#help-33

1 messages · Page 89 of 1

brazen jungle
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??

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what is this

jagged relic
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The first one

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You should post the whole question

ebon depot
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If I choose the first one then I’d have first 5 choices, then 4 and finally 3

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543= 60 choices

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But that does not include all possible combinations of the other letters

jagged relic
ebon depot
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How????

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I have three As
A1,A2 and A3

jagged relic
ebon depot
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Why is it different every time

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Why can’t it just be simple

jagged relic
ebon depot
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I get that

jagged relic
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That's the reason permutations and combinations are different

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P(5,3) = 5! 4! 3! = 60

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That's what you did

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C(5,3) = [5! 4! 3!] / 3! = 10

ebon depot
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Yes because that is only because I remember doing another where I just divide by the factorial of all letters that are the same

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3As result in 3! In denominator

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It has nothing with me understanding why

jagged relic
ebon depot
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I want to be able to utilize the formula

jagged relic
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Oh okay hold on

ebon depot
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But I can’t distinguish between them

jagged relic
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If you arrange the letters like CARAMBA, but count each A as different (like you said, A1, A2, A3)

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then you use permutations

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but since the A's aren't different

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you need to divide by the number of ways you can arrange A1, A2, A3

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It can be A1, A2, A3, or A2, A1, A3, or A2, A3, A1, ...

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That's 3! arrangements

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They all count as the same solution

ebon depot
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Yes

jagged relic
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So what exactly don't you understand?

ebon depot
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Everything

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Since I still can’t solve it

jagged relic
ebon depot
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A1,A2,A3 A2,A1,A3 = 2
A1,A2,A3 A2,A1,A3 = 1

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So the above is combinations

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And bottom permutations

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What does n and what does k stand for infor combinations and permutations?

jagged relic
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The other way around, assuming you meant 6 instead of 2...

ebon depot
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No I meant 2 and 1

jagged relic
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Then that makes no sense

ebon depot
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Then I don’t understand?

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Like I can’t think as quick as you are professors

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I need a structured way to actually understand

jagged relic
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If you have 3 different objects, there are just 3! different ways to order them

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If you have 3 identical objects, there is only one way to order them

ebon depot
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Yes

jagged relic
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Well, in CARAMBA, you have 4 different consonants and 3 identical vowels

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You can order the consonants in 4! different ways, and you can order the vowels in only one way

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The rest is determining how to place the vowels such that they don't touch each other

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For that, you need to think about what it means for the vowels not to touch each other

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It means there is at least one consonant in between

ebon depot
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Yes

jagged relic
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In other words, you can place only one vowel between two consecutive consonants

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(or zero)

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There are 3 places you can insert a vowel between two consonants, and also 2 places at the ends (between a consonant and nothing)

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So there are 5 places where you can insert one or zero vowels

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You have 3 vowels to insert

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So you need to choose 3 places out of the 5

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That's literally what combinations are used for: choosing k things among n

ebon depot
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I'm so sorry Nel but i'm reading it over and over but i just don't get it

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I assumed since this was a question about permutations or combinations i'd have to choose one of them

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and then just utilize the formula based of n and k

jagged relic
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Not sure what to tell you, maths is not about applying one specific formula every time

sleek mantle
ebon depot
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fine take over my channel

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.close

marsh citrusBOT
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kind perch
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please say this isn't as complicated as it looks

kind perch
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starting on part (a)

past frigate
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It isn't

kind perch
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phew which do i do first integrate or partial fraction it?

past frigate
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What do you think, by looking at it?

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Is there a way to integrate it directly?

kind perch
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integrate

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when i integrated it i got $(1/3)x^3+(3/2)x^2+4x+2$

past frigate
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As final ans?

elfin berryBOT
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sealpup321

kind perch
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as its not a fraction with a polynomial denominator

past frigate
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For partial fraction you need the degree of denominator to be greater than that of numerator

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So try long division first

kind perch
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what do you mean its not over anything?

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i did the long division before integrating

past frigate
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What did you get

kind perch
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$x^2+3x+6+(2/x-1)$

elfin berryBOT
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sealpup321

past frigate
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=the numerator is it?

