#help-0

1 messages · Page 291 of 1

grave quartz
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I mean U can use the same technique you would use to find a quartic normally

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right for understanding purposes u have 2 sets of complex conjugates

patent topaz
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yes

grave quartz
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to work out the polynomial you can simply

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$$(x-2i)(x+2i)(x-(2-i))(x-(2+i))$$

ocean sealBOT
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SWF ;)

grave quartz
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because you have 4 roots

patent topaz
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yeah, that's my problem- expanding the brackets leaves me with $(0-4i^2)$, right?

ocean sealBOT
#

WayneTundra

grave quartz
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eh

patent topaz
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rather, the first difference of squares

grave quartz
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it shouldn't

patent topaz
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sorry, i'm misunderstanding then. x-2i: the x component is zero?

grave quartz
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what

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ye

patent topaz
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(x-2i)(x+2i)=(0x-2i)(0x+2i)?

grave quartz
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The polynomial should be $$x^4 -4x^3 +9x^2 -16x +20$$

ocean sealBOT
#

SWF ;)

grave quartz
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here

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just expand the brackets as I put them up there

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follow that working

patent topaz
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huh. thanks for the help, it's very much appreciated.

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is the minus in $x-(2\pm{i})$personal preference?

ocean sealBOT
#

WayneTundra

patent topaz
#

.close

lone heartBOT
#
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lone heartBOT
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vapid shuttle
lone heartBOT
quartz trout
#

hi, i have a problem in understanding tangents and normals using derivatives i dont understand how to proceed, i understand its basics to some extent but i get stuck really easily,i dont know if these kind of questions are entertained but any kind of suggestion would help

vapid shuttle
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I was hoping someone could verify my work for this

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$f(x,a)=\frac{ax}{a^2+x^2}$

ocean sealBOT
#

Austiin

vapid shuttle
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ax is a product of continous functions

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a^2+x^2 is a sum of continous functions

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their quotient is continous unless the denominator equals 0

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so that is

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$a^2+x^2=0 \implies a=x=0$

ocean sealBOT
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Austiin

vapid shuttle
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So really we only need to show continuity at (0,0)

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elsewhere it is garuanteed by our theorems for sum/product/quotient of continous functions

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so we consider

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$\lim_{(x,a)\to (0,0)} \frac{ax}{a^2+x^2}$

ocean sealBOT
#

Austiin

vapid shuttle
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this is equal to

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$\lim_{x\to 0} \frac{0}{x^2}$

ocean sealBOT
#

Austiin

vapid shuttle
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since a is a constant, not a variable

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if it approaches 0 it must be 0

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so this limit is just 0

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now we have to compare this to our function evaluated at (x,0)

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$f(x,0)=\frac{0}{x^2}=0$

ocean sealBOT
#

Austiin

vapid shuttle
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so our f(x,a) is continous at (0,0) so it is continous everywhere

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and the exact same work for f(a,y)

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is that good enough?

worn fox
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lemme just rejig your argument a little

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if a = 0, f(x,a) is the zero function to everything is fine nothing to do there

vapid shuttle
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same for f(a,y)

worn fox
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for a non zero, its just $\lim_{x \to 0} \frac{ax}{a^2+x^2}$

ocean sealBOT
#

ΣΑCu

worn fox
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you dont have to worry about two variable limits here

vapid shuttle
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which is 0/a^2=0

worn fox
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yep

worn fox
young finch
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@vapid shuttle

vapid shuttle
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what are the points of these limits

young finch
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oh wait youre actually austin

vapid shuttle
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if we do not compare them to the function at that point

quartz trout
rose sigil
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@vapid shuttle

worn fox
vapid shuttle
quartz trout
worn fox
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but atleast for f the limit is easy bc theres no indeterminant form to finding the limit does just amount to plugging the limit point in

young finch
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no you didnt

worn fox
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lol help-0 moment

vapid shuttle
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you're interrupting my channel @quartz trout I have posted my question in here, that is why you need to go to an available help channel instead of this one

vapid shuttle
quartz trout
vapid shuttle
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no worries

worn fox
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if you just found the value at x=0 then you haven't checked the limit, it just happens in this case that the limit is easy and amounts to the same procedure

vapid shuttle
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Okay can we restart a little here

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I'm getting a bit confused

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we have this

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we have immediately that it is cont. everywhere except possibly (0,0)

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that is all we need to show

worn fox
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not (0,0)

vapid shuttle
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what do you say is the procedure

worn fox
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these are functions of one variable now

vapid shuttle
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oh

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f(x,a)

worn fox
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a is arbitary but fixed

vapid shuttle
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yes

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okay

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so

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f(x)=(ax)/(a^2+x^2)

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we wish to show is continous everywhere

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the only case where it might not be, is a=0 and x=0

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so now our procedure?

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compare limit x->0 to f(0) ?

