#help-26

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exotic dome
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Now you know the whole lower part

orchid hatch
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yea

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54

exotic dome
#

And the upper part is 1/4 of the whole triangle (similar triangles)

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So the lower part is 3/4 of the whole triangle

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So multiply the lower part by 4/3 to get the whole triangle

orchid hatch
#

yea

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s0

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72

orchid hatch
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3 more

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Three squares with sides of lengths two, four and six units, respectively, are arranged
side-by-side, as shown so that one side of each square lies on line AB and a segment connects the
bottom left corner of the smallest square to the upper right corner of the largest square. What is the
area of the shaded quadrilateral?

exotic dome
#

I never do the math though so that’s on you

orchid hatch
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i cant wait to sleep

orchid hatch
exotic dome
#

Ok

exotic dome
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Use Thales to find the question mark lengths

orchid hatch
#

?

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uhh

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ok

#

idk tht

exotic dome
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Let x be the small one and y the big one

orchid hatch
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i think its 18 the entire thing

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wiat nvm

exotic dome
#

x/6 =2/(2+4+6)

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Right ?

orchid hatch
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ye

exotic dome
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x = 1

orchid hatch
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mhmm

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then

exotic dome
#

y /6 = (2+4)/(2+4+6)

orchid hatch
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3

exotic dome
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y = 3

orchid hatch
#

area is 8

exotic dome
#

So now you can compute the area right ?

orchid hatch
#

yea

#

((1+3)*4)/2

exotic dome
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I never do the math

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That’s on you

orchid hatch
orchid hatch
#

In triangle ABC, AC = 21, BC = 28, and ∠ACB = 90◦. The bisector of ∠ACB meets AB at D.
Find the length BD

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hmm

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c = 35

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ratio is /49

exotic dome
#

Need to go

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Brb

orchid hatch
orchid hatch
#

AD is 15

orchid hatch
#

AD is 15

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BD is 20

limber elbow
orchid hatch
#

Using the same diagram as in Problem 12, find CD

orchid hatch
limber elbow
#

do you have the ratio or should i use trigonometry?

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like about the cd

orchid hatch
limber elbow
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what angle it makes or any information about it

orchid hatch
#

i think CD is also 20

limber elbow
#

okay soo untill you tell me the relation of angle c with the line cd it's not possible to determine it

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like if it's bisected then it's fine we can find it

orchid hatch
#

yea

limber elbow
#

soo angle c is bisected ?

orchid hatch
#

In triangle ABC, AC = 21, BC = 28, and ∠ACB = 90◦. The bisector of ∠ACB meets AB at D.
Find the length BD.

limber elbow
#

that makes it easy

orchid hatch
#

ye

orchid hatch
#

and is BD 20?

limber elbow
#

yeah then you are right my friend

orchid hatch
#

then waht is CD?

limber elbow
#

TBH you got me rolling how is this even solvable

orchid hatch
#

lol

orchid hatch
exotic dome
#

Are you still on this one V

orchid hatch
orchid hatch
#

i got AD = 15; BD = 20; I need to find CD

limber elbow
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just done

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wait a sec

orchid hatch
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i think its 20 ngl

orchid hatch
orchid hatch
limber elbow
orchid hatch
orchid hatch
#

wait nvm

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i figured mistake

limber elbow
orchid hatch
#

In the diagram, triangles BQA, BQP, PQD, and BPC are all 30◦-60◦-90◦ triangles. If
AD = 12, then find the area of rectangle ABCD.

orchid hatch
limber elbow
orchid hatch
#

one angle is 30 another is 60 and last is 90

limber elbow
limber elbow
orchid hatch
#

i think it is 144root(3)

orchid hatch
limber elbow
#

i used rote push

orchid hatch
#

ok

limber elbow
#

naming with variables

orchid hatch
#

ok

limber elbow
#

hey you can use co-ordinates i guess it's 144*sqrt(3)

orchid hatch
#

In rectangle ABCD, P is a point on side AB, and Q is the intersection of BD and CP.
If the area of triangle PBQ is 8, and the area of triangle CDQ is 18, then find the area of rectangle
ABCD

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2nd last one

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i got 60

limber elbow
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yeah

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you're right

orchid hatch
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ok

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In the diagram, ABCD is a square with side length 13, DP = BQ = 5, and
AP = CQ = 12. Find PQ (((((i got sqrt(178)))))

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hmm

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do u have any clue

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i kinda guessed too

limber elbow
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nah i am solving RN

orchid hatch
#

ok

limber elbow
#

might take a bit i am using co-ordinates and stuff

orchid hatch
#

ye

orchid hatch
limber elbow
#

17*sqrt(2)

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just let me

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cehck ones

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yeah

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17*sqrt(2)

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@orchid hatch

orchid hatch
#

ok

limber elbow
#

want me to send the solution ?

orchid hatch
#

sure

limber elbow
#

kk

orchid hatch
#

i gtg

#

im not too sure its 17root(2) but i think it is that

limber elbow
#

place the square with coordinates (D at origin):
A = (0, 13), B = (13, 13), C = (13, 0), D = (0, 0).

