#help-38

1 messages · Page 131 of 1

verbal idol
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💀

dense breach
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snow would solve this in 2 minutes using complex numbers

tulip vapor
#

fr?

dense breach
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probably

tulip vapor
#

but thats cheating fr

frozen plover
#

snow would take one look at this and decide its not worth anyones time

tulip vapor
#

same as uni student solving 8th grade questions

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@amber python

wet dragon
frozen plover
#

don't ping them...

dense breach
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idk I can't

verbal idol
frozen plover
tulip vapor
#

havent yall studied complex numbers

wet dragon
#

anyway

worldly wing
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Isn’t the first bracket equal to 21

verbal idol
#

yeah you can use de movire

worldly wing
#

Yeah I remember that result

verbal idol
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in this question

verbal idol
tulip vapor
#

could be, then the second must simplify to 5 to make final answer 105

verbal idol
#

but proving it is hard

dense breach
#

$\tan(x) = \f{e^{-ix}-e^{ix}}{e^{ix}+e^{-ix}}i$ or something

solid kilnBOT
#

thewizardofOU

tulip vapor
tulip vapor
wet dragon
tulip vapor
#

8 of my neurons died just by looking at this

wet dragon
#

i was trying something

tulip vapor
#

woa

verbal idol
#

(cosx+isinx)^n= cos(nx)+ isin(nx)

tulip vapor
#

,w $$\left(\tan^2 \frac{\pi}{7} + \tan^2 \frac{2\pi}{7} + \tan^2 \frac{3\pi}{7}\right) \cdot \left(\cot^2 \frac{\pi}{7} + \cot^2 \frac{2\pi}{7} + \cot^2 \frac{3\pi}{7}\right)$$

worldly wing
tulip vapor
#

snoww

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help us mere mortals out

verbal idol
tulip vapor
#

,w explanation $$\left(\tan^2 \frac{\pi}{7} + \tan^2 \frac{2\pi}{7} + \tan^2 \frac{3\pi}{7}\right) \cdot \left(\cot^2 \frac{\pi}{7} + \cot^2 \frac{2\pi}{7} + \cot^2 \frac{3\pi}{7}\right)$$

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fkin give the stepss

worldly wing
#

That’s not how wolframalpha works…

tulip vapor
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WHAT THE F

verbal idol
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wow

tulip vapor
#

IM TRAUMATIZED

verbal idol
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bro @tulip vapor

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the solution on the internet is the best one

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you gotta follow it

tulip vapor
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but i dont wanna use some random ass identities i dont even know

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even if i get the solution now, theres no point

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because using this method wont click in my mind ever

verbal idol
#

it is useful for jee

tulip vapor
verbal idol
tulip vapor
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thats the formula

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whats*

verbal idol
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yeah thats important here

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oh

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see

tulip vapor
#

both my trig functons and equations is done but i havent been taught that tan(nx) thing

marsh forum
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was about to suggest using complex numbers

verbal idol
#

you can see the pattern

#

tan2x = 2tanx / 1- tan^2x

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tan 3x = 3tanx - tan^3x/ 1 - 3tan^2 x

tulip vapor
verbal idol
#

if you see the pattern

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tan (2x) = S1/S0 - S2

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where Sn is sum of tan(x) taken n at a time

tulip vapor
#

whaaaaaa

verbal idol
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(this was taught to us im not lying)

tulip vapor
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hold on

verbal idol
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yes

tulip vapor
#

lemme use normal identities

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$$\left(\tan^2 \frac{\pi}{7} + \tan^2 \frac{2\pi}{7} + \tan^2 \frac{3\pi}{7}\right) \cdot \left(\cot^2 \frac{\pi}{7} + \cot^2 \frac{2\pi}{7} + \cot^2 \frac{3\pi}{7}\right)$$

solid kilnBOT
#

Aryan07

frozen plover
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tan(nx) is a neat pattern

tulip vapor
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yeah so

verbal idol
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tan 3x = S1 - S3/ S0 - S2

verbal idol
tulip vapor
#

taking pie/7 as theta

verbal idol
#

its soo good

tulip vapor
#

But using triple angle, we would have to square it up

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thats too much steps

verbal idol
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no other way

worldly wing
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you can try finding an equation which has roots tan(pi/7), ...

verbal idol
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but bro wont listen

worldly wing
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ah, I see

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that seems to be the easiest way other than like

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expanding everything out

verbal idol
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yeah

wet dragon
verbal idol
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mb gotta go

worldly wing
#

$4\theta=\pi-3\theta$ and take tan on both sides

tulip vapor
solid kilnBOT
#

kheerii

worldly wing
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should work

tulip vapor
#

but wheres 4theta in the question 💀

worldly wing
solid kilnBOT
#

kheerii

tulip vapor
#

yeah

wet dragon
worldly wing
#

also, $\tan(4\theta)=\tan(\pi-3\theta)$ has roots $\frac{\pi}{7},\frac{2\pi}{7},\frac{3\pi}{7}$

solid kilnBOT
#

kheerii

wet dragon
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@dense breach

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Why did you skull emoji me

tulip vapor
dense breach
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for repeating kheeri