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but f(0) is undefined if a=0

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so I am stuck

worn fox
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ah no so

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if a=0, then f(x,a) = 0 for all x

vapid shuttle
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what about x=0

worn fox
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the function is the zero function the second you decided a was 0

vapid shuttle
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hmm

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I don't see how that works

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if x is 0 that is still division by 0

worn fox
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think about the family of functions a/x

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if i pick the function where a=0, thats just the zero function

vapid shuttle
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unless x=0

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is what I would think

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because isn't that saying

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0/x = 0

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for all x

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but what about x=0

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it is undefined

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@fallen verge

fallen verge
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What have you done now

vapid shuttle
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i divided by 0

fallen verge
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Oh god we're doing stuff with poles

vapid shuttle
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poles?

fallen verge
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No im being stupid

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Ignore me

worn fox
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yeah i think you're right im being dumb

vapid shuttle
fallen verge
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What

vapid shuttle
fallen verge
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You know i dont understand mv, why did you call me here

vapid shuttle
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as sigma pointed out

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it isn't multivariable

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a is arbitrary but fixed

fallen verge
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So what are you trying to prove

vapid shuttle
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f(x,a) continous for all x

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let $a\in \mathbb{R}$ and $$f(x)=\frac{ax}{x^2+a^2}$$ we need to show $f(x)$ is continous

ocean sealBOT
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Austiin

worn fox
# ocean seal **Austiin**

my issue (or perhaps confusion) was that proving this limit is equal to f(0,0) would imply continuity of f(x,y) at (0,0) as you've just changed the name of y

vapid shuttle
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no it wouldn't

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because I just set a=0

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you can't just set y=0

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y can range

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the paths

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remember the curves

fallen verge
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Have you considered the fact that it doesnt not necessarily approach 0?

worn fox
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you were letting a go to 0 in that latex

vapid shuttle
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the fact that it does not not necessarily approach 0

fallen verge
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I meant one not

vapid shuttle
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not letting a->0

fallen verge
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Should approach 1/2 if you approach it when a=x

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if you approach it on any line a=cx, you get the limit=c/(1+c^2)

vapid shuttle
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uh

fallen verge
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So the limit does not exist

vapid shuttle
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a is constant

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it can't equal x

worn fox
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ah, take the limit as x goes to zero first

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and then set a = 0

vapid shuttle
vapid shuttle
worn fox
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idk maybe just cry then

vapid shuttle
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😭

fallen verge
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lim y->a f(x,y) is not always equal to f(x,a)

vapid shuttle
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eric pls save me

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I know you're out there

worn fox
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okay well f(x,0) is zero everywhere except maybe x=0

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have a good night

vapid shuttle
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you too

worn fox
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the issue here isn't the limit right, its what the value at x=0 is

fallen verge
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I think that its not always the case that $$\lim_{(x,y) \rightarrow (0,0)} f(x,y)= \lim_{x \rightarrow 0} \lim_{y \rightarrow 0} f(x,y)$$

ocean sealBOT
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GarlicBredFr

vapid shuttle
fluid kettle
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austiin

vapid shuttle
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this question is so stupid

fallen verge
worn fox
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what have you done

vapid shuttle
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it doesn't involve all relevant information

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in the question

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it says

worn fox
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fuck SAKE

vapid shuttle
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f(x,y) as in example blah

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but then gives f(x,y) anyways

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but

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in example blah

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h(0,0)=0

worn fox
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AAAAAAAAAAAAAAA

vapid shuttle
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AAAAAAAAAAAAAAAAAAAAAAAAAAAA

fallen verge
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🔋

worn fox
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would be a tiny battery

vapid shuttle
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ok

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so literally all we care about are those limits then

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f(x,0)= 0 unless x=0, but in this case it is f(0,0) which is defined to equal 0

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so now we just need to care about the lim x->0 of f(x,0)

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which is 0

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ty lhopitalsrule

worn fox
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so in the case where a=0, the function is zero literally everywhere but x=0, you could just do epsilon shite

vapid shuttle
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same for the f(a,y)

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and we are done

vapid shuttle
fallen verge
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Im still confused

worn fox
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im talkin about the limit

vapid shuttle
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it is single variable limit

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just use lhopitals

fallen verge
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Austin i want my i back

vapid shuttle
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ok

worn fox
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you are literally the epsilon delta guy

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omg he got automuted

fallen verge
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Lmao what

worn fox
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he missed the l on like

fallen verge
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Oh well, i guess we'll get back to it at some point

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Should i coose?

