#help-10

1 messages · Page 387 of 1

feral tide
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is this right

obtuse pebbleBOT
feral tide
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@everyone

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anyone know

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is it right

serene moss
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Question 1 is right

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Both are right

feral tide
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ok ty bro

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yo

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@serene moss

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are these all right

serene moss
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I'll check.

feral tide
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ok ty

serene moss
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Hey @feral tide

feral tide
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ye

serene moss
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Look at Q.3

feral tide
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its wrong?

serene moss
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I think you are wrong there

feral tide
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ok

serene moss
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Say the distance is x

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You get tan40=x/45

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x=45.tan40=37feets

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Q4 is correct

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Q5 is correct

feral tide
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@serene moss

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yo i think 3 is right

serene moss
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one min

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Yeah you are right

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Sorry, my bad

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Made the wrong diagram in my mind lol

cosmic fog
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Whatever he said is wrong

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U cannot do that

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U have to convert sinx - cosx purely as sin or purely as cos function

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So u have to multiply and divide by the square root of the sum of squares of coefficients of sin and cos

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In this case that evaluates to root(1² +( -1²))

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So 2 times (sinx - cos x)/root2

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2 times sin(x-pi/4)

obtuse pebbleBOT
#

@feral tide Has your question been resolved?

#
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obtuse pebbleBOT
#
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fresh copper
#

what are the subgroups of the dihedral group D6 as permutations of the numbers 1-6?

fresh copper
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<@&286206848099549185>

rancid shadow
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just ask chatGPT, and it gives you a PERFECT answer.

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I just did it.

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👍

fresh copper
rancid shadow
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then what do you want exactly

fresh copper
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i want the subgroups of gorup D6

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as in C3,C2, V4, etc

rigid plaza
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Wait so you know the subgroups

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But not how to represent them?

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Very different problems

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@fresh copper

fresh copper
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ill show u what im making

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when i press the subgroup, it should highlight the elements

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@rigid plaza

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@rancid shadow

rigid plaza
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What is your question exactly about what you need to do

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Where are you stuck

fresh copper
rigid plaza
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!status

obtuse pebbleBOT
#
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
fresh copper
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1

rigid plaza
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Think of rotations and reflections

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And how those act as generators of the dihedral group

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How can use a subset of them as generators for the subgroups

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Once you can identify all the subgroups

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The next part is easy

fresh copper
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i actually dont get this

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can you give me an example?

rigid plaza
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Do you know what a dihedral group is?

fresh copper
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so D6 is a regular hexagon

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and the group of D6 means the ways u can rotate/reflect it to keep it the same

rigid plaza
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"Is" is a very strong term

fresh copper
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ok not is, but you can interpret it as one

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and i am using a hexagon with vertic as 1 2 3 4 5 6

rigid plaza
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Yes

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What are the generators of D_6 geometrically

fresh copper
rigid plaza
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You need a single reflection and a single r60 to generate the whole group

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What other rotations will give you sub groups?

fresh copper
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mupltilpes of 60?

rigid plaza
fresh copper
rigid plaza
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Anyways after you have analyzed the structure in terms of reflections and rotations

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Just draw a hexagon with vertices labeled to find permutations in terms of numbers

rigid plaza
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What the subgroups are

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gtg good luck

obtuse pebbleBOT
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@fresh copper Has your question been resolved?

fresh copper
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hell naw

fresh copper
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☠️

obtuse pebbleBOT
#

@fresh copper Has your question been resolved?

obtuse pebbleBOT
#
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outer cargo
obtuse pebbleBOT
outer cargo
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i know the answer is 0 i just dont know wtf went wrong

slate monolith
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!rotate

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.rotate

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mm

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the bot

outer cargo
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ill rotate it

slate monolith
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ok thx

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.original

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!original

obtuse pebbleBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

slate monolith
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is that the original q

outer cargo
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there

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having a hard time with gifs

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greatest integer functions

slate monolith
outer cargo
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what original?

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like the original equation?

slate monolith
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ye

outer cargo
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yup

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thats the given

prime pilot
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r u sure the answer is 0?

slate monolith
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x/(x-1) + x

outer cargo
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what do you guys think

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idk what went wrong

prime pilot
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is that a ceiling function or a floor function

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ohh its a floor function

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yeah its 0

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lemme explain

outer cargo
slate monolith
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me neither -_-

outer cargo
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a floor function involves a positive subscript right?

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i think

prime pilot
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The floor function ⌊x⌋ returns the greatest integer below the input (basically the nearest integer below it)

thick chasm
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gif is also known as floor function

slate monolith
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erm is this hs math or uni math or smth else

prime pilot
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therefore, if x is approaching 1 from beneath it (from the negative side), the floor of all of those values no matter how close they are to 1 will be 0

slate monolith
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oh

outer cargo
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im trying to study advance because my uni has online lectures uploaded on yt

prime pilot
outer cargo
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yes

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one question tho

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perhaps it isnt

eager niche
obtuse pebbleBOT
# outer cargo

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

prime pilot
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we’re looking at values really close to 1, but below it

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so x-1 is gonna be really close to 0, but below it

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meaning that the floor function of all of these numbers will be -1

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remember the subscript -, after the 1, just tells you that you’re approaching 1 from values below it

outer cargo
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okay i think i get it

