#help-0

1 messages ยท Page 696 of 1

coral pagoda
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You're still talking about this problem right?

rich basin
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yes

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I was wondering why isn't my answer correct

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And what operators do i require to obtain the right answer and for what reasons do i need to use that oeprator for

coral pagoda
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Okay, well we know there are 8C4 different ways to seperate coats into two piles

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You got that down good

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Now we need to consider the total number of possobilities

rich basin
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Like wouldn't that be 2^8 -2

coral pagoda
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Our initial thought would be to just add 8C1+8C2+...+8C8, but there is one tiny problem: [ \binom{n}{k}=\binom{n}{n-k}.]

ocean sealBOT
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dackid (jump king +)

rich basin
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The only problem here is that you can have duplicates

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But that was when i thought of dividing 2^8 by 2

coral pagoda
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So in regards to this problem, choosing to have 2 coats in the left pile and 6 coats in the right is the same as having 6 coats in the left pile and 2 in the right

rich basin
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,w solve ((8 choose 4))/ (2^8/2 -2)

ocean sealBOT
rich basin
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Which still isn't the right answer

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Yeah choose 2 on the left is the same as choose 6 on the left

coral pagoda
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Okay, well dividing by 2 does seem like it would get you there, but there is a problem: there are exactly 9 different types of combinations if you have 8 items.
8C0,8C1,8C2,8C3,8C4,8C5,8C6,8C7,8C8.

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So just dividing by two isn't going to give you 8C0 through 8C4 (which is what we want)

rich basin
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yeah

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I don't think 8C0 to counts, because that wouldn't really be dividing

coral pagoda
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That all depends. Can we have 1 pile empty in this problem?

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Also, 8C0 is 1, not 0

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There are no division issues here

rich basin
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,w solve (8 choose 4) divide ((2^8-2)*(4/7))

ocean sealBOT
coral pagoda
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You done trying random stuff?

rich basin
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Okay

coral pagoda
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Thank you. Let us assume we can have an empty pile (that is still two piles).
So we end up with the following probability [ \frac{\binom{8}{4}}{\binom{8}{0}+\binom{8}{1}+\dots+\binom{8}{4}}.]

ocean sealBOT
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dackid (jump king +)

coral pagoda
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And that will get you your result.

rich basin
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let me try that

coral pagoda
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If you can't have an empty pile, then just omit 8 choose 0

rich basin
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,w solve (8 choose 4) divide ( + (8 choose 1) + (8 choose 2) + (8 choose 3) + (8 choose 4))

ocean sealBOT
rich basin
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Was wondering why can't you use 2^8 -2 but then add like some constrains

coral pagoda
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Well, this isn't 2^8-2 for one. Second off, why are you getting that in the first place?

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I understand where you are getting 2^8 (which we have addressed has duplicates), but where you get -2 is beyond me.

rich basin
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becasue 2^8 includes the casess such as 8 choose 0 and 8 choose 8)

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,w solve (8 choose 0) + (8 choose 1) + (8 choose 2) +(8 choose 3) + (8 choose 4) + (8 choose 5) + (8 choose 6) + (8 choose 7) + (8 choose 8)

coral pagoda
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Ah, okay. Well there are more duplicates than 2.

rich basin
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,w solve 2^8

coral pagoda
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I know that the sum of the combinations is 2^{number of items)}

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I am aware of this

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But we have already addressed there are many duplicates in here, so this is clearly not right.

rich basin
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Okay thanks

coral pagoda
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Happy to help

alpine sable
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Hey, doing this quick probem for my homework

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I'm not quite sure how to find the coordinate points for this.

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Would very much appreciate some guidance here

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I know how to find the terminal angle but not the coordinates

dark granite
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isn't that just the unit circle?

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or am I reading that graph incorrectly?

alpine sable
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No it is the unit circle but

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it'

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is not one of the points that's on the unit circle explicitly

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the question is asking me to calculate the coordinates idk how to

dark granite
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For starters, I'd use x^2+y^2=1

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that'll give you coordinates *on * the edge of the unit circle.

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but it's kind of unclear what coordinates you were asked to find

alpine sable
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the coordinates at this reference angle

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in radians btw

dark granite
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oh

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I get it now

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give me a sec

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so the coordinates is (cos(pi-2.7),sin(pi-2.7))

alpine sable
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wait you can do that

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wait youre right

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holy shit im stupid

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i forgot how to do thsi LOL

dark granite
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we sure can!!

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Note that those are coordinates on the unit circle

alpine sable
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yea

dark granite
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if your teacher was asking for points on the line, then there's more work to be done, but sounds like you got it from here

alpine sable
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idk i was

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looking online for how to do this i forgot that

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yea.

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thanks

dark granite
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you're welcome!!

somber osprey
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whats 1+1?

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oh its 2

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nvm

zenith hemlock
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How do i continue?

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I use
dy/dx=[ f(x+h)-f(x) ]/ h
Formula (first principle)

karmic dew
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Someone pls help me understand z-scores

neat mesa
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does anyone know how to solve this??

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#3 and #4

wanton turtle
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Multiply and divide by sqrt(x+h) + sqrt(x)

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You'll be left with h in the numerator which cancels out with the h in the denominator

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After which you can substitute 0 as the indeterminacy has been removed

slow silo
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Mathematical induction

dark granite
slow silo
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thanks anyways

dark granite
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you're welcome

thorn kindle
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49^n + 24^(n-1)

dark granite
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yeah showing $25|49^n+24^{n-1}$ for all integers $n>0$ is equivalent to showing the statement @slow silo wanted to prove

ocean sealBOT
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logician_pdx

cobalt ledge
oblique goblet
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Whats an angle sector?

gentle flame
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Can anyone help with how youโ€™ll complete this with fractional powers ๐Ÿคทโ€โ™‚๏ธ

cobalt ledge
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By that you mean simplify?

noble crypt
cobalt ledge
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(27x^-2)^2/3 = 27x^-4/3 = 1 / 27x^4/3 no?

noble crypt
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for example if you have $(25x^2)^\frac{1}{2}\implies(5^2x^2)^\frac{1}{2}$

ocean sealBOT
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ใ‚ใŸใ—

noble crypt
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then you can get $5^2$ and $x^2$ together and cancel the 1/2 power

ocean sealBOT
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ใ‚ใŸใ—

noble crypt
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so in the end you remain with 5x

noble crypt
cobalt ledge
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Eh fine

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Not used to giving help yet lol

noble crypt
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no problem

hollow pelican
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guys how to do 3b?

