#help-13

1 messages · Page 213 of 1

fluid rivet
#

Oh thank god, thanks.

hollow minnow
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After writing down all that you can work backward

fluid rivet
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Oh dw I've done this before but for some reason I had a brainfart moment where I forgot how to calculate the remainder for the first part of the euclidean theorim and I couldn't remember for the life me. Thanks for the save!

hollow minnow
cedar kilnBOT
#
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ionic finch
cedar kilnBOT
ionic finch
#

How did they arrive from one equality to other?

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I understood 0<=a+b<=2n-2

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as the maximum we have is n-1, thus n-1+n-1= 2n-2

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but 2n-2 is also equivalent to n-2 mod n, not n-1

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Essentially my question is, does first inequality imply other?

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<@&286206848099549185>

mental trail
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either a+b <= n-1 and we're done

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or a+b > n-1, which means a+b-n <= n-2 <= n-1

ionic finch
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Oh, makes sense,

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n-1 already belong to Zn, now we see how big can a+b get

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a+b<=n-2, and clearly it’s less than n-1 in modulo

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like that?

mental trail
wraith daggerBOT
#

rafilou2003

ionic finch
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I mean if I do usual addition i get something less than 2n-2, taking modulo of it is less than n-2<n-1

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@mental trail

cedar kilnBOT
#

@ionic finch Has your question been resolved?

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potent saffron
#

are u guys good at pre algebra

cedar kilnBOT
umbral dew
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no

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just ask ur question

glass horizon
#

hes not good at pre algebra i think

sly pier
glass horizon
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im not good either

drifting marlin
cedar kilnBOT
umbral dew
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?

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wtf is that

sly pier
umbral dew
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oh

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how does that even matter rn

umbral dew
sly pier
potent saffron
hollow minnow
#

You know y=mx + c

umbral dew
cedar kilnBOT
# potent saffron
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
spare plaza
#

hi

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i am new to discord

umbral dew
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ok

spare plaza
#

can you guys tell me wht u guys are discussing

hollow minnow
spare plaza
#

no like is this where i get or help smn (cuz i would like to help someone)

hollow minnow
#

You can help someone yes

spare plaza
#

oh cool

cedar kilnBOT
#
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gusty grove
cedar kilnBOT
gusty grove
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i need help

digital cliff
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what have you tried

gusty grove
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ill send ya

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gimme a min

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idk if i did this ryt, but i couldnt solve anyway

digital cliff
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definitely not right

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im not sure how you did that

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but i can say youre overcomplicating it

gusty grove
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yea ik, i was trying like everything

digital cliff
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are you aware that $\left(\frac{p}{q}\right)^{-1}=\frac{q}{p}$

wraith daggerBOT
#

AℤØ

gusty grove
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i tried to make the base equal

gusty grove
digital cliff
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you just need to do that to one of them and youll have the same base

gusty grove
digital cliff
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wait

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nvm, im high

gusty grove
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thats wat i was tryna do inna way

gusty grove
digital cliff
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the exponent isnt across everything, at least i think its not, so that wont work

gusty grove
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i moved the right hand side to left, so i can get base q, then i tried to make the powers equal

digital cliff
#

i can see how one could get $p^{2m+3}=q^{10-m}$

wraith daggerBOT
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AℤØ

digital cliff
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how did you get this first bit

gusty grove
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i just moved the whole right hand side to left

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lemme send a pic

digital cliff
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so you subtracted?

gusty grove
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this is the whole thing

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im 100% sure that im wrong here

digital cliff
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that second line wouldnt make sense

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how did you do that

gusty grove
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i tried to make the base equal

digital cliff
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you mean a common denominator?

gusty grove
#

yes

digital cliff
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youd have to multiply the right fraction by q^{m-8} or multiply the left fraction by q^{8-m}

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you wouldnt get what you did

gusty grove
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i dont get it >_<

digital cliff
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$\frac{p^{2m+2}\cdot q^{m-8} - p}{q}=0$

wraith daggerBOT
#

AℤØ

digital cliff
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were you given any information beyond whats there

gusty grove
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no thats the whole question

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and the answers

digital cliff
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honestly im suspicious

gusty grove
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my first time doing a sum like this

digital cliff
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im not entirely certain you can get the answer unless the exponent is across the entire fraction

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gimme a min

gusty grove
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am i missing a formula or something for this ?

digital cliff
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yeah, if its not, then the value of m would have to be in terms of p and q

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so its either none of the above, if its intentional

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or its one of the others if not

gusty grove
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oh okay

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i might try this in primal mode too lol

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ill try putting numbers to variables and see if i can go anywhere

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Thanks alot tho for ur time

digital cliff
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np

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if you do it as being over the whole fraction, you do get one of the numbers there btw

gusty grove
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oh okay

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thanks bra

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.close

cedar kilnBOT
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cedar kilnBOT
#

@crimson sedge Has your question been resolved?

cedar kilnBOT
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@crimson sedge Has your question been resolved?

cedar kilnBOT
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@crimson sedge Has your question been resolved?

dire geode
#

Use squeeze theorem for both

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Both sine and cosine are between -1 and 1

cedar kilnBOT
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crimson sedge
#

X^2-ax-bx-abx how to simplify

cedar kilnBOT
versed fulcrum
#

What are the common factors?

cedar kilnBOT
#

@crimson sedge Has your question been resolved?