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i need more exercises

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thank you

prime pilot
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this means the floor function of x - 1 as x tends to 1⁻ is -1

prime pilot
outer cargo
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.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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brisk yacht
obtuse pebbleBOT
brisk yacht
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kinda confused on what to do

prime pilot
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in order to combine those fractions, you'll need all of them to have a common denominator

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once you've done you can just add/subtract the numerators, while keeping the denominator the same]

brisk yacht
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whats the common denominator?

prime pilot
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in this case it's gonna be 12x^2

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ik that becasue, the lowest common multiple of 3, 4 and 6 will be 12

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and the highest power of x there is x^2

brisk yacht
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ok

#

ty

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.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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onyx sentinel
#

I have A^(-1) = [(detA)^2]/detA, can I cancel the determinant in the denominator and the square in the numerator?

onyx sentinel
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Like we do using numbers?

gilded needle
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the equation doesn't make sense, the LHS is a matrix and the RHS is a number

onyx sentinel
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wait

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let me show the original problem

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@gilded needle

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I have done this so far

timid silo
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You could stop here

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Further simplifying would get you |A|^5 =1
Since the power is odd you could say
|A|=1

onyx sentinel
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Aigh aight

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thanks

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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rough stump
#

Prove that { tan ( 135° +θ ) * tan ( 45° - θ ) = sin2θ - 1 / sin2θ + 1 }

obtuse pebbleBOT
#

@rough stump Has your question been resolved?

rough stump
#

<@&286206848099549185>

dreamy fox
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Okay wait I'm doing it on paper

rough stump
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ok thanks

dreamy fox
#

Is your question correct?

royal flint
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Lhs is just -1

dreamy fox
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LHS is coming -1

rough stump
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wait let me re check

dreamy fox
royal flint
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Rhs is -tan^2 theta-45

rough stump
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sorry one this is wrong

royal flint
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Lhs is just -1

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I was so confused

rough stump
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Prove that { tan ( 135° + θ ) * tan ( 45° - θ ) = sin2θ - 1 / sin2θ + 1 }

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sorry guys

rough stump
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u got the answer

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so quick

royal flint
dreamy fox
rough stump
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can u teach me

dreamy fox
rough stump
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ok

royal flint
rough stump
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i did this problem 3 times but not getting answer

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Thanks btw

dreamy fox
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That happens initially to all of us

royal flint
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Yeah there are some general patterns

dreamy fox
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True

royal flint
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Like if lhs has theta and rhs has 2 theta, usually you have to use sin2 theta or cos 2 theta stuff

rough stump
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ok

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Can I ask one more question (short one)

dreamy fox
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Sure

rough stump
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The absolute least value of sqrt(2)* sinx - sqrt(2)*cosx is:

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Absolute least value mean function smallest value? right

dreamy fox
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Yes.

rough stump
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-1 < = sin < = 1 , -1 < = cos < = 1

dreamy fox
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That approach won't work in this question

rough stump
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ok

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sqrt(2) [ sinx - cosx]

dreamy fox
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Haven't you heard of the concept of maximum and minimum value of f(x)=Asinx +Bcosx?

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There's a general formula

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I can show you if you haven't

rough stump
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hmmm

dreamy fox
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Hmmm means?

rough stump
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  • sqrt ( a^2 + b^2 )
dreamy fox
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Yes

rough stump
dreamy fox
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So in this case you need to use it.

rough stump
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it is 2

dreamy fox
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Not really

rough stump
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2

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-2 , 2

dreamy fox
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Yes.

rough stump
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but this is not correct option

dreamy fox
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Huh

rough stump
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according to my text book

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0 is correct option

dreamy fox
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I'm pretty sure that's wrong.

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Does your question

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Include

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Non negative?

rough stump
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nope

dreamy fox
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I believe the given answer is incorrect then.

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0 will surely be a vaue at x=π/4

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But that isn't the min.

rough stump
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ok

dreamy fox
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(a) must be the one

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Wait are u a jee aspirant??

rough stump
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not reallly

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but some thing like that

dreamy fox
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Oh ok

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NDA?

rough stump
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I am from Pakistan

dreamy fox
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What then?

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Oh I see

rough stump
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You Indian

dreamy fox
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Yep

rough stump
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great

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Nice to meet you

dreamy fox
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Same here!

rough stump
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Can u tell me

royal flint
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Ooh

rough stump
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where minus go in above question when we solve tan (135)

royal flint
#

What grade

rough stump
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12th

royal flint
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Nice

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I just finished 12th

dreamy fox
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The - sign is multiplied inside the bracket

royal flint
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Also buddy sleep it's like 1.30 here I am done with school so I can do anything 😂

dreamy fox
royal flint
dreamy fox
#

JEE aspirant??

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Bear?

royal flint
#

Nah I am going to us

dreamy fox
#

Oh nice

royal flint
#

Wbu?

rough stump
dreamy fox
#

Yeah prepared for JEE now going to Jadavpur University EE

dreamy fox
royal flint
royal flint
#

12th was so stressful 😭

rough stump
#

Thanks

royal flint
#

Cbse?

dreamy fox
royal flint
dreamy fox
royal flint
dreamy fox
#

Which uni are u going bro

stoic yacht
#

!redir

obtuse pebbleBOT
#

This channel is only for on-topic discussion. Please take casual conversation to #discussion or #chill.