Point P is the intersection of the circles centered at A and D with radii AP = 12 and DP = 5.
Solving:

(x – 0)² + (y – 13)² = 12² ( using the cricle equation )

x² + y² = 5²
gives the left intersection:
P = (–60/13, 25/13).

Point Q is the intersection of the circles centered at B and C with radii BQ = 5 and CQ = 12.
Solving:

(x – 13)² + (y – 13)² = 5²

(x – 13)² + y² = 12²
and taking the point to the right of the square gives:
Q = (229/13, 144/13).

Now compute the vector PQ = (289/13, 119/13).

Then,
PQ² = (289/13)² + (119/13)²
= (289² + 119²) / 169
= 97682 / 169
= 578
= 2 × 17²

PQ = 17√2.

there you go took me a while to get it from image to text correctly cause my handwriting is aah soo good haha !

orchid hatch
#

oh lol

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ok ig

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ty

limber elbow
#

welcome mate

orchid hatch
#

.close

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#
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plush seal
#
  1. Compare the V(i) that you calculated for times 7, 13, 21, and 25s. with the Vavg for the intervals that included those times. in which cases are the V(i) and Vavg nearly the same? quite different? Explain why.

Since the instantanious velocity is the tangent of a position time curve, it can be calculated by the infinitesimal change in position with respect to time. Since we are only given a finite number of points, calculating the tangent at a p(7) is approximately the same as finding the secant of the two points closest to p(7) (e.g: p(6), p(8)). Therefore, since we are only given a finite set of points, Vavg and V(i) are approximately the same.

plush seal
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i have

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quite literally

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no idea if my analysis was right

patent owl
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SPH3UI.. godspeed soldier

plush seal
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acc this is for an in class lab i didnt even submit 💀

patent owl
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i think the idea is, you want to find V_avg for the specific phase, and compare it with V_i in each case.

plush seal
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here’s the graph

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you can barely read it tho

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that graph is for

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vavg

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the table is for position

patent owl
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no that's perfectly fine

patent owl
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and then you should be comparing 5 different times, with each interval, to see when it's close and when it's far

plush seal
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pretty sure they would all be the exact same

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since im just calculating for vi

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and in this case

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vi = vavg

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so vavg=vavg

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yeah i cross referenced

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all of these are almost the exact same

patent owl
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with the Vavg for the intervals that included those times
i interpreted this as being the velocity over each phase, since that actually has the potential to be different

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so for phase 1, it's the average velocity between 0.0 and 8.0 seconds

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i mean i could be wrong about this wording. but like you said, vi = vavg, and i doubt they would give you a question that easily

plush seal
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then graph the average velocity

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which is where that graph came in

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iroc is basically just

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the closest two points to a given curve gives you the tangent of the curve

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which is basically

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we are making the secant so much smaller

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that it basically becomes the tangent

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which is essentially what im doing

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if we expand the iroc's tangent

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we get a secant

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and since vavg is a secant from all the points on the position graph

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if we calculated for vi on a point

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it would be the same as vavg

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since we do the exact same calculation

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because we cant find the actual derivitive

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anyways that just how i interpreted it as

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i might be wrong plus its hella late

patent owl
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hmm, im actually gonna double back and say that your thinking makes more sense here, because they also included 13s which is on the cusp of each phase

plush seal
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im just going to act like im right and move on from this shitty course

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alr lol thank you

patent owl
#

in that case, your analysis is pretty much correct. i might word your second sentence like this, though:

Since we are only given a finite number of points, our closest approximation for the tangent at p(i) is finding the secant....
and you could also add to the ending sentence:
since we are only given a finite set of points, V_avg = V_i within the closest possible approximation

#

but i think you get the point across fine without those changes

patent owl
#

(but i honestly think 4U was easier than 3U, because the bs rules start to make a bit more sense)

plush seal
#

i have like a 50 average in this course because

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im taking 4U next sem

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so this wont count to my uni marks at all

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so who gives a shit

plush seal
patent owl
plush seal
#

not to flame her like

patent owl
plush seal
#

she prolly a good teacher for some people

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but like

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we spent 2 hours on a single lesson

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which took me

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15 minutes of self study

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then she assigned 15 homework problems EVERY DAY 💀

patent owl
#

"closest approximation" and "within the given degree of precision" i think describe these kinds of things rly well

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i do NOT miss the amount of mandatory SPH homework

plush seal
#

what you end with

plush seal
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i havent done any of it

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theres 15 days of homework

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ive gotten 0/5s on all of em

patent owl
# plush seal what you end with

its been a while and i forgot what my transcript looked like. i think i got 91-93 for both courses bc i did all the work (it was covid i had nothing else to do)

plush seal
#

nicee

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im at a solid 60

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okay tbf

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thats not my fault

patent owl
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ya if u can get the work in, you should

plush seal
#

on my quiz

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i wrote x1 = (fraction1) x2 = (fraction2)

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and the equation was in time

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so i got a ZERO on that ENTIRE PART

