#help-10

1 messages · Page 162 of 1

timid silo
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the sum is simply f(x) by definition

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and the expansion is the series you asked for

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they gave you the series

tepid urchin
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oh ok

timid silo
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you give them f(x)

tepid urchin
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can you do an example?

timid silo
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ok

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take sine function

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sin(x) = sin(0)+sin'(0) * x + sin''(0)/2x^2 + ..= sin(0) + x - x^2/2 + ...

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by writing this sum using the sigma notation

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you get this

tepid urchin
#

o

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how

timid silo
tepid urchin
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also how would I solve this without knowing that this was the taylor series of sinex

timid silo
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especially that you have pi there

tepid urchin
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im in calc || so if theres any method with that

timid silo
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what are the courses in calc ?

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just the titles

tepid urchin
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first it was derivitves then intagrals, now series

timid silo
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taylor must be there somewhere

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is this a homework question

tepid urchin
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its a past exam quesiron

timid silo
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oh so it covers all calculus right ?

tepid urchin
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nop

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its not the final yet

timid silo
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it covers which part

tepid urchin
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series

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i can send you a picute

timid silo
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yes send me

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taylor must be there, otherwise your teacher is nuts

tepid urchin
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oh well there ya go

timid silo
tepid urchin
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;n;

timid silo
# tepid urchin

they literally say power series, I can't imagine anyone taking a course in power series without knowing taylor expansion

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if you check your notes you'll find them

tepid urchin
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so do I just have to memorize a bunch of them?

timid silo
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hence the 2n+1 in powers

tepid urchin
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what ones should i memorize?

timid silo
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you can also memorize the general formula, and then find the expansions with it

tepid urchin
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oh ok

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ill do that ty

timid silo
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Yw !

tepid urchin
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can you help me with another problem?

timid silo
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ok go ahead

tepid urchin
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question 1 on the exam

timid silo
tepid urchin
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whats that

graceful pollen
timid silo
timid silo
tepid urchin
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why is the plus or minus sign upside dwon

timid silo
graceful pollen
timid silo
timid silo
tepid urchin
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ok

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what would be an answer to the 1st question?

graceful pollen
timid silo
tepid urchin
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lol

timid silo
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But you know the trick now

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wolfram can also give the answer

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(I think)

tepid urchin
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idk how to use it

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everytime i do it fucks it

timid silo
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write the sum by writing the symbols (like you would with a pen)

tepid urchin
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ok

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but it looks very divergent bc the exponents keep getting bigger

timid silo
timid silo
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that's what a radius of convergence means

tepid urchin
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righ

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t

timid silo
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(1/2)^n gets smaller when n gets bigger

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but 2^n explodes

tepid urchin
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ok

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so

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i plug in the numbers

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but then what?

timid silo
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just keep x

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interval of convergence = interval of x where the series is convergent

tepid urchin
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ya

timid silo
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this is a full course on power series, take your time

tepid urchin
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;n;

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ok

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i feel like im missing somthing

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can you solve it on a piece of paper?

timid silo
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wait i'll draw a solution in my computer, I am lazy bastard

tepid urchin
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lol

tardy epoch
tepid urchin
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I have the solution

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I just need to see the full prosses

timid silo
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work out the rest

tardy epoch
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If the professor gives a solution, you should understand it that way first

tepid urchin
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?

tardy epoch
tepid urchin
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then what

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this is the answer btw

timid silo
tepid urchin
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thats what my friends been saying

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hes been working on this all night going crazy saying that this is wrong

timid silo
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@tardy epoch am I allowed to post the full solutin

timid silo
tepid urchin
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lmfao

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no way

timid silo
tepid urchin
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Dr.Lang

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no one likes him

timid silo
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lol mr. lang is a bastard

tepid urchin
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yes

timid silo
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he bastardizes his students lol

tepid urchin
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he got divorced recently

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so all is fair now

timid silo
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oh he should be in a bad mood then

tepid urchin
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24/7

timid silo
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lol

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anyway this is the solution I wrote

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n goes from 0 to infinity

tepid urchin
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all righty

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how did you get that

timid silo
tepid urchin
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the series

timid silo
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taylor lol

tepid urchin
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ok ok

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ohhhhhhh shiiiiiiittttttttttt

timid silo
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this is a general formula

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not easy at first

tepid urchin
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the -1 is the signs

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the ^n is the ohhhhhhhhhhhhh

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okokokokokowkerfionvoidflkb

timid silo
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lol

tepid urchin
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gimme a practice problem

timid silo
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about taylor ym

tepid urchin
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sure

timid silo
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ok lets say find the expansion of log(1+x)