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crimson sedge
#

x*2-ax-bx+abx

cedar kilnBOT
versed fulcrum
#

!status

cedar kilnBOT
#
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
crimson obsidian
#

Factoring?

livid hound
#

also did you mean x^2?

cedar kilnBOT
#

@crimson sedge Has your question been resolved?

crimson sedge
#

Sorry I didn’t give enough info but yeah I need factoring

crimson sedge
livid hound
#

first thing to do would be to identify if all terms have a common factor

cedar kilnBOT
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long belfry
cedar kilnBOT
long belfry
#

A bag contains 3 red, 4 blue and some black balls. If probability of drawing
blue ball is - , then number of black balls in the bag is

tidal zodiac
long belfry
#

oki

cedar kilnBOT
#

@long belfry Has your question been resolved?

long belfry
#

only one has been resolved blud

cedar kilnBOT
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crimson sedge
livid hound
#

yes, and what i said is the first step in approaching the task

cedar kilnBOT
#

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crimson sedge
crimson sedge
#

It becomes x(x-a-b-ab)

opal basin
#

x^2 - ax - bx + ab, right?

opal basin
#

because ab doesn't have a factor of x

cedar kilnBOT
#

@crimson sedge Has your question been resolved?

livid hound
#

original had an x unless that was a typo

cedar kilnBOT
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quaint skiff
#

Hi. I need help with this limit please. I tried to do it by factorising with x and x^2, but it doesn’t seem to work. Thank you

tired mirage
#

Do you know L'Hôpital's?

quaint skiff
tired mirage
#

tried dividing by x^2?

quaint skiff
tired mirage
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you divide both the numerator and denominator with x^2, equivalently this can be stated as multiply the numerator and denominator with 1/x^2

cedar kilnBOT
#

@quaint skiff Has your question been resolved?

quaint skiff
#

I tried to do it by substitution. X=1/x

quaint skiff
#

<@&286206848099549185>

tired mirage
#

can you send the picture rotated? 😇

quaint skiff
quaint skiff
tired mirage
#

you didnt substitute it completely, since still have x-> 0-, it should now be x-> -inf

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and what happened here?

quaint skiff
tired mirage
#

ah

quaint skiff
tired mirage
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yes since (-inf)^2 vs e^-inf we have e^-inf wins making that 0 and we then have -inf-0

quaint skiff
tired mirage
#

well, then you are gotten to the goal!

quaint skiff
tired mirage
#

Have good day!

quaint skiff
#

You are very kind and helpful

quaint skiff
tired mirage
#

remember .close

quaint skiff
#

.close

cedar kilnBOT
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teal geyser
#

$y = e^{-\sqrt{\abs{ln(\abs{ln(\abs{x})})}}}$ has minima and maxima along the asymptotes of $y'$ instead of roots (there aren't any). Why?

wraith daggerBOT
cedar kilnBOT
#

@teal geyser Has your question been resolved?

white latch
#

Uhhhhhhhh there are no roots in the function

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as eulers number itself can never equal 0

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I think you meant critical points.

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There are no critical points in our case.

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specifically for when the derivative is 0 there are no critical points on our function

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but for the sections where the derivative does not exist (the vertical asymptotes)

peak relic
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For example, |x| (in red) has a minimum at 0, and in the derivative (in blue) we see that it has a jump discontinuity which jumps over 0.

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this makes sense because the function goes from decreasing to increasing, so it should have a minimum at that point.

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here's another example. in red, i plotted x^(2/3). this function has a cusp at 0, which gives it a minimum. in the derivative 2/3 * x^(-1/3), we see that there's a vertical asymptote at 0. that happens because the slope at the cusp goes to -infinity from the left, and +infinity from the right. but even so, the slope jumps from negative to positive (past 0) and so the original function has a local minimum there.

#

the takeaway is: critical points of y are the points where either y' = 0 or where y' doesn't exist. you'll have to check whether any of these points gives you a local min or a local max.

teal geyser
#

True

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Perfect, thank you

#

-close

#

.close

cedar kilnBOT
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feral nacelle
#

Graph looks something like this

cedar kilnBOT
feral nacelle
#

Unless if I flip the values upside down the graph does go through the origin

swift siren
#

why are you starting with 1/280

feral nacelle
#

1/280 is smaller than 1/80

swift siren
#

ah yeah mb lol

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realized it as soon as i said it

feral nacelle
#

But I don’t get why the graph is backwards

swift siren
#

well it doesnt look like you associated the right pressures with the volumes

feral nacelle
#

How come, I marked it accordingly

swift siren
#

1/280 m^-3 should correspond to 100 kPa

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and so on

feral nacelle
#

Let me try

swift siren
feral nacelle
swift siren
#

close enough to be honest

feral nacelle
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It has to go through origin as a straight line tho