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Or the entire question

kind perch
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what do you mean?

past frigate
kind perch
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$(x^3+2x^2+3x-4)/(x-1)$

elfin berryBOT
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sealpup321

past frigate
elfin berryBOT
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Lorentz

kind perch
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yes

past frigate
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Right

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So you get
$$x^2 + 3x + 6 + \frac{2}{x-1}$$

elfin berryBOT
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Lorentz

kind perch
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yup

past frigate
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Now integrate it

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Oh

kind perch
past frigate
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One of the terms should be in form of ln tho

past frigate
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The 2/(x-1) term

kind perch
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I mean you are right but I am confused

kind perch
elfin berryBOT
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sealpup321

past frigate
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I see

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Yeah you'll need to integrate that too

kind perch
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ye i did to get 2-2x

past frigate
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Integration of 1/x is ln(x)

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$\int \frac{2}{x-1} dx$

elfin berryBOT
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Lorentz

past frigate
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And we have this

kind perch
past frigate
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Np I guess

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I assumed you knew that

kind perch
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so how would i use that then?

past frigate
kind perch
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so $ln|1/2 * x-1|$

elfin berryBOT
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sealpup321

kind perch
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?

past frigate
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No wait that 2 is a constant, it would be multiplied with the ln thing

past frigate
kind perch
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or $2ln|x-1|$

elfin berryBOT
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sealpup321

past frigate
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Yes that

kind perch
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cool 🙂

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alright so once i have this new number how do i turn it into a partial fraction?

past frigate
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Which new number?

kind perch
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$(1/3)x^3+(3/2)x^2+6x+2ln|x-1|$

elfin berryBOT
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sealpup321

past frigate
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That's your final answer

kind perch
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huh?

past frigate
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The integral of the question

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Yes

kind perch
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do i not need to do the whole A/x-1 + B/x-1 +C/x-1

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or whatever the numerator and denominator would be in this case

past frigate
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I thought so too, but after using long division the denominator of 2/(x-1) was a direct integration

kind perch
past frigate
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I mean like you can directly integrate 1/x to ln x

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Instead of some partial fractions thing

kind perch
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strange... thanks 🙂

past frigate
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I was confused too

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Np

kind perch
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yup checked and its correct thanks for all the help

past frigate
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Coz for partial fracs the degree of denominator should be more than numerator

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So I didn't know any other way

kind perch
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🤷

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.close

marsh citrusBOT
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gusty sorrel
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Where did condition 2 and 3 come from?

marsh citrusBOT
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@gusty sorrel Has your question been resolved?

gusty sorrel
#

<@&286206848099549185>

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😭

gusty sorrel
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.close

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muted grail
#

need some help with this question

marsh citrusBOT
muted grail
#

Someone pointed out that we can define a function g(x) = f(x) - x and since both f(x) and x are continuous functions then so is g(x).

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then we can use the fact that f(x) is a bounded function to look at two values a and b such that a > b

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and g(a) and g(b) have opposite signs

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this would imply the existence of a g(c) = 0, according to the bolzano's theorem.

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this is the part I'm confused about.

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how does the fact that g(x) is bounded (due to f(x) being bounded) and continuous (due to both f(x) and x being continuous) imply that there exists values a and b such that g(a) and g(b) have opposite signs?

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<@&286206848099549185>

spark siren
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as f is bounded there are values m and n such that m < f(x) < n for all x. now think about what does this mean for g.

muted grail
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hmm

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it would just mean that g is bounded too

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right?

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wait actually

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if g(x) = f(x) - x

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regardless of if f(x) is bounded or not, the x isn't bounded

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which would mean that g is not bounded

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right?

spark siren
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take an x between m and n.

muted grail
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ohh

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at some point x = f(x)

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and there will be g(x) = 0

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right?

spark siren
muted grail
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"for x large enough f(x)-x < n-x < 0 -> g(x) < 0" so in this line, we are essentially taking the largest possible f(x) which is n, and we take a value x, and since x isn't bounded, it can be any real number

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so we take x such that n - x < 0 -> g(x) < 0

spark siren
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no, not the largest possinle. thsi would be infinity. just an x which is > n.

muted grail
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but it wouldn't be infinity

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as f(x) is bounded?

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said bounds being n and m

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right?

spark siren
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if x > n then also x+1, so a largest x cant exist.

muted grail
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i said largest possible f(x)

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x is unbounded. there isn't a largest x right?

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we can select x however we like

spark siren
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we take an x which is > n.

muted grail
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ok got it

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which proves the exictence of a negative g(x)

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and then do the same to prove the exictence of a positive g(x) value

spark siren
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yes

muted grail
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and then since it is continuous

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we have proven that there exists a g(x) = 0

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the we have 0 = f(x) - x => f(x) = x

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which proves part i

spark siren
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yes

muted grail
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ok dope

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just a quick question

muted grail
spark siren
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the boundary could be asymptotic

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eg. arctan x

muted grail
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aympstotic boundries

spark siren
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arctan is bounded, what is m and n if you think there should be an "=" in m<=f(x)<=n?

muted grail
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f(x)

spark siren
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take f(x) = arctan (x), say what is m and n such that m <= f(x) <= n, and for what x is f(x) = m and for what x is f(x) = n?

muted grail
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idk how arctan behaves at different values

spark siren
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you do not know the function arctan?

muted grail
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i know the function

spark siren
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is ir bounded?

muted grail
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yes

spark siren
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what is the upper bound?

muted grail
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ik how it looks like

muted grail
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one radian

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I don't remember honestly

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arctan was the function that took lengths as arguments and gave degrees right?