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@vapid shuttle welcome back

vapid shuttle
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I'm back

worn fox
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watch those fingers

vapid shuttle
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oopsie

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okay

#

@worn fox

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may I present to you

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hopefully

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something good

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$f(x,a)=\frac{ax}{a^2+x^2}$

worn fox
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the alt j song?

ocean sealBOT
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Austin

vapid shuttle
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tontinous everywher except a=x=0 immediately from composition/product/sum of continous functions theorems

fallen verge
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Thanks for the i

vapid shuttle
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so now we consider

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let a=0

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and take lim x->0

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this is

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$\lim_{x\to 0} \frac{0}{x^2}=0$

ocean sealBOT
#

Austin

vapid shuttle
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and if we are considering the case of a=x=0

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this is defined in our function the same as f(0,0)

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which we defined to be 0

fallen verge
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You can use epsdel here right

vapid shuttle
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so we get the limit equal to the value

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and it is continous there

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please tell me that is good ???

worn fox
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yeah but you have considered the limit in the case a =0

vapid shuttle
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I just did!!!>!??!?!?!?!?

worn fox
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i think your woes about dividing by 0 were valid

vapid shuttle
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dear god

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where is the division by 0 happening now

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the f(0,0) is defined by the function

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so no worries there

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the limit comes from lhopital

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I should be fine?

worn fox
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oh youre lhopitaling fine

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honestly im just scared of you after the automute

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whatever you say

vapid shuttle
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wait a minute...

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what if I was onto something big

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and that is why the mods muted me

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to stop me from my realization

fallen verge
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We want your fields medal

vapid shuttle
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the mods wanted my fields medal

vapid shuttle
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I feel bad now

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you made me feel bad

worn fox
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its half 1 AM i do not have the brain capacity for eps del lol

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i think what you did was fine and im just slow

vapid shuttle
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how can we do eps delta for x=a if f(a) is undefined

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wait wtf am I doing

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no don't say anything

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don't

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mods mute him

worn fox
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you should have 0 < |x-0| < del implies |f(x,0) - f(0,0)| < eps

vapid shuttle
worn fox
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or that

vapid shuttle
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so

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I need

worn fox
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honestly this probs sucks

vapid shuttle
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$|x|<\delta \implies |f(x)|<\varepsilon$

ocean sealBOT
#

Austin

worn fox
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0 < |x|

vapid shuttle
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let epsilon>0

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thanks sherlock

worn fox
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its important

vapid shuttle
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ik I'm jk

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uhh

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here

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if

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$0<|x|<\delta$

ocean sealBOT
#

Austin

vapid shuttle
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then x is nonzero

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then f(x) is 0

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then since eps>0

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|f(x)|<eps

worn fox
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yeye

worn fox
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im more confortable with that than the other way

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feels better

vapid shuttle
#

Final draft

#

Are we good?

#

.close

lone heartBOT
#
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vapid steppe
#

is it true that if you get (nonzero)/0 when doing direct substitution into a limit, that the limit is one of the infinities?

upbeat hornet
#

what do you mean?

vapid steppe
#

like lets say you have $\lim_{x\to c}\frac{f(x)}{g(x)}$

ocean sealBOT
vapid steppe
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and you know f(c) does not equal 0

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and g(c)=0

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will the limit have to be either plus or minus infinity?

mystic vortex
vapid steppe
#

yea but like just when you do direct substitution

upbeat hornet
vapid steppe
#

im trying to see if this statement is always true: If $\lim_{x\to 0}{\frac{f(x)}{x}}=1$, then $f(0)=0$

ocean sealBOT
mystic vortex
#

No, f could be piecewise

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Do you have the condition that f is continuous?

vapid steppe
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i know that f is defined for all real numbers

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not necessarily continuous tho

mystic vortex
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Wait lemme think

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Right, so no

vapid steppe
#

is it true that If $\lim_{x\to 0}{\frac{f(x)}{x}}=1$, then $\lim_{x\to 0}{f(x)}=0$

ocean sealBOT
mystic vortex
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You could have f(x) = 0 for all x not equal to 0, f(x) = 1 for x = 0

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Hmm

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Pretty sure yeah

vapid steppe
#

but when you do direct substitution and get like 2/0 or something doesnt that mean its an asymptote

mystic vortex
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Assuming the direct substitution was valid I believe so yeah

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Oh

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I think instead of an asymptote it could also be DNE

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not sure actually

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I'm probably not the person who should be helping you rn

vapid steppe
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is lim as x->c of f(x)/g(x) always the same of lim of f / lim of g

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even if the limit dne

mystic vortex
#

I recall there being some condition for that, lemme check

upbeat hornet
mystic vortex
#

The condition is that the limit of g(x) is not equal to 0

vapid steppe
near apex
vapid steppe
#

side question does $\lim_{x\to 0}{\sin{\frac{\pi}{x}}}$ exist

ocean sealBOT
near apex
#

No

vapid steppe
#

how do you know

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is it cuz its not 0/0

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since sin is continuous can you like bring the sin out of the limit

near apex
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Because argument is either positive infinity or negative infinity and sine is an oscillatory function.

vapid steppe
#

and just evaluate limit of pi/x

vapid steppe
mystic vortex
#

So that's sin of undef

vapid steppe
#

oh yea lim of pi/x doesnt exist on both sides of 0

upbeat hornet
#

infinitely many times

vapid steppe
#

oh so dne

upbeat hornet
near apex
mystic vortex
#

Oh it also gave the condition that both limits exist

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Of f and g

near apex
#

Ah. Makes sense now.