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after Aryan already responded

worldly wing
tulip vapor
#

😭

worldly wing
#

theta=pi/7 is an obvious step, from where you have 7theta=pi

dense breach
#

it was really more of a slow build up

worldly wing
#

after this 4theta=pi-3theta should also not be too hard to think of

tulip vapor
worldly wing
#

whenever you have this kind of form you need to split your theta into two parts

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it's a similar method to how we find $\cos\left(\frac{\pi}{5}\right)$ and the other trig ratios

solid kilnBOT
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kheerii

worldly wing
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$5\theta=\pi\implies 3\theta=\pi-2\theta$

solid kilnBOT
#

kheerii

tulip vapor
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i have memorized pie/5 and other important ratios tho

worldly wing
tulip vapor
#

hmm

tulip vapor
worldly wing
tulip vapor
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and I would be doing tan(A+B) 💀

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hold on let me write it down

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but

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why are we bothered with 4theta here

worldly wing
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We aren’t

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We just need to split it up somehow

tulip vapor
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but out of so many different ways why only 4theta = pie-3theta

worldly wing
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It’s the easiest

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If you did it as 5theta=pi-2theta you would need to find tan(5theta)

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Although this approach will work as well

tulip vapor
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but I would have to find 4theta too and i dont know that formula

worldly wing
#

The formula for tan(nx)

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It’s pretty handy

tulip vapor
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well you could learn endless formulas but that'd be pointless

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like tan(10theta)

frozen plover
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real for that

worldly wing
#

If you refuse to learn any approach which will help you solve this question, nobody can help you.

tulip vapor
worldly wing
#

Who says this involves complex numbers…?

tulip vapor
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the people earlier

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so whats the formula for tan(nx)?

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the general formula

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@worldly wing

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...

frozen plover
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wolfram probably has it

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,w tan x

tulip vapor
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what am i supposed to look for in this'

frozen plover
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nothing

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none of them are what you wnt

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here

tulip vapor
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whats k

frozen plover
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index variable for the summation

tulip vapor
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am i supposed to know what that means

delicate pagoda
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tan(nx) is equal to a sum of things from 0 to n

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divided by another such sum

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that's just an identity of the tan function

tulip vapor
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hmm

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i think im beyond saving

frozen plover
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[ \sum_{k = 1}^{10} k ]

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Do you know what this means

tulip vapor
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nope

solid kilnBOT
#

Bob l'éponge

frozen plover
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oh boy

tulip vapor
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i dont know what this summation function upper and buttom thing means

frozen plover
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It means you put the value that it starts from

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in this case 1

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up to the value on top

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in this case 10

tulip vapor
#

oh

frozen plover
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so this sum is just 1 + 2 + 3 + 4 ... 10

tulip vapor
#

ahh

delicate pagoda
tulip vapor
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yeah whats the next step now

frozen plover
#

Do you know what [ \binom nk ] means

solid kilnBOT
#

Bob l'éponge

tulip vapor
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no

frozen plover
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Okayy maybe this formula isn't for you

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[ \binom nk = \f{n!}{k!(n-k)!} ]

tulip vapor
#

thats from binomial theorem ig, that chapter we'll study in future

delicate pagoda
#

the binomial coefficient describes how many ways there are to choose k of n elements

solid kilnBOT
#

Bob l'éponge

tulip vapor
#

so in short im cooked

frozen plover
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ask your teacher about the problem

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i doubt you'll be assigned something you haven't been taught the tools for

tulip vapor
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after doing theory of my trig function and eqn chapters i decide to hit some cengage or other modules, but internet decides to hit me up with this question

tulip vapor
frozen plover
#

¯_(ツ)_/¯

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maybe some jee folk can help you

tulip vapor
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usually 11 out of 10 people in help section are indians prepping for jee

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idk why they abandon me today

frozen plover
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half of your problems aren't worth solving

tulip vapor
#

WDYM

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anyone can solve ez problems

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the real dudes stay for hard questions

frozen plover
#

sure but the whole point of your exam is to get as much in as little time as possible

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you're no superhero for doing something anyone else can't

tulip vapor
frozen plover
#

¯_(ツ)_/¯

tulip vapor
#

mods should create jee role

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so I can summon JEE army

frozen plover
#

you said you aren't to spend more than 5 minutes, this channel's been open for an hour

tulip vapor
#

fr

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lol

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but

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its like a challenge

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first time is always a longer time period

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@frozen ploverhow to find range of sqrt(9tan^2 A+ 4cot^2 A + 13)

frozen plover
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AM > GM probably

tulip vapor
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so I did 9tan^2 + 4cot^2 >= 12

frozen plover
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uh why

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oh

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sure

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yeah

tulip vapor
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OH

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YEAH

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fk mb i did some dumb addition mistake

tulip vapor
#

is it only for reciprocal functions

frozen plover
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for positive reals

tulip vapor
#

I mean can you find range of ANY function with this?

frozen plover
#

it's only useful in certain cases

frozen plover
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but the condition for it to be true is positive real

tulip vapor
#

hmm

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.close

trim joltBOT
#
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earnest frigate
#

im lost please

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trim joltBOT
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@earnest frigate Has your question been resolved?