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so wouldve been a 100

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got like

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a 75 i think

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or an 80 on that

patent owl
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and this is why i do not like physics

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in the first-year uni course for physics at my school, they gave us the standard "6-step method to solve a problem" thing

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they wanted full explanations for each step for each problem, or else you lose like half your marks

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and the multiple choice was 15 questions out of 5 points. no half points.

plush seal
#

yeah cause all of the marks are like only process work bullshit

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physics pisses me off but like as a subject

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its better than math

patent owl
#

im kind of whining now. but i really don't understand why they care so much, if the method and answer are correct

plush seal
#

bro my ENTIRE answer was right but i just forgot to do t1= and t2=

patent owl
plush seal
#

holy shit this teacher

plush seal
#

theres not many physics servers tho

patent owl
#

no sympathy from me unfortunately

plush seal
#

i dont blame you lol

patent owl
#

yeah apparently the big one is dead?

plush seal
#

yeah

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alr ima go

patent owl
#

sounds good, good luck ^-^

plush seal
#

.close

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#
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grand solar
topaz sinewBOT
grand solar
#

I'm wondering if I went about proving injectiveness right

#

in the back of the book the solution said it follows from r^-1 existing

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I didn't use that but is mine also right?

outer portal
#

think of 2 * 5 = 0 (mod 10)

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Oh nvm completely misread

outer portal
#

think of 2 * 5 = 0 (mod 10)

grand solar
#

thats true

outer portal
#

You can just use that r^-1 exists on both sides

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also (mod n) is written once per equation instead of each side

grand solar
#

oh ok

#

are we multiplying both side by r^-1?

outer portal
#

yes

grand solar
#

hmm

#

is the operation were dealing with addition or multiplication for Z_n

outer portal
#

It’s just the same operation as between s and r

grand solar
#

does r inverse exist because U(n) is a group?

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or does it exists because Z_n is a group?

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r is just some integer mod n so even if it's inverse didn't exist in U(n) I would still be able to use it's inverse from Z_n?

topaz sinewBOT
#

@grand solar Has your question been resolved?

grand solar
#

im stuck on proving homomorphism

valid marsh
valid marsh
grand solar
#

wait so

#

oh ok

#

so sr is multiplication but were in addition

valid marsh
grand solar
#

so alpha(xy) is alpha(x + y)

valid marsh
#

So you need to show that alpha is a homomorphism from (Z_n, +) to itself

#

and notice that the group operation is + in both the domain and the codomain

grand solar
grand solar
#

would that mean we would not be able to assume the inverse exist

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I was thinking since were dealing with Z_n and r is just an integer mod n we could just still assume it inverse existed

valid marsh
grand solar
#

U(n) is numbers relatively prime to n under multiplication mod n

valid marsh
grand solar
#

well I never knew if multiplication mod n is a part of U(n)

valid marsh
#

addition isn’t (on U(n))

valid marsh
#

because it is a theorem that every r which is coprime to n must have an inverse mod n

grand solar
#

why wouldn't 8 be the inverse of 2 mod 10?

valid marsh
valid marsh
quasi depot
grand solar
#

but in Z_n 2 has an inverse mod 10 right

#

I think im confused on why we cant use that inverse

valid marsh
valid marsh
grand solar
#

so we have sr for r in U(n), and say I want to show alpha is injective
then xr = yr, and I want to multiply

-- oh I think I see, I was confused on why we coudn't use it here, but thats because were multiplying here and 2 inverse in Z_n is not the same as 2 inverse in U(n)? There's a lot going on so my brain is getting kind of jumbled thinking of different operations

quasi depot
valid marsh
grand solar
#

ok ill keep that in mind, thanks for the help guys

#

.solved

topaz sinewBOT
#
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#
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grand solar
topaz sinewBOT
grand solar
#

so I want to show that G is isomorphic to H?

#

and both of their group operations is addition

#

yeah this question has me kind of lost

loud oasis
#

take G and H as groups under addition. then prove they are isomorphic

grand solar
#

So I need to find a function that relates the two groups, ok ill think some more about it

#

though kind of confused on how I would relate a real number with a matrix but hmm

#

ill try and see if I can get something

#

maybe det or something

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oo I think det might do it?

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a^2 - 2b^2

#

and thats (a - sqrt(2))(a + sqrt(2)b)

#

ill see if I can use this

loud oasis
#

i would say the notation is suggestive here

topaz sinewBOT
#

@grand solar Has your question been resolved?

clear python
grand solar
#

did i show Onto correctly?

clear python
#

Yup looks good

#

Now you have to check the next part

grand solar
#

ok thanks i’ll try

grand solar
clear python
#

Yes

grand solar
#

ok

grand solar
#

thank you for help, onto my last question

#

.solved

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#
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stark crater
#

how to solve the integral of (l+a+x)^-2

topaz sinewBOT
stark crater
#

I dont know about u du method there was I role I think that can be followed to solve such thing

maiden plank
#

$\int_0^L (l+a+x)^{-2} \dd x$?

stark crater
#

not 1 L

maiden plank
#

oh

rough furnace
#

what's L

stark crater
#

yes

maiden plank
#

are l and a some constants?

stark crater
stark crater
#

and integeral limits from 0 to L

#

if that would help

thorny flameBOT
#

Céline

stark crater
#

yes that is it

rough furnace
#

$\int \frac{1}{(c+x)^{2}} \dd x$

thorny flameBOT
#

Alexis_Fx

rough furnace
#

Do this look familiar to you?

stark crater
#

yea same form as our problem

#

but it is in denominator instead

rough furnace
#

What's the differential of -1/(x+c)

stark crater
#

wait.. that was arc tan smth right?

