#help-19

1 messages · Page 198 of 1

amber schooner
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,w lim x to -inf arctan(x)

amber schooner
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and clearly arctan(0) = 0

shy grove
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I see

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so it evaluates to 0 instead of π

amber schooner
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what does?

shy grove
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wait nvm

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isnt the inequality false here

amber schooner
#

both the a and b limits are pi/2

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so you add them and get pi

amber schooner
shy grove
#

so this is false for f(x) = f'(arctan(x))

amber schooner
#

well for f(x) = 1/(1 + x^2) yea you actually have equality

shy grove
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but you did claim this inequality is sometimes true, right?

amber schooner
#

don't say inequality btw

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inequality refers to <, <= etc

shy grove
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oh

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right

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so its a nequality as per \neq

amber schooner
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so long as the left side is convergent

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so both the integrals exist

shy grove
narrow crypt
#

X is odd. It’s from the rhs

amber schooner
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no if both the integrals on the left converge then the cauchy principal value will be equal

shy grove
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oh well

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but I guess I get it now

amber schooner
#

this is interpreted to mean does equality hold

shy grove
#

for all intents and purposes I can write improper integrals from -∞ to ∞ as lim(a→∞) from -a to a

shy grove
odd edgeBOT
#

@shy grove Has your question been resolved?

#
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odd edgeBOT
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weary orchid
#

Can somebody please provide its solutions with proper steps ...

weary orchid
#

<@&286206848099549185> help me

narrow crypt
#

holy notation

solar peak
#

it simplifies kind of nicely

mystic saffron
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L

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L'hopital thez

solar peak
weary orchid
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nothing i cant think how to approach t

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it*

warped badger
mystic saffron
solar peak
warped badger
#

No way they put sin(tan(arcsin(x)))

weary orchid
solar peak
weary orchid
#

thanks

weary orchid
narrow crypt
#

[ \arctan \left(\frac{x}{1} \right) = \arcsin \left(\frac{x}{\sqrt{1+x^2}}\right)]

clever fjordBOT
narrow crypt
#

${\tan x \sim x}$ when ${x \to 0}$?

clever fjordBOT
solar peak
#

u have to expand it upto 2 terms

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1 term wont do

narrow crypt
narrow crypt
solar peak
#

yeah

solar peak
#

not even 2 terms

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3 terms

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thats crazy

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this is a nice question

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@weary orchid are u here?

weary orchid
#

it is a pyq of jee advanced

weary orchid
solar peak
#

ohh makes sense

solar peak
#

or are u having some problem with that?

weary orchid
solar peak
#

ok sure

solar peak
weary orchid
#

ah it is not written in pdf

solar peak
#

i dont think it is a pyq tho

weary orchid
#

but there is hint availaible i am sending it

solar peak
#

yeah

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but to use the expansion ull first have to simplify the trignometric expressions

solar peak
#

now i gtg now so wait for someone else to help u or else u can ping @ helpers

weary orchid
#

ok thanks for the help

odd edgeBOT
#

@weary orchid Has your question been resolved?

weary orchid
#

yes

subtle raft
#

You can .close if you are done

weary orchid
#

.close

odd edgeBOT
#
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odd edgeBOT
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versed knoll
#

Can someone explain why to find the number of divisions, we do n+2 choose 2 instead of n-1 choose k -1, where k is the number of divisions

late dust
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Can you elaborate

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Is it example 22?

versed knoll
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Refer to the explanation under the problem please

late dust
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I'm not sure what you're referring to with "divisions"

versed knoll
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Like if I have a sum

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Let’s say 3

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How many ways can I add up to 3

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I could have 1+1+1

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Or 2+1+0

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Or 3+0+0

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Right

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That’s what I mean

late dust
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Well, yeah, so two divisions

versed knoll
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No 3

late dust
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Right, I'd call that 3 parts, not divisions, but sure

versed knoll
#

Oh sure

late dust
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So ok, k = 3

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So it's something choose 2

versed knoll
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Right but in my problem they did something + 2 right for k

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That’s what I didn’t get

late dust
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Let me double check something

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Right so imagine you have three boxes into which to distribute 5 items

versed knoll
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Oh ok yeah

late dust
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(and boxes can be left empty)

versed knoll
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K

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So this is just boxes and balls

late dust
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I'm guessing you're talking about stars and bars but learned another name for it

versed knoll
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Yeah

late dust
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Anyway, you can equivalently lay out the 5 items in a row, and place two separators somewhere

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Separators can both be in the same place, and can be between two items or at the beginning or the end

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How many ways to do that?

late dust
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Because that makes three sets

versed knoll
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Oh I see yeah

late dust
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That's why I didn't like the term "divisions"

versed knoll
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So I guess 4 choose 2