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@earnest frigate Has your question been resolved?

earnest frigate
#

.close

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rotund grove
#

,w derivatives

rotund grove
#

,w integrals

rotund grove
#

,w limits

rotund grove
#

okay sorry im going to the bots section

#

.close

trim joltBOT
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pallid cedar
#

ok so this is a question on a practice quiz i narrowed it down between 2x^2+5x+2 and 6x^2-x-2 but i can't figure out which one of them is right because both of them interset the quartic function twice at y=0

knotty quest
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Just divide as u normally do?

pallid cedar
#

what do you mean?

knotty quest
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Did u ever divide quadratic or cubic with linear?

pallid cedar
#

it's just polynomial divison right?

knotty quest
#

Yes

pallid cedar
#

why would it be with linear?

knotty quest
#

No i mean like

pallid cedar
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isn't it quartic division by quadratic?

knotty quest
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That process

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U have 2 options

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Try diving the thing with ur options

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Remainder is zero then that is the answer

pallid cedar
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ok give me a min to do that for both factors

knotty quest
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Ok

pallid cedar
#

ok so this is the point where i was at with my first factir

knotty quest
#

Yes

pallid cedar
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wait nvm i realize my mistake

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the first factor divides evenly

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both divide evenly

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(6x^4+23x^5+18x^2-12x-8)/(2x^2+5x+2) = 3x^2+4x-4

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and the other factor gives (x^2+4x+4)

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would i just pick the first factor bc x^2 + 4x + 4 can be factored further into (x+2)(x+2)

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@pallid cedar Has your question been resolved?

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trim joltBOT
slate barn
#

how to solve this limit

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i dont know where to start

dense breach
#

I would start by taking the log of the whole thing

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since log is continuous you can move it inside the limit

slate barn
#

ah true

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and then?

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slate barn
delicate bobcat
#

well

#

notice that you can bound the top part by pi/2

delicate bobcat
#

since arctan(inf) --> +pi/2

slate barn
delicate bobcat
#

but ugh ^(1/n) makes me think about taking ln or doing e^(...)

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woeful totem
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woeful totem
#

Are there ways to define functions that are piecewise functions kind of like this, but in non piecewise form, like an actual function

woeful totem
#

Sign just gives the sign of the number correct

lusty delta
#

yes

woeful totem
#

Could you explain the floor function, is it describing the periods of the function, and counting what "piece" it's on

lusty delta
#

plot the graph or individual components to see how it looks

woeful totem
#

Okay I understand this now. Thanks

#

.close

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tall prawn
#

Hey friends. I've been struggling with something in writing Mathematics: how to start a list of biconditional statements. It's something I come up against quite a lot, but I can't figure out the right way to go about it. Please can someone look at the two images I've posted, and tell me if Version 1 or Version 2 is correct? 🙂

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#

@tall prawn Has your question been resolved?

trail ingot
#

what is ‘the series’

tall prawn
#

Hey, thanks for the reply. Ah yeah sorry, I should have included that in the post. (Although, I don't think it really matters to my question. I'm interested in the writing, in the parts of the images I've highlighted) 🙂

rugged harness
#

would you be able to continue this on your own?

tall prawn
#

Hey Xene, thanks for the reply. My question is not about how to solve this specific problem. My issue is, I am trying to understand how to correctly write a situation like I've highlighted in the images I've posted: how to start a series of biconditional statements. I think my pictures explain it better than I can in words!

rugged harness
#

oh

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my bad bro

#

saw only the second image

tall prawn
#

No worries 🙂

#

Anyone got any insight into my original question? 🙂

tall prawn
#

.close

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@tall prawn Has your question been resolved?

trim joltBOT
#

@tall prawn Has your question been resolved?

simple haven
#

@tall prawn please forgive me, other than the text at the top indicating the version number, and very minor differences in how the words are written (n.b. literally how, as they appear to be all the same words), I am unable to spot the difference between your original two images.

Can you highlight the difference for me? Because apparently I am bad at reading.

#

Actually I think I found a difference being the text "the following equations hold" being included in the second and omitted in the first.

#

If this is the only difference, I don't see a significant problem with either including or excluding that phrase.