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I was getting stuck with infinity/infinity case.

rocky loom
#

could someone help with geometry?

near apex
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Where individual limits don't exist but f/g does.

rocky loom
#

or is this not for geometry

vapid steppe
mystic vortex
#

I think it also specified it being the limit approaching a real number

vapid steppe
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cuz lets assume that f(0)=0, then u would have 0/0 implying to use lhopitals rule which then the limit exists

mystic vortex
#

No

vapid steppe
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oh is it cuz 0/0 doesnt necessarily imply the limit exists

mystic vortex
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F(0) is not the same as the limit approaching 0

upbeat hornet
near apex
#

No, but being 0/0, they can apply l'hopital. Right?

vapid steppe
#

yea

upbeat hornet
vapid steppe
near apex
mystic vortex
#

But the limit might not be 0/0 just cause f(0) = 0

vapid steppe
#

so its not never true

mystic vortex
#

It is stated nowhere that f is continuous

near apex
mystic vortex
#

I gtg

vapid steppe
#

but also like limit as x->0 of x/x^2 dne

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even if its 0/0

near apex
vapid steppe
#

chatgpt said consider f(x)=x+1 and evaluate lim as x to 0 of f(x)/x

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the limit is 1

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but f(0)=1

vapid steppe
near apex
#

Lol. Same thought.

vapid steppe
#

so like back to basics for a limit to exist that means that the left hand limit equals the right hand limit

near apex
#

Yes

vapid steppe
#

im trying to think of counterexamples

near apex
#

Well, tag me if you come up with something.

upbeat hornet
vapid steppe
#

it isnt lol cuz that limit dne

vapid steppe
#

wait nvm

lone heartBOT
#

@vapid steppe Has your question been resolved?

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sand pendant
#

If the second and fourth terms of a G.P. are 8 and 32 respectively, what is the sum of the first four terms?

ivory fern
#

!status

lone heartBOT
#
What step are you on?
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5. I have a question about someone else's worked solution
6. None of the above
young finch
#

what's a GP

violet bear
young finch
#

ah

#

i figured it was geometric something

lone heartBOT
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@sand pendant Has your question been resolved?

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wary wyvern
#

hy

#

help mee

mental flame
#

This channel is also occupied scooby

wary wyvern
#

ohh what i need to know answers?

#

plss im new to b dicord

#

should u help mee

left isle
#

click on the link and read it

mental flame
#

Nobody is going to help you until you create your own Channel

wary wyvern
#

ahh

#

so i need to quit

young finch
#

assuming F(x) is the anti derivative

wary wyvern
#

?

young finch
#

so that means F'(x)=f(x)

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so whats your issue

#

just a property of derivatives

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f'(x)=0 for certain x values where f(x) has extrema

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not really backwards

placid zinc
#

When the function hits a minimum, the slope is 0 there. You can see that as a root of the derivative

young finch
#

if you just shift it over to make F(x) f(x), then f(x) is f'(x)

#

.close

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devout hare
#

It is known that a conic section is the geometric locus of points in a plane α for which the ratio between the distances to a fixed point F (focus) and a fixed line d (directrix) is equal to a non-negative constant e (eccentricity of the conic). This concept extends to the definitions of ellipse, hyperbola, and parabola, with the first two being constructed from a pair of perpendicular directrices to the support of the major axis (or real axis in the case of the hyperbola, 2a units of length), located at a distance of a/e units from the center of the curve, where "e" is the eccentricity. In this sense, how is it possible to deduce that the eccentricity of both an ellipse and a hyperbola is necessarily c/a, where c is the focal distance and a half of its major/real axis length, from its definition?

devout hare
#

I don't know where to begin

lone heartBOT
#

@devout hare Has your question been resolved?

devout hare
#

<@&286206848099549185>

lone heartBOT
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@devout hare Has your question been resolved?

devout hare
#

.close

lone heartBOT
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oak perch
#

No

#

$f(x)^{2}+3f(x)=g(f(x))=x^{2}-3x$ therefore $|f(x)+\frac{3}{2}|=|x-\frac{3}{2}|$

ocean sealBOT
#

Cogwheels of the mind

oak perch
#

So it’s definitely not unique. Infinitely many. If you require f to be continuous then 4 many, if you require f to be differentiable then 2 many.

deep quartz
#

ah I see, that makes a lot more sense, thank you for your help

oak perch
#

Np

deep quartz
#

.close

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flat roost
#

Is it possible to find the area bounded by the lines y = x+3 and y = 6-2x without looking at the graphs with integration?

flat roost
#

"and the x-axis"

west girder
#

Yes

young finch
#

set the equations equal to each other and solve

#

that'll give left bound and I think right bound will be obvious

upbeat hornet
flat roost
flat roost
young finch
#

in this case you have to split it up into two integrals

#

or put them in terms of y

tardy stag
#

tbh if i were doing this integral I'd probably do a very rough sketch first

flat roost
#

wait what if

#

i find the intersection point

#

of the two lines

#

and then integrate from left bound to that point, then that point to right bound

young finch
#

thats what I said by splitting it up into two integrals

flat roost
tardy stag
young finch
#

you don't need a graphing calculator to sketch two linear lines

upbeat hornet
cedar juniper
#

The equations are for straight lines, you dont need to integrate

flat roost
#

yeah that works

young finch
#

what is affine

upbeat hornet
upbeat hornet
flat roost
#

if the equation is y = x+ constant its linear right

#

straight line

upbeat hornet
upbeat hornet
flat roost
#

i see

#

thanks guys\

#

.close

lone heartBOT
#
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lone heartBOT
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west girder
#