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How do I know what intervals I need to go up in

swift siren
#

well for all intents and purposes of this question that's asking you to explain why these measurements verify boyle's law, it can be assumed that the slight discrepancy is due to measurement errors

feral nacelle
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You’re graph is straight ish

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Mine looks like an exponential

swift siren
#

the big part of boyle's law isn't necessarily that it goes through the origin, but that pressure is inversely proportional to volume

feral nacelle
#

Ik but the marking scheme specifies it has to

swift siren
#

well then just make your line go through the origin ;)

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even if it technically isnt the line of best fit

hardy zephyr
feral nacelle
#

I want to actually get the question right tho

swift siren
swift siren
#

since i assume you're being asked to plot this by hand?

feral nacelle
hardy zephyr
#

its multiple choice

feral nacelle
swift siren
swift siren
#

with someone else's question

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this line works even though it isn't the best fit technically

feral nacelle
# swift siren

How would ik by which intervals to go up by on the left tho

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Would I go up by 40 or what

swift siren
#

well it seems you can go up by 50 and get a nice graph

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really just something that doesnt make it too compressed

feral nacelle
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Lemme try

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Nope

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Back at the issue of it looking exponential

swift siren
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probably because your x axis is janked up

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your increments seem to be just the points from the table

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and you spaced them equally

feral nacelle
swift siren
#

there is not the same distance between your increments

feral nacelle
#

How would I properly increment them

swift siren
#

it seems like you could get away with having it in increments of 0.0010

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since the max value is 0.0125 and the min is 0.0036

feral nacelle
#

I’m going to try brb

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It worked 😭😭🙏🙏

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It was the increments not being spaced properly that was the issue

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Thank you so much for your patience

cedar kilnBOT
#

@feral nacelle Has your question been resolved?

cedar kilnBOT
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hollow minnow
#

Have you tried drawing a graph

cedar kilnBOT
#

@jovial mist Has your question been resolved?

hollow minnow
#

Maybe you could argue x_(i-1) <= sqrt(x_i • x_(i-1)) <= x_i

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It should still be fine no? each deltaxi will be the same for Ln or Rn or any sum

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Right for different intervals but if we just look at one interval we can use the same detla xi for Ln, Rn

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Yeah

cedar kilnBOT
#

@jovial mist Has your question been resolved?

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crimson sedge
#

pls help

cedar kilnBOT
dire geode
crimson sedge
#

@astral gazelle

astral gazelle
#

Ah, hello

#

Imma need to see your question tho

crimson sedge
austere hull
#

can you expand it

astral gazelle
#

Oh, right, tricky stuff indeed! The trick is to do it in smaller sections

crimson sedge
#

ye i thought i could

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but it says its wrong

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i got answer a=54

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b=540

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c=900

fickle trellis
#

uh well.

crimson sedge
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d=1000

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its taking so long to send srry

astral gazelle
#

Not quite, no - to be honest, I'm not sure if your working is on the right track

#

Could you step ne through what you tried?

fickle trellis
#

I could say, it's wrong.

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!show

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!show

cedar kilnBOT
#

Show your work, and if possible, explain where you are stuck.

umbral dew
#

,w expand 5(3x+10)^3

astral gazelle
#

Bruh

umbral dew
#

okay waait

astral gazelle
#

That teaches nothing ;-;

umbral dew
#

that could be just

fickle trellis
umbral dew
#

copied

#

ik

crimson sedge
#

i expanded it so it was 5(3x+10)(etc)(etc)

astral gazelle
fickle trellis
#

aight no thats a bit offensive

astral gazelle
#

A good way to proceed then would be to join together two of the 3x + 10 terms to get:
5(...)(3x + 10)

crimson sedge
#

then i multiplied the first to brackets for 5(9x^2+60x+100)(3x+10)

astral gazelle
#

Nice!

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That's right so far

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What did you do next?

crimson sedge
#

then i tried multiplying those two to get 5(27x^3+270x^2+900x+1000)

#

@astral gazelle

astral gazelle
#

Yeah just checking

crimson sedge
#

ok thanks

astral gazelle
#

Ah, I'm seeing an issue with your x^2 and x terms

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I'm not sure how you arrived at 270 and 900

crimson sedge
#

?

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for x^2 i did 60x times 3x for 180x^2

astral gazelle
#

Oh yeah my bad ;-;

crimson sedge
#

and then 9x^2 x 10

astral gazelle
#

Yup that checks out

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Yeah I'm an idiot mb

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All good!

crimson sedge
#

and for the x, i did 100 x 3x for 300x and then 60x x 10 for 600x

astral gazelle
#

Yup

crimson sedge
#

so 900x

astral gazelle
crimson sedge
#

yeah my mistake every 2 times i get it wrong it changes answer

#

im in middle of this question as we speak

crimson sedge
astral gazelle
#

Oh, right

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Yeah, checks out

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You just wanna take that 5 inside

crimson sedge
#

ok and then i times all by 5

astral gazelle
#

Yup!

crimson sedge
#

yea

astral gazelle
#

Sorry again for the false alarm

crimson sedge
#

135x^3 + 1350x^2 + 4500x + 5000

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would that be right?

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NVM I GOT IT!