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flat spruce
#

why is this not diagonalizable over R, the eigenvalue of 3 has equal algebraic multiplicity and geometric multiplicity, no?

flat spruce
#

char. poly.

unique minnow
#

I mean the diagonalization would mean that you get a diagonal 3x3 matrix of the eigenvalues, but 2 of them are complex

flat spruce
#

oh shit yeah that was stupid of me, I was going purely off the definition

unique minnow
#

So even if one of them fills its eigenspace, you`re still missing two

flat spruce
#

thank you!!!

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unique minnow
#

Nw

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marsh forum
#

$\exists x\forall y(x<y)$

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solid kilnBOT
#

ƒ(Why am. I here)=I don't Know

marsh forum
#

Trying to figure out why this statement is false

#

We're dsiscussing over W btw

#

so this means there exists x for all y such that y>x

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ooh

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say y is 0

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there's no smaller number belonging to W

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right?

vagrant marsh
#

whats W

amber python
#

whole numbers?

exotic jetty
#

TIL whole numbers are non negative

marsh forum
vagrant marsh
#

what is the statement saying?

#

how do you interpret it?

marsh forum
#

there exists x, for all y, such that $y>x$

solid kilnBOT
#

ƒ(Why am. I here)=I don't Know

vagrant marsh
#

try saying it without using exists or for all

marsh forum
#

how? $\forall$ means forall, right?

solid kilnBOT
#

ƒ(Why am. I here)=I don't Know

vagrant marsh
#

yes

marsh forum
#

ok, there is a x for every y such that y>x

exotic jetty
#

there is a whole number such that any other whole number is greater than it?

vagrant marsh
marsh forum
#

oh, right.

vagrant marsh
#

i.e. there is a smallest element of W

marsh forum
#

got it

#

got it, thanks

#

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latent axle
#

Is there something more to part a in question 13 other than just cancelling the xs?

knotty locust
#

Yes there is more

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What about when x=0

latent axle
#

Uh

knotty locust
#

xf(x) is defined piecewise

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Since f(x) is

latent axle
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it will be sinx as long as x is not 0

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What’s wrong with saying that

knotty locust
#

So you have to show that it agrees with sin(x) in both cases

latent axle
#

Wdym

knotty locust
#

As the problem asks for 0<= x <= pi

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You can’t ignore when x is 0

latent axle
#

Hmm

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Then how can I prove it

knotty locust
#

What is sin(x) when x is 0?

latent axle
#

0

knotty locust
#

And what is xf(x) when x is 0?

latent axle
#

0

knotty locust
#

🔠

latent axle
#

What

knotty locust
#

You’re done

latent axle
#

So I’m just proving continuity

knotty locust
#

No you’re proving that they’re equivalent functions

latent axle
#

No integration involved?

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Odd for this book

knotty locust
#

In part a there is no integration

latent axle
#

Yeah

knotty locust
#

Part a helps with part b

latent axle
#

Sure but how does that like

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Solve it

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I guess

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because it’s only sinx when x is not 0

knotty locust
#

No

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You proved earlier that it worked for x is 0 aswell

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Reread what we did

latent axle
#

Both are 0/0

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Whether x is there or not

knotty locust
#

No, both are 0

latent axle
#

Wha

knotty locust
#

so when x is 0

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f(x) is 1

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Agreed?

latent axle
#

Sure

knotty locust
#

Sure or yes?

latent axle
#

Yeah it is

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For the second piece

knotty locust
#

So when x is 0, x*f(x) = ?

latent axle
#

0

knotty locust
#

x*1

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And x=0, so this is 0

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As you said

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So when x=0, xf(x) = 0

latent axle
#

but it’s 0/0 times 0

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Isn’t that illegal

knotty locust
#

No

#

There’s no division going on

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Anywhere

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Its x multiplied by f(x)

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f(x) is 1

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And x is 0

#

So it’s just 0*1

#

No division

#

x * f(x)
Equals
x * 1 (When x=0, f(x)=1 is why we make this replacement)
So
0 * 1
=0

#

So ignoring the top half of the function, for other values of x

#

All we’ve shown is that

latent axle
#

Okay

knotty locust
#

When x is 0, xf(x)=0

#

Does that make sense now?

latent axle
#

But how does that help us in (x)(sinx/x)

#

We proved 1*0 is 0

knotty locust
latent axle
#

So I can revolve it without it being defined at that point

knotty locust
#

It is defined at that point

#

its defined to be 1

latent axle
#

Well yes only because it’s piecewise

#

But in the integral lies (x)(sinx/x)

knotty locust
#

bruh I typed this wrong

#

let me fix

#

ignore that

solid kilnBOT
#

Austin

#

Austin

knotty locust
#

Agree? with this?