If we have an infinite double cone and a plane, how do we know the cross section is a parabola or hyperbola?

west girder
#

We can easily see if the cross section is an ellipse, but a parabola and hyperbola share the same features in the scenario of an infinite double cone

oak perch
#

By comparing two angles

west girder
#

Which?

wind cloak
#

if you tilt it hard enough it's a hyperbola sotrue

#

hyperbolas have two branches so you can figure it out that way

oak perch
#

α<β ellipsis, α=β parabola, α>β hyperbola

west girder
#

Is the big X the double cone?

oak perch
#

Yes, a slice of it

west girder
#

Oh I see

#

That’s very cool

oak perch
#

It is

#

Ancient Greek people discovered it I think

west girder
#

Is there a name for this fact so I can look into it?

oak perch
#

Can’t help with that. I only started reading math in English since undergraduate level.

west girder
#

It’s alright I’ll probably be able to find if I look hard enough

#

Thanks!!

oak perch
#

So I don’t know what it’s called in English. And I don’t even remember this has a name.

#

Np

wind cloak
west girder
#

Ok thanks!

#

.close

lone heartBOT
#
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west girder
#

Oh I just realized, the parabola won’t look the same

#

It just clicked that the plane is parallel to the edge of the double cone in a parabola

#

The fact is intuitive

lone heartBOT
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spare fern
#

How would I differentiate this?

lone heartBOT
spare fern
#

$$-6xe^{-2x}$$

ocean sealBOT
#

Lex1729

flat vale
#

product rule

hushed locust
#

product rule + chain rule

spare fern
#

so is u and v both negative?

#

for example is it u = -6x and v = e^-2x

#

or u = -6x and v = -e^-2x

hushed locust
#

pick one to be negative

spare fern
#

alright so u = -6x and v = e^-2x

#

so u' = -6 and v'= -2e^-2x

#

is this correct?

hushed locust
#

so far yes

spare fern
#

hold on I'll send the full question

#

Here is my working

#

Just not sure where I messed up haha

spark sky
spare fern
#

but it is -6x * -2e^-2x

#

which is positive

spark sky
# spare fern which is positive

no i meant the first part, it should be -12e^-2x + 12xe^-2x
New to differential equations, so I might be pointing at the wrong thing.

spare fern
#

I don't understand

#

are you talking about the part of the screenshot you sent me?

spark sky
#

yeah

spare fern
#

but the original gradient function is -6xe^-2x -e^-2x

#

we would need to use the product rule to find the second derivative of that

spark sky
#

Sorry I don't think I qualify helping you with this since I am literally new to these concepts

flat roost
#

@spare fern

#

the second line here is an extension of the first, right?

spare fern
#

yes

flat roost
#

then it is wrong

spare fern
#

Oh I see now

flat roost
#

it should be -6xe^2x - e^-2x

#

if you take out the e^-2x, you should get e^-2x (-2(3x+2)+3)

#

simplified to e^-2x(-6x-1)

spare fern
#

Thanks for pointing that out I'll redo the problem again from the start

flat roost
#

you are welcome, good luck

bold magnet
#

solve for values of x in range 0<=x<=360 Q.3sec.sqr.x-2tanx=8

flat roost
#

thanks

bold magnet
#

how can i type square in keyboard

flat roost
#

square root?

bold magnet
#

neh a square like 2sqr

flat roost
#

huh

bold magnet
#

power

flat roost
#

^2?

#

OH

#

do you mean

#

sec^2x-2tanx =8

bold magnet
#

yeh

#

tnks

#

yes

flat roost
#

ok here is what i thought of

#

sec^2x - 2tanx = 8

#

use the 1+tan^2x=sec^2x identity for the sec^2x

#

1+tan^2x-2tanx = 8

#

tan^2x-2tanx-7=0

#

now we have a quadratic

bold magnet
#

yeah I got it thnks a lott

flat roost
#

👍

lone heartBOT
#

@spare fern Has your question been resolved?

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lone heartBOT
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steel olive
lone heartBOT
steel olive
#

What's wrong in my soln

#

I'm getting 5

#

Correct answer is 17

oak perch
#

You can order numbers of this form like this:

#

(a,b,c): a>=b>=c
(a,b,c)<(a’,b’,c’) iff a<a’, or a=a’, b<b’, or a=a’,b=b’, c<c’

#

So there are (a+1)(a+2)/2 many of them of the form (a, - , -)

steel olive
#

oh ya got it i didnt count all cases

oak perch
#

Don’t close it yet

steel olive
#

yea,so basically like the numbers wherw a = 0,b = 0 and c=1 and their permutations,they will be counted as a single integer

#

right?