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Cause you have 4 spaces between the numbers?

late dust
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Yes but both separators can be in the same place

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I'm trying to find a nice way to explain how that makes it different

versed knoll
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So it’s like 4 choose 2 plus 4

late dust
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Ok so if the separators had to be in different places, and between two items, you'd just get 4 choose 2, because 4 spots between items and 2 separators

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Here however, separators can be in the same spot, and can be at either end of the item row

versed knoll
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Right

late dust
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So instead of trying to place the separators, think about the items and the separators together as a row of objects

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Now you choose two of these objects to be the separators

versed knoll
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So it’s like 7 choose 2

late dust
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How many objects? 5 + 2

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So 7, choose 2

versed knoll
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Right

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Ok tysm

late dust
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So to go back to the original, you have three boxes, that's k=3

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And n=5 for example

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So you get n+k-1 choose k-1

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That's the general formula

versed knoll
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Oh ok

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This is for any divisions right

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Where order matters

late dust
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Yeah

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Some parts might be a bit complicated but overall it's a good explanation with proofs

versed knoll
#

Ok I will

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Tysm

odd edgeBOT
#

@versed knoll Has your question been resolved?

odd edgeBOT
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somber river
odd edgeBOT
crystal charm
#

!status

odd edgeBOT
#
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
somber river
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can't even begin

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tried to factorize into eh... x+1 form but doesn't work

weary orchid
somber river
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you figure that out

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this the complete question

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No diagram attached

weary orchid
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ok i am trying to solve it

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can you tell me the answer

somber river
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ehhh

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you already got?

weary orchid
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no for my answer suerity

somber river
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Given is 0

weary orchid
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ok

mystic saffron
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hint: x²+3x+2=0

somber river
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what...... where did ya get that

mystic saffron
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basically

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i would group like

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everything

somber river
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Okay......

weary orchid
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you can use legendre three square theorem also i got the answer

mystic saffron
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x²+y²+z²+3(x+y+z)+5= 0 can be taken into x²+3x+2+y²+z²+3y+3z+3=0

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and x²+3x+2 can be factorised

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same for y and z

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should take u somewhere

somber river
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ehhh

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Sowwy I cant be as far sighted as ya

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lie let's say I facotrise it to x-a and x-b

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so what

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Y^2 won't have +2 will it and same for z^2

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basically I can't repeat this for that

mystic saffron
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you can:)

somber river
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Hmm..... Okie I shall try

mystic saffron
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try

somber river
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x+2)(x+1) +3(y+z+1) = 0 hmm.....

mystic saffron
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no

somber river
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eh...... what t do now

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hello?

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wth

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<@&286206848099549185>

abstract epoch
#

maybe try converting into (x+1.5)^2, (y+1.5)^2 and (z+1.5)^2

crystal charm
#

I was thinking of rewriting the expression as something like $\sum_{cyc}^{}(x+\frac{3}{2})^2=\frac{7}{4}$

crystal charm
abstract epoch
#

its not x+3 tho, right?

clever fjordBOT
#

឵឵MxRgD

abstract epoch
#

yeah that seems right

crystal charm
abstract epoch
#

but what do we do after this?

abstract epoch
#

but im not sure about it

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oh wait multiplying on both sides by 4, then applying mod (remainder) 8 on both sides gives no real solutions

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because a^2 can have the values =0,4,1(mod 8) and no combination of the sum of 3 squares gives 7(mod 8)

odd edgeBOT
#

@somber river Has your question been resolved?

odd edgeBOT
#
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humble basalt
odd edgeBOT
humble basalt
#

I have currently proven that the left formula is less than or equal to 2 and the right is greater than or equal to the square root of two. And the condition for the equality of the inequality is that the n numbers are equal, and both sides of the inequality are equal to the square root of two.

bitter folio
#

头晕

humble basalt
#

Forgive me, I don't have an English version of this question for the time being.

humble basalt
#

bitter folio
#

新加坡

humble basalt
#

哦那没事了

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会中文就好😃

bitter folio
#

我代数挺烂

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只会几何KEK

humble basalt
#

这题应该也是偏难的

bitter folio
#

我的不等式只能 muirhead 或用笨方法

bitter folio
humble basalt
#

听说有东南亚奥林匹克的难度()

bitter folio
humble basalt
#

蹲人

bitter folio
#

在这里

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用了titu 不等式可以吧

bitter folio
humble basalt
humble basalt
bitter folio
#

看起来我无法帮你

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不好意思

humble basalt
#

没关系哒哈哈

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每个人都有自己擅长的领域嘛

bitter folio
#

希望你能得到帮助

#

我去搞几何了 bye

humble basalt
#

好的呐KEK

odd edgeBOT
#

@humble basalt Has your question been resolved?

