#help-38

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dusty mist
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subbed values greater than 0 into here

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and none of the answers gave me 0 😦

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Ik that means they don't intersect, but I dont trust myself

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I feel like I messed up somewhere

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<@&286206848099549185>

split chasm
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shouldn't be subbing in integer values like that,
doesn't actually show whether there's a t that actually work

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just solve d = 0 and see if there are positive real solutions

dusty mist
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but the ship is changing directions at 8:30pm

split chasm
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i mean at the very end

dusty mist
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while the helicopter changes directions at 9:00

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huh

split chasm
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after you've got their positions at 9

dusty mist
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yep

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did I make mistakes?

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or is it fine

split chasm
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looks fine

dusty mist
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alr

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didnt work

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t has to be greater than 0

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That means they dont intersect

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I def messed up somewhere

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oh my god

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could this be it

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was theta supposed to be 90-16.26

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wait no

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<@&286206848099549185>

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here is the full question

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little egret
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how i do 10a?

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full dock
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bum chicken

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bum chickoen back on vectors again

little egret
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we are doing 3d now

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and im stuck on 2d

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😭

full dock
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U know i should be able to do this but i dont like geometry

full dock
little egret
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i had a methods test today

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it told me to evaluate 16e^9/9

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how

full dock
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evaluate it as in do what

little egret
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evaluate

full dock
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o

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use ur calculator

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ezpz

little egret
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non calc

full dock
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let e = 3

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ez

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thars how u do it as an engineer

iron pier
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it's probably (a+b)/2 lmao

simple panther
iron pier
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I forgot my basic geometry theorems

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but it looks like it'd be that πŸ’€

little egret
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thats right

iron pier
# little egret why>?

ok see that's the problem πŸ’€ i forgot whatever theorem could let me say such a thing

little egret
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1/2(a+b)

simple panther
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🧠 16e^9/9 = 16e^1 = 16e = 16Γ—2.7 = 43.2

little egret
simple panther
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πŸ˜‚πŸ˜‚

iron pier
little egret
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WHATS HEURISTIC

full dock
iron pier
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it'd hold true for a rectangle

full dock
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math monks guys

iron pier
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to be honest tho, maybe the question is asking you to prove this result yourself

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that'd be a lot more fun

iron pier
full dock
little egret
full dock
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the Trapezoid Midsegment Theorem

little egret
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I DID THIS LAST YEAR

simple panther
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You'll basically prove this theorem this way (hopefully)

little egret
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i remember finding AD and BC

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and BD

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i think

full dock
iron pier
little egret
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ohh i meant

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theres a way\ to do it wtihout the hteorem

iron pier
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...by proving the theorem and then using it πŸ’€

full dock
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we'll call it the bum chicken trapezoid theorem

iron pier
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beautiful name

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let's generalize it to n dimensional euclidean space

little egret
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.close

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wraith hinge
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i cant mental math this one

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wraith hinge
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is this correct?

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is there a trig identity counterpart for arcsin (u) ?

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@wraith hinge Has your question been resolved?

fair beacon
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you got the first term right

wraith hinge
fair beacon
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it should be 19 not 29

wraith hinge
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huh???

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how

fair beacon
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i can't tell where you went wrong because i don't understand anything you've written

wraith hinge
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my mouse handwriting is truly terrible 😭

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(8x-5)/sqrt(7+6x-x^2)

native shuttle
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Just send original

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Is that the original?

fair beacon
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8x-5 = A+B(-2x+6) = -2Bx + 6B + A

wraith hinge
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\int\frac{8x-5}{sqrt(7+6x-x^2}

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huh

native shuttle
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Put a $

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at the beginning and end

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edit it

wraith hinge
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$\int\frac{8x-5}{sqrt(7+6x-x^2}

native shuttle
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end

wraith hinge
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great it cant read mine

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$\int\frac{8x-5}{sqrt(7+6x-x^2}$

native shuttle
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u can edit message

fair beacon
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it's wrong anyways

native shuttle
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AT BOTH

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beginning and end

solid kilnBOT
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rivenrivers

fair beacon
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$\int\frac{8x-5}{\sqrt{7+6x-x^2}},dx$

native shuttle
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better

solid kilnBOT
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carburetor

fair beacon
wraith hinge
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i wonder where i failed my factoring

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OH

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MY

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GOODNESS

fair beacon
wraith hinge
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lksdfgoksdfg

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THANK YOU

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paper jay
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paper jay
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is this diagram correct ?