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that's literally all I know about it

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and how it looks like

spark siren
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anyway, if a function is bounded this only means, that there are upper and lower bounds. that does not mean, that the function reaches the bounds. and ix k is an upper bound then also k+1, k+2, k+3, ---

muted grail
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ok got it

marsh citrusBOT
#

@muted grail Has your question been resolved?

marsh citrusBOT
#
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jaunty pelican
#

what is the easiest way to solve a system of linear equations

zenith python
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it depends on how many equations you have?

jaunty pelican
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just 2

shell ether
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Send it

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i can't imagine

zenith python
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my favorite method is reduction

jaunty pelican
shell ether
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maybe gauss jordan method

jaunty pelican
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how would you do that

shell ether
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@zenith python say something

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I forgot this method

main idol
jaunty pelican
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I don't

main idol
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You can just use algebra

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There are many ways, one could be multiply one equation by a number so that when you add them you eliminate a variable

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Like the first eqn by 3

shell ether
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or replacement

main idol
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Or second equation by -4

jaunty pelican
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where did you get -4 from?

main idol
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Try it all 3, none are better than the other

main idol
jaunty pelican
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0

shell ether
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So we can erase this shit

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Like add first equation to second

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And we'll get rid of x

jaunty pelican
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add everything?

shell ether
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And we'll be able to solve y

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Yes

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But

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First of all

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Multiply second equation by -4

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All second equation

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And then addition

jaunty pelican
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im still confused where your getting the -4 from

shell ether
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we multiplied x by -4

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And got -4x

jaunty pelican
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but there is no -4 in the equation

shell ether
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So we can do 4x+(-4x) and got 0

shell ether
main idol
jaunty pelican
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4x+y=15

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x-3y=7

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you mutiply the second equation ^ correct?

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by a number

shell ether
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YES

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Yes

jaunty pelican
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i got that

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so would you substite x with 4 since the first equations x is 4?

shell ether
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Nah

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don't touch first equation

jaunty pelican
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ok

shell ether
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multiply second by -4

jaunty pelican
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bro

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where did you get the -4 from?

shell ether
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well as i said

main idol
shell ether
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We can multiply our equation by any number

main idol
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4 + ? = 0

jaunty pelican
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any

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so 4 (10)

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would that work

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or does it have to be 0

shell ether
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Whaat

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4(10) what it means

jaunty pelican
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cause you said we can mutiply our equation by any number

shell ether
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You can't replace x

shell ether
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you can do (x-3y=7)×(-4)

jaunty pelican
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-4x+12y=-28

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?

shell ether
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Yes

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So add the first equation to second

shell ether
jaunty pelican
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12y^3=13

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?

shell ether
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no

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12y

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Just 12y

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Why in 3 power

jaunty pelican
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but 12y+y = 12y^2?

shell ether
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Nah

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It's 13y

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Just

jaunty pelican
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is it because theres a 1 infront of y?

shell ether
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12y+y=12y+1y=13y

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🙂

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Yes

jaunty pelican
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ok got it

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so 13y=13

shell ether
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Yes

jaunty pelican
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y=1

shell ether
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You found y

jaunty pelican
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ok so whats the next steo

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step

shell ether
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4x+y=15

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solve for x

jaunty pelican
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do i replace y for 1?

shell ether
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you can

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But

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you can do it after

jaunty pelican
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x=5?

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4x+1=15

shell ether
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x=(15-y)/4

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Hope you can do it

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And then replace

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so the answer isn't 5

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Oops

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14/4

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Solve it

jaunty pelican
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wait

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if the y was a positive how did it turn into -

shell ether
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well

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You know that

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Bro

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I'm confused that you don't know basics

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x+y=0

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Solve for x

jaunty pelican
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😕

shell ether
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x+5=0

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Solve it

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What you'll get

jaunty pelican
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x=-5

shell ether
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yes

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So why fucking sign changed

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...