odd edgeBOT
#

@humble basalt Has your question been resolved?

vagrant oxide
#

问题是什么

#

odd edgeBOT
#

@humble basalt Has your question been resolved?

odd edgeBOT
#
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gusty cave
#

can someone help me here nobody replied to me in other cannel so closed it and came here

gusty cave
#

I closed it

mystic saffron
#

alr for this

snow socket
mystic saffron
odd edgeBOT
# snow socket

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

marble laurel
gusty cave
#

oo

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sorry

marble laurel
#

Nw

#

Now, the problem tells you that you have a present day price

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And the annual rate of depreciation and the time are given

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Can you identify the present value, the time, and the rate of depreciation?

gusty cave
#

yes..
the rate of depreciation is 16% per annum, Present Value is 9260 rupees and Time is 3 years

marble laurel
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Time is 3 years to the past or to the future?

gusty cave
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past

marble laurel
#

Alright so how would you write it? t = ???

gusty cave
#

t= -3 maybe

marble laurel
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Now do you remember the formula?

gusty cave
#

maybe it is v/(1-2/100) the whole square

marble laurel
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Hmm...what is v?

gusty cave
#

v is present value

marble laurel
#

Okay

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So is it like this?

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$v \left(1-\frac{2}{100}\right)^2$

clever fjordBOT
#

VulcanOne

gusty cave
#

yes

marble laurel
#

Okay you got the form, but you didn't place the given info properly

gusty cave
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yeah

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so instead of v its should be 9261 and 2 should be 16 maybe and raised to whole sq is 3

marble laurel
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Right

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But is it 3?

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Or -3?

gusty cave
#

-3 but like

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isn't it like u cant have power negative

marble laurel
#

You can

gusty cave
#

oo

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my bad so it is -3

marble laurel
#

$a^{-3} = \frac{1}{a^3}$

clever fjordBOT
#

VulcanOne

marble laurel
#

Remember

gusty cave
#

we did not learn this yet

marble laurel
#

Huh

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Alright

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Keep it in mind

gusty cave
#

ok

marble laurel
#

So can you find the value 3 years in the past?

gusty cave
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yeah now I got it

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thanks so much

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for helping me out

marble laurel
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Nw :)

gusty cave
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I wish there were teachers like you

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shall I close it now?

marble laurel
#

Sure

gusty cave
#

thx bye

#

.close

odd edgeBOT
#
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odd edgeBOT
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dull tundra
#

Can anyone message me and help me with my geometry its literally the basics

twin inlet
#

just ask ur question

dull tundra
#

Ok

twin inlet
#

here

dull tundra
#

My question is

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How do I figure out the planes on a question like this

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I'm on question c

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@twin inlet

merry kestrel
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Think like a prism placed on the paper

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triangular prism

dull tundra
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I would think 8 ? Would that be right

marble laurel
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It asks how many sides does the triangle prism have

merry kestrel
#

yeah count

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If I gave you an actual triangular prism in hand

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How many sides does it have?

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Let’s start, there is one that is the base

dull tundra
#

So the answer is 8

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@merry kestrel @merry kestrel @marble laurel

marble laurel
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How do you reach 8?

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This is the prism right?

dull tundra
#

Yea

marble laurel
#

Can you point out in a remix of the image the 8 sides?

#

Note:
the solid line means the line is in the front
the dotted line means the line is behind the shapes

odd edgeBOT
#

@dull tundra Has your question been resolved?

odd edgeBOT
#

@dull tundra Has your question been resolved?

odd edgeBOT
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mortal trench
#

Can some1 explain (C,alpha) summation to me

mortal trench
#

So I understand C1 that makes intuitive sense

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Just the average of partial sums

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But like I don't understand 2 and up

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The wikipedia article is unbelievably dense about this

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It's not just me being dumb I swear

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<@&286206848099549185>

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<@&286206848099549185>

manic sleet
#

!15m

odd edgeBOT
#

Please only use the <@&286206848099549185> ping once if your question has not been answered for 15 minutes. Please do not ping or DM individual users about your question.

manic sleet
#

oh wait nvm I cannot read time KEK

quasi sparrow
#

would be helpful if you posted the wiki link

tidal matrix
#

In mathematical analysis, Cesàro summation (also known as the Cesàro mean or Cesàro limit) assigns values to some infinite sums that are not necessarily convergent in the usual sense. The Cesàro sum is defined as the limit, as n tends to infinity, of the sequence of arithmetic means of the first n partial sums of the series.
This special cas...