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is my working wrong?

ionic jewel
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,w sqrt(3)sin(x)+2cos(x) = 1

ocean sealBOT
ionic jewel
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the answer is a bit less than 2, so yes

hollow pelican
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but i dont rly know which part of it is wrong

rigid smelt
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a^2 != 3^2 to start with

hollow pelican
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ans is still wrong tho

shrewd otter
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The previous question hasn't been solved, this chat is occupied.

quasi flame
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sorry

rigid smelt
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your answer is correct

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tho, thats not the general solution to sin(phi + theta)=1/sqrt(7)

hollow pelican
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this is the correct ans

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i only got 1 of the ans right

clear rampart
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In a packet of spaghetti, one-third of the strands of spaghetti are intact, but the rest have been snapped into two pieces. of all the pieces of spaghetti from the packet (broken and whole), what is the largest fraction guaranteed to be at least as long as half an unbroken strand?

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can anyone help me?

rigid smelt
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then you still need the general solution

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to figure it out

shrewd otter
rigid smelt
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like i said tho, you are going in the right direction

hollow pelican
rigid smelt
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sin(x)=a for -1<=a<=1

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do you know the general solution to this equation?

shrewd otter
rigid smelt
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to figure out the solutions in the interval?

shrewd otter
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Right, but there are finitely many, it seems kind of redundant.

rigid smelt
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i mean you could also get two terminal angles and then add 2pi periods to it

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either way is fine

hollow pelican
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i am confuse

latent tundra
shrewd otter
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We can probably use the fact that sin and cos are injective on this interval.

latent tundra
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can know how to do this???

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can i

shrewd otter
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Calculate the surface area of everything but the slope and multiply by two.

latent tundra
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do i need to calculate the slant height???

rigid smelt
hollow pelican
rigid smelt
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yes

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well not exactly

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but yes

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a reference angle by which you can add the periods to, to get the solutions in the interval

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its inevitable whatever way you do it

hollow pelican
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but isnt my ref angle 0.3875

rigid smelt
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no....

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thats arcsin(1/sqrt(7))

hollow pelican
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ohh thats not the working for ref angle?

rigid smelt
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do you remember that sin(x) = a for -1<=a<=1 has two solutions?

hollow pelican
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yea

rigid smelt
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those two solutions are x=a and x=pi-a

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this is me not referring to the general solution btw

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for now just take them as your reference angle

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also next time, dont approximate your answer till the very end

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we'd like to have the least error in calculation

hollow pelican
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ok

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my 1st ans is still wrong

rigid smelt
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you are still not getting my point

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you are supposed to take the reference angle and add 2pi to them

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until you exceed 2pi

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the angles you get during the calculation that are in [0,2pi] are the accepted ones

vale wigeon
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good question

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what does this mysterious acronym stand for?

dark granite
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Iโ€™m not sure

vale wigeon
feral owl
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Anybody can solve this?

coral cosmos
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Woah mate, atleast some of these lol

feral owl
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send answers priv

coral cosmos
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1st) substitute 3 in place of x , if you get 0 then that function is divisible by (x-3)

shrewd otter
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Wait, hold on.

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Why should we send the answers privately?

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This is kinda sketchy.

feral owl
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Send it here

coral cosmos
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I can tell you how to do it, won't send the answer ๐Ÿ™‚

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You gotta try mate, otherwise you won't learn

shrewd otter
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This isn't an exam, is it?

coral cosmos
hollow swan
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isnt this just a) x = 5 and b) x = 6

vale wigeon
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yes

hollow swan
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bruh

coral cosmos
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I prefer you to not help him now, not being mean or something... it's for his own benefit

hollow swan
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most of the questions arent that hard

coral cosmos
hollow swan
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it was to say

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how tf do u not know the answers to those quesitons

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i mean not judging

coral cosmos
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Oh lmao, I get it now

hollow swan
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but... grade 11

coral cosmos
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Wait he isn't in grade 11

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Is he?

hollow swan
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i think that means grd 11 idk

coral cosmos
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Hmm but on the contradiction the questions are too easy

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I am in grade 11 myself

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and I used to get these questions in exams when I was in grade 8th ๐Ÿ˜…

hollow swan
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i j finished grade 9 and ik more than half of these

dry thunder
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yep

upper notch
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Can someone explain me derivatives of function in easy language?

vale wigeon
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how familiar are you with basic physics?

shrewd otter
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The derivative at a point (x, f(x)) is the rate of change of the function f at that point.

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Big number => function grows quickly.

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Small number => function grows slowly.

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Big negative number => function falls quickly

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Small negative number => function falls slowly.

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Zero => function does not change.

woeful pulsar
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the derivative is basically the best linear map that approximates the function input around x mapping to the output around f(x)

shrewd otter
woeful pulsar
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well this is pretty easy considering the context in multivariable calculus

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the op didn't mention if the function is a single variable function

plucky crow
# feral owl send answers priv

i can teach you how to complete these questions (long division), however i do not see what gain anyone gets if i do them for you

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if you wanna learn yourself what youll need to know is: factor theorem, remainder theorem, polynomial long division

wanton spoke
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are a and b parallel? what proofs can I input to justify my answer?

feral pier
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Yes they are both 180 degrees

wanton spoke
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is there, like, a proof for that? a theorem perhaps?

feral pier
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I forget what the angle is called

wanton spoke
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these proofs are the only ones that are given to us

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and I don't see anything that fits

feral pier
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We know it's 180-69 so it it 111

wanton spoke
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but that doesn't prove anything, does it?

feral pier
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It's basically the Converse Of The Alternate Angles Theorem

wanton spoke
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alternate what

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exterior?

feral pier
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Interior

wanton spoke
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what the

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no it isn't.

feral pier
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Both would work right

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You have four interior and exterior angles

wanton spoke
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but for it to be "alternate interior", both angles should not be adjacent, right?