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thanks bro

astral gazelle
#

Ayyyyyy

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Happy to help - but to be honest you did it all yourself, I was just encouragement :0

crimson sedge
#

thanks for the encouragement then bro

cedar kilnBOT
#

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spice monolith
#

Heya , i need help with understanding the wording of a maths question

spice monolith
#

I am a little confused at what it is asking me here?

glass sky
#

perform dimentional analysis

spice monolith
#

yeah but

#

is it asking me to define the SI units of mass over volume?

glass sky
#

just try to find the dimentions of density with given info

#

not unit

#

dimentions
in form of M^a L^b T^c

spice monolith
#

its just kg/m^3?

glass sky
#

that is unit

#

what would be the dimention

spice monolith
#

i never got to do dimensional analasys

glass sky
spice monolith
#

so im a little behind on how it works

#

the question itself dosent have any numbers in it so my brain is confused

glass sky
#

i would suggest redo the question of dimentional analysis from ncert / ask your teacher to explain the topic?

#

1 sec i can try to explain

spice monolith
#

yes please that would be appreciated

glass sky
#

hm so wee need to answer in terms of M L T

#

do you know what that means?

spice monolith
#

no

glass sky
#

M - mass unit
L - lenght unit
T - time unit

these are the fundamental units
all units can be formed with the product of these units

spice monolith
#

wait so

#

it would be

#

kg^M

glass sky
#

nope

#

so if density is mass / volume

#

what should be the dimention for mass

spice monolith
#

kg^m?

glass sky
#

no?

#

what is the unit of mass

spice monolith
#

kilograms

glass sky
#

so the dimention will be M L^0 T^0

spice monolith
#

yee

glass sky
#

what is it for volume

spice monolith
#

one second lemme try this

#

bear with

glass sky
#

np try

#

take your time

#

i had trouble with this too at first

spice monolith
#

L M^0 T^0?

glass sky
#

not quite

#

close tho

spice monolith
#

L^3?

glass sky
#

YES

#

BINGO

spice monolith
#

OHH

#

okay this is sorta making sense

glass sky
#

mass/volume???

spice monolith
#

okay okay lemme type this out

#

M L^0 T^0 / L^3 M^0 T^0 ?

glass sky
#

yeah so what you left with?

spice monolith
#

M L / L^3

#

wait no

#

M / L^3

glass sky
#

yeahhh

spice monolith
#

the rest cancells out

glass sky
#

or M L^-3 T^0

#

L^0 is 1 anyways

#

it was just the way of writing

spice monolith
#

okay now am confused LOL one second lemme decipher this

glass sky
#

its like at which dimention a thing depends on

#

mass / lenght / time

#

anything to the poiwer 0 is 1 right

spice monolith
#

ohh okay

glass sky
#

i just wrote it as like convection

spice monolith
#

it makes sense now

glass sky
#

yeahhh

#

also instead of denominator use exponential law and write it in negative power thing

#

like M L^-3

spice monolith
#

my brain is too small for this LOL

glass sky
#

1/L = L^-1

#

got it?

spice monolith
#

okay quick mini question too

glass sky
#

sup

spice monolith
#

when it says

#

show that the expression is homogenious?

#

does that just mean , re arrange the expression to = 1?

glass sky
#

wait

#

are you talking about homogenious in certain degrees?

#

like a equation is homogenised with degree 2 means that every term has the degree 2

spice monolith
glass sky
#

not sure what it means here

spice monolith
#

i was told it just means show that the expression can = 1

glass sky
#

not sure if this helps

#

but yeah this works

#

makese sense

spice monolith
#

okay

#

thank you though , the first part works for me for now

glass sky
#

cool np

spice monolith
#

I will come back to the homogenious bit in a different ticket at a later time

glass sky
#

(do lmk when you get the answer)

#

im kinda curious

#

just dm when you get if if you can

spice monolith
#

add me

#

.close

cedar kilnBOT
#
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kind ridge
cedar kilnBOT
kind ridge
#

I have a question

#

I'm working on a project for algebra, and they want us to make a word problem based on two parabolas and their intersections. I made the parabolas and found good intersections, but I didn't know what to do for the real-life situation. They said I cannot use vertical motion, which cancels out all projectile motion. Does anyone have any ideas?

#

Ping me if you can help.

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#

@kind ridge Has your question been resolved?

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torpid urchin
#

could someone explain to me how to set this question up? i know im setting my expectation=100 but im not sure where the deductable fits in

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#

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@torpid urchin Has your question been resolved?