#

arctan(x/a)/ sqrt(a) maybe

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wait I think am wrong

rough furnace
stark crater
#

ok -1

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nah wait

#

-ln (x)

rough furnace
#

no....

marsh charm
#

alright what is the antiderivative of x

stark crater
#

we subtract -1 from the x+c that would give us (x+c)^-2

rough furnace
#

So antiderivative of (x+c)^-2 is -1/(x+c)

#

Does this look familiar to you?

stark crater
#

alr.. it is same as our problem

#

so it should be

#

-1/(l+a+x)

rough furnace
#

yessss

#

That's not the way we suppose to solve integral but it works just fine in this case lol

stark crater
#

there is no rule for this case?

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I mean

rough furnace
#

Yes we do, I don't remember which one tho

stark crater
#

when we get antiderivative of (x+c)^n we should do that and such ?

#

I see..

#

that works too

rough furnace
#

$\int (x+c)^n=\frac{1}{n+1} (x+c)^{n+1}$

thorny flameBOT
#

Alexis_Fx

rough furnace
#

iirc

stark crater
#

oh wait

#

so I was watching this video

#

and when they solved this integration he added 1 , which makes sense.. Then mulitplied by -1

#

I belive it is the differential of l+a-x maybe

rough furnace
stark crater
#

no ignore the yello circle

rough furnace
#

oh okay

stark crater
#

it is from the video itself

#

I mean -1 x -1

#

the second -1 here

rough furnace
#

I'm not sure where that came from

stark crater
#

this seems to be the differentiation of whatever inside the parenthesis from numerator

stark crater
rough furnace
#

where the x came from

stark crater
#

u mean dx ?

rough furnace
#

,w int (l+c-x)^(-2)

rough furnace
stark crater
#

ommm..

rough furnace
stark crater
#

it is impossible to get x according to my problem

#

yeah I just noticed that, sorry

rough furnace
#

there was two -1 because this's -x

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Not +x

stark crater
rough furnace
#

Wel chain rule is quite painful to explain

#

You should watch youtube

stark crater
#

I know what is chain rule

#

u just do dertivative to what is inside the parenthesis

#

sorry for my english btw but I think u got what I said

rough furnace
#

okay okay

#

That's like everything you need I think

stark crater
#

yeah..

#

thanks alot

#

bye

#

.close

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#
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stark crater
#

hello again

topaz sinewBOT
stark crater
#

using those integrations

#

I wanna find dE_y

#

that is my solution

#

however, I am not getting zero. my lecturer said that The result of E_y must be zero .. can anyone pls tell me where I have gone wrong ?

neon iron
#

U are missing a -ve sign

neon iron
#

Try to simplify maybe it will work

stark crater
neon iron
#

U got it?

stark crater
#

x-xp ? why tho ?

neon iron
#

Look at your initial integra

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The one u used as refrence

stark crater
neon iron
#

Yes

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Now in the ques (x-xp)^2= (xp-x)^2

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And u have the formula for (x-xp)^2

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I haven't simplified it but there's no mistake now so it should work

#

U got it?

stark crater
#

lemme try to solve it

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but xp is a different thign

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we are integerating in terms of x

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and in that initial integral we should are integrating in terms of x too

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so

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we should have negative sign outside right?

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because it is -x not +x

#

still.. I dont see any different that would lead to zero

stark crater
# stark crater

the first term is going to have L and last term cant have that L

#

how it will cancel each other

neon iron
#

Consider the situation of integral of (x-a)^2

stark crater
#

(x-a)^3 /3 ?

neon iron
#

According to you integral of( x-a)^2 and (a-x)^2 must be different but they are not
You can expand them and check

neon iron
stark crater
#

yeah..

#

I see..

neon iron
#

You got it?

#

Try to simplify

#

Maybe it will work

stark crater
#

yeah I will

#

thanks

#

.close

topaz sinewBOT
#
Channel closed

Closed by @stark crater

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topaz sinewBOT
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topaz sinewBOT
shrewd birch
#

also is there a better way to solve it?