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and they're not even.. interior angles.

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do you really know the topic

feral pier
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Ok

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I was wrong about the interior bit

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But they are parrrrl

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If the angles remain the same

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The lines will

wanton spoke
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wdym remains the same

feral pier
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Since we have the line intersecting the alternate angles then we know the angles are the same

wanton spoke
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yo not to be rude but

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the things you're saying,, doesn't make sense

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i mean, it's good that you're helping me but

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don't just answer to questions that you don't really know

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some kid might believe you immediately without asking for any reasons lol

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and that could result to confusions

wanton spoke
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i'll just post the image again so u don't have to scroll up.... someone answered and just made me confused lol

"are a and b parallel? what proofs can I input to justify my answer?"

glass lichen
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Not sure how you can reason stuff about line b without assuming b is parallel, since FCZ patterns require them to be parallel

wanton spoke
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hm

wanton spoke
glass lichen
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no they're clearly parallel.

wanton spoke
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why do you think they're parallel?

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i mean a might be 1 degree slanted towards right

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like, the main task is to determine whether they're parallel or not

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and we didn't tackle about FCZ patterns so that might.. not be it

glass lichen
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however like I said, FCZ stuff requires they be parallel

wanton spoke
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is it, like, the only way to prove that they're parallel? the FCZ stuff?

glass lichen
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Not sure, I only know FCZ patterns for angle congruence

wanton spoke
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hm

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oh wait.

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this satisfies one of the proofs now

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i used the vertical angle and alternate interior theorems

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what do you think

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since the two lines are intersected by a transversal, and the alternate interior angles are congruent, then they are parallel?? bc of Converse fo the Alternate Interior Angle Theorem??

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not sure lol idk what im doing

glass lichen
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no clue what alternate interior angles are

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but yes, those agree with FCZ

shrewd otter
wanton spoke
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oop- wait... that's true..

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hm

glass lichen
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Yeah, you cant deduce anything about b's relation to a from only knowing stuff about a

wanton spoke
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dlkfjdal it's an error maybe, i'll ask my teacher tom... im tired wanna sleep :()

shrewd otter
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That sounds like a good idea.

agile compass
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express x in terms of p, given the fact that p = ln(x), do the same for y

quaint trout
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Need to keep applying log rules

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Specifically there is one about products and one about powers

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Apply the product one first, then the power one

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What is I?

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Please send a picture of your steps

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It looks like you are assuming it's equal to 0. This is an expression you are simplifying. Not an equation.

upper notch
shrewd otter
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ln(1) is not 1.

quaint trout
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ln(1) - 13ln(x) - 16ln(y). Very good. But, where does the equals sign come from??

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Okay

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And you can simplify ln(1)

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Then you are done

neat merlin
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What is your favorite geometry channel on YouTube?

tame elm
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i tried looking at the answer but i dont understand it, can someone help?

woeful pulsar
tame elm
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oh, okay(?

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cause i tried solving by the rule of, if they are multiples of the same vector then i could find k but, uh, didnt work-

vale wigeon
tame elm
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i dont understand where the 5/8 comes from

vale wigeon
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it's to make the a components match up

coral cosmos
vale wigeon
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one of the vectors is a scalar multiple of the other

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@coral cosmos this does not answer linglingbee's question

coral cosmos
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oh

tame elm
vale wigeon
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no

coral cosmos
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Ok yes, two vectors are parallel means the vector 2 is some multiple of vector 1
so a1 + b1 = x(a1 + b1)
= xa1 + xb1

If you match components then
a / xa1 = b / xb1 = 1/x comes out to be constant

vale wigeon
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if you scale a vector by 5/8 you scale the whole vector by 5/8, not just one component

smoky relic
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8.795 - 2.485 : 35 = 8.724
Because We divide it first
Is that true?

smoky relic
coral cosmos
smoky relic
coral cosmos
coral cosmos
smoky relic
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I have 5 1/2 ๐ŸŽ and 6 3/4 ๐Ÿ
After few days 1/7 from both apple had Rotten
It's mean
5 1/2 + 6 3/4 - 1/7
Or โž— 1/7?

vale wigeon
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what do you want to find? how many apples have rotted, or how many apples didn't rot?

smoky relic
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Ohh
Sorry,How many Apples didn't rot?

vale wigeon
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then that'll be $\frac{6}{7} \times \left( 5 \frac{1}{2} + 6 \frac{3}{4} \right)$.

ocean sealBOT
smoky relic
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Wait
I Will write my answer

vale wigeon
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...is english not your native language, by the way? you sound like you're struggling.

smoky relic
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Yes, sorry ๐Ÿ™๐Ÿ˜‚

vale wigeon
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i know it's unlikely but it may be worth trying anyway: what is your native language?

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(if you don't want to answer, you don't have to)

smoky relic
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Indonesia

vale wigeon
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okay nevermind

smoky relic
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I want to fall in love with math and try to do some elementary school question and i have forgot a lot.
Then want to ask someone to ensure my answers

vale wigeon
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you want someone to check your answers?

smoky relic
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Yes

vale wigeon
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okay, post the problems and your answers here and people can check them

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if possible, you could upload a picture

smoky relic
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Is that okay?
thank you sm

vale wigeon
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yes, that's how this server works

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you post a problem, you show what you've done so far, and people check it to see if you made any mistakes, and point you in the right direction or highlight your mistakes (as appropriate)

smoky relic
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Awesome

covert berry
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$$f: \real \to \real$$
f is a continuous function. Find functions f such that:
$$f(xy) + f(x + y) = f(xy + x) + f(y)$$

woeful pulsar
ocean sealBOT
woeful pulsar
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substituting y with 1 might be useful for calculating f on integers

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can you perhaps find enough relations to calculate f on integers?