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or cos(x)

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anyway bro I gotta go

tepid urchin
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mk tysm

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life saver

timid silo
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you can find this stuff in the internet

tepid urchin
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ya

timid silo
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with practice problems

tepid urchin
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wait

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how are you new and a helper?

timid silo
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i mean the group

tepid urchin
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oh lol

timid silo
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it's probably a new thing

tepid urchin
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nvm

timid silo
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because I joined it before

tepid urchin
#

read the rules ✨

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.close

obtuse pebbleBOT
#
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vital frost
obtuse pebbleBOT
vital frost
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@tardy epoch that

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in fact i understand

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.close

obtuse pebbleBOT
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lost wharf
obtuse pebbleBOT
lost wharf
#

i'm not sure about my answer

narrow fiber
#

Do you understand what the question is asking?

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@lost wharf

lost wharf
narrow fiber
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I'll send a pic

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This is the set-up

lost wharf
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ok

narrow fiber
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Imagine "the lever" along with the square being rotated in the direction of the arrow (ccw)

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They're basically asking how much do you need to rotate until the square reaches the 4th quadrant

lost wharf
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ok

narrow fiber
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How much do you think it needs to rotate?

lost wharf
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about 90

narrow fiber
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If it rotates 90°

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It will reach only up to the second quadrant

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Will it not?

lost wharf
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so 180 so that it can reach the 4 quadrant

narrow fiber
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hmm

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Are you using a phone currently?

lost wharf
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no

narrow fiber
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Ah

lost wharf
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doing my assignment

narrow fiber
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I thought I'd tell you to try rotating your phone 180° and see where the square ends up

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But you can't really do that on a pc

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unless you rotate your head?

lost wharf
#

i get it now

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it 270 degrees

narrow fiber
narrow fiber
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Exactly

lost wharf
#

thanks

#

.close

obtuse pebbleBOT
#
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warm siren
obtuse pebbleBOT
warm siren
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anyobody know how to get started on this

robust sedge
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Do you know the formulas for going back and forth between polar and cartesian coordinates?

warm siren
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no i dont think i recall

robust sedge
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I think that's where I would start

obtuse pebbleBOT
#

@warm siren Has your question been resolved?

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pallid vapor
#

hi would it be possible to get some help here. im trying to see how the transfer function (marked 2) comes from its laplace transform above. i cant seem to understand. would be helpful if someone could show me the steps taken to reach the 2nd transfer function (marked 2)

pallid vapor
#

this one

obtuse pebbleBOT
#

@pallid vapor Has your question been resolved?

obtuse pebbleBOT
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silent perch
#

A golf ball is struck from a point 23m to the left of the hole and lands at a point 17m to the right of the hole. It reaches a maximum height of 10m

-Determine an equation to represent the path of the golf ball

-When the ball is directly above the hole, how high in the air is it?

silent perch
#

if anyone could do step by step with me that'd be appreciated

obtuse pebbleBOT
#

@silent perch Has your question been resolved?

obtuse pebbleBOT
#

@silent perch Has your question been resolved?

tranquil tide
silent perch
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No

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There's a diagram though

tranquil tide
#

can i see

silent perch
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No I don't have my text book but like

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I can draw what it looked like

tranquil tide
#

ok wait are you american

silent perch
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Canadian

tranquil tide
#

is this mechanics

silent perch
#

no

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quadratics

tranquil tide
#

ah

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im pretty sure the diagram gave you some numbers

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ok wait can you draw it

silent perch
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Only the same numbers

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well actually

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it told be to label it myself

tranquil tide
#

is it distance against time

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distance on the y time on the x

silent perch
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no time

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I need to make an equation

tranquil tide
#

ok it was prob horizontal distance and vertical distance then

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right?

silent perch
#

yyeah

tranquil tide
#

Ah

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origin is the golf hole

silent perch
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point on the left is 23,0 I think and point on the right is 17,0

silent perch
#

I need to make an equation

tranquil tide
#

ok 1 sec

silent perch
#

ok

silent perch
#

Rip

tranquil tide
#

😋

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Ok my walk through was a bit messy tho

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have you heard of completing the square

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ok i hope you can read this

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if u want a better step by step tell me before i go sleep ok bye

obtuse pebbleBOT
#

@silent perch Has your question been resolved?

obtuse pebbleBOT
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karmic vale
#

can i use universal generalization like this? I was trying to prove how a universal conditional statement is logically equivalent to its contrapositive and used universal generalization to do that

obtuse pebbleBOT
#

@karmic vale Has your question been resolved?

karmic vale
#

<@&286206848099549185>

next loom
#

this seems about right

obtuse pebbleBOT
#

@karmic vale Has your question been resolved?

obtuse pebbleBOT
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obtuse pebbleBOT
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spark field
obtuse pebbleBOT
spark field
#

how was this solved?