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hardy swift
#

Whats the point of the x?

cedar kilnBOT
south tundra
#

To emphasize that the composition $f \circ g$ is being applied to some variable $x$

wraith daggerBOT
#

A Lonely Bean

south tundra
#

Just writing $f \circ g$ would mean you are referring to the composition itself

wraith daggerBOT
#

A Lonely Bean

hardy swift
#

Does it mean f(g(x))? Cuz sometimes the question just gives you something to put in it other than x

south tundra
#

Yes

hardy swift
#

Can you write anything istead of x

south tundra
#

As long as it's in the domain of g

hardy swift
#

But it has to be a variable if you want to replace it with something?

south tundra
#

What do you mean?

tepid sail
wraith daggerBOT
#

nosqldb

hardy swift
#

In one of my questions it tells me to put f inside g and it tells me what both those functions are

tepid sail
#

so yes, you can input any $x \in$ R into the function f o g

wraith daggerBOT
#

nosqldb

hardy swift
#

Or is the "(something)" the variable used and it doesnt have to be "directly" put into the inner function?

south tundra
wraith daggerBOT
#

A Lonely Bean

south tundra
#

Not sure if I still understood your question though

#

What would putting the variable not "directly" into the inner function look like?

cedar kilnBOT
#

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crimson sedge
#

this graph is not a one-to-one function, right?

crimson sedge
#

the x value 0 has multiple y values?

sharp lotus
#

i mean its probably just going through 0, 0 and the rest of the values are close, but a screen has only so many pixels to cram different tiny decimals in, you can't really say unless you have an equation you can see what's going on analytically, looks one to one to me

crimson sedge
#

One to one means there is no value of y that has 2 x’s mapping to it

#

But no this is a function probably so there by definition cannot be 2 values for the same x

#

oh okay

#

thanks guys

#

.close

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agile grail
cedar kilnBOT
agile grail
#

How do i do this

hollow minnow
#

Which part?

agile grail
#

the question

#

How do i know which one must be true

hollow minnow
#

Oh okay yeah

#

Well do you have any idea

agile grail
#

I know what the answer is, I just don't know why

sharp lotus
#

so if 4b = 9a, obviously 4 is a factor of the left side, correct?

agile grail
#

why?

sharp lotus
#

because 4b = 4 * b

agile grail
#

oh yeah

sharp lotus
#

thats kinda the definition of a factor

agile grail
#

nvm

#

I get it now

sharp lotus
#

so that means 4 must also be a factor of 9a right? (9a sorry)

agile grail
#

why 9b

hollow minnow
#

9a

agile grail
#

yeah

sharp lotus
#

ok so it's either a factor of 9 or a factor of a right? well obviously not of 9

agile grail
#

ohhhhhhh

#

that makes so much sense

#

and the same applies for 3 being a prime factor of b

sharp lotus
#

yeah

agile grail
#

ok thank you

#

.close

cedar kilnBOT
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jolly knoll
#

Does someone know of a online course on yt or someother website that does calculus? I have to study it by myslef and i have a textbook but was wondering if there is some course that could help me

jolly knoll
#

for reference

#

The set of real numbers and related properties. Complex numbers: algebraic, trigonometric and exponential forms. Limits of numerical sequences. Numerical series and convergence tests. Functions of one real variable and limits of real functions. Continuous functions and related properties. Study of the graph of a real function. Some optimizations problems. De L'Hospital's Theorems and Taylor's Formula. Integral calculus for real functions. The definite integral and its properties. Indefinite Integrals and integration methods. Improper integral and convergence tests. Power and Taylor series. Introduction to Fourier series. Ordinary differential equations, existence and uniqueness results. Linear ordinary differential equations and methods of solution of some ordinary nonlinear differential equations.

#

syllabus

#

that i want to do

#

books that i have are biocalculus by james stewart

#

and

#

Calculus A complete course 9th ed Pearson by Robert A. Adams ......

jolly knoll
#

thank you i missed that

cedar kilnBOT
#

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meager finch
cedar kilnBOT
meager finch
#

Can someone review my work and tell me where I went wrong

arctic condor
#

nah what its not even that hard ur trolling

arctic condor
# meager finch

anyway um its at the 2nd step, youre multiplying everything by 4, but 4*(1/4)x is not 4x

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torpid urchin
#

could someone help me out with this question

cedar kilnBOT
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velvet mortar
#

Create a new channel with question

cedar kilnBOT
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hard flame
#

Hello!

cedar kilnBOT
hard flame
#

I don't know how to do this other than drawing the carteaian plane and checking exactly: A line that passes through the points (3,-7) and (14,k) has a slope of 5/6. Determine the exact value of k

patent hearth
#

do you know the definition of slope?

hard flame
#

yes

#

like rise over run

#

and y2-y1/x2-x1

patent hearth
#

great!

#

what are exactly y2, y1, x2 and x1?

hard flame
#

k-(-7)/ 14 - 3 = 5/6

patent hearth
#

yep

#

now solve for k

hard flame
#

oh

#

okay I dont know why I didnt think of that

#

lol

#

thanks

#

.close

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rare sail
cedar kilnBOT
rare sail
#

been trying for 1 hr

#

tough ass problem

cedar kilnBOT
#
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
hollow minnow
#

what have you tried

#

turn this into dxdy and change bounds

cedar kilnBOT
#

@rare sail Has your question been resolved?

rare sail
rare sail
#

usually, I could graph it and look at the graph but this idk

spark cosmos
rare sail
#

oh right, just remembered that

spark cosmos
#

graph it and and should look ok

rare sail
#

Alright Im gonna giv etht a try

spark cosmos
#

tell me what you come up to. cuz i have a 1 integral that i have difficulty solving

rare sail
#

But its with respect to two variables

#

idk how to change that

spark cosmos
rare sail
raw gulch
#

btw: i have calculated this integral, changing order of integration and then it works really nice