#

@latent axle

latent axle
#

Yes

knotty locust
#

Okay

#

And so we can simplify the top case, since x is not 0, they cancel

#

and we can simplify the bottom case, its x, which is 0

#

so

solid kilnBOT
#

Austin

knotty locust
#

So do you then also agree with this?

latent axle
#

Us

#

Yes

knotty locust
#

We have to show it for both cases

#

If 0<x<=pi

#

We’re already done, because it is sin(x)

#

Right?

latent axle
#

Uh

#

But it’s sinx/x

knotty locust
#

No

#

where are you getting that from

knotty locust
#

Look here

#

you agreed with this

#

you said, this is xf(x)

#

right?

latent axle
#

Okay yeah

knotty locust
#

and we want to show its equal to sin(x)

latent axle
#

Yes

knotty locust
#

maybe it makes more sense to write this

#

$$xf(x)=\begin{cases} \sin(x) \quad 0<x\leq \pi \ 0 \quad x=0\end{cases} ?= \begin{cases} \sin(x) \quad 0<x\leq \pi \ \sin(x) \quad x=0 \end{cases}$$

solid kilnBOT
#

Austin

knotty locust
#

because the thing on the right is just sin(x), yes?

#

just written case-wise, so you can compare them more directly

latent axle
#

Okay

knotty locust
#

Does it make sense to write it like that or not?

latent axle
#

Yeah I guess

knotty locust
#

If it doesn't make sense, what is confusing you

latent axle
#

Nothing I suppose

#

Just never seen it displayed like that

knotty locust
#

Okay, so now we want to show that they're actually equal not just "?="

#

we will go case by case

#

starting with the top case

#

Are they equal for 0<x<= pi?

latent axle
#

Yes?

#

Equal to what?

knotty locust
#

yes

#

to eachother

#

the left hand side is xf(x)

#

the right hand side is sin(x)

latent axle
#

The top and bottom to each other?

latent axle
knotty locust
#

consider first when 0<x<=pi

latent axle
#

yes

knotty locust
#

this means showing that the top lines of both sides

#

are equal

#

which of course they're

#

since they're both the same thing

#

Then consider when x=0

latent axle
#

if f(x) is sinx/x for 0<x<=pi

#

Yes that’s true

latent axle
knotty locust
#

when x=0

#

what is the left

latent axle
#

yeah x times sin(0) is 0

latent axle
knotty locust
#

It literally does not have times sin in it

#

no

latent axle
#

for x is 0

knotty locust
#

Are you looking at the same image as me?

#

this image

latent axle
#

it’s just the 0?

knotty locust
#

yes its just the 0

latent axle
#

Okay

knotty locust
#

We showed that earlier

latent axle
#

well yes x*f(x) is 0 for x is 0

knotty locust
#

ok

#

and what about the right hand side

latent axle
#

So it’s true for both upper and lower case

knotty locust
#

what is it when x=0?

latent axle
knotty locust
#

I said "when x=0"

latent axle
#

It’s 0

knotty locust
#

yes

#

so they're equal

#

in both cases

#

so xf(x) = sin(x)

#

for all x

latent axle
#

okay

#

because x*0 is 0 and x *sin(0) is 0

knotty locust
#

because 0*1=0 and sin(0)=0

latent axle
#

so xf(x) can be expressed as just sinx

#

Okay I guess that makes sense

knotty locust
#

Awesome

#

This will be useful in part b

trim joltBOT
#

@latent axle Has your question been resolved?

trim joltBOT
#
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royal escarp
#

i need help understanding how completing the square can be used to find the vertex of parabolic equation

sick onyx
#

u know the genral form of the parabola?

#

u have to compare the genral form with the final eq

main sigil
#

Completing the square converts the parabola from standard form (ax^2 + bx + c) to vertex form (x-h)^2 + k. And in vertex form the coordinates can be found simply as (h, k)

royal escarp
#

Ah I see

#

How can k be found exactly?

#

It's my understanding that h is b/2

trim joltBOT
#

@royal escarp Has your question been resolved?

royal escarp
#

<@&286206848099549185>

wraith hinge
#

hey

#

you pinged helpers ?

#

@royal escarp i saw your ping i js was helping another guy with potential energy

#

took ages having to explain it

#

hey mate u there ?

royal escarp
#

yeah im here

#

isnt that physics?

wraith hinge
#

yeah

#

ppl ask for chemistry

#

physics

#

and other stuff commonly

#

may i ask what your inquiry was ?

#

id love to help

#

btw sry for the wait

royal escarp
#

i need help understanding what k is algebraically in vector form

wraith hinge
#

may i ask for what level

#

is this o levels or a levels

#

if so what type of vectors ? do you mean the vectors in triangles

#

in further mathamatics

royal escarp
#

oh sorry

#

i want to find the vecor of a parabolic equation

#

its my understanding

wraith hinge
#

a parabala ?