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like spam lots of small numbers to see if you can force a system of equations

covert berry
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But how will it help me on reals?

woeful pulsar
strong furnace
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displace to get f(x+y)-f(y)=f(x+xy)-f(xy) this should help probabl

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you can get a differential from here ()

covert berry
woeful pulsar
covert berry
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;-;

woeful pulsar
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though it's not symmetric hmm
so you might want to swap x and y and see what you get

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left hand side is symmetric but right isn't

strong furnace
strong furnace
woeful pulsar
alpine sable
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Why is part (c) not just the integral of x from 0 to 4?

woeful pulsar
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and it doesn't really make sense to integrate position

alpine sable
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I'm integrating position though

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Why not?

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Is there a way to do this without computing $\int_0^2 x' - \int_2^4 x'$?

ocean sealBOT
jaunty crane
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It wants me to draw straight line

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Any solution?

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I dont understand it

alpine sable
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For y>10?

jaunty crane
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Yea one of them

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Can u please show me

alpine sable
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I can

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For any value x, y will be anything greater than 10

jaunty crane
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I dont understand can you please draw one of it for me

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It says we need to draw straight line

alpine sable
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Shaded region is what y cannot be

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Anything above the line drawn is a good solution for y

jaunty crane
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Owhhh OK thank you

alpine sable
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So on the y axis is where you look

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y values above 10

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Shaded region is values below 10

jaunty crane
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Oh I understand can

alpine sable
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Makes sense? Do the next one and I will check for you

jaunty crane
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The question ask about straight line

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Should i just draw the straight line

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And should I color the part below y

alpine sable
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I dont know what convention you use

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An altenative way can be this

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The idea is to show the 10 is not included

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But all values above are

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However, I like the first way more. Because it shows that we can only look at the values above 10 regardless of x

jaunty crane
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Oh I understand now thank you so much

alpine sable
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Ultimately depends on what your professor says

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Yeah no problem :)

plucky crow
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counting from 19-30

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youre actually counting 31-19 terms right

alpine sable
#

A jumbo jet needs to reach a speed of 360 km/h (๔ฐ 224 mi/h) on the runway for takeoff. Assuming a constant acceleration and a runway 1.8 km (๔ฐ 1.1 mi) long, what minimum accel- eration from rest is required?

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Please check my working: The jet has at most 1.8/360 hours, so y'(1.8/360) = a_x * 1.8/360 = 360, and so a_x = 72000

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But the correct answer is supposed to be 36000, where would I need to divide by 2?

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I started with y''(t) = a_x, and so y'(t) = a_x t + y'(0), and y(t) = a_x t^2/2 + y'(0) t + y(0)

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So It should be right, but I am getting 72k, not 36k

floral jungle
dusk smelt
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ee

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ew

hazy dome
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By using a kinematic equation

alpine sable
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@hazy dome But that's what I am doing?

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I have y''(t) = a_x, and then I integrate to get y'(t)

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Since it is from rest, y'(0) = 0

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So we are left with y'(t) = a_x t

hazy dome
#

Try using (final velocity)^2=(initial velocity)^2 +2ad

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Idk where ur getting derivatives from

alpine sable
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What about my working though?

hazy dome
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But where did you get derivatives from?

alpine sable
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What do you mean?

hazy dome
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Your work above is just derivative stuff

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But it wonโ€™t help in answering the question

alpine sable
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How will it not? I am calculating the velocity at the last possible second

hazy dome
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Hmm

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Your method is confusing to me

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Try kinematic equations and see what you get

alpine sable
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Where did your formula come from

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Can you show me how to derive it?

hazy dome
alpine sable
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lol

hazy dome
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I donโ€™t have the ability to prove it, itโ€™s just a kinematic equation

alpine sable
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We're supposed to derive the equations we need to use

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Like I am doing above

hazy dome
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Hmm

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Well you kinda stated the elementary concepts of rectilinear motion above

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But that wonโ€™t lead you anywhere

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You said that the second derivative of the position function is acceleration, which is true, but doesnโ€™t help because we arenโ€™t given a position function

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We have enough info to use a kinematic equation though

alpine sable
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What do you mean?

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Our position function is y = a_x t^2/2

hazy dome
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Hmm

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Can you please send a pic of the original problem?

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I think that will clear things up

alpine sable
neat mesa
#

Hi, can someone please check my work??

glass lichen
hazy dome
alpine sable
hazy dome
alpine sable
#

What info do I lack?

hazy dome
#

You need to use physics

neat mesa
hazy dome
glass lichen
hazy dome
#

Positions at certain times

neat mesa
#

Alright thank uuu

alpine sable
#

It's at 0 at t = 0, and supposedly at 1.8 km at t = 1.8/360

hazy dome
#

You donโ€™t even know how long itโ€™s gonna take for the airplane to reach the end

alpine sable
#

Of course I do, it's 1.8/360

hazy dome
#

Thatโ€™s not true

alpine sable
#

And why not?

glass lichen
#

$x=1800m \ v_i = 0 \ v_f = 100m/s \ a=?$

ocean sealBOT
hazy dome
#

Look to the above

#

You HAVE to use physics

#

Thereโ€™s no other way

alpine sable
#

I am using physics lol.

glass lichen
#

so what kinematics equation are you using?

leaden lily
#

Hey guys I have a function that goes from R ---> R
how can I draw a non motonic function ?

alpine sable
#

@glass lichen You agree with me that y''(t) = a_x, right?

glass lichen
#

sure

alpine sable
#

So y'(t) (acceleration) = a_x t + y'(0)

#

But y'(0) = 0 since it is from rest

#

So we're left with y'(t) = a_x t

glass lichen
#

ok but how do you find the time?

hazy dome
#

Use one of these

#

These are kinematic equations

dusk smelt
#

time is relative, so just write down any answer

glass lichen
alpine sable
#

@glass lichen Why not 1.8/360 hours?

dusk smelt
#

it is

glass lichen
#

it's not since the speeds are well below .1c before relativisitc correction is even needed

hazy dome
glass lichen
#

anyway

alpine sable
dusk smelt
#

depends on the observer

glass lichen
dusk smelt
#

no u

hazy dome
#

We now know how long it takes the plane to reach the end

alpine sable
#

So now we just solve y'(1.8/360) = 360

hazy dome
#

But we donโ€™t even know y

alpine sable
#

Yes we do...

hazy dome
#

You canโ€™t derive something you donโ€™t even know

alpine sable
#

y'(t) = a_x t

#

What you're saying doesn't make sense

#

I start with acceleration and then I integrate to get velocity

#

I am deriving the velocity equation

hazy dome
#

Ok cool... but now what?

glass lichen
#

what n/c is correct, but it's not really using physics persay, just calculus

alpine sable
#

What do you mean now what???