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also i think the answer is a) 110Β° (corresponding L)

b) 70Β° (interior angles)

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is that correct ?

obsidian zealot
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the diagram is correct

paper jay
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what about the answers of a and b

obsidian zealot
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for a we can analyse quadrilateral KLBC

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since KL || BC it's a trapezoid

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the interior angles add up to 360

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KLC = BKL

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if we let KBC = x, 220+2x=360

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x=70ΒΊ

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AKL is similar to ABC by AAA

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so its also 70 for b

paper jay
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what is the reason ?

obsidian zealot
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wdym

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for which parte

paper jay
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for both a and b cus i need to add a reason in my answer

obsidian zealot
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you can say this

by interior angles of trapezoid
220+2x=360
x=70

paper jay
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and what about for b?

obsidian zealot
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umm

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by similar triangles (AAA)

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although you could write the whole process if there's enough space

paper jay
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okok thanks

solid kilnBOT
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Couldn't find an attached image in the last 10 messages.

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knotty saffron
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find 2 numbers whose sum is a, if the product of the square of one by the cube of the other is to be a maximum

knotty saffron
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i'm having a hard time with the pattern of problems like these (applications of minima/maxima) can anyone help me out step by step?

obsidian zealot
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we first need an equation in one variable

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cal lthe numbers x and y

knotty saffron
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i got x+y = a
x^2y^3 = P

obsidian zealot
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ya

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can you make it in terms of x

knotty saffron
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x = a-y?

obsidian zealot
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like

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define P only using x

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sorry πŸ˜…

knotty saffron
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x^2(a-x)^3

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like that?

obsidian zealot
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yea

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then u find the maximum

knotty saffron
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i find the derivative of that, right?

obsidian zealot
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yeah

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then u equate it to 0

knotty saffron
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okay wait

obsidian zealot
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im waiting πŸ›‘

knotty saffron
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i got -3x^2(a-x)^2 + 2x(a-x)^3

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sorry i'm quite slow

obsidian zealot
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thats right

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now we factor to find the roots

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those will be the critical points

knotty saffron
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x(a-x)^2[-3x+2(a-x)]

obsidian zealot
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can u simplify the []s

knotty saffron
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x(a-x)^2(-5x+2a)

obsidian zealot
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yaaaaa

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so what r the roots

knotty saffron
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x=0
a-x=0 ; x=a
-5x+2a = 0 ; x=2a/5

obsidian zealot
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ya

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theres only one maximum do u know how to find it?

knotty saffron
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by finding the second derivative?

obsidian zealot
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noo

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thatll be way harder than necessary

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try plugging into the original P

knotty saffron
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108a^4/3125

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ah wait

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3a/5

obsidian zealot
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yess

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so whats y

knotty saffron
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i thought that was y

obsidian zealot
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oh

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yea

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i meant like plugging in the x=0/x=a to find that 0 and a are roots of P and thus can't be maxima

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the other one, 2a/5, is correct

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and you find (2a/5, 3a/5) ❀️

knotty saffron
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ohh okok

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thank you! is it alright to ask another question?

obsidian zealot
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ok

knotty saffron
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A rectangular field of given area is to be fenced off along the bank of a river. If no fence is needed along the river, what is the shape of the rectangle requiring the least amount of fencing?

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knotty saffron
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.close

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jaunty sparrow
#

I need to scale this shape down by a factor of 1/24. how should I do that? btw the bottom function says x=

jaunty sparrow
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hmm I should color code my functions

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ight idk if it made it easier to understand at all, but I colored each function the same as it's reflection

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as for the dotted line, I just ran out of colors so I made it dotted lol

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I guess it would save a lot of hassle if I never had to scale it down at all

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I could just scale the rest of the shape up instead (this is only a part of it)

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But idk what kinda implications that would have when I want to 3D print this shape

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jaunty sparrow
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Rip

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velvet bolt
#

🀣 i like this question

jaunty sparrow
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angerysad that makes one of us

naive crest
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you have an eq y = 8 {-66 <= x <= -56}
wouldn't y = 8/24 {-66/24 <= x <= -56/24} be the scaling down ?

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like y' = y/24 and x' = x/24

jaunty sparrow
naive crest
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your points are of the form (x, f(x)) {a <= x <= b}
so I'd say to replace by (x/24, f(x)/24) {a/24 <= x/24 <= b/24}
so (x, f(24x)/24), {a/24 <= x <= b/24}

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like your first eq should become y = (0.5714(24x+83)-77.143)/24 {66/24 <= x <= 73/24}

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etc

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jaunty sparrow
jaunty sparrow
#

er

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it would need to be x/24 = 78/24

naive crest
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you replace x = 78 by x = 78/24

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and you scale the limits of y

jaunty sparrow
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ight thanks that worked

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now I just need to figure out how to rotate this thing

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I'll ask that question when I am ready for it

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hardy rivet
#

tg 30 + tg 60

1 - tg 30 + tg 60

How i simplify this ??

zinc ginkgo
#

use tangent sum formula

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or plug in the special values for tan(30 deg) and tan(60 deg)

hardy rivet
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but how i simplify more than this ?