#

u mean the stuff in functions right ?

royal escarp
#

you can do this my completing the squares

#

yes

#

X^2

wraith hinge
#

i have some notes on this

#

just gotta ask

#

what level of studies are you attending

#

is this for 16-18

#

or 14-16

royal escarp
#

umm

#

the class is calc 1

wraith hinge
#

because vectors change drastically

royal escarp
#

but this is just review

#

im just rusty

wraith hinge
#

vectors are in both pre calc and calc

royal escarp
#

pre calc

wraith hinge
wraith hinge
#

so just common vectors in two dimensions

royal escarp
#

correct

wraith hinge
#

may i ask for the question you wish to have help with ?

royal escarp
#

i want help with the general idea

wraith hinge
#

pardon ?

royal escarp
#

but i can provide a question if that would help

wraith hinge
#

im afraid im struggling to understand

#

that would help yeah

royal escarp
#

sorry i mixed up my terms

#

im really sorry

#

vertex

wraith hinge
#

nah its no problem

royal escarp
#

vertex

wraith hinge
#

i was just confused

#

OHHHH

royal escarp
#

not vector

wraith hinge
#

THATS WHY

#

alr u want some notes on it as well ?

#

jesus you scared me there

royal escarp
#

just the vertex

#

haha

wraith hinge
#

i thought i had to do vectors of a parabola

#

ight so u know how there are quadratic functions right

#

the general graph is something called a parabola

#

a parabola graph is a graph which is used when dealing with quadratic functions as it has 2 x values

#

so look

royal escarp
#

yes

#

i know what the vertex is

wraith hinge
#

the parabola has the axis of symetry the vertex and the y intersept

royal escarp
#

yes

#

but if i want to find that numerically

wraith hinge
#

its the highest or lowest point depending on which side the parabola is on

royal escarp
#

ax^2 + bx + c

wraith hinge
#

ahh makes sence

royal escarp
#

thats standard

#

i want

wraith hinge
#

yeah

royal escarp
#

(x-h)^2 + k

wraith hinge
#

to find the vertex from the two points right ?

royal escarp
#

where h and k are the vertex

wraith hinge
#

sorry what ?

royal escarp
#

once you complete the square

#

thats the format of it

wraith hinge
#

are you talking about two parabolas ?

#

sorry your phrasing is confusing me a little

royal escarp
#

no

#

okay let me provide a problem

wraith hinge
#

k

royal escarp
#

Number 6

wraith hinge
#

$(x - h)^2 = x^2 - 2hx + h^2$ do you mean this ?

solid kilnBOT
#

Exornion

wraith hinge
#

mate

#

you got it all wrong

#

when they tell you to graph it

#

they mean to draw the parabola

royal escarp
#

I'm aware

wraith hinge
#

there cant be 2 vertexes though

royal escarp
#

But you need certain information to graph it don't you?

wraith hinge
#

no not really

#

this is quite enough information

royal escarp
#

Like where it crosses the x axis

#

The y axis

wraith hinge
#

you get that from the equation

royal escarp
#

And where the vertex of the parabola is

#

Which is what I'm trying to understand

wraith hinge
#

ahh makes sence

royal escarp
#

Since that's what I'm having trouble grasping

wraith hinge
#

but let me help you here

#

all the points of the graph can be found

#

i have quite a lot of notes from my gcses

#

on this self same subject

#

first off

#

the parabola opens upwards

#

because the coefficent is positive

royal escarp
wraith hinge
#

second off you can find the vertex

#

by using the formula

royal escarp
#

How

wraith hinge
#

$x = -\frac{b}{2a}$

solid kilnBOT
#

Exornion

wraith hinge
#

for the given formula

#

a is 2

#

and b is 4

#

so x is -1

#

the parabola starts at -1

#

it intersects the 2 points

royal escarp
#

what about the y value

wraith hinge
#

wait let me find the other thingy

#

ill do it rn

#

so look

#

you Substitute x = -1 back into the function to find the y-coordinate of the vertex:

#

f(-1) = 2(-1)^2 + 4(-1) + 3 = 2(1) - 4 + 3 = 1

#

see this

#

i tried to write it well

#

but it isnt so neat

#

but its equal to 1

#

so the vertex is at (-1,1)

#

@royal escarp

#

is this good enough ?

#

i could clarrify more

#

if you need me to

royal escarp
#

its -2,1

wraith hinge
#

;-;

#

sry mb

#

i miscalculated

#

i went a bit fast

#

havent done 2d quadratic functions in a while

royal escarp
#

thats okay

#

regardless

wraith hinge
#

look u want the steps to graph a quadratic function

#

i can send an image of my past notes

royal escarp
wraith hinge
#

tho they are messy

royal escarp
#

actually no

wraith hinge
royal escarp
#

its suppossed to be -2,-1

wraith hinge
#

oh mb i alr sent

#

but there are the steps

#

sry for the mistake

#

have a good one mate !