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That's the same

jaunty pelican
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cause you subtracted

shell ether
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Sooo

shell ether
jaunty pelican
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ok lemme go back

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we solved for y and got 1

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so we have to plug that into our first equation 4x+y=15

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?

shell ether
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yes

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We can

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But we can firstly solve for x

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And it will be easier

jaunty pelican
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and to solve for x we divide?

shell ether
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yes because it's 4x

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We need x

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So we divide by 4

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is it understandable

jaunty pelican
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15/4 is a decimal

shell ether
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yes but

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You have -y

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(15-y)/4

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because you first substract

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By y

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Both sides

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And then divide by 4

jaunty pelican
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ohhhhhhh i get it now i was overcomplicating it

shell ether
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so

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What is the answer

jaunty pelican
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4?

shell ether
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nah

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(15-y)/4

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Replace y by 1

jaunty pelican
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14/4

shell ether
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What you'll get

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Yes

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Solve it

jaunty pelican
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thats another decimal

shell ether
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What is 14/4

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Can you simplify it?

jaunty pelican
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yea into a decimal

shell ether
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Do it

jaunty pelican
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3.5

shell ether
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🙂

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so what is the general answer?

jaunty pelican
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3.5 and 1?

shell ether
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nah

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Usually people say (x;y)

jaunty pelican
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yea as a ordered pair

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(3.5, 1)

shell ether
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yes

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Good

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Recommend you this cheat method

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Cause it's much easier

jaunty pelican
#

the method im learning is complicated

shell ether
#

you should first learn how to do simple/medium/hard linear equations

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Not even systems

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Anyway I'll go

marsh citrusBOT
#

@jaunty pelican Has your question been resolved?

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dusk meadow
#

A hen knows how to count. We put it in front of a packet of 2024 eggs. She counts the eggs from the first packet and places them in a second packet. Each time she has counted 4 eggs, she lays an egg which she places in the packet of those she still has to count.

How many eggs will the hen count in total?

dusk meadow
#

<@&286206848099549185>

stoic slate
#

Wasn’t this solved yesterday?

dusk meadow
#

yeah but i have a problem

#

im getting another answer

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my original answer was 2698

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but then i got 2695

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help plz

#

<@&286206848099549185>

#

anyone

marsh citrusBOT
#

@dusk meadow Has your question been resolved?

dusk meadow
#

<@&286206848099549185>

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help

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.close

marsh citrusBOT
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honest current
#

Hello

marsh citrusBOT
honest current
#

Can I get help with this

#

<@&286206848099549185>

marsh citrusBOT
#

@honest current Has your question been resolved?

honest current
#

<@&286206848099549185>

lethal cairn
#

gosiogiusdg

marsh citrusBOT
#

@honest current Has your question been resolved?

marsh citrusBOT
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lyric kelp
marsh citrusBOT
lyric kelp
#

why is C negative?

#

at the end of the second line

gleaming pecan
lyric kelp
#

so it doesnt matter correct?

gleaming pecan
#

but it doesn't matter at all, really

lyric kelp
#

the sign of C

#

ah okay tyy

#

.close

marsh citrusBOT
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flat grail
#

I'm trying to compute $$\lim_{n \to \infty} {(3^n + 1)^\frac {1}{n}}$$ by the squeeze theorem. is it ok to use $$(3^n)^\frac{1}{n} \leq (3^n + 1) ^\frac{1}{n} \leq (3^{n+1})^\frac {1}{n} $$

fathom ridge
#

well you do get the right answer so

elfin berryBOT
#

lewis_f04

flat grail
#

I'm not sure if it is ok to say that $$(3^n + 1) ^\frac{1}{n} \leq (3^{n+1})^\frac {1}{n} $$ without proof as it isn't trivial

elfin berryBOT
#

lewis_f04

paper raptor
#

couldn't you say that for sufficiently large $n$, $3^n+1\leq 3^{n+1}\implies (3^n+1)^{\frac{1}{n}}\leq (3^{n+1})^{\frac {1}{n}} $

elfin berryBOT
#

PajamaMamaLlama

flat grail
#

for sure, I've just never got feedback from my lecturer on how exactly this is to be done, and my exam is tomorrow

#

if thats how you'd do it, I'll use that

#

thanks for the help

paper raptor
#

I'd probably ask someone else but that seems sufficient

marsh citrusBOT
#

@flat grail Has your question been resolved?

marsh citrusBOT
#
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whole jetty
#

Given the following functions find the image of 0, and 2 in each case, and the antiimage of –3, 0.

marsh citrusBOT
#

@whole jetty Has your question been resolved?

marsh citrusBOT
#

@whole jetty Has your question been resolved?

marsh citrusBOT
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cerulean oxide
marsh citrusBOT
cerulean oxide
#

how do i do this?