#

and they are asking for 101st smallest integer

oak perch
#

Yeah. Next calculate maximum $m$ such that $\sum_{a=0}^{m}\frac{(a+1)(a+2)}{2} \leq 99$, so $\frac{m^{3}}{6}+m^{2}+\frac{11m}{6}+1 \leq 99$

ocean sealBOT
#

Cogwheels of the mind

oak perch
#

m=6

#

So the 86 th minimal number is (7,0,0)

#

There are b+1 many numbers of the form (7, b, -)

#

Similar method or direct calculation

#

The 101 th minimal number is

#

(7,5,0)

#

=2431

#

Then

#

Done, 17 indeed

oak perch
steel olive
oak perch
#

b+1 many of the form (a,b,-) right?

#

From (a,b,0) to (a,b,b)

#

So how many numbers are of the form (a, -, -)? Sum of numbers of numbers of the form (a, b, -): b from 0 to a, so Σ(b+1): b from 0 to a

#

(a+1)(a+2)/2 many

#

BTW, at the beginning, I define order in that form because a<a’, we can have (a,b,c)<(a’,b’,c’) because divide by 3^a on both sides, we have (a,b,c)/3^a= 1+3^(b-a)+3^(c-a)<=3<3+3^(b’-a)+3^(c’-a)<=(a’,b’,c’)/3^a

#

The rest is similar

#

Got it?

lone heartBOT
#

@steel olive Has your question been resolved?

steel olive
#

loy

#

lot

#

.close

lone heartBOT
#
Channel closed

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Use .reopen if this was a mistake.

oak perch
#

Okay , np

lone heartBOT
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sick kayak
#

Can anyone provide and explain the solution for this

tardy tapir
#

,rotate

ocean sealBOT
oak perch
#

For n large enough

#

2^(1/2)-2^(1/(2n+1)) converges to sqrt(2)-1

#

Which is smaller than 1

#

So it will converge to 0

sick kayak
#

Ooh

#

Yes yes thank you

oak perch
#

Np

wind cloak
#

,w solve product from k = 1 to infinity 2^(1/2) - 2^(1/(2k + 1))

wind cloak
#

seems legit

oak perch
#

Of course it is, it is actually
0<=a_n<=a_N (sqrt(2)-1)^(n-N)

#

For some N

sick kayak
#

.close

lone heartBOT
#
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formal rune
#

Help factorise g

lone heartBOT
vale wigeon
#

what's troubling you?

formal rune
#

How to break brachet

#

Exponent is throwing me off, has been a while bc we don’t do easy math at higher

azure tapir
#

well

vale wigeon
#

you don't want to expand here just yet.

azure tapir
#

is your question $5(x+1)^2-4(x+1)^3

#

$5(x+1)^2-4(x+1)^3$

ocean sealBOT
#

Sunset

formal rune
#

Yes

azure tapir
#

do you know the

#

bodmas rule

#

?

vale wigeon
#

@azure tapir are you about to suggest that op expand this entire thing?

#

cause thats gonna be both painful and obstructive

azure tapir
#

no

#

just this

#

$5(x^2+1)-4(x^3+1)$

ocean sealBOT
#

Sunset

vale wigeon
#

this is incorrect lmfao

#

(x+1)^2 ≠ x^2 + 1

#

and (x+1)^3 ≠ x^3 + 1

formal rune
azure tapir
#

peter dont lisen to me

formal rune
#

Ok

vale wigeon
#

anyway...

formal rune
#

Help

vale wigeon
#

for factorization you will want to pull out (x+1)^2 from both terms here.

formal rune
#

How

vale wigeon
#

you know the distributive law, yes?

formal rune
#

Yes

vale wigeon
#

and you also know (x+1)^3 can be written as (x+1) * (x+1)^2, yes?

formal rune
#

Yes

vale wigeon
#

$5 \cdot (x+1)^2 - 4(x+1) \cdot (x+1)^2 = [5 - 4(x+1)] \cdot (x+1)^2$

ocean sealBOT
formal rune
#

Can you dumb it down pls

ocean sealBOT
#

Sunset

formal rune
#

More step

vale wigeon
#

there was never any 5(x^2+1) !!!!

azure tapir
#

no

#

it was a miss splet

vale wigeon
#

ok but why did your latex end up here

azure tapir
#

spelt

vale wigeon
#

can you state the distributive law for me?

formal rune
#

Is like

#

A(b + c) = ab + ac

#

Right

vale wigeon
#

no capitalization on the a

#

but yes

#

now

#

this law goes BOTH ways.