#

seems like an easy soln but it took time fro me

#

bcoz what id do is make 4 pairs of x,y

#

<@&286206848099549185>

#

hi

topaz sinewBOT
#

@shrewd birch Has your question been resolved?

shrewd birch
#

.close

topaz sinewBOT
#
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silk carbon
#

???

topaz sinewBOT
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winter temple
#

what is (f) about? Since we have the ordered basis $\beta={1,x,x^2}$, I see that $f(x):P_2(F)\to P_2(F)$, and $[f(x)]_{\beta}$ is the matrix representation $f(x)$ in the ordered bases $\beta$. But I couldn't figure out what $f(x)$ is.

thorny flameBOT
hardy wing
#

What is $\beta$?

thorny flameBOT
#

Stitches

winter temple
#

$\beta={1,x,x^2}$ the standard ordered basis of $P_2(F)$

thorny flameBOT
hardy wing
#

so you want 3-6x+x^2 in terms of the elements of beta no?

winter temple
#

Umm, I thought $f(x)$ should be a linear transformation with a $3\times 3$ matrix representation?

thorny flameBOT
hardy wing
#

No that's T

#

You multiply f(x) (as a vector) by T (a transformation matrix), to get the output of the transformation (as a vector)

#

f(x) is a possible input to your transformation T

#

Distinct from T(f(x)), which would be the output of applying the transformation T on f(x)

winter temple
#

ohh

#

ig $[f(x)]_{\beta}=\begin{pmatrix}3\-6\1\end{pmatrix}$?

thorny flameBOT
hardy wing
#

yeah thats all

winter temple
#

alr thanks

#

.close

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#
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arctic prairie
#

proof for the image of an interval by a continuous function is an interval

flat pike
#

!status

topaz sinewBOT
#
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
#

@arctic prairie Has your question been resolved?

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calm charm
#

But to find the $f (x)+g(x)$ graphic just add the ordinates for each x?

thorny flameBOT
#

Reginald Puddingface

void vapor
#

I don't know why you said but at the start but yes

#

(this follows from how addition of functions is defined)

topaz sinewBOT
#

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undone walrus
topaz sinewBOT
neat jasper
#

what have you tried?

undone walrus
#

nothing. I don't understand

neat jasper
#

Okay

#

do you know what:
a) a topology is
b) an open set is
c) continuity is?

undone walrus
#

i do

neat jasper
#

all 3?

undone walrus
#

not continuity on topology tho

neat jasper
#

okay so

#

you want me to keep it abstract or show how it's based on continuity of real functions?

undone walrus
#

the simplest way pls

neat jasper
#

a function is continuous if the preimage of every open set is open

undone walrus
#

okay

neat jasper
#

so you need to check f^{-1}(S) for all open S, what are the open sets here?

undone walrus
#

{a}

#

?

void vapor
#

Those are not all the open sets

undone walrus
#

{b} and {a,b}

#

?

#

empty set and X ?

void vapor
#

{b} is not open

void vapor
opal vault
undone walrus
opal vault
#

A function f:X-> Y is continuous at x if for any open set V that contains f(x), there is an open set U containing x such that f(U) subset V

#

I'll latex it one sec

#

A function $f:X\to Y$ is continuous at $x\in X$ if for any open set $V\subseteq Y$ that contains $f(x)$, there is an open set $U\subseteq X$ containing $x$ such that $f(U) \subseteq V$

thorny flameBOT
#

Raphaelisius Maximus MMIII

neat jasper
#

oooh

#

I take it back

opal vault
#

"Study the continuity at the points a and b of ..."

neat jasper
#

the question says "continuity AT"

#

yeah yeah youre 100% right

#

@undone walrus as you would expect, there's a theorem

#

a function is continuous iff it is continuous at every point

#

but it can be continuous at some points and not others

undone walrus
#

yes right

neat jasper
#

thank you for the correct Raphael

undone walrus
#

so we want {a} and {b} to be in V ?

neat jasper
#

V?

undone walrus
#

this V

neat jasper
#

let's go through the 2 cases

undone walrus
#

okay

neat jasper
#

first you have f(a)=b

#

which means you want to consider every open set containing the element b

#

what are they?

undone walrus
#

X

neat jasper
#

right, that's the only one

#

is it open?

undone walrus
#

right

#

yes

neat jasper
#

so f(x) is continuous at x=a

#

where f(a)=b

undone walrus
#

ok perfect

neat jasper
#

now you do the other one

#

it's different of course

undone walrus
#

of so f(b)=a

#

there are two open sets containing a

#

{a} and X

neat jasper
#

right, so you need to look at

#

f^{-1}({a}) and f^{-1}(X)

#

the second one you already checked from the earlier part

#

wait actually i cheated

neat jasper
#

rather

#

I skipped a step you might not have gotten yet

#

so, pretend i didnt say it

#

😓

undone walrus
#

dont worry!

neat jasper
#

remember that inverse image distributes along union

#

so you can test f^{-1}({a,b}) = f^{-1}({a}) cup f^{-1}({b})

#

(regular image does not have this property)

#

(only inverse image)

#

let me write that in latex so there's fewer curly brackets

undone walrus
#

okay

neat jasper
#

$$f^{-1}({a,b}) = f^{-1}({a}) \cup f^{-1}({b})$$

thorny flameBOT
#

gfauxpas

undone walrus
#

ok right

opal vault
neat jasper
opal vault
neat jasper
#

silly me

#

forward image distributes along union, but forward image does not distribute along intersection. inverse image distributes along both

undone walrus
#

of so f^-1 {X} = f^1 {a} union f^-1 {b} ?