rough stump
#

ok

royal flint
royal flint
dreamy fox
#

Woahh 😭

stoic yacht
#

all good :)

dreamy fox
rough stump
#

Thanks guys

#

again

royal flint
#

Byee so nice talking to u

rough stump
#

You to bye

#

.clsoe

#

.close

obtuse pebbleBOT
#
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onyx sentinel
obtuse pebbleBOT
#
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lone bobcat
obtuse pebbleBOT
lone bobcat
#

wtf does this even mean

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thats not even echelon is it

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type 2 echelon matrix, is a regular upper triangle

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with extra columns

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and to say first and third colomns are basic, what?

stoic yacht
#

basic columns are sometimes called pivoted or leading

lone bobcat
#

pivoted

stoic yacht
#

as in, that column has a pivot in RREF

lone bobcat
#

meaning 0s infront

stoic yacht
#

pivoted columns have a nonzero entry in that position in RREF

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the first pivot is the 2 in the first column, so the first column is pivoted

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then stair-stepping down by moving one down and one to the right, there isn't a 0 there so the second column isn't pivoted

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the next nonzero entry at that level is the 5 in the third column, so the third column is pivoted

lone bobcat
#

but shouldnt the 5, be a 1?

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for echelon

stoic yacht
#

you could technically further simplify the second row by dividing by 5, yes

lone bobcat
#

so summarising

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2 and 5 are the leading elements of their respective rows so those columns are the pivots

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or basic columns

stoic yacht
#

you usually refer to the 2 and 5 as being the pivots

lone bobcat
#

hm

stoic yacht
#

and you say those columns are "pivoted" or "leading" or "basic"

lone bobcat
#

hm

#

k

stoic yacht
#

just a terminology thing

lone bobcat
#

2,5 pivots, basic columns

#

tyvm

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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tardy heart
#

Hi I am confused why there are 2 cos^2

obtuse pebbleBOT
tardy heart
#

Where did this come from?

latent walrus
#

thats just equivalent to 1

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theyre making a common denominator

tardy heart
#

How do we know though?

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Like why isnt it sin over sin

latent walrus
#

because the denominator of the fraction is cos^2

tardy heart
#

Ohhh

latent walrus
#

you could do sin/sin sure but it wouldnt be useful in any way

tardy heart
#

They just want it to be same?

latent walrus
#

they need a common denom to combine the terms into a single fraction

stoic yacht
#

they have a/b + 1, and they want to write it as one fraction. by writing 1 as b/b, that becomes a/b + b/b = (a+b) / b

tardy heart
#

OHHHH

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I SEEE

#

Thank you so much!

#

.close

obtuse pebbleBOT
#
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tardy heart
#

.reopen

obtuse pebbleBOT
#

tardy heart
#

Sorry one more question

#

Why do we need to simplify this to begin with?

#

tan^2 looks simplified?

latent walrus
#

i wouldnt say you need to, its just what it wants you to do, having a single term is arguably simpler than multiple if possible

tardy heart
#

Oh ok thank you

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I just have a hard time figuirng out if I need to simplify or not

latent walrus
#

unless it asked you to i wouldnt stress about it

tardy heart
#

Kk awesome

#

Thanks again

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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astral cypress
#

I was studying for descrete mathematics(not really sure if it's the right name since im not a native english speaker). It's basically the base of the computer thinking, graphs, combinatorics, relations etc.. so not to prolong it too much the topic im confused about is combinatorics precisely combinations, for example question says you have a 5 digit number then, it has to be palindrom and the sum of all digits has to be 6, i have couple of setups im thinking about. I would split all possible forms of 5 digit number in "categories" so 1) the "shape" of the number should be aabaa 2) abbba etc.. the part im stuck at is the how do i set this up as a combination like n over k for combinations since aabaa can only be 1 number and it's 11211 but that's just using logic i want to know how to "mechanically" get to the answer coz i assume there won't be always logical answers or there might be just too many of them to do it this way. here's also a picture of how i was thinking

astral cypress
#

a

cunning pebble
astral cypress
cunning pebble
#

oh and yeah the area of maths is called discrete mathematics

astral cypress
#

amazing

cunning pebble
#

Discrete maths is in my opinion very intuition based class, you need to practice attention to details, this is essential especially when it comes to combinations and stuff like that. Concepts arent that difficult(they get more difficult at higher level), but yeah theres a lot of room for silly mistakes or wrong assumptions.

astral cypress
#

i understand that but i just got to it several days ago because i couldn't follow the lectures from university because of private reasons so any info on anything will be helpful in passing this exam

#

the only reason im just a bit irritated about this is that i can't see that way, for example counting all palindrom 5 digit numbers i just wouldn't know how to set that up that's what i was asking in the first place since there are a ton of them i can't count them

#

.close

obtuse pebbleBOT
#
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weary reef
warm shaleBOT
#

StrangeQuarkAL

weary reef
#

0 <= a_1, a_2, a_3 <= 6

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a_1 > 0

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Still gotta use some logic to count it but it's slightly easy I'd say

astral cypress
#

im assuming my labling is fine as well?

weary reef
#

Yeah that's fine

astral cypress
#

i did get similar solution where it says 2a+2b+c=6 i just had no clue how do i use that

weary reef
#

My answer was more in response to "how to mechanically"

astral cypress
#

yeah and im seeing the pattern, in these im just not really getting what these equations are telling me and i feel like im missing out on a lot

weary reef
astral cypress
#

so let me get this straight, not to bother you all night, is that equation able to tell me what the solutions are and if not what at least how many are there ?