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the header is (C, alpha) summation

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from this link:

Note that [the (C,2) sum] would not be the Cesaro sum of the Cesaro sum but rather the limit of the Cesaro transform of the Cesaro transform of the sequence s_1, s_2, ⋯
but this kinda remains unhelpful

dull tundra
#

@mortal trench calculate the y value of the x intercept them reverse then should be the answer

tidal matrix
#

For the Cesàro sum of a series?

tidal matrix
#

so it seems like you would want to take the sum of the sum, alpha times, and take a limit of that

graceful viper
mortal trench
tidal matrix
#

so if you can find that, maybe it is a good concrete example

#
  • dj's method seems easiest practically speaking
odd edgeBOT
#

@mortal trench Has your question been resolved?

odd edgeBOT
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ember shell
#

My screenshot is loading immensely slowly

ember shell
#

hey why do i need to factor the -1?

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Yippee

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So basically midway through solving the problem I got a bit confused

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So I took a look at the answer key because I knew that b and a had to be reversed to cross out

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So the way they did it was by multiplying the bottom by negative 1

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But like wouldn't that just be changing the equation to get the outcome you want?

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How is that even possible

forest sky
#

b - a = -1(a - b)

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it's factoring

ember shell
#

Lemme think about that

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Omg!

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Wait that makes sense kinda?

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So u remove the negative 1

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So then it all becomes negative reasonable

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Cuz ur just taking it out

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Okay thank uu

#

.close

odd edgeBOT
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patent sun
#

what i need to do exactliy

odd edgeBOT
#

Please don't occupy multiple help channels.

patent sun
#

ok

wanton bison
#

Is y a real or natural number?

patent sun
#

both ?

rough birch
#

try taking a logarithm on both sides, and using exponent properties of logarithms

patent sun
#

ok thx

#

<3

#

.close

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twin vigil
odd edgeBOT
twin vigil
#

Question 8 how to continue from here onwards

odd edgeBOT
#

@twin vigil Has your question been resolved?

faint knot
#

I found a BS way you couldve solved this

#

this is cos(70 - x) = 2 sin x cos 40
now just assume that cos(70 - x) = cos 40, and notice that sin 30 = 1/2

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gloomy shell
#

can someone help me

odd edgeBOT
gloomy shell
#

for trigonometry

unkempt lichen
#

please send your question

gloomy shell
unkempt lichen
#

your job is to find a?

gloomy shell
#

im not sure about the answers,

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yeah

unkempt lichen
#

what have you learnt and tried?

gloomy shell
#

i got 16.7cm as my answer

unkempt lichen
#

ok, let's check it

gloomy shell
#

but the answer key says 11cm

gloomy shell
unkempt lichen
#

does your answer key have workings?

gloomy shell
#

nope

#

it only says "a=11.15cm"

unkempt lichen
#

how did you get 16.7cm?

#

because if it's the same method as mine, i don't see what's wrong here personally

gloomy shell
#

15sin48/sin42 = 16.7

#

the sine rule

#

a/sin A = b/sin B

unkempt lichen
#

ok that was a little overcomplicated, you could have just done 15 tan 48

gloomy shell
#

yeah

#

i figured

unkempt lichen
#

but i got the same as you that way

gloomy shell
#

alr

#

so the answer key "11.15cm" is incorrect?

unkempt lichen
#

sure you looking at the answer to the correct question?

gloomy shell
#

yeah

unkempt lichen
#

then i can't explain the discrepancy

#

i agree with your answer though

gloomy shell
#

okay thank you so much

unkempt lichen
#

sure

#

!done

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gloomy shell
#

.close

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unkempt lichen
#

<@&268886789983436800>

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snow socket
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snow socket
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.close

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left mist
#

how come there are 4 values although sin(thetre) = +1/2 only has 2 values i thought?

nimble blaze
#

firstly theta, not thetre
and how do you only have sin(theta) = 1/2

left mist
#

oh wait nvm

#

i figured it out

#

my b

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tulip cradle
#

In the graph you see a half circle with radius one and a curve f(x) = sqrt(x/2). I don't understand why they subtract the second integral and not add it.

tulip cradle
#

It expresses the area of the grey zone btw

wooden python
#

subtracting the second integral is equivalent to adding the integral of sqrt(x/2)-sqrt(1-(x-1)^2)

tulip cradle
#

Oh okay

#

because then f(x) lies above the circle?

wooden python
#

yes

tulip cradle
#

Alright

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lone elbow
odd edgeBOT
unkempt lichen
#

you're not stuck, right?

lone elbow
#

hmm

#

it would be useful to determine all the pairs in R

lone elbow
#

for symmetric 1 pair,
c R b

#

for transitive 1 pair
d R d

#

for reflexive and symmetric, 5 pairs
d R d, b R b, c R c, f R f, c R b

#

for symmetric and transitive, 4 pairs
d R d, b R b, c R c, c R b

#

for equicalence relation, 5 pairs
d R d, f R f, b R b, c R c, c R b

odd edgeBOT
#

@lone elbow Has your question been resolved?