marsh citrusBOT
#

@cerulean oxide Has your question been resolved?

cerulean oxide
#

<@&286206848099549185>

marsh citrusBOT
#
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cerulean oxide
#

how do i do this?

marsh citrusBOT
cerulean oxide
#

Not sure how to procede

deft apex
#

Do you have any working for anything at all?

cerulean oxide
#

what does that mean?

stoic slate
cerulean oxide
#

i think you have to think the values of lambda

#

i found them to be:
"3, -1 + 2sqrt(2), -1 - 2sqrt(2)"

#

for A

#

that is what i've done so far

marsh citrusBOT
#

@cerulean oxide Has your question been resolved?

cerulean oxide
#

<@&286206848099549185>

final skiff
marsh citrusBOT
#

@cerulean oxide Has your question been resolved?

stoic slate
# cerulean oxide so?

So nothing, I’m just explaining what he was asking cause you said “what does that mean?” Referring to him, and that meant you didn’t understand him

cerulean oxide
#

sorry i am a bit lost on this part of linalg

#

(A-lambdaI)*x=0, right

cerulean oxide
#

this woul be it, right

main idol
cerulean oxide
main idol
#

Where did 3 come from

main idol
cerulean oxide
#

the first eigenvalue

#

is found to be 3

#

i hope its correct

main idol
#

Looks right

#

Find a vector v such that Av = 3v

#

You can arbitrarily pick the one of the components of v to be 1

cerulean oxide
#

i might have made a mistake

#

this is wolfram alphas answer

main idol
#

The order doesn't matter

#

Your eigenvalues look the same

cerulean oxide
#

i am not missing 1 thing

#

no nvm

#

nice

cerulean oxide
marsh citrusBOT
#
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main idol
#

.reopen

marsh citrusBOT
#

main idol
cerulean oxide
#

i tried to do:
(A-lambda*i)*x=0

main idol
cerulean oxide
#

yeah i wasnt rly sure what x should be

main idol
#

You're solving for it

#

It's unknown at the moment

cerulean oxide
#

x = -y -z:
x= -y

#

z is a free variable

#

right

#

@main idol is this what you meant

main idol
main idol
cerulean oxide
#

(A-lambda*i)x=0

#

yeah, that is also what i've done

#

we are essentially solving (A-3I)*v=0

hardy slate
#

yeah so you have one of them

#

(1, -1, 0) is an eigenvector with eigenvalue 3

#

now get the other ones

cerulean oxide
cerulean oxide
#

agree?

#

"So the three eigenvalues are: $\begin{bmatrix} 1 \ -1 \ 0 \end{bmatrix}$, $\begin{bmatrix} 1 \ 1 \ 1 \end{bmatrix}$, and $\begin{bmatrix} 1 \ 1 \ 1 \end{bmatrix}$."

elfin berryBOT
#

// mav

cerulean oxide
#

@hardy slate after i've found these, what am i supposed to do

hardy slate
#

oh wait it's the identity matrix

#

wait, what

cerulean oxide
#

is it incorrect?

hardy slate
#

sorry one sec

#

the way you work it out is different to what i'm used to

#

this shouldn't be right

#

like ok

#

you're saying A (1, 1, 1)^T = (-1 - 2sqrt(2)) (1, 1, 1)^T

and A (1, 1, 1)^T = (-1 + 2sqrt(2)) (1, 1, 1)^T ?

cerulean oxide
#

mhh ok yh

#

both are the same

hardy slate
#

yeah that's impossible

cerulean oxide
#

ill use a comptuer to what it gets

hardy slate
#

you should probably learn how to solve systems of linear equations

#

that's pretty important

cerulean oxide
#

i think i can do that already

#

that is what we are doing right now

hardy slate
#

well, you gotta learn how to do it correctly then

cerulean oxide
#

it is correct

hardy slate
#

it's not

cerulean oxide
#

i am aware its because i did it for the wrong matrix

#

so my eigenvalues are wrong

#

everything is wrong

hardy slate
#

oh what

#

okay?

cerulean oxide
#

i put a -1 on a 1 that should be +1

#

which is why i got such weird values

hardy slate
#

that'll do it

cerulean oxide
#

give me 5 min

#

wow yeah

#

the eigenvalues are now -3,3,3

#

which makes it a lot easier

#

how do i even write up an answer for this

cerulean oxide
hardy slate
#

so any vector st. x+y+z = 0 will be an eigenvector with eigenvalue 3

#

so you can just take any vector that isn't 0

#

so like, (1, 1, -2)

#

actually you want two eigenvectors for 3

#

so you want to find a second orthogonal eigenvector to that

#

to make the matrix orthogonal

cerulean oxide
#

this would be correct, right

hardy slate
#

for L = -3

#

you need x = y + z

#

but 2 != 1 + 0

cerulean oxide
#

why 2!?