#

It comes out to a_x = 72000

#

But the correct answer is 36000

#

I'm asking why

hazy dome
alpine sable
#

@hazy dome You can't derive your formula

hazy dome
#

Using kinematics, I got 2.7777777

alpine sable
#

You have to be able to derive it

glass lichen
#

You can derive it

hazy dome
#

M/s^2

alpine sable
#

@glass lichen I meant he can't

#

Not that it can't be derived, in general

glass lichen
#

ok, who gives a shit if he cant

hazy dome
#

Chill

alpine sable
hazy dome
#

I just know what they teach me

alpine sable
#

So I shouldn't be using something we haven't learned how to derive, just because I got it from Discord

hazy dome
#

Here letโ€™s think about this logically: if the acceleration is 72000, do you know how fast the plane would be moving???

alpine sable
#

Yes, twice as fast as it should be.

hazy dome
#

Because acceleration is the rate of change of velocity

alpine sable
#

So that's what I am asking, where do I need to divide by 2?

hazy dome
#

Weโ€™re gonna assume that this acceleration is in m/s^2, thatโ€™s WAYYYYY too fast for any airplane

dusk smelt
#

guys, everything is relative, theres no wrong answer here

alpine sable
#

@hazy dome You're wrong.

hazy dome
hazy dome
#

Via a pic

alpine sable
#

I already did, but I will do it again

dire pilot
#

would this be equal to 8f + 4g or do you not multiply the 2 by the 4 and 2

glass lichen
#

it isnt

alpine sable
#

$y'' = a_x \implies y' = a_x t + y'(0)$, however we know that $y'(0) = 0$ as it is from rest. So then $y'(t) = a_x t$, and we wish that $y'(1.8/360) = 360$ as that is the final velocity and the most amount of time we have, so $y'(1.8/360) = a_x \cdot 1.8/360 = 360 \implies a_x = 72000$

ocean sealBOT
hazy dome
#

Except itโ€™s actually 4fg

leaden lily
dire pilot
#

varibale

#

variable*

leaden lily
#

you multiply 4 by 2f and 2g by 2f

alpine sable
#

<@&286206848099549185> I wrote the original question like 20 minutes ago so I will ping now

glass lichen
#

where are you getting 1.8/360?

dire pilot
alpine sable
#

1.8 km/360 km/h

glass lichen
#

yeah but why are you doing that?

alpine sable
#

1.8 km is as far as we can go

glass lichen
#

yeah

alpine sable
#

Why wouldn't I do that?

dire pilot
#

are you sure tho because wouldnt you only multiply the number not the variable

alpine sable
#

We want the minimum acceleration

glass lichen
#

cause it's wrong

hazy dome
#

Iโ€™m telling you you gotta use physics

glass lichen
#

it means the vehicle is travelling at 360 for the whole 1.8

dire pilot
alpine sable
dire pilot
#

bro

hazy dome
#

THATS IT

leaden lily
#

@dire pilot replace the variable by a random number like 2 and it might make it clearer for you if you have real numbers instead of letters

dire pilot
#

๐Ÿ˜ญ

glass lichen
#

@leaden lily @dire pilot the channel is in use, stop posting

hazy dome
#

Thatโ€™s what I was forgetting

dire pilot
#

sorry

hazy dome
#

Ok @alpine sable so where you went wrong is by dividing 360 by 1.8. By doing that, you assume that the plane is traveling constantly at 360 km/h the whole time, but thatโ€™s not true at all. Itโ€™s accelerating, the speed is always increasing

glass lichen
#

IN USE

hazy dome
#

I appreciate your effort @alpine sable , but the only way to solve this problem is by physics

alpine sable
#

@alpine sable I got 2.78 m/s^2

hazy dome
alpine sable
#

You are both getting 36k

#

In km/h^2

#

Okay, so what should I do?

hazy dome
alpine sable
#

Yes, this is from the second chapter of a physics book

hazy dome
#

Perfect

#

So what you need to do is write down the givens and then consider the 3 kinematic equations

#

Only one of those equations will assist you in getting the correct answer

alpine sable
#

What 3 equations?

#

Position, acceleration and velocity?

hazy dome
#

No

alpine sable
#

Hello.

hazy dome
#

These 3

alpine sable
#

I don't know how to read those

hazy dome
#

I think your main issue is youโ€™re staying centered on Calculus

#

Which is fine, but it wonโ€™t always help

alpine sable
#

I've decided to create my own mathematical theory or mathematical model which will describe geometrical objects and nature. Is there anyone who'd be interested in this?

hazy dome
#

Ok here are the variables: vf is final velocity, vi is initial velocity, a is accel, d is distance, t is time

#

Also deal with SI units only, so that means meters, seconds, and meters per second

#

Otherwise you will get an incorrect answer

alpine sable
#

So v_f is just y'(t) = y'(0) + a_x t, like I was saying

#

And distance is simply y = y'(0)t + a_x t^2/2

#

Also like I was saying

hazy dome
#

Yea, but donโ€™t think about it through a Calculus lense

alpine sable
#

You're not making any sense

#

Where do you think they come from?

hazy dome
alpine sable
#

Anyway, the last equation we have not derived yet

hazy dome
#

Yes these problems are derived from Calculus but they need to be used algebraically

alpine sable
#

So we can't use it

hazy dome
#

Via direct substitution

smoky relic
#

Excuse me,
3 ร— 14/4
Am I could multiply immediately or Should i simplify it first ?

hazy dome
#

Simplify 14/4 then go from there

#

It makes the multiplication easier

alpine sable
#

So what you're saying is I could've used calculus this whole time

#

All I needed to do was solve for t

#

You saying not to use Calculus was entirely wrong...