rapid hound
#

probably helps if it’s in english

lone elbow
odd edgeBOT
#

@lone elbow Has your question been resolved?

void yew
#

ok you've got a)right
b)right
c)right
d)right
e)right
f)right
catthumbsup

#

Imagine I used Roman numerals instead of letters

#

Haha

#

@lone elbow

lone elbow
#

i appreciate it

#

@void yew

#

.solved

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rich wasp
#

$$ \iint_R dx dy $$
$$ R = [0, a] \cross [0, b] $$

clever fjordBOT
manic sleet
rich wasp
#

idk which expression the integral would be equal to

#

hold on im sending u a photo

#

acc nvm

#

it's just ab

#

right

manic sleet
rich wasp
#

ty

#

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rich wasp
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keen bison
#

Guys, I have an exam tmr and I am cooked. 1st year uni math. calc and algebra. there are about 30 questions. I would really appreciate if someone could explain and help me get through them.

echo relic
#

Can someone please help

keen bison
#

please dm me if you are able to hop on a call with me

glass vault
odd edgeBOT
soft terrace
#

does this help?

glass vault
#

bro i feel bad for chetti getting his channel robbed lol

echo relic
#

?

glass vault
#

eddy open ur own help channel

soft terrace
#

oop, good point

echo relic
#

How

soft terrace
#

!occupied

odd edgeBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

echo relic
#

!open channel

#

Open channel

#

@mod open channel

#

!occupied

odd edgeBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

soft terrace
#

@echo relic just repost your question in one of the unoccupied help channels 🙂

echo relic
#

Thanks

indigo dirge
#

@keen bison if you have a specific problem that you need help with, post it here! Don’t ask to ask :)

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#

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mystic saffron
odd edgeBOT
mystic saffron
#

i got 6 but its wrong

odd edgeBOT
#

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

mystic saffron
#

i got help from this server

#

and um

marble laurel
#

Well could you post how you got 6?

mystic saffron
#

ok

mystic nova
#

hmmcat Let me see

mystic saffron
mystic saffron
marble laurel
#

Wait what?

#

Why is Pythagoras in that form?

mystic saffron
zinc glacier
#

it follows from similar triangles

mystic saffron
#

i might have messed up

zinc glacier
#

where does the first formula come from?

mystic nova
#

It's not Pythagoras

mystic nova
marble laurel
#

Ah

#

Alright

mystic nova
#

He's not allowed to use trig tho

zinc glacier
#

you familiar with angle bisector theorem?

mystic saffron
#

ya

#

ray that divides an angle into two equal angles

mystic nova
#

Using area then [ABC]=[ABQ]+[AQC]=>AB.AC=sin(45).AQ.AB+sin(45)AQ.AC

mystic saffron
#

mhm

mystic nova
mystic saffron
#

oh

#

we did that

mystic saffron
mystic nova
#

What's the answer

#

Do you have it?

mystic saffron
#

we got 6

mystic saffron
mystic nova
#

I mean the correct one

#

Do you have one?

mystic saffron
#

no

mystic nova
#

I think it's 24

mystic saffron
#

thats too high

#

ngl

mystic nova
#

Hmm

#

True

mystic saffron
#

idk lol

#

so what do we do

#

try trig

mystic saffron
mystic nova
#

Try 24

#

I mean everything i did lead to 24 lol

mystic saffron
#

ihave an idea

#

nvm

mystic nova
#

Could you try 24 for me

mystic saffron
#

ima do 24

#

alr its loading

#

dang'

#

its correct

#

but how

#

tysm

#

im done

#

ty @mystic nova

#

bye

#

.clos

#

.close

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#
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last junco
#

If i have to find the growth speed for a certain point in a function, do i just differentiate the function and insert my x?

amber schooner
#

if by growth speed you mean the derivative then yes

last junco
#

Yes, thank you

#

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frozen musk
odd edgeBOT
frozen musk
#

tried following this

#

I got y=0 and y=3 and I drew those lines

#

then I use sign analysis and found positive for y<0 and y>3

#

and negative from 0<y<3

#

idk what to do now

odd edgeBOT
#

@frozen musk Has your question been resolved?

wanton bison
#

You can draw a few vectors of the form (x',y') = (1, y(y-3))

#

Can do a table

frozen musk
#

okay let me ask this first

#

y'(t)=f(y) which means for my problem f(y)=y^2 -3y

#

so f'(y) = 2y-3?

wanton bison
#

No

#

You dont need f' wrt y

frozen musk
#

do we need to find stability?