#

also use .close when you are done

royal escarp
#

.close

trim joltBOT
#
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trim joltBOT
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torn shale
#

Not only did my teacher tell me that this function (x^2+y^2=y) is not implicit

torn shale
#

He also said that we cant simplify it and turn it to non-implicit using quadratic formula

#

I need clarifications 🤨

hallow kite
#

how are you defining implicit and explicit?

#

i believe explicit is when you can algebraically rearrange for y to equal only a function of x

#

and implicit is anything else

torn shale
#

Implicit is everything else

torn shale
#

Y=2+3xy^4 is implicit

torn shale
formal sage
#

It is the same thing

trim joltBOT
#

@torn shale Has your question been resolved?

torn shale
torn shale
wraith hinge
#

but it's defined a bit differently (more generally) than the way you defined it

wraith hinge
torn shale
wraith hinge
#

yeah, you can't

torn shale
#

Y^2-y+x^2=0

#

A is 1

#

B is -1

#

C is x^2

wraith hinge
#

you'd need -2xy for this to be a perfect square

#

and you have -y

#

also the quadratic formula doesn't apply here

torn shale
torn shale
#

Why

wraith hinge
#

well it's not a quadratic is it?

torn shale
#

But like

#

Isnt c is the coefiicent of y^0

#

Whats wrong eith applying it there

wraith hinge
torn shale
wraith hinge
#

I mean, you could technically factorize this but

#

I don't see why you would want to

#

you get a very very messy answer

#

also it'll only be defined for a specific domain

torn shale
wraith hinge
# torn shale Oh hmm

$\left( y - \frac{1 + \sqrt{1 - 4x^2}}{2} \right) \left( y - \frac{1 - \sqrt{1 - 4x^2}}{2} \right) = 0$

solid kilnBOT
wraith hinge
#

this is the factorized form

#

not very useful

torn shale
#

Formula

wraith hinge
#

no this is the factorization of y^2 + x^2 - y as two binomials

torn shale
wraith hinge
#

as a constant

#

however

#

note that

#

for the solutions of this to be real

#

we need a non-negative discriminant

torn shale
#

1-4x^2 is equal to or bigger than 0

wraith hinge
#

so the factorization is only valid for $x \in \left[-\frac{1}{2}, \frac{1}{2}\right]$

solid kilnBOT
wraith hinge
torn shale
#

That makes sense

torn shale
# wraith hinge yeah

Ok so the answers for my questions are: yes the function is implicit and it we can factorize but with a certain domian

#

Would it be explicit

#

After we factorized it

wraith hinge
solid kilnBOT
wraith hinge
#

so no, it's implicit

torn shale
#

Ok ok

#

Ty

#

.close

trim joltBOT
#
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trim joltBOT
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quartz cave
#

Im not sure where i'm going wrong for part b

quartz cave
#

v^2 = u^2 - 2as

#

25 = 25 - 2 * 9.81 * s

#

19.62s = 0???

proper kernel
#

if the ball is at its highest point, what would its velocity be

#

(its velocity wouldnt be -5)

quartz cave
#

omg im so stupid

quartz cave
proper kernel
#

yea

quartz cave
#

so s = 25/19.62

#

1.27 m

#

tysm

proper kernel
#

np

quartz cave
#

.close

trim joltBOT
#
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regal roost
#

Hi, is there any difference in way this is solved (i mean is my calculation correct?) second photo is another example solved by professor

trim joltBOT
#

@regal roost Has your question been resolved?

trim joltBOT
#

@regal roost Has your question been resolved?

trim joltBOT
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low mountain
#

Goofing up a bit with that question 7

trim joltBOT
low mountain
#

I think I'm supposed to use an inverse trig substitution but what exactly

oblique valley
#

Have you ever learned about separable equations?

marsh forum
#

hint:- if $\frac{dy}{dx}= f(x$, it's the same as $dy = f(x) dx$

shy nacelle
solid kilnBOT
#

ƒ(Why am. I here)=I don't Know

low mountain
marsh forum
#

for DEs

shy nacelle
marsh forum
#

oh, x= 3 __ should work

shy nacelle
#

And dy part one step

marsh forum
#

what do you think x should be ?

low mountain
#

I'm struggling with the integral of dy/root(9-y^2)

shy nacelle
#

1/√(a²-x²) = sin^-1 x/a

low mountain
#

I think Im getting somewhere

shy nacelle
marsh forum
trim joltBOT
# shy nacelle 1/√(a²-x²) = sin^-1 x/a

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

shy nacelle
#

You can derive by assuming x = 3sinø

marsh forum
#

this isn't a formula everywhere

shy nacelle
low mountain
#

Yeah I figured out the thing thanks

#

.close

trim joltBOT
#
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trim joltBOT
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trim joltBOT
candid aurora
#

oh sec i see i did some minor errors in the 2nd line. THis is the correct one:

#

here the correct one

trim joltBOT
#
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rapid horizon
#

Can anyone explain fifth euclid postulate?

bold gulch
#

Hello i need help with ona radicals

lyric ether
bold gulch
#

Ok sorry

lyric ether
rapid horizon
#

Ohh i understood

lyric ether
rapid horizon
#

So the fifth one says we extends lines on the side which those sum of interior is less than 180°

#

They will intersect each other after some time

lyric ether
rapid horizon
#

Yes

#

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#
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severe stump
#

I just for the life of me cannot wrap my head around this.

severe stump
#

I know that the rref is 1s down the diagonal, but how do I pull scalars from a bunch of 1s???

#

Any prompt assistance greatly appreciated. Test in 10 minutes.

shy nacelle
#

Hii

#

We need to fix scalars such that we get 0 adding along rows

severe stump
#

Right

shy nacelle
#

So they can be linearly independent

severe stump
#

I don't know how to get the scalars.

shy nacelle
#

You know

severe stump
#

I really don't. I wouldn't have asked the question if I did.

shy nacelle
#

-5x + 0×y + 2z = 0

#

So we can form 3 eqns and solve

severe stump
#

Doesn't that defeat the purpose of using matrices if I'm going to solve it algebraicly?

shy nacelle
#

You need fast answer ?

severe stump
#

It's a linear algebra class

#

I'm sort of required to use matrices.

severe stump
#

What's the point of rref'ing if I don't even use the matrix?

#

That's the entire point of this class.

shy nacelle
#

you see we get trivial solution if we try solve using matrix method

severe stump
#

Right.

#

But how can I use a matrix to get the scalars

#

Just seems insanely backwards if they're teaching us all these things specifically to find scalars, then you can't use those tools to find these specific scalars.

severe stump
#

Cuz 3x1+2x2=0 and -x1-x2=0

#

So (3x1+2x2)+3(-x1-x2)=0, and -x2=0

#

Which then gives me x1=0, and x3=0

#

Test time. Rip me

#

.close

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#
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plush igloo
#

but there's nothing wrong with writing a system of equations and simply solving them for the unknown variables

trim joltBOT
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rapid horizon
trim joltBOT
rapid horizon
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2 lines x axis

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Y axis

marsh forum
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what's the question?

rapid horizon
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It is asking About symmetric lines

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@marsh forum

marsh forum
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ah

ocean latch
rapid horizon
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Did you read my explanation?

ocean latch
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what explanation?

ocean latch
rapid horizon
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@ocean latch

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Leave the chat simply

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No need your suggestion there are many

ocean latch
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bro what standard? your english broken asf

rapid horizon
rapid horizon
ocean latch
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bro why you getting riled up? 💀, you can type in hindi, I understand

ocean latch
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bro why yall Indians get all riled up & defensive? like yall straight up start hurling curses or some zesty ahh replies, this is a math server tho, so I wouldn't respond further, good luck

trim joltBOT
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@rapid horizon Has your question been resolved?

trim joltBOT
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rustic nest
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Sketch the graph of a function on [-1, 2] that has a local maximum but no absolute maximum

lofty walrus
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!status

trim joltBOT
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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
rustic nest
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i dont know where to begin

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1

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1 or 2

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also maybe 4

lofty walrus
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you know what local and absolute maximums are yes?

rustic nest
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kind of but not really,,, here's' what i think i know..

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local max and min are beginning and endpoints if closed [], and if there is a point on the graph it can be a local min or max, also if there are dips or waves then that is also a local min/max

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absolute im not certain

tepid hamlet
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!original

trim joltBOT
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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.

rustic nest
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the question i wrote is the origina;

lofty walrus
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do you know of a function on some interval that has no absolute maximum?

rustic nest
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no

tepid hamlet
lofty walrus
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yes there is

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the function doesn't need to be continuous

rustic nest
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im not looking for a function

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i need to draw a graph

tepid hamlet
lofty walrus
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here is an example of a function that has no absolute maximum: 1/x on the interval (0, 1]

rustic nest
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Sketch the graph of a function on [-1, 2] that has a local maximum but no absolute maximum

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this is my question.

tardy hemlock
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Also, since it only asks you to sketch it, I'd assume it doesn't want you to give an algebraic expression for it.

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So you can just "draw anything" that fits the description

rustic nest
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yeahh

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but idk how not to draw an absolute max

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my TA said theres always an absolute max

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he is obviously wrong

lofty walrus
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not when the function isn't continous

tepid hamlet
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only if you assume continuous like belabutter said

rustic nest
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ok what would that look like on a grapph then lol

tepid hamlet
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here's a simple example

rustic nest
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oh

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so that is a local max

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and the absolute max doesnt exist