#

so from ab + ac you can get a(b+c)

#

this is called "factoring out a" or "pulling out a"

#

do you understand this yes or no

formal rune
#

Yeah

vale wigeon
#

yeah so that is what i am doing here

formal rune
#

Like tht

formal rune
vale wigeon
#

-4(x+1) isn't equal to (-4x+1)

#

and i am not even touching that anyway

formal rune
#

Oh

vale wigeon
#

$5 \cdot (x+1)^2 - 4(x+1) \cdot (x+1)^2 = [5 - 4(x+1)] \cdot (x+1)^2$

ocean sealBOT
vale wigeon
#

i am factoring out (x+1)^2

#

despite ie being written with more than one letter it is still a thing that in principle can get factored out

formal rune
#

Where did the five go

vale wigeon
#

it didn't go anywhere...

formal rune
#

G is my end goal btw

#

Why is this not clicking for me 😭

vale wigeon
#

i really don't know how to 'dumb it down' even further

formal rune
#

Can you do it step by step

vale wigeon
#

i am trying to show you one step

#

this is one step

formal rune
#

Oh

vale wigeon
#

it cannot be broken down any further

formal rune
#

So the textbook is wrong ?

vale wigeon
#

no, the textbook is not wrong.

#

we just won't be finished after this one step.

formal rune
#

But if it can’t be broken down any further

#

Oh

vale wigeon
#

THIS ONE STEP can't be broken into smaller sub-steps.

formal rune
#

I’m confused, so this step can’t be used to get the answe in the textbook?

vale wigeon
#

qe4rjgjfsdrnhqearjhsrth

#

this is one step. towards the solution.

formal rune
#

Oh 😭

vale wigeon
#

i didn't show you the steps that FOLLOW it.

#

because you're saying that this one step by itself confuses you.

#

so we can't move on yet.

formal rune
vale wigeon
#

it's the distributive law!!!

#

ac - bc = (a-b)*c

formal rune
#

What do I need to learn to make me not get confused

#

Oh

#

Let me process this

#

So in this scenario

#

C = (x+1)^2

#

?

vale wigeon
#

yes

#

lowercase c but yes

formal rune
#

But what about the other (x+1)

vale wigeon
#

wym

#

for the purposes of our step it can just stay as is

#

we'll handle it in the next step

formal rune
#

Got it thanks

#

This was correct, right ? @vale wigeon

vale wigeon
#

no

#

you didn't factor it correctly

#

i showed you exactly how to do it and you messed it up

formal rune
#

😭

#

Which line

#

Wait

#

I see

#

So far so good ? @vale wigeon

vale wigeon
#

no

#

b is 4(x+1) not just 4.

formal rune
#

Oh

#

Ohh

#

@vale wigeon like that

vale wigeon
#

yes now you've reproduced my thing

formal rune
#

Yessss

#

This is right ?

vale wigeon
#

yes now it is

formal rune
#

Yay thx

olive ice
# formal rune

no hate man but your paper looks like someone shot it with a sawed-off shotgun with all the therefore symbols 🤣

lone heartBOT
#

@formal rune Has your question been resolved?

lone heartBOT
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#
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severe stump
#

Can someone explain how the distributive property works and how can I apply in math problems

desert elm
#

couuld somebody possibly explain and help me for a maths problem?

vale wigeon
#

@desert elm the other person got here first -- please get your own channel. #❓how-to-get-help for instructions.

#

@severe stump
a * (b + c) = a*b + a*c

#

the applications of the distributive property are very broad and numerous so it's impossible to just summarize it all in one discord chat

#

but applying the distributive property is often called "expanding" or "factoring" depending on which direction you go

lone heartBOT
#

@severe stump Has your question been resolved?

severe stump
#

How am I supposed to get the value of x

vale wigeon
#

eh?

#

wait what

severe stump
#

Wait

vale wigeon
#

are capital X and lowercase x meant to be the same

#

maybe send a picture of you're in doubt

severe stump
#

Sadly I didn't get a picture of it

vale wigeon
#

ok now i'm even more confused at what you're supposed to do.

#

are you able to send a picture?

severe stump
severe stump
#

😔

vale wigeon
#

do you have perfect memory

severe stump
vale wigeon
#

i think you don't

#

right now it's neither possible nor impossible bc we don't have a clearly written problem statement

severe stump
#

Given equation:
2y^2-3y+4

question:

  1. y=y+1
severe stump
#

.close

lone heartBOT
#
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lone heartBOT
#

@quasi trail Has your question been resolved?

lone heartBOT
#

@quasi trail Has your question been resolved?

azure tapir
#

tip

#

make your paper clear and readable

lone heartBOT
#
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vital wyvern
lone heartBOT
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alpine sable
#

I have this graph with the above and I'm tasked to find the range of a in terms of p

alpine sable
#

where do I start?

#

what does f(x) and g(x) even have in common?

#

and what does a, b, c correspond to in a graph?