#

like the exact numbers

weary reef
#

It should be possible but I can't say I'm familiar with the methods unfortunately

astral cypress
#

yeah yeah understandable, doesn't matter imma dig anyways thanks a lot for reaching out you did put me on a right track tho so i appreciate it a lot

weary reef
#

I usually just the equations to make it into a simpler exhaustive process

obtuse pebbleBOT
#
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twilit bay
obtuse pebbleBOT
twilit bay
#

theres a second part to this question\

#

b. Calculate an estimate of the lower boundary of the masses of the heaviest 50% of these animals.

twilit bay
twilit bay
#

like i first did 50% of 2226 which is 1113 so we know we get heaviest starting from number 1114

#

but afterwards then i calculated cumulative freq which showed me that 13-32 has 1590

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but if we bring that in half to 13-22 and 23-32 which is a freq of 530 and 530 each

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then we get to now 1060 which is even closer

#

then finally using that i got 23kg

#

but how do u get 23.5

obtuse pebbleBOT
#

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tardy heart
#

How do I solve this if the tangent of 270* is undefined?

tardy heart
#

Nvm it doesnt want me to solve

#

332

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bold zinc
#

is this saying $s = \sqrt{((R-r)^2}+h^2)$

obtuse pebbleBOT
warm shaleBOT
bold zinc
short spire
#

Well that extra parenthesis is unambiguously telling you it’s $s = \sqrt{(R-r)^2+h^2}$

warm shaleBOT
craggy osprey
#

the root is all thw way

bold zinc
#

oh ok

#

thank you for clearing that up

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full egret
#

whenever i put the matrice into my calculator it doesn't give me an answer, what am i doing wrong?

full egret
#

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drifting nova
#

am i supposed to reject?

obtuse pebbleBOT
drifting nova
#

at 0.05

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drifting nova
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.reopen

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desert cipher
#

Just making sure I’m right on 2. I’m not exactly sure how to do this so I could be wrong, but the RREF form of the matrix just doesn’t make sense to me if U is a linear combination of those vectors. Do I have this right?

grizzled shore
#

If your rref is correct then you’re right

desert cipher
#

Row 3 shows that the system is inconsistent right?

grizzled shore
#

An inconsistent system means there does not exist a, b, c ∈ ℝ such that v = av₁ + bv₂ + cv₃

desert cipher
grizzled shore
#

So you can’t make v out of a linear combination of v₁, v₂ and v₃

desert cipher
#

Yea

#

Alright

#

Just making sure I wasn’t wrong cause I’m still a little shaky

grizzled shore
#

It’s correct!

desert cipher
#

Thanks bro!

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viral valley
#

Hey! Trying to solve this problem regarding subspaces. It's from the "Linear Algebra Done Right" Textbook. I know how to prove if a set U is a subspace of a vector space V. There are 3 rules: 0 element in U, closed under addition, and closed under multiplication.
However, I am really struggling to understand what "set of continuous real-valued functions on the interval [0,1]" means, and what R^[0,1] means. I've been searching the internet to find an explanation and I can't.
In addition, I don't know how a "0 element" could exist in a set of functions. Also how can we be closed under multiplication if there are only functions and no scalars?

stoic yacht
#

iirc, R^[0,1] is notation for the set of all functions f: [0,1] -> R

viral valley
#

[0,1] is the domain (continuous interval)?

stoic yacht
#

yes

viral valley
#

would the function work on any number outside of [0,1]?

stoic yacht
#

its defined domain would be specifically that interval

#

for example, f(x) = 0 is an element of R^[0,1]

#

any value in [0,1] is in the domain and gets mapped to a real number

viral valley
#

ah okay awesome

stoic yacht
#

so clearly continuous functions f: [0,1] -> R is a subset of R^[0,1]

#

just a matter of showing it's a subspace, i think you can prove all three conditions pretty easily

#

adding continuous functions gives a continuous function and since R is closed under addition, it's still real valued

#

scaling a continuous function by a constant gives a continuous function and since R is closed under multiplication, it's real valued

viral valley
#

Ah

stoic yacht
#

as for what the zero element looks like in a set of functions

#

the zero element is the unique "vector" such that if it's added to any other vector, that vector's value is unchanged after the addition

viral valley
#

f(x) = 0?

stoic yacht
#

so my earlier example, f(x) = 0, is exactly your zero element

#

yeah

viral valley
#

Ohhh my gosh

stoic yacht
#

are the two spaces the same?

viral valley
#

yes

stoic yacht
#

no

#

R^[0,1] is the set of all functions that map from [0,1] to R

#

but not every function is continuous

#

which means the space of all continuous functions mapping from [0,1] to R is a subset of that space

viral valley
#

oh thats true

#

oh this makes so much sense now

#

thank you so much!!!!

#

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random grotto
#

Hi, I'm studying matrices and I had a question. If the rows of a matrix are linearly independent, does that also menat the determinant of A is 0?

random grotto
#

Because I think its right in saying that if the columns of A are linearly dependent then the det of A is 0

remote skiff
#

Not as stated no

random grotto
#

So I was thinking from another angle

random grotto
gilded needle
#

if the rows are LI (and it's a square matrix) then the det is nonzero

stoic yacht
#

determinant is 0 when there's linear dependence, otherwise nonzero

random grotto
#

Yea sorry I should mention that the matrix A is n * n

stoic yacht
random grotto
#

Ah sorry I see now

#

Okay so that means if the rows of A are linearly independent, then the detmerminant of A is not 0

#

I see, thank you all

#

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warm shaleBOT
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mint nebula
#

Consider the square ABCD and the points K (AB), L (BC) and M (CD) such that the Triangle AKLM is
rectangular isosceles, with the right angle in L. prove that the right AT and DK are perpendicular.

mint nebula
#

I think that the problem is really easy, yet I'm missing on a theorem or lemma.