neat jasper
neat jasper
undone walrus
#

nice

neat jasper
#

is that open?

undone walrus
#

no?

neat jasper
#

what is it

#

what's the set

undone walrus
#

because it is {b} union {a}

#

so {a,b}

neat jasper
#

=X

undone walrus
#

ok so it is an open set

#

right?

neat jasper
#

indeed

#

now you have to check f^{-1}({b})

#

err

#

which one were we up to

#

b or a

#

f^{-1}({a})

undone walrus
#

f^{-1}({a})

#

exactly

neat jasper
#

=?

undone walrus
#

which is {b}

#

right?

neat jasper
#

open?

undone walrus
#

not open

neat jasper
#

so f(x) is not continuous at x=b

#

typo

#

by the way, if you want to think of why this is a definition of continuity

#

think of epsilons and deltas as open epsilon-balls and open delta-balls

#

there are open sets

undone walrus
#

for it to be continuos at x=b it would have to be open at both f^{-1}({a}) and f^{-1}(X)

neat jasper
#

correct.

undone walrus
neat jasper
#

these are*

#

they're not the ONLY open sets, but you'll learn why with real functions in the standard topology it's good enough to only check open balls

undone walrus
#

okay

#

thank you so much

neat jasper
topaz sinewBOT
#

@undone walrus Has your question been resolved?

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merry helm
#

how is it not

topaz sinewBOT
torpid shard
#

is it not what

merry helm
#

blue van

#

sorry had to think for a sec

#

it literally has the highest for all 3 months

sharp pagoda
#

its clearly violet

#

oh wait

merry helm
#

correct answer is A (red)

#

idk why

sharp pagoda
#

actually not its green

#

oh wait no its red

#

i was trying to do this in my head lol

#

its not hard

merry helm
#

i dont get why you need to calculate anything, can't you just which one has the highest mileage in all 3 months

torpid shard
#

its the blue van

sharp pagoda
#

no

#

its the red

#

because its the end of month not start

torpid shard
#

this discussion is so stupid

#

Check on a month by month basis

sharp pagoda
#

why

#

its just november-august

torpid shard
#

Blue has always the highest amount of mileage no matter the month

sharp pagoda
#

huh

torpid shard
#

No combination of months could lead to other having more mileage

sharp pagoda
#

its asks for the greatest distance between september 1st and november 30th

merry helm
torpid shard
#

If the blue van is not the answer in the problem, then the problem is wrong

sharp pagoda
#

no you're wrong

torpid shard
#

🥀

sharp pagoda
#

blue clearly has 83392-73959=9433

torpid shard
#

Oh, is this the general reading not the absolute amount

#

im so freaking dumb

#

lol

sharp pagoda
#

bruh

torpid shard
#

just search what month has the highest difference from august to november

sharp pagoda
#

red has 78853-68240=10613

sharp pagoda
#

and you're telling me im wrong bruhhhh

#

and btw i already calculated that in head its red

sharp pagoda
torpid shard
#

when i looked that they were all increasing i figured its accumulating

sharp pagoda
#

i read the task normally.

merry helm
#

.close

topaz sinewBOT
#
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topaz sinewBOT
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merry helm
topaz sinewBOT
merry helm
#

i don't understand how we can tell the opposites from the other die

#

just by looking at a different die

ruby tree
#

Well you can see the opposites on this die, can you list them?

#

(also why do they go back and forth between dice and die breadpensive )

sharp pagoda
#

yea

ruby tree
#

@merry helm ?

drifting swift
#

i would try drawing nets of both dice and filling in based on the visible faces

#

oh wait hold on

#

this is ONE die you're looking at.

ruby tree
#

Yes it's completely determined

drifting swift
#

definitely draw a net for it and fill it in based on available info

#

take note of how the six-face is oriented

ruby tree
#

OP doesn't feel like answering though, so catshrug

merry helm
#

on the other die (which is shown)

#

3 and 1 are opposites, 4 and 2 are opposites, 6 and 5 are opposites

merry helm
merry helm
#

i only have info on the die shown

drifting swift
#

so then you're saying the opposite-face pairs on the first die are 1-3, 2-4 and 5-6

#

those totals are 4, 6 and 11 so you cannot have any of the same totals on the second die

sharp pagoda
#

nor 7

merry helm
#

would a fast way be to just check all of the available options

sharp pagoda
#

yea

merry helm
#

and see if those add up to the restricted totals

#

oke

drifting swift
#

forbidding total 6 gives you this right away

#

the third unmentioned pair also shouldnt add up to 4, 6 or 11

#

or 7

#

ok now actually im stuck too

#

D is out but i cant rule out any of the others

#

oh wait

ruby tree
#

You can't have the same sum on one die

drifting swift
#

C is out bc 2+6=3+5

#

A is out for the same reason

#

yeah

merry helm
#

why

#

8 is not a restricted total

#

right?

drifting swift
#

it's not restricted but in that option it ends up duplicated on the 2nd die

sharp pagoda
#

i think its easier to think about the sides of the dices

#

its ranging from 3 to 11, with 4, 6, 7, 11 out

#

and the sum must be 21

#

its not hard to see that its should be 3, 8, 10

merry helm
#

okay ty

#

.close

topaz sinewBOT
#
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topaz sinewBOT
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opaque ridge
topaz sinewBOT
opaque ridge
#

How do i get the values of the roots?