#

<@&286206848099549185>

echo socket
alpine sable
#

i see

echo socket
#

If it's positive, the parabola goes up, and if it's negative, it goes down

alpine sable
#

so p here will definitely be smaller than a

#

and p will be positive

#

or not

echo socket
#

But that is not the case

#

The greater the absolute value of a, the thinner the parabola is

alpine sable
#

ohhh I see

echo socket
#

So here we deduce that a is positive and less than p

alpine sable
#

is there an explanation to why is that the case?

echo socket
#

So the slopes tangent to the graph become more vertical

#

Hence it looks thinner

alpine sable
#

ahh

#

makes sense

#

let me write this down

echo socket
alpine sable
#

right

#

now what does b and c here represent?

echo socket
#

c is basically the elevation, you will see the graph be lifted as you increase the value of c

#

And b is kind of hard to explain in this case, I think it would be a bit more clear if you played around with its value in desmos

alpine sable
#

i see

#

alright

#

thanks a lot

#

.close

lone heartBOT
#
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lone heartBOT
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placid spire
lone heartBOT
placid spire
#

laplace for this one?

#

this is the solution

#

I understand the top part

#

but not the bottom

#

They used this formula sheet:

#

number 3 and 15

#

15 is used on the bottom part

#

But i dont see how they can split it up in two different ones?

#

number 15 I dont understand tho

#

it says e^-at * f(t)

#

what is f(t)?

#

I assume f(t) is t^2 / 2

uncut torrent
#

yeah

#

f(t)=t^2/2

#

so in the form e^(-at)*f(t), a=2 right

#

they're using formula 15 because they found the laplace transform for f(t)

placid spire
#

I see

#

what about this one

#

they use 22 and 5

#

I dont understand when they used 22

#

They got that L{te^-t}

#

how did they get that?

#

that should be the F(s) from 22, but where does it come from

#

we have that e^-(t-3) but that isn't te^-t?

tacit arch
#

Do you know what u(t-d) is

placid spire
#

not sure

tacit arch
#

It's defined in your book

#

Look for it

lone heartBOT
#

@placid spire Has your question been resolved?

placid spire
#

it doesnt say what u(t-d) is

#

I see second shift theorem tho

#

but that doesnt explain how e^-(t-e) turns into te^-t

lone heartBOT
#

@placid spire Has your question been resolved?

lone heartBOT
#

@placid spire Has your question been resolved?

tacit arch
tacit arch
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u(t - d) is a composition of functions

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i recommend reviewing those

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,tex .transformation rules

ocean sealBOT
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riemann

hazy torrent
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hi

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how to solve 10-5

tacit arch
lone heartBOT
lone heartBOT
#

@placid spire Has your question been resolved?

lone heartBOT
#
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young finch
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im a bit confused on how unfixed eigenvectors can be, when computing them im seeing that it can go one of two ways, setting one variable as the free variable and writing the eigenvector based off that, or setting the other variable as the free variable

young finch
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i feel like my question does not make sense

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like here, couldnt it [1,-1,0] or [-1,1,0]?

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<@&286206848099549185>

pallid scarab
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The first vector is -1* the second one so they're linearly dependent

young finch
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right

vapid shuttle
young finch
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but i still dont understand any logical reasoning to make it [-1,1,0] instead of [1,-1,0]

young finch
pallid scarab
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Because we just chose it

vapid shuttle
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show original matrix

pallid scarab
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Both are valid eigenvectors

pallid scarab
young finch
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so there are multiple eigenbasis that are all the same thing?

vapid shuttle
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those are not eigenvectors of that matrix

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those are vectors in the nullspace of that matrix

young finch
pallid scarab
vapid shuttle
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no

pallid scarab
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AX = 0 = 0X

vapid shuttle
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yes

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hah

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but anyways he wrote lambda=-2 so that isn't what he meant

vapid shuttle
pallid scarab
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Right :)

vapid shuttle
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Ax will be <2,-4,0>

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which is not -2 * x

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however it is 2 * x

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so the difference is a change in sign

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input <-1,1,0> instead

pallid scarab
vapid shuttle
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Ax will get <-2,4,0>

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oh shit

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yeah

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I was thinking about only the first row

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my bad idk what I'm doing

young finch
pallid scarab
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[1,-1,0] and [-1,1,0] are both valid eigenvectors for lambda = -2

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But since they're linearly dependent

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You can only choose one of them for your eigenbasis

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They chose [-1,1,0] in the solution

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You're equally valid to choose [1,-1,0] instead

young finch
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okay

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is this the same for eigenvalues with a multiplicity of 2?

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when solving for htem

vapid shuttle
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sometimes you can choose 2 independent ones in that case

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sometimes you can't

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depends on if the eigenvalues are degenerate

young finch
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im a degenerate

pallid scarab
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Honestly same

young finch
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okay so if i can write it as x1=cx2 then it can also be x_2=cx_1

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but theres certain obvious cases where it has a set eigenvector for the eigenvalue

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okay i think i get it

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thank you!

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.close

lone heartBOT
#
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proven haven
lone heartBOT
proven haven
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dont mind that i put quadratic

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alg 2

vapid shuttle
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I mind

proven haven
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it was accident

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lol

vapid shuttle
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are you sorry

proven haven
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yes

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so how do you solve this

grave quartz
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plot the points lol

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I forgot to say the last time

proven haven
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how to plot points

grave quartz
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it willl be obvious

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well y = f(x) here

proven haven
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oh

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okay

grave quartz
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so think of the right column as y values and the left is x

proven haven
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okok