#

so [2,1,1]?

hardy slate
#

!= means 'not equals'

#

but anyway yeah that would work

#

ok

#

so you have two eigenvectors, one for 3 and one for -3

#

now you just need another eigenvector for 3

#

it should be orthogonal to the other two

#

wait actually hmm

#

the problem now is that (1, 1, -2) isn't orthogonal to (2, 1, 1)

#

so

#

we could do (0, 1, -1) instead and that would work

#

and then we'd need one more

cerulean oxide
#

for L=-3?

hardy slate
#

no

#

(2, 1, 1) works for L = -3

cerulean oxide
#

L=3 [0,1,-1]

#

right

hardy slate
#

right

#

and then we need one more for L = 3

#

orthogonal to the first two

cerulean oxide
#

i though that would jsut be the same

#

but it isnt?=

hardy slate
#

?

#

ok so essentially

#

for L = -3, you need x = y + z and x = 2y

#

2 constraints

#

so there's only sorta 1 dimension of possibility

#

but for L = 2 you only need x + y + z = 0

#

1 constraint

#

so there's 2 dimensions of possibilities

#

a whole plane of possible eigenvectors

#

you want to find 2 orthogonal eigenvectors in that plane

#

we already have (0, 1, -1) so we need another one

cerulean oxide
#

ok, but if i insert L=3 again

#

do i not get the same value

hardy slate
#

wdym

#

there's lots of possible solutions to x + y + z = 0

cerulean oxide
#

yeah

#

infinite

hardy slate
#

right

#

so we can find 2 orthogonal eigenvectors in that plane

#

with eigenvalue 3

cerulean oxide
#

yeah ok

#

what could another one be

hardy slate
#

so you want x + y + z = 0, and it needs to be orthogonal to (0, 1, -1) as well

#

think about it

cerulean oxide
#

so

#

i need to fidn an orthogonal to (0,1,-1)

#

(1,1,1)

hardy slate
#

ok

#

but you also need x + y + z = 0

cerulean oxide
#

mhh idk then

hardy slate
#

ok

cerulean oxide
#

(1,1,1) is orthogonal to (0,1,-1) tho

hardy slate
#

it is

#

but you also need x + y + z = 0

#

but 1 + 1 + 1 = 3

cerulean oxide
#

yh

hardy slate
#

so

cerulean oxide
#

bit too high

hardy slate
#

how do you tell if something is orthogonal to (0, 1, -1)

cerulean oxide
#

dot product =0

hardy slate
#

right

#

so what's the dot product of (0, 1, -1) with (x, y, z)

cerulean oxide
#

y-z?

hardy slate
#

right

#

so you want y - z = 0

#

and you want x + y + z = 0

cerulean oxide
#

y=z

#

x=-2?

#

no

#

yh idk

hardy slate
#

??

#

anything that works

#

please

cerulean oxide
#

y-z=0 just meanst y=z

hardy slate
#

yes

cerulean oxide
#

so i hae x=-2y

hardy slate
#

yes

cerulean oxide
#

that is what i wrote

#

in the start

hardy slate
#

ok but you need a vector

#

find an eigenvector like that

cerulean oxide
#

1,-2,-2

hardy slate
#

??

#

x = -2y

#

not y = -2x

cerulean oxide
#

-2,1,-2

hardy slate
#

bruh

cerulean oxide
#

why isnt that right tho

#

y=z
x=-2y

#

y=x/-2

#

like what

#

z=x/-2

hardy slate
#

??

#

you need x = -2y and y = z right

cerulean oxide
#

yes

#

then y=x/(-2)

hardy slate
#

but you need y = z

cerulean oxide
#

you divide by -2 on both sides

#

then z is also just x/-2

hardy slate
#

ok

#

let's start over

cerulean oxide
#

no no

hardy slate
#

we need x = -2y

#

and y = z

cerulean oxide
#

how is thatn ot correct

hardy slate
#

pick any z

cerulean oxide
#

ok

hardy slate
#

that isn't 0

cerulean oxide
#

x =- 2y

#

y=z

hardy slate
#

no

#

pick

#

a number

cerulean oxide
#

48

hardy slate
#

ok

cerulean oxide
#

lets go with 1

hardy slate
#

z = 48

cerulean oxide
#

instead

#

z=1

hardy slate
#

ok

#

z = 1

#

then y = z so y = 1

#

then x = -2y so x = -2

cerulean oxide
#

yes

hardy slate
#

so it needs to be (-2, 1, 1)

cerulean oxide
#

which is what i wrote like 800 years ago

hardy slate
#

because y needs to equal z

#

no

cerulean oxide
#

ok now i will write it

#

(-2,1,1)

hardy slate
#

ok

cerulean oxide
#

and everyone is very happy

hardy slate
#

so what you've ended up with is three eigenvectors, all of which are orthogonal to each other