#

so it loosk that iwas intentioally designed for this method

rare sail
#

I see. I’m taking a quick break and ill get right bsck to it and try that

#

Thanks yall

cedar kilnBOT
#

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hollow cloak
#

They're just factoring terms without i and with i

faint yacht
#

its not adding up tho

#

cause the terms that like cos^4 theta dissapeared

#

unless im missing something critical here

hollow cloak
#

No they didn't

faint yacht
#

oh wait what

#

lol

hollow cloak
#

They're just pulling terms with i out

faint yacht
#

wait lmaoooooooooooo

hollow cloak
#

And btw i^2 is -1

faint yacht
#

i read

#

the bottom bit

#

as a completely different line

#

LMAO

#

i was literally clueless

#

ok lol what a silly

#

mistake

#

alr thanks for poining it out

#

.close

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sand jay
cedar kilnBOT
sand jay
onyx dove
#

you need to perform long division before the partial fractions
if you look at the first line, you'll see that one side has u^3 but the other only goes up to u^2

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#

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fallen oxide
#

So for this question, I am stuck on c). I am just not quite sure how to get this as a percentage, and nothing I have tried is working.

cedar kilnBOT
#

@fallen oxide Has your question been resolved?

fallen oxide
#

<@&286206848099549185>

cedar kilnBOT
#

@fallen oxide Has your question been resolved?

fallen oxide
#

<@&286206848099549185>

bold vine
#

this is more of an engineering or physics problem than a math problem

#

Ik there's a physics server linked somewhere in this server

cedar kilnBOT
#

@fallen oxide Has your question been resolved?

fallen oxide
cedar kilnBOT
#

@fallen oxide Has your question been resolved?

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#

@fallen oxide Has your question been resolved?

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raven walrus
#

tell the values of x,y,z amaong the following 50, 18,34

hollow minnow
#

Whats the issue

crimson sedge
#

Are we gonna calculate it like a rectangle?

#

Then just use a formule

hollow minnow
#

From picture y<x<z

#

Oops

#

I think it’s reasonable to say that

crimson sedge
#

SA=2lw+2lh+2hw

raven walrus
plucky owl
#

You gave the values of 50, 18, 34

raven walrus
plucky owl
#

What's the largest and the smallest, then x is defaulted to the last value

hollow minnow
#

z is the largest and y is the smallest

raven walrus
#

(i knew z is biggest so it is 50, x is a bit small so its 34 and y is the smallest so its 18)
what i want you to do is, tell what is the breadth, length and height

plucky owl
#

Well height is normally the vertical distance

#

Length is the horizontal

#

And breadth is the width

#

But it also depends on the perspective

raven walrus
#

so height would be 50, length would be 34, and width which is breadth is 18 right?

raven walrus
plucky owl
raven walrus
#

supoose i am the seller and i am selling this,
what should be the profectional answer?

plucky owl
#

If you were selling it, perspective is from the front

#

Like if you were looking at it from the x side

raven walrus
raven walrus
# plucky owl .

so like should i put
height = 50
length = 34
and
width = 18

#

right?

plucky owl
#

Sure

raven walrus
# plucky owl Sure

and like is there some math rule like lengh has to be the biggest measurement?

plucky owl
#

No

#

It's based on perspective

raven walrus
#

this is what bard says

plucky owl
#

As mentioned, based on perspective

raven walrus
plucky owl
plucky owl
#

I told you what perspective is more ideal

#

But it's option based, it's up to you on how you want to view it

raven walrus
#

okey,
but generally we can concider height as vertical distance right?

plucky owl
#

That's what I stated multiple times

raven walrus
#

how in this would you would consider lenth as 24 cm, height as as 15cm and widgh to be 6 cm right

#

@plucky owl

cedar kilnBOT
#

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#
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sand cradle
#

Regarding the proof from earlier

cedar kilnBOT
sand cradle
#

That we did with @crimson delta

#

How would we generalize this?

#

To A_1 x ... x A_n

sand cradle
crimson delta
#

induction would work, yes

#

(A_1 x ... x A_(n-1) ) x A_n

sand cradle
restive hedge
sand cradle
#

Oh

crimson delta
#

its pretty fast so yeah sure why not

sand cradle
restive hedge
sand cradle
sand cradle
#

And paste in our proof above

crimson delta
#

yes

sand cradle
restive hedge
crimson delta
#

you also need that if |A|=|B|, then |AxC| = |BxC|

#

which you might have proven before, dunno

sand cradle
#

But it's just induction in English

restive hedge
#

ah sure. it's a pedantic point anyway

sand cradle
#

This'll be a long proof, lol

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Just the base case is half a page

crimson delta
#

the base case is the hard part here

sand cradle
crimson delta
#

replacing A_1 x ... x A_(n-1) by eg N

#

well ok actually no you dont need it

#

nvm

cedar kilnBOT
#

@sand cradle Has your question been resolved?

sand cradle
crimson delta
#

by IH the set (A_1 x ... x A_(n-1) ) is countably, so its again countable x countable

sand cradle
#

Another page long section, lol?