hazy dome
#

Also to be a little more open-minded

alpine sable
#

What you are saying does not make sense

#

I was using the physics equations derived from calculus

hazy dome
#

Physics and Calculus overlap but there are problems that lie exclusively in their own fields

alpine sable
#

I was deriving them in front of you

hazy dome
alpine sable
#

I was deriving the acceleration, position and velocity equations

hazy dome
#

Look, why are we even arguing about this?

alpine sable
#

They cannot be different

hazy dome
#

What about you spend some more time in your physics class until you get to kinematics

#

So that you can learn it from an actual qualified individual instead of some stranger in Discord

alpine sable
#

I am reading about that, but we need to derive every equation we use

#

Instead of using a "physics reference table"

#

Like you told me to

hazy dome
#

Wait for a professional to introduce these topics

alpine sable
#

lol

#

We've been going over kinematics

#

But like I've said 20 times now, we can't use random formulas without showing their complete derivation

hazy dome
#

Try it out via direct substitution

alpine sable
#

My point is you kept saying not to use Calculus

#

Even though I solved the problem without any reference tables

hazy dome
alpine sable
#

The problem was I didn't realize I was assuming the velocity to be a constant 360 km/h

hazy dome
#

Because you assumed the speed was constant

alpine sable
#

Right, but that has nothing to do with calculus

#

Nor does it have anything to do with deriving formulas using calculus

#

Which is what you were arguing against doing

hazy dome
#

<@&286206848099549185> umm a little help please...

alpine sable
#

Anyway, it's simple to solve now: y'(t)/y''(t) = t, and so 1.8 = y'(t)^2/y''(t) * 1/2 implies y''(t) = 360^2/3.6 = 36000

#

km/h^2

lavish cypress
alpine sable
#

Notice how I didn't assume a single formula

#

I derived them all myself

#

This dude confusing

lavish cypress
#

You did assume a formula

alpine sable
lavish cypress
#

That v = d/dt x

alpine sable
#

No, that's how we're taught. If we define y(t) to be the position at time t

#

Then y'(t), is, by definition, the change in position at time t

alpine sable
lavish cypress
#

What

#

Why are you asking about another server in this one

alpine sable
#

good question

floral jungle
alpine sable
#

Check dms

hazy dome
#

That looks painful

floral jungle
#

yeahh ;-;

smoky relic
#

I mean, the answer will still same?

hazy dome
#

Yea

#

Because itโ€™s just multiplication and division

#

Theyโ€™re interchangeable in terms of order

smoky relic
#

Great,
Thank you!

hazy dome
#

Youโ€™re welcome!

still steeple
#

I finished everything in the practice test but i'm not sure what they are asking me to do in 1. b)

hazy dome
#

Basically substitute k into f(x) then do a little algebra

still steeple
#

what does it mean like -2f(k)

#

so is it -2(k^2-2k-9) = 2?

cobalt ledge
#

Write f as a function of k instead of x, and multiply the entire function by -2, then set it equal to 2

#

Yes

still steeple
#

oh ok

#

thank u

cobalt ledge
#

Np

alpine sable
#

How is the domain of this graph [0, inf)? what about at x = 3?

marble comet
#

it's bc it drops down

#

jump discontinuity

#

but u can see that at (3, 2) it has an open hole

#

but at (3, .5) it has a closed hole

#

indicating that the function drops from 3, 2 to 3, .5

#

so technically 3 is part of the domain

#

closed circle indicates it includes that point

#

and open circle means it doesn't

ancient creek
#

yeah g(x) is still defined at x = 3

gusty hinge
#

can anyone tell me how to proceed with this type question, I am new to probability

vale wigeon
#

@gusty hinge is this your first intro to formal probability theory, with formal arguments involving measures and all that fun stuff? or is this your first introduction to probability in general?

#

or to put this another way, have you taken any basic probability classes such as those which would have you compute probabilities for dice or card games?

gusty hinge
#

I know just very basic probabilty

lavish cypress
#

Interestingly enough I've seen this question like 3 times in the past couple of days thunk

gusty hinge
#

how we take example for p(Aintersectionb)=p(A).p(B)

vale wigeon
#

that's only true when A and B are independent...

gusty hinge
#

how to take such example

#

wouldn't it be just hint and try

vale wigeon
#

well you can start by drawing some pictures

#

both parts 1 and 2 have many different possible answers

#

so you can try making pictures to represent the sets you're choosing for your events

alpine sable
#

A worldโ€™s land speed record was set by Colonel John P. Stapp when, on March 19, 1954, he rode a rocket-propelled sled that moved down a track at 1020 km/h. He and the sled were brought to a stop in 1.4 s; see Fig. 2-28. What acceleration did he experience? Express your answer in terms of g (๔ฐ 9.8 m/s2), the acceleration due to gravity. (Note that his body acts as an accelerometer, not a speedometer.)

#

How do I find the acceleration he experienced?

#

I found that -202 m/s^2 is the acceleration of the sled (I think)

#

But how do I find his acceleration?

ionic jewel
#

so it's the same

alpine sable
#

But what does it mean to express in terms of g?

ionic jewel
#

g = 9.8m/s^2

#

2g = 2(9.8m/s^2)

#

divide your answer by 9.8 and slap a g on the end

alpine sable
#

oh Hahahahahahaha

ionic jewel
#

,calc 202/9.8

ocean sealBOT
#

Result:

20.612244897959
alpine sable
#

Lmao, okay thanks

ionic jewel
#

about -20.6g

vale ridge
#

can anyone help me with this question. Its
2x+5y=7
x-3y=-2
I have to like solve for y and x so I can get a coordinate. Thanks guys.

copper summit
#

x=3y-2 @vale ridge

#

now put in the first equation as x

neat mesa
#

Can someone help me w this?