zinc ginkgo
#

it's not pretty, but you can rationalize the denominator by multiplying the top and bottom by the conjugate

hardy rivet
#

thx man

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austere matrix
#

how does pie actually work

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ionic pendant
#

given any circle, if its circumference is $C$ and its diameter is $D$, then $\pi$ (``pi'') is the ratio of its circumference to its diameter: [ \pi = \frac CD ]

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ionic pendant
#

it turns out that this ratio is the same for every circle

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austere matrix
#

oh ight

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solemn sleet
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solemn sleet
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can someone explain where to start with this

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im very lost

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i though i could just use trig to find the force on the ramp

nimble stone
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that is indeed how you do it

obsidian zealot
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yes

solemn sleet
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or projections but the answer is 12 and im getting 48

nimble stone
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how are you doing it?

solemn sleet
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so i thought sin(30) = 24/ramp

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ramp = 48N?

nimble stone
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got it a bit mixed

it would be sin(30)=ramp/24

solemn sleet
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but 24 isnt the hypotenuse

nimble stone
#

how did you draw your triangle then?

solemn sleet
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is that no what ur supposed to do

nimble stone
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when we are finding components we typically want the force to be the hypotenuse, because then the other sides are our perpendicular components

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in this case, perpedicular to the ramp and parallel to it

solemn sleet
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also

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the force always need to be the hypotenuse?

nimble stone
#

its because we are looking at the force parallel and perpendicular to the plane, when you draw the triangle as you did, youre taking the 24N to be a component of a larger force, in this case the 48N you calculated

solemn sleet
#

okay so how do i draw the triangle here

nimble stone
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pretty much this

solemn sleet
#

how did they get this

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or oh

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is that the end of the ramp?

nimble stone
#

eh

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that line is just representing the weight force

solemn sleet
#

ohhhh

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how do you know that its 30 degress tho

nimble stone
#

oops

solemn sleet
#

oh!!

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okay

#

thank you, that makes sense

#

:)

#

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bleak ridge
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rose inlet
# bleak ridge

ok so you have that region in the first quadrant under y = x^2 from x = 0 to x = 1

bleak ridge
#

yes

rose inlet
#

for each slice of this solid, perpendicular to the x axis, the cross section is a quarter circle

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the radius of that quarter circle is just the distance from the x axis up to y = x^2

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which is?

bleak ridge
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distance from where

rose inlet
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how far the curve is from the x axis

bleak ridge
#

like at 0 it would be x=0 it would be 0 and at x=1 it would be 1?

rose inlet
#

it would not be one

bleak ridge
#

oh

rose inlet
#

since the curve is y = x^2, the vertical distance from the x axis to that curve is just x^2

bleak ridge
#

okay

rose inlet
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so the radius of each quarter circle is x^2

bleak ridge
#

okok

#

so

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the equation of a semicircle is

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1/4 pi r^2

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so i get

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1/4 pi x^4

rose inlet
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exactly

bleak ridge
#

and then i integrate that?

rose inlet
#

!!!

bleak ridge
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okay awesome thank you

rose inlet
#

and then you need to integrate from x = 0 to 1

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np

bleak ridge
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im just a little confused why

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its so different than doing like

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a semi circle

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like i usually just use the pi / 8 formula for that right

rose inlet
#

yea for semi circle its pi /8

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but since we're dealing w quarter

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its pi/4

bleak ridge
#

so would it not just be pi / 16 for quarter

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how does it become bigger

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oh ig i see

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bc if the radius is on it then it would be larger vs the whole diameter

rose inlet
#

exactly if ur working with the radius

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the numbers r usually bigger cuz the diamater is twice the radius

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once u sqare it that factor of 4 comes in

bleak ridge
#

tysm

rose inlet
#

np

bleak ridge
#

so i can just use the pi/4 formula if this comes up again right

#

quarter circles

rose inlet
#

yes ofc as long as u have quarter circles

bleak ridge
#

cool

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crimson thunder
#

how would one go about this

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west sleet
#

Or do polynomial long division

crimson thunder
west sleet
#

Alright then comparing coefficients it is

crimson thunder
#

wait i kinda need to do long division for my test ;-;

west sleet
#

Alright alright

crimson thunder
#

does comparing coefficients work for everything?

crimson thunder
west sleet
#

Uh I mean yea but

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Sometimes a bit long

crimson thunder
#

ohh ok

west sleet
#

Actually depends but anyway

crimson thunder
#

yea this is all i got ;-;

west sleet
#

Just remember to distribute the negative

crimson thunder
west sleet
#

So -27x^6+216x^3

crimson thunder
#

ohhh!!

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but like how do i subtract 216x^3 from 0x^5

west sleet
crimson thunder
#

OH SO WE ADD

west sleet
#

Yea

crimson thunder
#

do i pull down the 0x^4?

west sleet
#

And uh we can just add it to the x^3 part of the polynomial

crimson thunder
#

or do i add it it -217x^3?

west sleet
crimson thunder
#

alr! so -x^3?