#

Here's the drawing.

obtuse pebbleBOT
#

@mint nebula Has your question been resolved?

mint nebula
#

<@&286206848099549185>

#

I've found that LC + AK = KL

#

If it helps

obtuse pebbleBOT
#

@mint nebula Has your question been resolved?

mint nebula
#

<@&286206848099549185>

obtuse pebbleBOT
#

@mint nebula Has your question been resolved?

mint nebula
#

<@&286206848099549185>

warm sparrow
#

theres not T in your drawing or in the explenation so AT is the T suppose to be something else?

warm sparrow
#

oke well lets see then

#

oke so to prove that those are pupandicalair you got to prove that DKL~ ALK

#

and for that you need those variables that you already put in a and x

mint nebula
warm sparrow
#

well yes

#

but you got to give prove for that

mint nebula
#

and i think the agles LMC and KLB are congruent

mint nebula
#

@warm sparrow why do I need to prove that these triangles are similar

#

i don't think they even are similar

mint nebula
#

<@&286206848099549185>

rocky galleon
#

yes?

mint nebula
#

i need help with this problem Consider the square ABCD and the points K (AB), L (BC) and M (CD) such that the Triangle AKLM is
rectangular isosceles, with the right angle in L. prove that the right AL and DK are perpendicular.

rocky galleon
#

kk wait

mint nebula
tranquil sonnet
#

You can just length bash the whole thing

#

Solve for x

#

Solve for relevant lengths, And use converse of Pythagorean

mint nebula
#

Okay

#

And it should end up to knowing the sides of AKLD

mint nebula
#

I dont think I have enough lenghts though

#

like enough given lenghts

tranquil sonnet
#

assume teh square has side length 1

mint nebula
#

rather than calculus

#

but idk

gilded flower
#

Can i get help with something in this channel?

tranquil sonnet
#

no

mint nebula
#

sorry

gilded flower
#

Hooooow

tranquil sonnet
mint nebula
#

yeah those are not similar

tranquil sonnet
#

nvm yeah synthetic is probably better

#

i dont think computation is good

mint nebula
#

right

#

and also this is a 7th grade national olympics problem

#

they probably don't know computations lol

tranquil sonnet
#

ok

#

so do you see why JK=MC?

mint nebula
#

where's J?

#

you mean L?

tranquil sonnet
#

sorry AK=MC

mint nebula
#

oh

#

yeah KB = DM=x

tranquil sonnet
#

yeah

mint nebula
#

so by difference AK = MC

tranquil sonnet
#

ok note that DAK is congruent to ABC

mint nebula
#

Right

tranquil sonnet
#

now you can just calculate the slope of the lines and multiply them to get -1

#

because if the product of the slopes is -1 they are perpendicular

mint nebula
#

wait one sec

#

i wanna go sythetic all the way lol

tranquil sonnet
#

theres an angle chase too if you want

#

ok

mint nebula
#

let me see smth

tranquil sonnet
#

let <AKD=x

#

then

#

focus on quadrilateral KBL(intersection)

#

what letter is labeled at the intersection? sorry i cant see

mint nebula
#

I didn't lable it. Let's say it's T

tranquil sonnet
#

Ok

mint nebula
#

so KBLT

tranquil sonnet
#

yeah look at its angles

#

<BKD=180-x, <KBL=90, <BLA=<AKD=x

mint nebula
#

B has 90, TKL has 180 - x -

tranquil sonnet
#

and the sum of all angles should be 360

#

yeah

#

and this gives <KTL=90

#

so they are perpendicular

mint nebula
#

amazing

#

that was a beautiful solve tbh

tranquil sonnet
#

i suggested slope because its also very easy

mint nebula
#

yeah true

tranquil sonnet
#

rise/run = slope

#

so

#

AD/AK * -BL/AB

#

using the congruent triangles it simplifies to -1

mint nebula
#

what's nice about geometry is synthetic solving, at least thats what i like

tranquil sonnet
#

good

mint nebula
#

but when you're absolutely out of ideas, you can do that too lol

tranquil sonnet
#

i love synthetic

#

when you learn more advanced geometry youll see the beauty of synthetic

#

its absolutely amazing

mint nebula
#

i'm looking forward to that

#

anyways, thank you and have a great day

tranquil sonnet
#

np

#

u2

mint nebula
#

.close

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unkempt lotus
obtuse pebbleBOT
young crypt
#

can you make a formula for the distance between the point and the equation perhaps

unkempt lotus
#

Yeah d = sqrt((x-3)^2 + (y-0)^2)

vale pelican
#

who is y?

unkempt lotus
#

So y would equal sqrt(x)

young crypt
#

yes

vale pelican
#

we know who y is now lol

unkempt lotus
#

And x is ……. Something

#

Can u not skep steps

#

Skip*

young crypt
#

yea sorry mb

unkempt lotus
#

I don’t know how to get x

young crypt
#

thats fine we have an equation for the distance in terms of only x correct?

unkempt lotus
#

I kno x = x^1/2

#

Yeah true

#

My b

#

I was trying to get x in terms of y

#

But I forgot we just need the objective in terms of one variable

young crypt
#

so if we have an equation for d in terms of x, and we want to find the minium value of d what do we do

unkempt lotus
#

So I have sqrt(x^2-5x+9)

young crypt
#

yep

unkempt lotus
#

Which is (x^2-5x+9)^1/2

#

Then we take the derivative and get critical point

young crypt
#

exactly

unkempt lotus
#

So I need chain rule

young crypt
#

yea

unkempt lotus
#

Is that just bringing the (x) to 1/x and putting. x’ on top?