wanton bison
#

Well it says that in the task

frozen musk
#

sorry this topic is literally brand new to me

#

jumped head first into this problem before trying to learn the theory

wanton bison
frozen musk
#

okay

frozen musk
#

is this what you meant?

wanton bison
#

Yes

frozen musk
wanton bison
#

Well x' is always 1

#

Oh mb i misread

#

So for y=1 you would have the vectors (1,-2)

#

And as you noticed has negative orientation for 0<y<3

frozen musk
#

makes sense

#

for y=2 (2,-2)?

wanton bison
#

x'=1 always

frozen musk
#

?

wanton bison
#

You plot (x',y') not (y,y')

frozen musk
#

oh

wanton bison
frozen musk
#

right

#

okay cool

#

so just plot all these and draw lines connecting them?

wanton bison
#

Not lines

#

Like this (old example of my classes)

frozen musk
#

oh

#

this is from my book

#

idk how they got the lines

#

honestly I prob needa watch some videos on this before I can continue doing more problems

wanton bison
#

They drew the vectors see the small gray lines

#

They draw example functions that fit the direction field

#

Like for example in y=0 you just have the direction vectors (1,0) that implies a constant function like y=0 representing a solution

frozen musk
#

I get it now

#

okay cool yeah

#

I should be able to finish the problem then. and I'll try to figure out the stability and part b. if I can't I'll just come back in here

#

tysm

#

.close

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mystic saffron
#

parts?

odd edgeBOT
mystic saffron
#

im pretty sure its doable by parts

#

like u = lnx and v = arctg(x)

#

?

#

hm not really

#

arctan(x)/x is nightmare

#

oh nvm i figured it out

#

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frosty mango
odd edgeBOT
frosty mango
#

No l’hopital allowed or tripple angle trigonometric identity

#

Any hint?

subtle raft
#

Huh

bitter lodge
# frosty mango Any hint?

i would ||multiply top and bottom by x + sin(x)|| then consider ||appropriate small angle approximations||

frosty mango
#

Thx

#

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bitter lodge
#

oh yeah haha i was over complicating

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tame folio
#

I need help with how to solve these, which are called pythagorean and quotient identities?

tame folio
#

Help-

#

My precalculus quiz s tommorow and I still cannot solve a single equation

tame folio
lilac galleon
#

see tan theta = sin theta / cos theta , so we are multiplying cos theta to tan theta , in which the cos theta of tan theta will get cancelled

lilac galleon
#

$tan theta = \frac{sin theta}{cos theta}$

clever fjordBOT
#

Nobita18

lilac galleon
#

$tan (theta) = \frac{sin (theta)}{cos (theta)}$

clever fjordBOT
#

Nobita18

lilac galleon
#

theta is θ as you can see on your board

lilac galleon
# clever fjord **Nobita18**

now we are multiplying cos (theta) to tan (theta) , but we can write tan (theta) like this so then the cos (theta) which we multiplied and the one in denominator will get cancelled

#

@tame folio

tame folio
#

tan(theta) and cos(theta) gets cancelled if we multiply them?

lilac galleon
crystal charm
clever fjordBOT
#

឵឵MxRgD

tame folio
lilac galleon
#

$tan (theta) . cos(theta) = \frac{Sin(theta)}{cos(theta)} . cos(theta) = Sin(theta)$

clever fjordBOT
#

Nobita18

tame folio
#

Soo we rewrte them?

lilac galleon
unkempt lichen
tame folio
#

Soo, NAH

unkempt lichen
#

would you like a visual explanation?

tame folio
unkempt lichen
#

okay. let us work on this arbitrary right triangle.

tame folio
#

can we use this?

#

I think it's called a super hexagon from what I remembered with our lesson

mystic nova
tame folio
crystal charm
#

or maybe not, i'm not sure

unkempt lichen
tame folio
unkempt lichen
#

do you get this sequence?

tame folio
#

Kinda, I get the pattern.

#

Here's an equation my teachered showed us

unkempt lichen
#

alright, then you may proceed. sorry for interrupting

crystal charm
tame folio
#

The main thing I get about this topic is that if we multiply identities the result will come out whatever matches

tame folio
#

I'm also confused how there was a 1 there

tame folio
crystal charm
# tame folio Idk man

well you have a sin^2(x) on top which is canceled by the sinx. So that becomes sinx

tame folio
tame folio
#

Soo pretty much we just cancel out the identities and whatever is left is the final result?

lilac galleon
tame folio
lilac galleon
#

$\frac{sin x . sin x . cos x}{cos x . sin x} = sin x$

clever fjordBOT
#

Nobita18

tame folio
#

I forgot there was 3 sin(x);-;

unkempt lichen
# crystal charm

the square is above the i and not the n? new notation just dropped

crystal charm
tame folio
#

Also, every step is base on the reciprocal, pythagorean, quotient identities

tame folio
#

Y'all still alive?

lilac galleon
tame folio
#

Yay...