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wdym

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like create the riemann sum?

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ah so

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20-10/2

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= delta x

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@timid silo so upperestimate

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would be

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10+(k-1)deltax

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and lower estimate

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a+kdeltax

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?

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where n = 6

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then just multiply it out and use the rules

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and plug in n

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how?

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lower bound starts at 10 yea

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wdym as height

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you mean delta x?

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top is

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lower bound

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bottom is upper bound

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right ? @timid silo

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are u sure?

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the answer is -32

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and 8

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what

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im so confused

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how do we solve this

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bro what

warm shaleBOT
#

hannibal

spark field
#

yea

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wb it

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delta x = 5

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where did the 2 come from

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and n = 2

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so delta x = 5

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yea

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2 = n

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not delta x

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b-a/n is the formula

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how?

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oh yea ur right

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the width is 2

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mb

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i mistakened that

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oh i see

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Oh

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i get it now

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we just multiply

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it by delta x

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and lower estimate would just be x= 18 and under

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upper would be x = 20

obtuse pebbleBOT
#

@spark field Has your question been resolved?

spark field
#

yes it is

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its from x=10 to x= 18

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and its 8

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for when

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x = 10 to x= 20

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this just means find the antidervative right?

obtuse pebbleBOT
#
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spark field
obtuse pebbleBOT
spark field
#

wb midpoint

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how would this work

#

ik

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so i start from 14?

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im confused because we just estimated by f(x) * deltax

warm shaleBOT
#

hannibal

spark field
#

oooh

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so deltax = 1

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then

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wait no

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18-10/5

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ok so

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18-10/5

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then divide it agian

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by 2

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right

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so delta x = .8

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?

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um what

#

?

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subtract upper and lower

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then divide by 2

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-12

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which sint correct

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yea

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but that wouldnt really work

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💀

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we are given f(x) number

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wdym middle of interval

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yea

#

wb it

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ur not supposed to predicut f(x)

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answer is -20

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<@&286206848099549185>

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any1 know

fathom flicker
#

for example the video that you linked a screenshot of

spark field
#

organic chem

#

the formula is diff when we have f(x) so i didnt know how to do it when we are giving the value of f(x)

fathom flicker
#

It's not different

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for each rectangle f(x) is the height

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so like just looking at the picture for the video above

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f(x_i)

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say i=1

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this means f(1)

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which is the height of the rectangle at x=1

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which is just given in your table

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but if it wasn't, you would just plug x=1 into your function

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yet the formula remains the same

#

Watching the video should clear up your confusions.

obtuse pebbleBOT
#

@spark field Has your question been resolved?

obtuse pebbleBOT
#

@spark field Has your question been resolved?

obtuse pebbleBOT
#

@spark field Has your question been resolved?

obtuse pebbleBOT
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timid silo
#

how do i solve this question?

obtuse pebbleBOT
timid silo
#

i know A is circle and B is ellipse

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i understand they are asking in which points they will intersect

trim portal
#

both are centered at (0, 0). So you dont even need to perform calculations

timid silo
#

but how do i know where they will intersect what if circle is bigger and doesn't intersect at all

haughty coyote
#

You know their equations so you know them. Most notably the radii so you can draw them

trim portal
royal basin
#

you can just treat this as a system of equations lmfao

trim portal
#

You can either use substitution, or subtract/add those equations

timid silo
#

i don't know much about in these circles and ellipses so can u explain more?

leaden ginkgo
#

are you familiar with solving simultaneous equations? using substitution/subtraction?

trim portal
#

x^2+y^2=25, this is the circle
x^2+9y^2=144, this is the ellipse
To find the intersection, you need to find points (x, y) such that they lie on both the circle, and ellipse. I.e. they satisfy those equations

#

so just solve system of those equations

timid silo
#

ok first i will learn about solving these eqs

trim portal
#

sorry my battery is at 5% and I cant charge it rn, bye

leaden ginkgo
#

what’d they teach you in school, before they gave you this problem?

timid silo
#

this question is not from a school i am just self studying rn

leaden ginkgo
#

look up how to solve systems of equations

timid silo
#

👍

#

.close

obtuse pebbleBOT
#
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dry arrow
#

hello, is there any way to solve this aside from multiplying everything first then finding lcm?

royal basin
#

well you could break the 6^1 into 2^1 * 3^1

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so that the first number there is actually factored into primes and doesnt just appear as such

dry arrow
#

so it would be 2^3, 3^5, 2^4, 5^1, 3^2

#

then what?