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and we bring down the positive 8

west sleet
#

Ye

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Alright I gtg

#

But u got it

crimson thunder
#

oh alr!

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tyty!!

#

.close

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β€’ After 15 minutes, feel free to ping <@&286206848099549185>.
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marsh rapids
#

I’m confused on turning logarithms into exponential equations and so forth, can someone help me? Specifically this problem!!

quick tusk
#

e^ln(x) = x

marsh rapids
#

Huh

quick tusk
#

ln(x-3) = 4

#

You can eliminate the ln by exponentiating both sides

#

since e^ln(x-3) = (x-3)

marsh rapids
#

So I divide by -6?

#

On both sides

quick tusk
marsh rapids
#

And then do I put it back in exponential form?

quick tusk
#

dividing both sides by -6 gives you ln(x-3) = 4, right?

marsh rapids
#

Yeah

quick tusk
#

Presumably you're trying to solve for x?

marsh rapids
#

Yeah

quick tusk
#

You wan't to eliminate the ln. You can do so by raising both sides to the power of e, euler's number

marsh rapids
#

Do I switch it to e^4 = x-3

quick tusk
#

yeah, because when you take e^ln(something), the e and ln cancel each other out, leaving (something)

marsh rapids
#

And then I solve for x from there?

quick tusk
#

yes

marsh rapids
#

Ok thank you!

#

Ok I have one more question i need help on (e is tripping me up):

high patio
marsh rapids
#

And then put it into logarithmic form?

high patio
#

Yeah log both sides

marsh rapids
#

Ok is this right?

#

I’m not very good at math

quick tusk
#

no. don't forget, ln and e cancel each other out

marsh rapids
#

…huh

#

So is it: n-7 = log 335

knotty locust
#

Why did you write ln on one side and log on the other

marsh rapids
#

I don’t know

knotty locust
#

I.e ln

marsh rapids
#

I’m confused and literally on the verge of tears dude

knotty locust
#

Well that’s rather dramatic

#

What are your pronouns

high patio
high patio
knotty locust
marsh rapids
knotty locust
#

Let’s see if we can’t clear this doubt then it

#

e^(n-7) = 335

#

Is clearly fine right

#

Okay

#

Whatever we do now we want to preserve this equality

#

We want to do the same thing to both sides

#

Does that general idea make sense it?

marsh rapids
#

So would it be: n-7 = ln 335?

knotty locust
marsh rapids
#

…I don’t know

knotty locust
#

Okay so why do you think that equation is true

marsh rapids
#

I don’t know

knotty locust
#

Ok

#

So let’s not randomly ghess

#

Guess*

#

e^(n-7) = 335

marsh rapids
#

Sorry

knotty locust
#

This is where we are it

#

What can we do to this equation

#

To both sides

#

At the same time

#

We can multiply, divide, add, subtract, etc… aslong as we do the same thing to both sides

#

Obviously the power of e is messing us up yes?

#

So it’d be nice if we could do something to both sides that would get rid of that

#

What do you think we should do

marsh rapids
#

ln??

knotty locust
#

Yes we should take log base e (ln) of both sides

#

Then what is the equation

marsh rapids
#

Uh

#

n-7 = ln335

#

???

knotty locust
#

Yes

#

Great

#

Now what

#

It

marsh rapids
#

…Put ln335 in my graphing calculator

knotty locust
#

No

#

We want to solve for n

marsh rapids
#

…but then I’d find what n-7 is and could just add 7 to both sides and I’d have n

knotty locust
#

Yes

#

The calculator is also unnecessary here

#

It’s clearly ~5.8

marsh rapids
#

…

#

Ok

#

I’m just dumb

#

Do I solve for n after that

knotty locust
#

add 7

#

To get n

#

Like you said they

marsh rapids
#

How did you get -5.8? Calculator says positive 5.8

knotty locust
#

~

#

Is not -

marsh rapids
#

Huh

knotty locust
#

It means approximately

marsh rapids
#

Oh I can’t read very well

knotty locust
#

It’s squiggly

marsh rapids
#

Sorry

knotty locust
#

That’s okay it

marsh rapids
#

…do you have to say my pronouns like that…just call me dude or bro…

#

Or man…

#

Any work

knotty locust
#

Well I wasn’t sure

#

What you wanted because you say ask and I asked and you didn’t clarify

#

Idk how to use

#

Yours

#

My apologies dude

marsh rapids
#

It’s fine

#

So would n roughly equal 12.8

knotty locust
#

Yes

marsh rapids
#

Ok cool

#

Thanks

knotty locust
#

Np

marsh rapids
#

.close

trim joltBOT
#
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#
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dapper oxide
#

is (x, 0, 0) where x is varying, the x-axis? or is it just a point where x can be anything

orchid wagon
#

the locus of (x, 0, 0) when x varies over R is the x-axis

#

otherwise, (x, 0, 0) is just a point on the x-axis

dapper oxide
#

even though x is varying

trim joltBOT
#

@dapper oxide Has your question been resolved?

trim joltBOT
#

@dapper oxide Has your question been resolved?

gilded pulsar
dapper oxide
#

How would u graph (x, 0, 0) when x is varying but (x, 0, 0) is not the set of all points?

trim joltBOT
#

@dapper oxide Has your question been resolved?

simple panther
dapper oxide
#

So is it just a point or the x axis?