#

Like x’/2x?

#

And x is the (x^2-5x+9)

icy mirage
unkempt lotus
#

Wut

young crypt
unkempt lotus
#

They r trolling

#

<@&268886789983436800>

young crypt
unkempt lotus
dapper bloom
#

Don't troll here.

icy mirage
#

Sorry, my bad. Read (0,3) instead of (3,0)

unkempt lotus
#

Ok let me try that again

#

Now solve for d’(x)=0

young crypt
#

yes

unkempt lotus
#

And I can just multiply both side by denominator. So it is just 2x-5 = 0

young crypt
#

yea or you can think of it like you cant divide by zero so the only way for the right hand side to be zero is for the top of the fraction to be zero

unkempt lotus
#

So i get x is 5/2

young crypt
#

correct

unkempt lotus
#

Ok now get d(5/2)

young crypt
#

we dont need the distance just the y coordinate now

unkempt lotus
#

O

#

So I just plug it into the constraint

#

Y = sqrt(5/2)

young crypt
#

yes the original equation

#

yep

unkempt lotus
#

Ok cool

#

Thx

#

.close

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urban topaz
#

Hey can someone double check for me. I got 20 for my answer but the website says im wrong

frosty crypt
#

perhaps it's supposed to be 2,000 because x is in 100 dollars

#

because x=20 is correct

urban topaz
#

it was 2000 😭

#

thank you

#

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karmic hedge
#

Where was my sign error?

obtuse pebbleBOT
karmic hedge
#

sin^3(x)cos^2(x)

#

sin^2(x)sin(x)cos^2(x)

#

(1-cos^2(x))sin(x)cos^2(x)

#

(1-u^2)(u^2)

#

u^2-u^4

haughty coyote
#

you missed the - sign

karmic hedge
#

Where?

wooden cipher
#

what is du?

high lily
#

forgot about the conversion of dx to du

karmic hedge
#

u = cos(x)

#

du = sin(x)

wooden cipher
#

youre missing a dx

#

also are you sure about that

#

derivative of cos

karmic hedge
#

oh

#

Youre right

#

Mb I need a break I have been studying for too long 😂

#

Thank you everyone

#

❤️

#

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glass pilot
#

Can someone please help me with this problem?

obtuse pebbleBOT
smoky vigil
#

!status

obtuse pebbleBOT
#
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
smoky vigil
#

!showwork

obtuse pebbleBOT
#

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

glass pilot
#

I checked calculators online, but they show up as a complex conjugate

smoky vigil
#

can you draw a picture

obtuse pebbleBOT
#

@glass pilot Has your question been resolved?

glass pilot
smoky vigil
#

just a picture of the area, normal integral

smoky vigil
#

well, show the integral you've set up

obtuse pebbleBOT
#

@glass pilot Has your question been resolved?

glass pilot
#

Sorry for the late response I was travelling

smoky vigil
#

you can distribute, and split this into two integrals

#

both can be solved with trig sub

#

@glass pilot

glass pilot
#

How do I do that?

obtuse pebbleBOT
#

@glass pilot Has your question been resolved?

#
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brisk arrow
obtuse pebbleBOT
brisk arrow
#

My result seems a bit different from the answer?

#

Is it wrong?

narrow fiber
#

No it's correct

#

It just needs to be simplified

brisk arrow
#

How

deft magnet
# brisk arrow

(6*(2^-1)*3)^1/6
=(6*1/2*3)^1/6
=9^1/6
=3^2^1/6
=3^1/3

#

=(thirdroot)3

brisk arrow
#

I see

deft magnet
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#

@brisk arrow Has your question been resolved?

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lilac bloom
#

Can someone explain to me why $\sum\limits_{n=1}^{\infty}2\sin(\frac{3}{n})$ diverges? $n^\mathrm{th}$-term test is inconclusive here, I can't apply geometric tests, I can't apply power series tests, and we're not super far into series so I don't know how sine is described as a series. My gut instinct tells me that it does diverge since it oscillates, and i know that it does diverge anyways, but I don't know exactly why or how to prove it.

warm shaleBOT
deft magnet
#

sin(3/n) approaches sin(0) = 1?

lilac bloom
#

sin(0)=0

deft magnet
#

o

#

mb

#

not thinking

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💀

lilac bloom
#

if it were 1 then the nth term test would have told me it diverges and it's the first thing i checked

bronze mica
#

when x is small, sinx is approximately x, so in particular greater than x/2

#

so for sufficiently large n the terms of the series are greater than the terms of a harmonic series

wooden cipher
#

you can do limit comparison with 3/n

deft magnet
#

m

lilac bloom
#

oh

#

interesting

bronze mica
#

if you've not seen a formal definition of sine yet, I assume just stating that this is true will be fine in terms of rigour

lilac bloom
#

so, since $2\sin(\frac{3}{n})>\frac{3}{n}$ for sufficiently large values of $n$, the comparison test still applies?