#

How about this problem?

lilac galleon
#

(a-b)/b can be written like (a/b) - b/b

#

in your case a = 1 , b = cos^2 theta

crystal charm
lilac galleon
#

1-cos^2 theta = sin^2 theta

tame folio
#

Ohhh

#

I don't get it.

lilac galleon
#

there's an identity

#

$sin^2 (\theta) + cos^2(\theta) = 1$

clever fjordBOT
#

Nobita18

lilac galleon
#

so if you shift cos^2 theta on the right side , you get 1-cos^2 theta

lilac galleon
tame folio
#

Slr, I was doing something

lilac galleon
#

you do know whats ( Sin theta / Cos theta ) right

tame folio
#

identities?

lilac galleon
#

$tan (\theta) = \frac{sin (\theta)}{cos (\theta)}$

clever fjordBOT
#

Nobita18

lilac galleon
#

so $tan^2 (\theta) = \frac{sin^2 (\theta)}{cos^2 (\theta)}$

clever fjordBOT
#

Nobita18

lilac galleon
#

and when you solve the 1st step of your problem you get the right side , but we know that its value is tan^2 theta

#

so your answer is tan^2 theta

tame folio
#

The final or nah?

lilac galleon
#

the final answer

#

did you understand?

tame folio
#

Not entirely, more of a visual learner;-;

lilac galleon
#

$(1-cos^2(\theta)) = sin^2(\theta)$

unkempt lichen
#

think you missed a bracket somewhere

clever fjordBOT
#

Nobita18

lilac galleon
#

$\frac{(1-cos^2(\theta))}{cos^2(\theta)} = \frac{sin^2(\theta)}{cos^2(\theta)} = tan^2 (\theta)$

clever fjordBOT
#

Nobita18

lilac galleon
#

@tame folio

tame folio
#

Soo we cancel out the 2 cos^2?

lilac galleon
tame folio
#

I'm tryna make sense of this using superhexagon hold on

crystal charm
#

superhexagon?

#

ngl, I'm thinking of the game when you say superhexagon lol

lilac galleon
tame folio
crystal charm
#

looks confusing

lilac galleon
#

yep

crystal charm
#

is it meant to represent the trig reciprocals?

lilac galleon
#

yep in an easy way , but it aint a easy way

crystal charm
#

An easier way to remember which one is which is to look at the third letter. So for example.
cot(x) would be 1/tan(x)

#

sec(x) is 1/cos(x)

#

cosec(x) is 1/sin(x)

#

it was how I was taught, but tbh when you do a lot of trig manipulation. You just already have them memorised

unkempt lichen
#

that's an ingenious memorization method

tame folio
#

Soo cooked with what I'm doing

lilac galleon
lilac galleon
tame folio
lilac galleon
tame folio
#

Can you explain in a visual way like annotation?

odd edgeBOT
#

@tame folio Has your question been resolved?

crisp egret
#

help
help
Find the coefficient of x^10 in the expansion of (1 + x^2)^20

ashen yew
crisp egret
#

ig its the general expansion for binomial theorem

ashen yew
crystal charm
#

btw this is occupied still

unkempt lichen
#

!occupied

odd edgeBOT
#

Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).

crystal charm
#

and they already have there channel

unkempt lichen
#

also

#

!1c

odd edgeBOT
#

Please stick to your channel.

ashen yew
#

Am I helping someone who’s already got someone helping them or smth

crystal charm
#

currently this one is occupied though by someone else

ashen yew
#

Okay I think I get it now

odd edgeBOT
#
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hearty nest
#

The question states that f(x) is an increasing function, so why is f'(x) ≥ 0?

potent nexus
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What would be wrong with that

hearty nest
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f'(x) should be greater than 0, right?

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and not equal

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coz its states increasing and not non decreasing

potent nexus
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I would tend to agree but I think >= 0 is also correct

bronze citrus
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If it equals to 0 doesnt mean its decreasing

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Its constant

hearty nest
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yh

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its constant

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but

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nvm

summer wave
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Depend on your terminology but usually constant is increasing also

bronze citrus
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If the question states the function is stictly increasing then > 0 but if its just increasing >= 0

summer wave
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Ye

hearty nest
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acc to the ques?

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okok

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thanks

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.close

odd edgeBOT
#
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odd edgeBOT
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hearty nest
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f'(x)>0, how to find domain

odd edgeBOT
wooden python
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domain...?