How would I graph x=1 OR x=1.1 OR x=1.2

simple panther
#

Depends

#

If they mention that it's a point or they said x is fixed (or anything similar), then it's a point

#

If they mention that x is a parameter or ask you the locus of that point, it would be the x axis

#

Graphing x = 1 or the point at x = 1?

dapper oxide
#

I wanna graph (x,0,0) at x = 1 OR x=1.1.

simple panther
#

Then it's just a point whose x is 1 OR 1.1, y is 0 and z is 0

dapper oxide
#

Not at x=1 AND x=1.1

simple panther
#

Then?

#

Both together?

dapper oxide
#

Yes not together

simple panther
#

??

dapper oxide
simple panther
#

Yes

#

From - infinity to + infinity

#

That would be the x axis

dapper oxide
#

What if I wanna graph x=1 OR x=2 OR x=3, not AND

simple panther
#

-_-

#

It's just multiple points

dapper oxide
#

Would that also be the x axis

simple panther
#

Yeah, but they won't be together in the same graph

#

If it's or,

#

Then it's either 1 or 2

#

Not both together

#

So it's either this or that

#

If it is togethers then we would get the x axis

dapper oxide
#

How would u plot it?

#

One graph for x=1 and another for x=2?

simple panther
#

Yes

trim joltBOT
#
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#
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β€’ Be polite and have a nice day!

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signal sundial
#

If A is an infinite set, are we allowed to define |P(A)| and treat it as a real number? I have seen some prooofs just say that $|P(A)| = 2^\kappa$ where $|A| = \kappa$

solid kilnBOT
simple panther
solid kilnBOT
signal sundial
#

I think for powersets its 2^|A|

#

but usually those are for finite sets

somber ginkgo
signal sundial
#

so im not sure if u can do it for infinite sets

simple panther
somber ginkgo
simple panther
#

By considering kappa is infinite, I think you can

marble wharf
#

the expression 2^kappa is just defined to be the cardinality of P(A). its not actually exponentiation in the sense of like repeated multiplication or via taylor series or something

signal sundial
somber ginkgo
#

but here you shouldn't be thinking about them like normal numbers

signal sundial
#

Do you think i could find a bijection

somber ginkgo
#

write down relevant bijections/injections/surjections to show that |P(A) x P(A)| = |P(A)|

#

i gather this is for like an introductory uni course rather than a logic&sets course right?

signal sundial
#

yeah its like all encompassing proofs

#

sets fxns proofs logic counting etc.

somber ginkgo
#

if this were say a set theory course then it's possible to do cardinal arithmetic to show that the sets have the same cardinalities

#

(also remark - the assumption |A x A| = |A| is technically vacous cus it's always true lol)

signal sundial
#

wait are u sure?

#

cuz i mean just comparing element in a

#

u already have |A|

#

like (1,a0),(1,a1),...(1,an)

#

then that will already be |A| elements

somber ginkgo
signal sundial
#

ahh right

#

yes

#

youre right

#

i gues they give it as like a property

somber ginkgo
#

ofc it's not true for finite sets, but i.e. N x N has the same cardinality as N, R x R has the same cardinality as R etc.

signal sundial
#

that we should use?

somber ginkgo
signal sundial
#

Im a lil behind on lectures, but i think we went into sets/functions a fair amount

#

I think they would be fine with cardinal arithmetic to prove this

somber ginkgo
#

as in they gave you the assumption that |A x A| = |A| so you should probably use it

#

but i just wanted to remark that actually if you do more maths in later years @ uni, then turns out this property is always true lol

signal sundial
#

isnt it like u can just find a bijection for A x A and A if they are countably infintie?

marble wharf
#

(isnt |AxA|=|A| assuming aoc or something?)

somber ginkgo
marble wharf
#

(but not all logicians do)

signal sundial
#

Considering Im a first year 5 weeks into this course, do yuo think I should find a bijection or just use cardinal arithmetic without fuilly justifying every step?

marble wharf
#

bijection

signal sundial
#

Just asking because idk if it would be hard to find a bijection

marble wharf
#

cardinal arithmetic is proved by finding bijections anyway

signal sundial
#

alright thankls :)\

somber ginkgo
signal sundial
#

ohhhh okay

#

but thats like proven through bijection

somber ginkgo
signal sundial
#

any ideas on where too start with bijection?

somber ginkgo
signal sundial
trim joltBOT
#

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#
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#
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regal flint
#