crimson delta
#

why would you need to prove it again

sand cradle
# crimson delta why would you need to prove it again

Well, we are given $\mathbb N \rightarrow A_1 \times \dots \times A_{n - 1}$ is bijective and we need to show $\mathbb N \rightarrow A_1 \times \dots \times A_{n} = \big(A_1 \times \dots \times A_{n - 1}\big) \times A_n$ is bijective too.

crimson delta
#

no

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just talk about stuff being countable

sand cradle
crimson delta
#

also that wording makes no sense

sand cradle
#

There exists a function

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that is bijective

crimson delta
#

"there exists a map N->A1x...xAn-1 which is bijective"

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etc

crimson delta
#

lets not skip wording like that cause its crucial

sand cradle
crimson delta
#

that said, you dont have to say anything about any bijective maps here

sand cradle
#

Given A_1 x ... A_{n - 1} is countable

crimson delta
#

A_1 x ... x A_(n-1) is countable

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A_n is countable

sand cradle
#

Yes

crimson delta
#

so its again countable set x countable set

sand cradle
#

Yes

crimson delta
#

which you have proven in your base case is countable

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thats it

sand cradle
#

We've basically proven the general case of countable x countable in our base case, right?

crimson delta
#

yes

#

we have used nothing specific for A_1 and A_2

#

they are two general countable sets

sand cradle
#

.close

cedar kilnBOT
#
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cedar kilnBOT
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#

Please don't occupy multiple help channels.

umbral dew
#

@sand cradle ive pinged them already just in case ur gonna do so

#

<@&268886789983436800> pinging again to let u guys know they arent banned yet

slate lintel
cedar kilnBOT
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umbral dew
slate lintel
crimson delta
#

only timed out?

slate lintel
crimson delta
#

I thought thats what the little janitor role was for

umbral dew
#

💀

#

hayle....

slate lintel
cedar kilnBOT
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sand cradle
cedar kilnBOT
sand cradle
#

For injectivity, just pick l', m', n' and see if f(l, m, n) = f(l', m', n') => l = l', m = m', n = n'
What about its surjectivity though?

lethal jackal
#

well, are there any numbers l, m, n such that f(l, m, n) = 7?

#

surjective in this case means that f produces all of the natural numbers for suitable inputs

idle tusk
#

the function doesn't account for any number whose prime factorization includes primes greater than 7

cedar kilnBOT
#

@sand cradle Has your question been resolved?

cedar kilnBOT
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sharp hill
#

if i have a linear transformation f that I PROVED that dim(Ker)=0, function goes from R2->C, (C is here defined over R, therefore 2 dimensions), since R2 has 2 dimensions, C has 2 dimensions, and according to the equation dim(R2)=dim(Ker)+dim(Img), image of the function, R2 and C all have dimension 2. Now that means that the image, R2 and C are isomorphic. In my un slides though, theres a similar example, and he just deducts that the function is also surjective, therefore, an isomorphism. But the idea now is, we just found out that Image and C are ISOMORPHIC, but not the same vector space. How do you just say that the function is surjective from that?

sharp hill
#

because two vector spaces being isomorphic doesnt just mean that the Img=codomain

#

right?

dawn junco
#

there's not a lot of subspaces of C isomorphic to C

sharp hill
#

ah fuck that makes so much sense

#

would never think of visualizing it that way

#

thank you!!

#

.close

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#
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ivory finch
cedar kilnBOT
ivory finch
#

is it just like y=x?

rain drift
#

yep pretty much, the difference here is what the domain/co-domain is

hollow minnow
#

If A=R

rain drift
#

so let's start off with injective

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how would you start off the injective argument?

ivory finch
#

i suck at algebra so i just use graphs

rain drift
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oh I guess it's not asking you for proof, lol just a justification

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nvm

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ok so let's think about this logically

ivory finch
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injective pass horizontal line test

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surject covers all CODOMAIN i think?

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codomain or range, not sure actually

#

so for example y=x^2 is not either cuz injective has 2 value same with diff x

rain drift
#

correct on the surjective! Injective it also is true on a real number line but we aren't necessarily working with a real number line or graph here

ivory finch
#

surjective doesnt cover entire codomain if r to r

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codomain/range?

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anyway cuz negative numbers dont reach

rain drift
#

surjective just means that all points of the codomain (to clarify the range here is a subset of the co-domain) have a function mapping

ivory finch
#

but i think is surjective if R->R>=0?

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y=x^2

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cuz cover it now

rain drift
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yes I agre

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ok slow down a bit lol

ivory finch
#

and its ot a funct if R-> R+? cuz 0 no more?

rain drift
#

the question isn't asking for R -> R. It's asking for a generic set from A to A

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like it could be Z -> Z (the integers)

ivory finch
#

ok

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thats why im confused probs

rain drift
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or it could just be A = {1, 2, 3} so {1, 2, 3} -> {1, 2, 3}

ivory finch
#

very generic, so hard to intuitive

rain drift
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yeah no problem

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ok so let's take a step back

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start off from scratch

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Injective basically means that every element of the domain has a unique mapping to the co-domain (note that not all of the co-domain has to have a mapping with this definition)

ivory finch
#

agreed

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at most 1 mapping

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rite

rain drift
#

yep!