warm shaleBOT
wooden cipher
#

in calc, its common for people to be given lim x->0 sin(x)/x = 1

lilac bloom
#

also I realise now that $2\sin(\frac{3}{n})$ doesn't oscillate on $n\geq1$

warm shaleBOT
bronze mica
#

it changes direction once actually

#

it doesn't oscillate for n > 1

lilac bloom
#

I see

#

One more question

#

How would i prove $2\sin(\frac{3}{n})>0,;1<n<\infty$

warm shaleBOT
bronze mica
#

also yeah comparison test applies, because you can rewrite the series as (finitely many terms where the inequality doesn't work) + (still an infinite series where it does which is what you actually apply the test to)

bronze mica
lilac bloom
#

Oh

#

fair

#

Alright, thanks for clearing that up for me

#

That makes sense now

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
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wraith barn
obtuse pebbleBOT
wraith barn
#

i thought itd be like AB = AO - BO, but ig not

#

nvm

#

.close

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timid silo
obtuse pebbleBOT
timid silo
#

What do i do with the root

shut lagoon
#

Where did the bottom factor go?

timid silo
shut lagoon
#

You just multiplied the numerator by 1+sqrt(sin^2(x))

#

$\frac{a}{b}\cdot \frac{c}{c} = \frac{ac}{bc}$

warm shaleBOT
#

Azyrashacorki

timid silo
#

Right

shut lagoon
#

That should help, along with the identity $\sin^2(x) + \cos^2(x) = 1$

warm shaleBOT
#

Azyrashacorki

timid silo
timid silo
shut lagoon
#

Well the point isn't to cancel them out, otherwise you just did..nothing

#

Leave the factors there and expand the denominator.

timid silo
#

Ohh

minor furnace
#

I think the right answer isn't shown in the answer choices..?

high lily
#

as is, you can just direct sub
(but that doesn't lead to any of the answer options)

#

do you have the intended answer?

timid silo
shut lagoon
#

Oop didn't even think of plugging in 😅

minor furnace
#

it's supposed to be 1 + sqrt(3) / 2

#

it's not on there

high lily
#

I suspect they may have intended
x to pi/2 (instead of pi/3)

timid silo
#

Hmm

minor furnace
#

I would take that up with the instructor if applicable

obtuse pebbleBOT
#
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rose ferry
#

hey could someone show me the equation to this?

stoic yacht
#

they've actually given you the expression for the mass of the isotope over time

#

0.9174^t

#

just a matter of seeing when that equals 0.2

obtuse pebbleBOT
#

@rose ferry Has your question been resolved?

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near cairn
#

Does Jordan’s Lemma hold true for any $f(z)$or is it only for functions of the form $f(z)= e^{izt}g(z)$? I’m seeing conflicting results online\
I’m looking within a textbook and saw a video which both stated $f(z) = e^{izt}g(z)$ but in a different video I’m looking at, the person just writes a generic $f(z)$\
Did the person make a mistake here or is the $e^{izt}$ just kinda implied here in a $\frac{a}{a}$ kinda way?

warm shaleBOT
#

KySquared

brazen viper
#

So you generally use Jordan's Lemma to find the values of a path integral around a particular semicircular arc. The fact that it goes around the arc is where the exponential comes from, it's part of the parametrization of the curve.

#

So your function f(z) doesn't, in the general case, contain e^(izt), it's just that it picks up the e^(izt) because that's how we walk around a circular arc on the complex plane.

near cairn
#

Wait how?
I understand rewriting z as Re^(it) but its not like that can get factored out…?

#

Wait

#

Are you considering the e^(izt) as getting factored out?

brazen viper
#

It's not that it gets factored out

#

Ok, so starting from the beginning. Let's take an ancient problem I solved once.

#

So this contains a detailed work up of a particular integral

#

The complex analysis started at "our contour"

#

So the idea is, I want to evaluate the integral on 0 to infinity. But I only know how to evaluate it on a closed contour because of the residue theorem, right?

near cairn
#

Mhmm

#

So make a contour which includes the region you want

#

That much I get

brazen viper
#

So we set up a contour from -R to R along the real axis, and then a semicircular part with radius R

#

Our goal is to show that the semicircular part vanishes

near cairn
#

Agreed

#

Everytime I tried so far I would manually show it goes to 0 by expanding and pulling out Re^(i*theta)’s

brazen viper
#

$$
\begin{align*}
\oint_C \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \int_{-R}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{R} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{\pi} \frac{{\left(R \mathrm{e}^{i \phi}\right)}^{-2/5}}{1 + {\left(R \mathrm{e}^{i \phi}\right)}^2} , iR\mathrm{e}^{i \phi} , \mathrm{d}\phi \
\lim_{R \rightarrow \infty} \int_0^{\pi} \frac{{\left(R \mathrm{e}^{i \phi}\right)}^{-2/5}}{1 + {\left(R \mathrm{e}^{i \phi}\right)}^2} , iR\mathrm{e}^{i \phi} , \mathrm{d}\phi &= 0 \
\oint_{C, R \rightarrow \infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \int_{-\infty}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z + \int_0^{\infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z \
\int_{-\infty}^0 \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= - \int_0^{\infty} \frac{(-z)^{-2/5}}{1 + (-z)^2} , \mathrm{d}(-z) \
\oint_{C, R \rightarrow \infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z &= \left(1 + \mathrm{e}^{-2\pi i/5}\right) \int_0^{\infty} \frac{z^{-2/5}}{1 + z^2} , \mathrm{d}z \
\end{align*}
$$

warm shaleBOT
#

OmnipotentEntity
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

near cairn
#

And then explicitly showing it goes to 0 like that

brazen viper
#

Oh it was cut off, how sad

#

So you notice that I have a few copies of this integral with minor changes

near cairn
#

I don’t wanna do that each and every time and would prefer to just say “its 0 by jordan’s lemma”

brazen viper
#

But only one copy has the Re^(iφ)

near cairn
#

Mhmm

brazen viper
#

Right, and that's fine

near cairn
#

You switched back to writing it in terms of z for sone reason

brazen viper
#

Because it's pretty well understood that's what you're doing, if you're just doing applications