There are two boxes containing marbles of the same size and mass. The first box contains 5 red marbles and 5 green marbles, the second box contains 6 red marbles and 4 green marbles. Randomly take one marble from the first box and transfer it to the second box, then randomly take one marble from the second box (assuming the marble taken from the second box is red). Calculate the probability that the red marble is from the first box.

cedar flower
#

!status

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

1

marble karma
#

Alr

#

so

#

whats the probability the marble is red

#

from the first box

#

lets start here

regal flint
#

sorry im thinking a little bit

marble karma
#

5 red 5 green

regal flint
#

P(get red from box 2) = 5/10 * 7/11 + 5/10 * 6/11 = 13/22
P(get red from box and its origin is box 1) = 5/10 * 1/11 = 1/22
=> P(the marble is from box 1 assuming that it is red) = 1/22 : 13/22 = 1/13

#

Is it correct?

marble karma
#

no

regal flint
#

why?

#

@cedar flower help please

#

@marble karma please explain why it is incorrect

#

guys

cedar flower
#

P(a red marble is taken from the second box that originally in box 1 | the marble taken is red) = P(a red marble is taken from the second box that originally in box 1 AND the marble taken is red) / P(the marble taken is red)

#

yes, I think you are correct

#

if you can go "oh the actual solution is 1/4" then we can work out where we went wrong - but I don't see a problem w/it

trim joltBOT
#

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trim joltBOT
#
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Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

sudden seal
#

How does one check if a vector is parallell with a plane?

The task is as following:

A plane has a normal vector n = [3,2,-1]. Furthermore, a point P(-2, 1, 0) is inside the plane.

a) Find an equation for plane alfa.

I did this by using Ax+Bx+Cx = 0, and came to the following 3x+2y-z+4 = 0

b) Find the coordinates that cross with the plane and y axis.

(0, a, 0)

Set in values in the equation and solve for a

(0, -2, 0)

c) Research if vector [1,1,5] is parallell with the plane.

How do you start with this?

cedar flower
#

a vector that is parallel with a plane will be perpendicular to the normal vector

sudden seal
#

Alright, so I have to see if v * n = 0?

cedar flower
#

aye

sudden seal
#

where v is the vector and n is the normal vector

#

Alright great, thanks :)!

#

.close

trim joltBOT
#
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#
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paper jay
#

hi is this correct ?

trim joltBOT
undone gorge
#

Take triangle OTU

#

OU=OT (radius)

#

So it is an isosceles triangle

#

Now angle TOU=180-angle TOP

#

Now TOP = 64Β°

paper jay
#

so 116

undone gorge
#

So TOU = 180-64= 116Β° (UOP) is a straight line

undone gorge
#

Now in isosceles triangle base angles are equal (let's say x)

paper jay
#

so 180-116 divided by 2

#

?

undone gorge
#

So 2x+116=180

#

Sorry I was wrong 😭

obsidian zealot
#

you can just use inscribed angle theorem lol

#

32=64/2

paper jay
#

but is mine correct ?

obsidian zealot
#

yes

paper jay
#

even the reasoning?

undone gorge
obsidian zealot
#

yes

#

I haven’t checked d tho

paper jay
#

it’s ok thanks

obsidian zealot
#

yea I think it’s all correct?

paper jay
#

thank you

trim joltBOT
#

@paper jay Has your question been resolved?

#
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rich heart
#

I am currenttly on question 2 so sorry for not answering before, if anybody can help it would be hreat

obsidian zealot
#

what do the angle numbers here mean?

rich heart
#

just the angles

#

I am not sure

obsidian zealot
#

also fyi some of the questions are cut off lol

#

hmm it doesn’t denote congruency……….

rich heart
#

oh mb

#

qurstionm 3.2.2

#

question

#

I have no idea what to do

obsidian zealot
#

ok let’s just talk in terms of C123 and T2

#

bc that’s what’s on the diagram

#

we know C1 + C2 = 90

rich heart
#

yes

#

c1 tan chord with A

#

and thats it I think

obsidian zealot
#

have you proven 3.2.3?

rich heart
#

no

obsidian zealot
#

oh bc you need to prove this lmao

rich heart
#

how do I do this

#

I dont see an resemblance

obsidian zealot
#

is COT isosceles?

rich heart
#

doesnt say

obsidian zealot
#

ok let’s just state all the lines

#

C1 + C2 + C3 + C4 = 180

#

T2 + T3 = 180

#

T1 + T2 = 180

#

C1 + C2 = 90

#

so C3 + C4 = 90

#

and T1 = T3

rich heart
#

yes

obsidian zealot
#

COK and COS are right

#

is ABC right?