#

Number 14

copper summit
#

,rotate

ocean sealBOT
copper summit
#

trigo

neat mesa
#

??

small galleon
#

what is 9+10

sleek elbow
neat mesa
queen wigeon
neat mesa
queen wigeon
neat mesa
queen wigeon
neat mesa
queen wigeon
#

np

trail hamlet
#

hello im trying to understand how to check if a specific matrix is in the span of other matrices

#

i have those 3 and im trying to see if the bottom M_1 is in the span of the other 3

#

i found a video that explained it slightly, i put the vectors side by side and did guassian elimination

#

im just trying to understand if this is what im supposed to do?

royal fulcrum
#

What does it mean to be in the span?

mossy geyser
#

for M_1 to be in the span it should be expressible as a linear combination of A, B, and C

#

so for each entry of M1 you have a three variable equation

#

three variables four equations

glass lichen
#

they got help already...

whole prairie
#

Can you simplify 2xy + 2 = 6y dy/dx -2x dy/dx?

mossy geyser
sudden crater
brisk tree
#

Can someone help?

whole prairie
#

RHS?

sudden crater
#

Right hand side

whole prairie
#

Gotcha

#

So how would I factor it out? Just divide by those two terms?

sudden crater
#

6ydy/dx -2xdy/dx=

dy/dx (6y-2x)

#

then now that you have it factored just divide by 6y-2x on both sides to get dy/dx isolated

whole prairie
#

So it would then be:dy/dx = 2xy+2/6y-2x?

lavish cypress
# brisk tree

Try applying ibp as well as the integral of the inverse theorem.

sudden crater
#

Does anyone know how to do 12?

thorn kindle
#

discriminant of a quartic

vale sapphire
#

... how about no?

#

i mean

#

i guess it's the only way, but if it really is that that's bullshit

lavish cypress
#

I guess you can also do it using calculus

#

Find the local maxima and minima, and then set k appropriately

brisk tree
#

For using Integral of inverse theorem I need to know the antiderivative of f

sudden crater
thorn kindle
#

or do polynomial division

sudden crater
sudden crater
random pelican
#

what is 2 times x, is it 3x or 2x?

sudden crater
#

5x

random pelican
thorn kindle
#

2*x = 2x

random pelican
thorn kindle
#

why would it be 3x lmao

sudden crater
#

itโ€™s very likely theyโ€™re trolling

random pelican
thorn kindle
#

go to a different channel i can help you in a bit

random pelican
#

ok

thorn kindle
lavish cypress
thorn kindle
#

yes

warped phoenix
#

$\frac{2x^2}{\sqrt[4]{5}}$

ocean sealBOT
#

TheMane3

warped phoenix
#

can someone help me figure out how I would get the radical out of the denominator?

thorn kindle
#

12x^3 + 12x^2 - 24x = 0

sudden crater
#

x(12x^2+12x-24)= 0

#

x=0, 1, -2

#

what to do then?

#

actually

#

then I should just find the maxima/minima

thorn kindle
#

yes

arctic wren
#

Which one is the correct derivative?

sudden crater
#

-5 is a minimum, 0 is a maximum,

#

-32 is also a minimum

#

@thorn kindle what would I do now?

lavish cypress
warped phoenix
#

@thorn kindle i was told to do something like this: $\frac{2x^2}{\sqrt[4]{5}}\cdot \frac{\sqrt[4]{5^3}}{\sqrt[4]{5^3}}$

ocean sealBOT
#

TheMane3

warped phoenix
#

im not sure why...or how that would work\

#

because if i cross cancel all it does is leave me with had i originally had, except the 5 is cubed

#

<@&286206848099549185>

#

?

undone dock
#

4throot(5) times 4throot(5)^3 = 4throot(5)^4

slow monolith
#

is thi lane open

alpine sable
#

asking a question rn lol

thorn kindle
#

0<k<5

rocky silo
#

Hey, a quick question. What if the end of pi were to be found. Would it be rational and would it change any complex operation, afaik people just use it up to the 20th digit.

nocturne mirage
#

it has been proven that pi is irrational

#

so you cant find any last non zero digit of pi

#

it's litteraly impossible

lavish cypress
warped phoenix
#

@nocturne mirage i mean regardless hes asking what if

#

in some alternate universe where it could be found, would it have any impacts like he asked

elfin snow
#

exact value means without decimals

#

it has stuff like pi and square roots and other constants

lavish cypress
#

The exact value of pi, as a real number.

elfin snow
#

essentially, no approximations/rounding

#

3.14 is an approximation of pi but ฯ€ is the exact value

#

0.142857... is an approx for 1/7 but 1/7 is the exact value

rocky silo
#

Ah I see

#

Thanks

warped phoenix
#

Can someone explain to me how $x^{\frac{1}{5}}y^{\frac{1}{5}}=\sqrt[5]{xy}$

ocean sealBOT
#

TheMane3

winter bay
#

What part don't you get?

#

@warped phoenix

warped phoenix
#

ik that $x^{\frac{1}{5}}=\sqrt[5]{x}$

ocean sealBOT
#

TheMane3

warped phoenix
#

but does the y in there not change anything?

#

like wouldnt the y also make it $\sqrt[25]{xy}$

ocean sealBOT
#

TheMane3

#

dackid (jump king +)

warped phoenix
#

ohhhhhhhh

#

i see

ocean sealBOT
#

dackid (jump king +)

warped phoenix
#

ahhhh

#

๐Ÿคฆโ€โ™‚๏ธ

coral pagoda
#

Happens to the best of us :)

winter bay
#

@warped phoenix it's kind of like how $n(x+y) = nx + ny$

ocean sealBOT
#

visual of Petter's ascendance

warped phoenix
#

riiiiiiiiight

#

i see now

#

yikes

#

i need to memorize these rules better

coral pagoda
#

I don't think this particular exponent rule is one of the typical ones you see when doing exponent laws.