#

I plugged it into desmos but idk how to set the intervals

empty heron
opaque ridge
#

yea

#

one sec

empty heron
#

They’re called “point of interests”

opaque ridge
#

Yeah i put in those values but it said incorrect

empty heron
#

so it’s clickable

opaque ridge
#

because maybe its something about interval

#

(0,1)

empty heron
#

Not really uh maybe you need more sig figs

#

or like do you have any instruction

#

on how you should “approximate” your answer?

opaque ridge
#

doesnt state about rounding or anything

#

wait

gray mulch
#

Can't you just zoom in to the required level, e.g. with the mousewheel?

empty heron
#

oh it says 4dp

opaque ridge
#

decimel rounded to 4

#

places

#

yeah i see that

empty heron
#

can u show what you wrote out?

opaque ridge
#

Wait lemme write it out again

empty heron
#

Those points are clickable

opaque ridge
#

Yeah this is what the roots are

#

after i clicked the points

#

But it says incorrect

gray mulch
#

0.14285 is not rounded to 0.1428

opaque ridge
#

oh yea

empty heron
opaque ridge
#

there we go\

empty heron
#

Yeah your rounding is off

opaque ridge
#

got itright

#

thank you!

#

yeah that one number was off

#

.close

topaz sinewBOT
#
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crude quail
#

This is how far I've gotten, and I wanna know whether there are any properties im missing? I can't see how else to solve this

wintry meteor
#

,rccw

thorny flameBOT
stiff knoll
crude quail
#

Oh I see

#

But what about th triangle inequality?

#

It will be less than or equal to?

stiff knoll
#

less than or equal to yes

wintry meteor
#

Don’t think that’s useful here though

thorny flameBOT
#

Médicis

crude quail
#

Oh

stiff knoll
# thorny flame

you need to to analyse the function on $(-\infty , -1)$, $[-1, 1)$ and $[1, \infty)$

thorny flameBOT
#

Médicis

crude quail
#

Why those values specifically?

stiff knoll
royal hedge
stiff knoll
topaz sinewBOT
# royal hedge

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).

crude quail
crude quail
#

The magnitude of any point from 0?

crude quail
#

Ohhhh

#

Roght

stiff knoll
#

hence $|x+1| = x+1$ if $x+1 \geq 0$,

$=-x-1$ if $x+1<0$

thorny flameBOT
#

Médicis

stiff knoll
#

therefore for |x+1| you've got to study the function on $[-1, \infty)$ and $(-\infty , -1)$

thorny flameBOT
#

Médicis

stiff knoll
#

same thing for |x-1|

crude quail
#

How do those two relate?

wintry meteor
#

So when you add them together you have to treat where any term of the function can change separately

crude quail
wintry meteor
#

$|x+1| = x+1$ if $x+1 \geq 0$,

$|x+1| =-x-1$ if $x+1<0\$

$|x+1| = x+1$ if $x\geq -1$,

$|x+1| =-x-1$ if $x<-1$

thorny flameBOT
#

BBMaths

crude quail
#

Ohbhh

#

That makes sense

#

And then i would do the same thing for x-1?

#

How would one study these intervals though?

stiff knoll
#

well study them individually

#

they are distinct from one another anyway

crude quail
#

And then add them? And how does one study them?

topaz sinewBOT
#

@crude quail Has your question been resolved?

mint crescent
thorny flameBOT
#

Civil Service Pigeon

mint crescent
#

If you plot these on a number line, you should see how they split up the number line into three intervals: $(-\infty,-1)$, $(-1,1)$, $(1,\infty)$

thorny flameBOT
#

Civil Service Pigeon

mint crescent
#

Obviously you need to include $x=-1,1$, but you can just throw those on wherever

thorny flameBOT
#

Civil Service Pigeon

mint crescent
thorny flameBOT
#

Civil Service Pigeon

mint crescent
#

Ex. For $(-\infty,-1)$, $|x-1|=-(x-1)$ and $|x+1|=-(x+1)$, so $f(x)=-(x-1)-(x+1)$ for that interval

thorny flameBOT
#

Civil Service Pigeon

topaz sinewBOT
#

@crude quail Has your question been resolved?

topaz sinewBOT
#
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burnt swift
#

Knowing that $a, b \in \mbb{Z}$ and $\gcd(a,b) = 5$, find the possible values of $$\gcd(a^4 + b^4, 2ab^2)$$ Show an example for each case

thorny flameBOT
#

Renato

topaz sinewBOT
#

@burnt swift Has your question been resolved?

reef saddle
#

This looks like a previous imo question am i wrong?