#

oh it is

rich heart
#

i think so

obsidian zealot
#

C2 + C3 = 90

rich heart
#

im gonna be honest

#

I think im just gonna give up on this

obsidian zealot
#

C1 = C3 and C2 = C4 then

#

this is rly fun tbh

rich heart
#

im sorry man

#

im just no good at math

#

.close

trim joltBOT
#
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#
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crisp wolf
#

(Integral calculus) I have been trying to solve this for a while now, i tried using some substitutions but i always get 2 variables. I want to know what am i doing wrong or what should i consider doing instead

trim joltBOT
#

@crisp wolf Has your question been resolved?

crisp wolf
#

<@&286206848099549185>

obsidian zealot
#

unless you fix one of the sides, you will always have two variables

trim joltBOT
#

@crisp wolf Has your question been resolved?

crisp wolf
#

.close

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bronze jetty
#

Anyone help to find f(theta) please , i am unable to get a series for cancellations

bronze jetty
#

<@&286206848099549185>

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# bronze jetty <@&286206848099549185>

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sacred jackal
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#

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bright seal
#

5+5-5Γ·5 ???

trim joltBOT
clear cloud
#

Idk but <@&268886789983436800> do know

bright seal
#

Why?

#

Is the answer 1?

knotty oriole
#

Don't post troll problems here.

#

Use a calculator.

#

.close

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#
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bright seal
#

Why is it troll?

trim joltBOT
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glad patio
trim joltBOT
glad patio
#

im not sure

#

how to do this

#

this is question b)

dusky thunder
#

the surface area is the sum of individual areas of each side

glad patio
#

yes

dusky thunder
#

did you manage to express h in terms of x?

glad patio
#

oh do i just replace h with that

dusky thunder
#

yeah

glad patio
#

this doesnt seem right

dusky thunder
# glad patio

here ur second line, u make it 2(2xh) = 4x2h which doesnt make sense. write it as 4xh. even for the first term, write it as 2xh rather than 2x2h

trim joltBOT
#

@glad patio Has your question been resolved?

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hoary idol
#

How I finish solving this

trim joltBOT
zinc ginkgo
solid kilnBOT
#

riemann

gusty bone
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@hoary idol Has your question been resolved?

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silver sandal
#

can someone tell me where it went wrong?

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#

@silver sandal Has your question been resolved?

silver sandal
#

<@&286206848099549185>

silver sandal
#

ahhh..

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ok new approach

#

rip.

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yeah the questions wrong

#

.close

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limpid siren
#

Find the numbers of factors of n if n = a^x * b^y

round imp
#

Hello

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Any other information

queen burrow
#

there's a simple formula for this

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assuming a and b are primes

limpid siren
#

Yes, a and b are primes

queen burrow
#

the answer would be (x+1)(y+1)

round imp
#

Ah

queen burrow
#

basic combinatorics

round imp
queen burrow
#

lol

round imp
#

!nosols

trim joltBOT
#

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

queen burrow
#

sorry

round imp
#

Aiyo

queen burrow
#

so if you think logically

round imp
#

Anyway try to find an intuitive reason

#

Why is (x+1)(y+1)

queen burrow
#

you can have 1,a,a^2,.... as the factors

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upto a^x

round imp
#

Think of the conditions of p if p|n

queen burrow
#

and similarly 1,b,b^2...b^y

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for each factor you need to find a combination

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there are x+1 choices for a or it's power appearing in the factor,

#

and y+1 for b

round imp
#

Let him think ._. but okay

limpid siren
#

All factors of n can be listed as follows:
(a, a^2, a^3, a^4,....................., a^x) + (b, b^2, b^3,............................, b^y) - [x + y factors]

(ab, ab^2, ab^3, ab^4,..................., ab^y) - [y factors]
(a^2b, a^2b^2, a^2b^3,...................., a^2b^y) - [y factors]
........................ - x columns in total
(a^x * b, a^x b^2, a^x b^3,..........................., a^x b^y) - [y facotrs]

These are all the factors. Counting the number of factors we get:
(x + y) + (y * x)

round imp
#

+1 for 1

limpid siren
#

But the number of factors should be (x+1)(y+1)

round imp
#

1 is a factor

limpid siren
#

Of course

round imp
#

Ah yes

limpid siren
#

I was missing the 1.

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Thanks

round imp
#

Np

limpid siren
#

.close

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dusty mist
#

"a helicopter leaves point (24,12) while travelling at 25km/h in the direction of 343.74 true bearing. What is the position vector and velocity vector of this moving object?"