#

so now you just put them in a matrix next to each other and you have an orthogonal matrix P

#

done

cerulean oxide
#

does the order matter

hardy slate
#

no

cerulean oxide
#

so we have this

hardy slate
#

that isn't it

#

wait yes it is

#

ok

#

wait

#

what's happened

#

am i dumb

cerulean oxide
#

what?

hardy slate
#

the second and third aren't orthogonal

#

am i really dumb

cerulean oxide
#

what mistake did we make

hardy slate
#

god DAMN it

#

you solved the linear equations wrong!

#

i think? wait

cerulean oxide
#

i checked with computer

hardy slate
#

ok so

cerulean oxide
#

mhh

#

bruh

#

the -1

#

isnt supposed to be there

#

😭

hardy slate
#

there we go

#

jesus

cerulean oxide
#

on the right, its supposed to be [1,0,-1] top

hardy slate
#

right.

cerulean oxide
#

this has to be the right one now

hardy slate
#

ok

cerulean oxide
#

x=z

hardy slate
#

so what's the eigenvector here

cerulean oxide
#

y=z

#

i say x=1

hardy slate
#

ok

cerulean oxide
#

x=z=y=1=1=1

hardy slate
#

ok

#

so let's see

#

yeah so all of the columns of this are orthogonal now

#

so it works

#

finally

cerulean oxide
#

phew

#

now i have to show that with my now P matrix

#

P^-1*AP is diagonal

hardy slate
#

ok so i explains this ages ago

#

basically alright so

#

you have Av = Lv for each of the eigenvectors v

#

like ok

#

Av_1 = L_1 v_1
Av_2 = L_2 v_2
Av_3 = L_3 v_3

#

right?

cerulean oxide
#

mate listen

#

the question is just find P so this is diagonal

hardy slate
#

no this is fast

#

look

#

do you see what i'm saying

#

this answers your question

cerulean oxide
#

my question of the assignemnt

#

i asked if we have found P

hardy slate
cerulean oxide
#

yes

hardy slate
#

right

#

so then we can take like A(v_1 v_2 v_3)

#

AP

#

and this will be the same thing as PD

#

where D is a diagonal matrix with L_1, L_2, L_3 as the diagonal entries

#

so we have AP = PD

#

so P^-1 AP = D

#

so you're done, see

cerulean oxide
#

yeah idk what you've said

#

but this is true

hardy slate
#

$A \begin{pmatrix} v_1 & v_2 & v_3 \end{pmatrix} = \begin{pmatrix} \lambda_1 v_1 & \lambda_2v_2 & \lambda_3 v_3 \end{pmatrix} = \begin{pmatrix} v_1^T \ v_2^T \ v_3^T \end{pmatrix} \begin{pmatrix} \lambda_1 & 0 & 0 \ 0 & \lambda_2 & 0 \ 0 & 0 & \lambda_3 \end{pmatrix}$

elfin berryBOT
#

Kaisheng21

hardy slate
#

well ok this doesn't even work

#

you need the eigenvectors to all be unit length

#

but then it works

cerulean oxide
#

yeah but it works by just computing it

hardy slate
#

oh it does? sick

#

anyway i gtg now

#

in conclusion, you gotta get more reliable at solving systems of linear equations

cerulean oxide
#

i just didnt know how to compute P

#

if i knew that then its somewhat just boring algebra

hardy slate
#

yeah obviously you didn't know wtf was going on

#

but also you need to get better at systems of linear equations because you kept making the most basic errors, like holy

#

that wasted a lot of time

cerulean oxide
#

it wasnt to do wit that, sadly

#

it is me looking at my paper

#

and typing it onto the computer

#

and then putting wrong values

#

like misstyping

#

xd

hardy slate
#

idc how you do it but you gotta get it right

#

cya

cerulean oxide
#

cya

#

enjoy ur day

#

ty for help

marsh citrusBOT
#

@cerulean oxide Has your question been resolved?

marsh citrusBOT
#
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Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
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mystic minnow
#

what have you tried

unique basin
#

You have an optimization problem at hand here

Maximize or Minimize something

Subject to certain constraint(s)