burnt swift
#

is a question from my intro to algebra class

reef saddle
#

Confused with this

burnt swift
#

alrighty

quasi depot
#

Hint, think what prime numbers can divide both 2ab^2 and a^4 + b^4

burnt swift
#

care to elaborate ?

quasi depot
#

Sorry I am busy

burnt swift
#

from the gcd(a,b) condition what I get is that

#

5 | a , 5 | b

#

from there we get that

#

5^4 | a^4

#

so

#

a = 0 (mod 5)
and so
a^4 = 0 (mod 5)

#

similarly with the 5 | b condition I get that 5^4 | b^4
so b = 0 (mod 5)
and we get b^4 = 0 (mod 5)

#

so b^4 = 0 (mod 5)

burnt swift
#

because I got stuck with this one

quasi depot
#

Can 7 divide the gcd?

burnt swift
topaz sinewBOT
#

@burnt swift Has your question been resolved?

topaz sinewBOT
#

@burnt swift Has your question been resolved?

mortal steeple
#

5^4 | a^4
5^4 | b^4

so 5^4 | a^4 + b^4

#

and
5 | a
5^2 | b^2

so 5^3 | 2ab^2

#

so hcf is either 5^3 or greater for sure

#

@burnt swift

topaz sinewBOT
#
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pure talon
#

I need my work checked pretty pretty please

topaz sinewBOT
ruby cove
#

Good job

pure talon
#

YIPPEE

#

.close

topaz sinewBOT
#
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topaz sinewBOT
#
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pure talon
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The textbook says it converges so I might’ve made an algebra mistake

maiden plank
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you cannot cancel like this

pure talon
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my bad

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so what do i do?

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do i split the fraction?

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i mostly get an indeterminate form

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so do i L'Hopital?

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and then by L'Hopital, i get 1/0

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which is 0

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and since r is less than 1 bc r is 0 and 0<1, then that means it converges

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?

mortal steeple
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$\sum_{k=0}^\infty e^{-4} k = e^{-4} \sum_{k=0}^\infty k = -\frac1{12e^4}$

thorny flameBOT
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Wumpus Man

mortal steeple
pure talon
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OHHH WAIT e TO THE -4 IS A NUMBER

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i can move it out i forgot

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howd u get -1/12

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yk what i'll do it tmrw morning i have to wake up in 4 hours

mortal steeple
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1 + 2 + 3 ... = -1/12

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i dont remem tho

maiden plank
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nononono

mortal steeple
maiden plank
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oh ok

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back to cave for me

mortal steeple
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you should help, idk what convergence is

maiden plank
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i mean

outer laurel
pure talon
outer laurel
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that uh... says -k not -4

pure talon
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WHAT

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oh my god

maiden plank
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no wonder I couldn't figure out what happened

pure talon
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im actually going to sleep i cannot

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.close

topaz sinewBOT
#
Channel closed

Closed by @pure talon

Use .reopen if this was a mistake.

topaz sinewBOT
#
Available help channel!

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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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spiral flint
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Any line passing through origin in R3 .. dimensions??

spiral flint
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What is dimension?

quasi depot
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Size of basis

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Or equivalently the maximal size of a linearly independent subset

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Or the minimal size of a spanning subset

spiral flint
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So i can span with three basis?

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(1,0,1)(0,1,0)(0,0,1)

quasi depot
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!original

topaz sinewBOT
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Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

quasi depot
spiral flint
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Someone is asking me in dm

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It's an old chapter for mr

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I forget much of things

quasi depot
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What is he asking you

spiral flint
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@quasi depot

quasi depot
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A line has dimension 1, a planr has dimension 2

spiral flint
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Could you explain more please?

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Ohh i have an idea

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for equation in 3d

r=a+lambda b

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So i can easily see that we need only one vector to represent a line in 3d

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So dimension is 1

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For a plane we need two vectors one is normal and one is situated over a plane

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@quasi depot

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n (r-r_0)=0

quasi depot
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These are the dimensions of a line and a plane as subspaces of R^n

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Need to go

spiral flint
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Yes

spiral flint
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.close

topaz sinewBOT
#
Channel closed

Closed by @spiral flint

Use .reopen if this was a mistake.

#
Available help channel!

Send your question here to claim the channel.

Remember:
Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
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.

sick hawk
topaz sinewBOT
sick hawk
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hello everyone how are you all tonight

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so for this question i tried this method

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T X X C X X X X X

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X = Letters that are not T or C

quartz atlas
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Did you get the answer

sick hawk
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nah im asking why my methode is incorrect

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method

fallow igloo
quartz atlas
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T X X C X X X X X

Here X can be anything like you said , but we can move TXXC as whole throughout the word

sick hawk
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ok so C T can be swapped around
i choose 9 - 3(e) - 1(t) - 1(c)
so 2! * 4P2 * 6!/3!(three e)

fallow igloo
sick hawk
sick hawk
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6! for the TXXC

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and the other 5 letters

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5P2 for the 2 letters between the T and C

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and hello sky and night

quartz atlas
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Ok so did you get the answer by the method you said