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#

@dusty mist Has your question been resolved?

dusty mist
#

<@&286206848099549185> \

#

am I mutted πŸ‘…

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#

@dusty mist Has your question been resolved?

devout yew
dusty mist
#

would the velocity vector be [-24,7]

devout yew
#

I didn't do the calculation but I'd be surprised if you such a clean answer, what was your method?

dusty mist
#

uh

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would it be alright if I could give you the background to the question

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its a bit of a read

devout yew
#

yeah, go on

dusty mist
#

the question I asked was a simplified version of question 14

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here was my calculations for the velocity vector and position vector for the helicopters motion at 9pm using the 16.26 true bearing

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so my first approach was to substitute the theta value with the new 343.74 true bearing

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but then I got confused

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so I ended up with this

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which I hope I got correct

devout yew
devout yew
# dusty mist so I ended up with this

this is nice because it shows you really thought about the question instead of just plugging in the values to the position vector formula, which would give you the same answer just without the added satisfaction

dusty mist
#

wait I think I got the values messed up

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hold on

devout yew
#

I assume you mean the cosine and sine values right?

dusty mist
#

no like the actual x and y components

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the blue was supposed to be 24

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and the 7 was supposed to be -7 and 7

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hence the changed signsd

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😭

devout yew
#

ahh the classic sign mixup, nw mate

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#
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#
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native shuttle
#

What do I do after f'(x)

trim lichen
#

post the rest of the question

native shuttle
#

Oh just check for 1-1 and onto

solid plank
#

Why are you derivating it then?

native shuttle
#

To find 1-1

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Since if we do f(x1)=f(x2) we can't find

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So we need to do f'(x)

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And show it's strictly increasing/decreasing

solid plank
#

Oh okay you could do that too yeah

native shuttle
#

But idk what to do after f'(x)

solid plank
#

So equate f'(x) =0

native shuttle
#

hmm ok

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I am getting (11x^2-30x-20)/(7x^2+2x+10)^2

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For f'(x)

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So if f'(x)=0 I need to equate $11x^2-30x-20=0$

solid kilnBOT
#

devthemasked

solid plank
#

Yeah

native shuttle
#

So x=30+-root20/22

solid plank
#

And you're also have to make sure that $(7x^2+2x+10)^2=0$ won't have any variable satisfying it

solid kilnBOT
native shuttle
#

It cannot be 0

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Or f'(x) undefined

solid plank
#

Yeah that's why you have to make sure

trim lichen
#

what a crunchy question...

native shuttle
#

wdym by crunchy

solid plank
native shuttle
#

The solution is something else

trim lichen
native shuttle
#

Should I send that

trim lichen
#

but i can note the denominator has negative discriminant and so is always strictly positive

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and by the looks of it, the same is true of the numerator

solid plank
trim lichen
#

so no matter what x is, f(x) will be positive

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so just from this alone

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no hope for onto-ness

native shuttle
#

Wait why no onto

solid plank
trim lichen
solid plank
#

😭😭

trim lichen
#

what

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what's wrong

solid plank
#

nothing

native shuttle
#

Did you find discriminant of numerator and denominator

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of f(x)

solid plank
#

it would be negative, yeah

trim lichen
solid plank
trim lichen
native shuttle
#

Ok so if discriminant is negative the quadratic is positive

willow urchin
trim lichen
#

1 - 4Γ—2Γ—5 and 4 - 4Γ—7Γ—10...

native shuttle
#

yea'

trim lichen
trim lichen
#

whether it's positive or negative, you tell by the sign of a or c (which have to match)

native shuttle
#

ok

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ok so codomain is R

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and range is +R

trim lichen
#

no

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i didn't say what the range is

willow urchin
#

we dont know range = R^+, all we know is range is contained in R^+

trim lichen
#

i didnt claim the range is (0, +infty) -- and it isn't.

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what matters is that the range isn't R.

native shuttle
#

Oh

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So basically range cannot be -R

solid plank
#

you can say that the range would be a subset of R+

solid plank
native shuttle
#

ok

trim lichen
native shuttle
#

so not onto

willow urchin
#

-R is an abuse of notation

solid plank
#

frfr

willow urchin
#

just say the range cant include negative numbers

native shuttle
#

kk

#

Now how to check 1-1

solid plank
#

Can we adjust the numerator or denominator

#

I think that might make it simpler

native shuttle
#

how

solid plank
#

Nah we'll have to differentiate

native shuttle
#

yep

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I did that

#

I found roots of f'(x)

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Then what

solid plank
#

but I think you did something wrong there

#

if there are some roots for f'(x), that means it won't be strictly increasing/decreasing

native shuttle
solid plank
#

There are no real roots if D<0

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So yeah

native shuttle
#

Yea I got roots

solid plank
#

Uhh I got f'(x)= $(11x^2-30x-20)/(7x^2+2x+10)^2$

solid kilnBOT
native shuttle
#

So I saw at those particular roots the value of f'(x)=0 hence it will not be strictly increasing/decreasing

native shuttle
trim lichen
solid kilnBOT
solid plank
#

yeah thanks

native shuttle
#

-20

native shuttle
#

hmm k

#

see the answer

trim lichen
solid plank
#

It's says that function is increasing or decreasing in intervals

trim lichen
#

so they just say the derivative isn't sign-constant

solid plank
#

IT LITERALLY SAYS THAT IT IS MANY ONE FUNCTION😭😭

#

that means it is not one one

native shuttle
#

Yea I know

#

But the solution I got is also correct right?