

I'm guessing it's a translation question

vernal tinsel
#

the peak point of the first parabola(f(x) = ax² + bx + c) is (-4,4) and it asks for the peak of
f(-x+2)