#

The constraint is the fact that xy = c^2

#

Normally to maximize something you take the first derivative and set = 0

#

But because you have 2 variables in

ax + by

#

You cant do that easily

#

Use the known constraint to replace one of the unknowns

#

if you know xy = c^2 must be true

#

Then you can solve for x or y

#

And turn it into a 1 variable

#

Thats what i would do to start probably

#

You should be able to solve for x or y in terms of a, b, c

#

Then solve for y in terms of a, b, c

#

Treat a, b, c like constants

#

x = (c^2)/y

#

From the constraint

#

Plug that into the other expression

#

a * [(c^2)/y] + by

#

Take derivative of that with respect to y

#

And set = 0

idle ridge
#

.close

marsh citrusBOT
#
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idle ridge
#

(The user was banned)

#

(Sorry to waste your time)

unique basin
#

Oh np xD

marsh citrusBOT
#
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Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
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jovial mulch
#

Weird question,
Something like
v= 2t +2t^2 +2

A. Distance of Q from origin , when t =5
B. Total distance travelled of Q from origin in the first 5 seconds

vernal forge
jovial mulch
#

whats the difference

jovial mulch
vernal forge
#

in your case there is no difference

dusky viper
#

one is displacement one is distance i'd assume

vernal forge
#

but in general A is displacement and B is distance

jovial mulch
#

The distance of Q from O, when t=5
The total distance travelled by Q in the first 5 seconds

#

Thats the exact wording

vernal forge
#

yes

jovial mulch
#

Ah ok

vernal forge
jovial mulch
#

Yeah

jovial mulch
#

very wrrong

#

made it up

vernal forge
#

ah okay

vernal forge
#

well basically

jovial mulch
#

yeah one is the displacement

#

Understood

vernal forge
#

$\int_{\text{start}}^{\text{end}} v(t) dt$ - displacement \
$\int_{\text{start}}^{\text{end}} |v(t)| dt$ - distance \

elfin berryBOT
#

artemetra

jovial mulch
#

but thats weird

#

Whenever i did distance

#

I got it correct

vernal forge
#

yeah well you got lucky the object was not going backwards at any point in time

velvet cairn
vernal forge
#

yep

jovial mulch
#

so if it was -t^2

vernal forge
velvet cairn
#

Then u will have to find where the value is negative and integrate seperately

#

And then add the magnitudes

vernal forge
jovial mulch
#

right

#

thats cool you can plot it

#

didnt know

vernal forge
#

#desmos4life

jovial mulch
#

seriously amazed tho

#

welp thats it hehe

#

need to finish it

#

Thank youuu both

#

.close

marsh citrusBOT
#
Channel closed

Closed by @jovial mulch

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#
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Ask your math question in a clear, concise manner.
Show your work, and if possible, explain where you are stuck.
After 15 minutes, feel free to ping <@&286206848099549185>.
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• Be polite and have a nice day!

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jovial mulch
marsh citrusBOT
jovial mulch
#

Could you teach me how to use this

#

I understand everything you put in

#

How would I put in t= 5

#

[To find the distance]

vernal forge
#

do you know how to do definite integrals?

#

like the ones with the bounds?

#

$\int_1^3 x^2 dx$

elfin berryBOT
#

artemetra

vernal forge
#

can you solve this?

jovial mulch
#

yes

#

9 - 1

vernal forge
#

you sure?

jovial mulch
#

8

vernal forge
#

bruh

jovial mulch
#

oh wait

vernal forge
#

no

jovial mulch
#

yeah

#

dx

vernal forge
#

integrate it first

jovial mulch
#

I write it differently

#

2x

#

6 - 2

vernal forge
#

no that's derivative

jovial mulch
#

Oh yeah

#

Wait

vernal forge
jovial mulch
#

I SWEAR

#

NO BRO

#

idk

vernal forge
#

$\int x^2 dx$

#

can you do this

jovial mulch
#

Yes

elfin berryBOT
#

artemetra

jovial mulch
#

x^3/3

vernal forge
#

is this doable

vernal forge
#

so

jovial mulch
#

and then whatever that gets

vernal forge
#

$\int_1^3 x^2 dx$

elfin berryBOT
#

artemetra

vernal forge
#

$=\frac{x^3}{3} \mid_1^3$

elfin berryBOT
#

artemetra

jovial mulch
#

Yeah

#

26/3

#

But the problem I have

vernal forge
jovial mulch
#

So,
So far everyquestion I have done to do with distance I found out

#

Is that

#

Its always been here

#

Or in the exact middle, I found out

#

Now the question im doing right now, has situations where its on the other side