#

In the linked post, I had the linear integrals written as a function of z and the semicircular arc as a function of φ.

near cairn
#

Is that the f(z)e^(ikz) part?

brazen viper
#

Of course, it doesn't matter what variables you use

#

But the intention was there

near cairn
#

Mhmm

brazen viper
#

The point is that Jordan's Lemma only applies to arcs that limit to infinity

near cairn
#

Right, im not worried about the limits

brazen viper
#

And these will have a term of e^(iφ)

near cairn
#

Its specifically the functional part

brazen viper
#

Because they are circular arcs

near cairn
#

Okay I think I get it

brazen viper
#

So your original function can be anything, f(z), but the circular arc part of the integral will be Re^(iφ) f(z) because that's the nature of arc integrals

near cairn
#

Because $\int_c f(z) dz$ can be represented as $\int_{0}^{\pi} f(Re^{i\theta}) iRe^{i\theta} d\theta$ that is the functional representation that is satisfied for Jordan’s lemma because of the arc?

brazen viper
#

Only the semicircular arc portion of the contour integral

#

It's not the entire contour normally

near cairn
#

Oh I should’ve just wrote it as a curve not a closed loop

#

But you get the idea

warm shaleBOT
#

KySquared

brazen viper
#

Yeah, I see what you're trying to say now

near cairn
#

There we go

brazen viper
#

Nice grookey btw

near cairn
#

Thank youlisayay
Nice to see a fellow pokemon fan

#

Do you like competitive?

brazen viper
#

I... haven't actually played any game since Red Blue. >_>

near cairn
brazen viper
#

I pay a little bit of attention to competitive

#

Like YouTube stuff

#

I mostly just play poketwo, the discord game

near cairn
#

I played alot of comp a few years back but mostly stopped bc of school

#

I was kinda losing interest regardless so I doubt I’ll get back to it

#

Who knows

near cairn
brazen viper
#

Kinda wanted to try to make a showdown AI

near cairn
#

Most the time I spend w/ pokemon nowadays is shiny hunting

near cairn
brazen viper
#

But haven't really sat down and figured out how to make that happen yet.

#

Like, a random battles NN AI would be sick

near cairn
#

I know the very very basics of ML but if you’d like any sorta input I could try and throw my hat in the ring

#

Wouldn’t mind learning more ML
Especially since I considered going into data science lol

brazen viper
#

Anyway this is off topic. If you want discuss this we can jump over to #discussion or something. But I don't have anything smart to say about it really lol. I have done ML before, but not specifically reinforcement learning before.

obtuse pebbleBOT
#

@near cairn Has your question been resolved?

#
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glossy pike
#

i dont get why the correct answer is A not B. Is there flaws in my works?

glossy pike
#

<@&286206848099549185>

rancid shadow
#

if you get g(x) from f(x), you must move fx along x-axis -2, multiply 5 along and move -1 along y

#

that's the reason correct one is A

glossy pike
rancid shadow
#

just in the case of x axis

glossy pike
#

yeah

rancid shadow
#

let's assume that fx = 1/x and gx = 1/(x-1)

#

the corresponding answer is (x+1, y)

glossy pike
#

got it, thank you!

#

.close

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marble robin
#

how do i do this question im really confused !?

marble robin
#

<@&286206848099549185>

#

please help

young crypt
#

well what’s the formula for speed

icy oar
#

Well, the distance he ran is 450m

marble robin
icy oar
#

Hmm

young crypt
marble robin
#

but theres no time

marble robin
#

m

young crypt
marble robin
#

righ

#

right

#

ok got it thanks

young crypt
#

cause you have the speed for some sections and the distance travelled

marble robin
#

yes

obtuse pebbleBOT
#

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quaint bluff
#

hey, how do i find the intersection points between these 2 functions?

gilded needle
#

the most straightforward way is probably to consider the various cases, where 2x-4 >= 0 vs 2x-4 < 0, and similarly for 6-x

quaint bluff
#

and how do i proceed?

gilded needle
#

well 2x-4 changes sign at x=2, and 6-x changes sign at x=6
so you want to consider these intervals:
(-infty, 2)
(2,6)
(6,infty)

#

in each of those intervals, you can get rid of the abs vals and apply the appropriate sign

#

for example:

#

in (-infty,2) you have 2x-4 < 0 and 6-x > 0, so |2x-4| becomes -(2x-4) and |6-x| becomes 6-x

#

and similarly for the other two intervals

quaint bluff
#

.close

obtuse pebbleBOT
#
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sonic bolt
obtuse pebbleBOT
sonic bolt
#

does anyone have any idea what the answer would be to this solution?

#

nothing on the graph matches, quadratic doesn't give me a real number