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which is why it's also called 1:1

ivory finch
#

surjective then means every codomain thingy needs to have smthn in it rite

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but it can also be more than 1 domain element in each codomain

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then bijective means domain-> codomain, ONLY 1, and no missing rite

rain drift
#

yep! The rule for surjective is that all of the domain has to have a mapping to something codomain, and all elements of the codomain have to have a mapping

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I'll show you a simple more abstract example

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Let f : X -> Y, where X = {1, 2, 3} and Y = {0, 1}.
We define our function to have the following mapping f(1) = 0, f(2) = 1, f(3) = 1.
Notice here all of our elements in the codomain are "touched" and have a mapping, as well as all of the domain's elements map to something.
But since we have f(2) = f(3) = 1, then f is not injective in this case

#

let me know if that makes sense or if I need to clarify anything

#

Let me see if I can draw you up a quick visual

ivory finch
#

like this?

rain drift
#

yep exactly!

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sorry I don't have quick drawing tools at my disposal lol

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a small thing to make it more readable is maybe fill in teh dots, it looks like 00 and 01 🙂

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but yes you got the right idea

ivory finch
#

so now how it relate to my problem?

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seems like i know it

rain drift
#

yep exactly!

#

the logic for injectivity is that since I_A(x) = x, then all elements of A gets mapped to itself in the codomain, so each mapping is unique.
the logic for surjectivity is that since I_A(x) = x, then all elements of the co-domain have a mapping from the domain and all of the elements of the domain have some mapping to the co-domain.

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so it's bijective!

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with formal proofs there's some strategies using the formal definitions for injective or surjective. But it's just asking you to justify the answer with logic, not write a formal proof, so I think this would be acceptable 🙂

ivory finch
#

does this matter what the domain and codomain are?

rain drift
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well in this case they're the same!

ivory finch
#

wat if R->R+

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how do u know that

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they are same domain and codomain?

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Oh cuz A->A?

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same thing?

rain drift
ivory finch
#

So replace A with R, Z, N, etc?

rain drift
#

yep!

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yep!

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still applies

ivory finch
#

What is A

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a randomset that we can say?

rain drift
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just a generic set

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it doesn't matter

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it's abstracted away

ivory finch
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abstracted away?

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oh like its generalization? like when you have generics in java?

rain drift
#

what we're showing here basically is that if we have a set A and we map a function from A to itself, with the function f(x) = x for x in the domain, then it's bijective

rain drift
#

yep pretty much!

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in generics you inject the object type. Here the object type are just various sets

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but they have to have a mapping to themselves

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like say if A was the set of prime numbers and f: A -> A was defined as f(x) = x. Then all of the prime numbers just get maped back to themselves

ivory finch
#

all the prime numebrs to the prime numbers

rain drift
#

f(2) = 2, f(3) = 3, f(5) = 7, f(7) = 7 and so on and so forth

ivory finch
#

so there is never any conflict? like when its diff R->R+

rain drift
#

yeah let's take that example

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so we have a function from R to R+. Consider the function f(x) = x^2 + 1.

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this would be a surjective function, but not injective

ivory finch
#

no?

rain drift
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yep!

ivory finch
#

not surjective either?

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what about under 1

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R to R+

rain drift
#

ok wait let me take a step back

ivory finch
#

R+ means x > 0 rite

rain drift
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one moment

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yes correct

ivory finch
#

so then neeither?

rain drift
#

yeah sorry neither because technically we'd have an open hold where x = 0

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in reality it'd look like this

ivory finch
rain drift
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we have a hole at x = 0 since it's not in the codomain

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wait

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soryr

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i"m getting mixed up here lol

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yeah you're right it's neither

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nvm

ivory finch
#

is my graph good

rain drift
#

yeah that's sound logic.

ivory finch
#

my intuition is that the surjective must cover all codomain

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e.g. R->R+

rain drift
#

yep!

ivory finch
#

i focus on R+

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basically

rain drift
#

you were totally right

ivory finch
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to cover all the y's

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but then under 1

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there is no value

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so NS

rain drift
#

yep

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ok let me try another example to solidify this lol

ivory finch
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also NI cuz horizontal line

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thingy

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aight, brb5

rain drift
#

Here's a good chart to help cover the possibilities

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and if it's none of those cases, it's neither

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Ok so let's define a function $f : \mathbb{R}^- \mapsto \mathbb{R}^+$ and define $f(x) = -x^3$. Would our function be injective, surjective, bijective, or neither?

wraith daggerBOT
#

MellowDramaLlama

ivory finch
#

bi?

rain drift
#

very good!

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can you give me like a 1 or 2 sentence explanation (without graphs)?

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without graphs lol

ivory finch
#

😭

rain drift
#

we're training you up, you wont always have graphs at your disposal

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ok maybe an example that you can't graph

ivory finch
#

So x component is R-

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So LHS of graph is domain

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wait

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and y component is R+

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so upside of graph is codomain