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or do you want to simply solve the inequality f'(x)>0

hearty nest
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umm

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yh

wooden python
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progress?

hearty nest
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is domain not the right word??

wooden python
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i would say it is not

hearty nest
wooden python
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maybe if you showed the entire problem exactly as was originally stated to you then we could look for a better word

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ok, in that case

wooden python
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make a sign table

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for x going from 0 to 2pi

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take note 1-tan(x) will change signs when passing through infinity as well as through 0

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(sin(x)+cos(x))^2 is always positive and so serves only to exclude points where it's 0 (bc it's in the denominator and you can't divide by 0)

hearty nest
wooden python
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ok so you just want to pick which of these intervals it is increasing in

hearty nest
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hmm

wooden python
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your f'(x) looks wrong

hearty nest
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oh sorry there's a typo

wooden python
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this is why we have !xy kekehands

hearty nest
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you fixed it earlier

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its this in denominator

wooden python
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ok so then 1+(sin(x)+cos(x))^2 is always positive and even never 0

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so can be entirely ignored

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also cos(x)(1-tan(x)) is better rewritten back into cos(x)-sin(x)

hearty nest
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ok

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tryng

wooden python
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now you only need to find which of these intervals cos(x)-sin(x) is positive in

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which is considerably easier than your original question

hearty nest
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i got it!!

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thanksss

#

.close

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timid brook
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$\frac{(4^3)^{1/3}}{(4^{0.5})^{\frac{4^2}{4\sqrt{4}}}} ;-; \frac{\sqrt{4^2}}{(\sqrt{4})^2}$

clever fjordBOT
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Phantom

strange aspen
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!status

odd edgeBOT
#
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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
timid brook
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4

golden sonnet
odd viper
unkempt lichen
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hang on, you put 4

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show your work

odd edgeBOT
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@timid brook Has your question been resolved?

odd edgeBOT
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odd edgeBOT
mystic nova
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Same radius, M1M2=r\sqrt{2}

odd edgeBOT
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@upper pebble Has your question been resolved?

mystic nova
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I mean as long as M1M2 is r\sqrt{2} it can always make a square

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Why you have to made the diagram using coordinates btw

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Using geogebra geometry

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It's much easier

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No it's not, you don't have to use coord in geogebra geometry

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It's different from geogebra calculator btw

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There are a lots videos about it, most of geo main use it

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It has many features I can't describe all here

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Okay,... It's hard for me since the diagram doesn't label all the point

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And it's 12am here so I can't open my computer or get a paper

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You could ping other helpers for help

odd edgeBOT
#

@upper pebble Has your question been resolved?

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dawn roost
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I thought the answer is D, I’m abit confused differentiation on a graph. I have drawn f’ and f” but it seems wrong

amber schooner
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if the tangent line is above the curve then the function is concave down

unkempt lichen
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f' should be ||always decreasing|| in the domain, no? that should tell you something about f''

dawn roost
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So f’ will be like this right

amber schooner
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no

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f’ is decreasing

amber schooner
dawn roost
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I don’t really know how to draw f’

amber schooner
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it doesn’t really matter

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you don’t need to

amber schooner
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if you don’t understand what it means then just say so

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/how to apply it here

unkempt lichen
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another way maybe you can think about it is to imagine tangents at different points along f in the domain

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as you move along from a to b, what do you notice about the slopes of those tangents?

dawn roost
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So if f’ concave down, then f’’ increasing, like that right

amber schooner
amber schooner
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not of f’

dawn roost
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f is decreasing -> f’ concave down , f’ <0. Bc f’ concave down them f” becomes increasing -> f” >0 right 🥹🥹🥹

amber schooner
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no?

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f decreasing means f’ < 0. it does not mean f’’’ < 0

dawn roost
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Yeah, I understand the part f decreasing , f’ <0, f’ will have concave down. And bc it’s concave down f” will increase and > 0

amber schooner
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no

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where is f’ being concave down coming from?

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f’ being concave down means it’s second derivative is < 0

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which is f’’’

dawn roost
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I can’t really visualize it

amber schooner
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if f is concave down and decreasing then f’ < 0 and f’’ < 0

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do you agree

dawn roost
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Why does f’’ <0

unkempt lichen
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maybe it'd help

amber schooner
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this is a consequence/definition of being concave down

unkempt lichen
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sure, but as you move along from a to b and draw tangents at different points

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do the slopes of those tangents change?

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if so, are they steeper? shallower?

dawn roost
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They steeper

unkempt lichen
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they grow steeper downwards, right?

dawn roost
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Yep

unkempt lichen
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so that means, f' has a negative rate, aka f' is < 0 and constantly growing in the negative direction

amber schooner
unkempt lichen
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so f'' is the slope of the graph of f'

dawn roost
unkempt lichen
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if f' constantly grows in the negative direction, then f'' must be...?

dawn roost
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Oh, it will also be negative

unkempt lichen
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there we go

amber schooner
dawn roost
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Okay okay i got it now