#

So don't beat yourself up too much

warped phoenix
#

ah ok ty โค๏ธ catthumbsup

lofty terrace
#

How do I get started solving either the vector $\bar{a}$ or $\bar{b}$ from the equation $\bar{a}\cdot\bar{b}=|\bar{a}||\bar{b}|cos\theta$? I know both sides are equivalent as that's just a dot product, but if I only treat $\theta$ as the variable and solve for b, I'd expect two answers, but I can't get either of the vectors out of the dot product ๐Ÿ˜•

ocean sealBOT
#

jetp250

lofty terrace
#

Oops, that's small text

glass lichen
#

so you want to reconstruct a and b given the dot product?

lofty terrace
#

I have either a or b and want the other vector given the angle, the lengths of both vectors and the other vector

glass lichen
#

Ok so you can get a generic b vector using the other definition of dot product

#

then scale it up to be the correct length

#

since any vector on span(b) will give the same dot w/ a, you just need the one with correct norm

#

actually I think you can only know a plane of vectors, then get a circle as a subset of said plane

#

$b=\begin{bmatrix}x\y\z \end{bmatrix}\implies a\cdot b = a_xx+a_yy+a_zz$

ocean sealBOT
glass lichen
#

or whatever co-ordinate space you're working in

plucky crow
#

,w

#

bruh

#

,w solve

ocean sealBOT
glass lichen
#

you can use the website you know...

#

instead of spamming a help channel

lofty terrace
#

I'm doing this in 2D to keep it simple, but my initial attempt was to break down the vector into its components and solve for each dimension separately

glass lichen
#

ok so yeah, $a\cdot b=a_xx+a_yy$

ocean sealBOT
lofty terrace
#

that is an inadequate explanation, but I don't see why I have to re-scale it, and I'm not getting two results so it's probably not right to begin with

glass lichen
#

$a_xx+a_yy=\norm{a}\norm{b}\cos(t)$ is a linear equation, so you can get a vector whose span is the line

ocean sealBOT
lofty terrace
#

Seems like having actual linear algebra classes could be handy, I'm not even familiar with spans ๐Ÿ˜… Maybe I'll do some Googling on that and it seems like I could be able to solve it

glass lichen
#

span of a vector is the set of scalar multiples

lofty terrace
#

The equation is not hugely complex anyways and now that's a scalar form already

glass lichen
#

span of a set of vectors is the set of linear combinations of the vectors

lofty terrace
#

Yeah I'm hitting a total wall with terminology. It's better I look up all the terms and try again

plucky crow
#

can i post?

lofty terrace
#

Fine by me

plucky crow
#

,w solve (1/2)(n)(n+1)(n^2+n+1)=(100)(1/6)(n)(n+1)(2n+1)-(1/2)(n)(n+1)

plucky crow
#

why cant i cancel the factor of (1/2)(n)(n+1)

#

so im left with just a quadratic

#

if i do that then i get the bottom two solutions but not the top two

#

i was just wondering why i cant cancel the common factor

#

(as in divide both sides by it)

oak chasm
#

@plucky crow You can, but if you divide by something, going on past that assumes that what you divided by wasn't zero.

plucky crow
#

oh

oak chasm
#

So, you can divide by n and n + 1, but then you have three cases:

  • The case where those are divided out.
  • The case where n = 0.
  • The case where n + 1 = 0.
plucky crow
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so do i sub n = 0 and n = -1

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to find other solutions

oak chasm
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No.

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They're different, completely separate cases.

plucky crow
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oh

oak chasm
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You handle all three cases separately.

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You find all the solutions.

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You check whether each one makes the original equation true.

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Just because you divide by something doesn't necessarily make what you divided by equal to zero a solution to the original equation.

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That's why you have to check each solution.

plucky crow
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im a bit confused

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so what do i do with the information that n=0 or n+1 = 0

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to find a solution

oak chasm
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You solve those equations for n as well.

plucky crow
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what does check mean

oak chasm
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Then you check them in the original equation.

plucky crow
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oh so i sub n=0 in the originak

oak chasm
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Yes.

plucky crow
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and n=-1

oak chasm
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See if both sides end up equal.

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Also the two with radicals.

plucky crow
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well 0 it is yes

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yeahhh i think it may be easier instead of plugging the radicals into that massive eq

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to just

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not divide by those things

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lol

oak chasm
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Then you have to find the roots of a quartic.

plucky crow
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yep ill just factor

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lol

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ty for the help anyway

oak chasm
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You should be checking your solutions anyway.

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No problem.

wanton spoke
pulsar fractal
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if the first derivative of a function is abs(x), would 0 be considered a minimum

glass lichen
pulsar fractal
glass lichen
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you said the derivative is |x|

pulsar fractal
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yea

glass lichen
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|x|>=0 for all x in R

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since we use abs value to denote distance

pulsar fractal
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oh i see

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does a "sharp turn" on a derivative mean anything

glass lichen
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it means the 2nd derivative isnt defined there if it's a corner catshrug

pulsar fractal
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ok that makes sense

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thank you

worldly coyote
sleek elbow
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you need to bring all the w's to one side @worldly coyote

slender thorn
surreal merlin
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why do people still have school

arctic wren
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My book asks me to take the first 5 derivatives of f(x) = xยฒe^x and then find a formula for the derivative of number N of the above function. Here is my demo, is it correct?

alpine sable
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help please???

hazy dome
arctic wren
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A number X that divided by X+6 = 10/11, X/(X+6)= 10/11 -> 11x= 10x+60-> x=60

hazy dome
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Then go from there

arctic wren
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When you read try to write the equation as you are reading

alpine sable
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okay thanks

warped phoenix
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$y=\sqrt[3]{x-1}+7$

ocean sealBOT
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TheMane3

warped phoenix
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The domain would be all real numbers greater than 0, and the range is all real numbers

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for the above function

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right?

arctic wren
alpine sable
warped phoenix
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ah....

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right

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LOL

ocean sealBOT
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TheMane3

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TheMane3

warped phoenix
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if we were to graph these two, they would never intersect, right?

dusk smelt
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right

flat tundra
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I'm not sure if I got it right

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If one of the sides shown is head there are 3 possible cases
A) hh coin, it gives H
B) hh coin, it gives H
C) ht coin , it gives T

The probability of getting H is 2/3 = 66.66666...%. But I'm not familiar with calculating probabilities

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This conceptually makes sense , but I might be wrong

ionic jewel
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i vaguely think this is one of those ambiguous problems

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nah nvm i just ran out of brainpower today

flat tundra