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oh nvm i got it

#

thanks for that saved me

#

.close

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faint ore
#

hello

obtuse pebbleBOT
faint ore
#

i need a little bit of helping differentiating these types of problems

#

for example f(x) = 3x/(x^2+16)^1/2

leaden ginkgo
#

do you know about the various rules of differentiation

faint ore
#

yes

leaden ginkgo
#

what do you need help with then

faint ore
#

i guess just executing them properly

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here we go

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so 3x * (x^2+16)^-1/2

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product rule

leaden ginkgo
#

or just quotient rule

faint ore
#

u think thats better?

leaden ginkgo
#

i mean you won’t have to work with a negative power

faint ore
#

thats true

#

okay so [1/2 * (x^2 +16)^-1/2 *2x (3x) ] - [3(x^2+16)^1/2]

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all over x^2+16

#

correct so far?

leaden ginkgo
#

you’re doing product rule?

faint ore
#

no

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quotient

leaden ginkgo
#

quotient rule is minus

faint ore
#

oof yes

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slipped my mind thank u

leaden ginkgo
#

and it’s $\frac {f’(x)g(x) - f(x)g’(x)}{g(x)^{2}}$

warm shaleBOT
#

! saad

faint ore
#

yes

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okay so after simplifying a little further i get 3x/sqrt(x^2+16) - 3sqrt(x^2+16)

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over x^2 +16

leaden ginkgo
#

use more brackets or type in latex or on a piece of paper

faint ore
#

how do u do the texit thing

leaden ginkgo
#

enclose in $

faint ore
#

$\frac{3(x^2+16)^{1/2}- 3x^{2}(x^2+16)^{-1/2}}{x^2+16}}$

royal basin
#

\sqrt not /sqrt

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also \sqrt{...} not \sqrt(...)

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also i think you forgot to take the derivative of the root at one point

leaden ginkgo
#

enclose powers in {}

faint ore
#

there we go

#

nvm

#

look about right?

leaden ginkgo
#

f’(x)g(x) - f(x)g’(x)

#

you didn’t differentiate the sqrt properly either

timber island
#

Isn't f'(x) 2x in this case? If f(x) = x^2

faint ore
#

oh dang

leaden ginkgo
#

it’ll be chain rule and power rule

faint ore
#

one moment while i redo this

leaden ginkgo
timber island
#

Oh

leaden ginkgo
#

yes, 3x

faint ore
#

okay here we go

leaden ginkgo
#

you forgot chain rule, again

faint ore
leaden ginkgo
#

stop skipping steps, i can’t follow your logic

#

write out the quotient rule as you would

#

then you can simplify

faint ore
#

alrighty

warm shaleBOT
#

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

faint ore
#

look good?

leaden ginkgo
#

yes

#

you could’ve separated the 3 earlier actually

#

constant multiple rule

#

easier to differentiate

faint ore
#

i see

#

so now to simplify

leaden ginkgo
#

you can get rid of the negative power

faint ore
#

by square root right

leaden ginkgo
#

it just goes to the denominator and becomes square root $\frac {1}{2 \sqrt{x^{2}+16}}$

warm shaleBOT
#

! saad

faint ore
#

why a 2

timber island
#

Question: is the final answer
$$\frac{3-3x}{\sqrt{x^2 + 16}}$$

faint ore
#

wouldnt it be 3x^2/sqrt(x^2+16) * x^2 +16

#

since g(x) is getting squared on the bottom

leaden ginkgo
#

$\frac {1}{2} \cdot (x^{2} + 16)^{- \frac {1}{2}}$

warm shaleBOT
#

! saad

#

ItzKraken2

leaden ginkgo
#

$\frac {1}{2 \sqrt{x^{2}+16}}$

warm shaleBOT
#

! saad

faint ore
#

since theres a 2x after it the 1/2 and 2 cancel out

leaden ginkgo
#

yes

#

2x * 3x

faint ore
#

and the 1/2

leaden ginkgo
#

so you’ll just have 3x^2 in the numerator

faint ore
#

yup

warm shaleBOT
#

Blackbeard

okay so now i have $\frac{{3}{/sqrt{x^{2}+16}}$
```Compilation error:```! File ended while scanning use of \frac .
<inserted text> 
                \par 
<*> 786751657316581406.tex
                          
I suspect you have forgotten a `}', causing me
to read past where you wanted me to stop.
I'll try to recover; but if the error is serious,
you'd better type `E' or `X' now and fix your file.```
faint ore
#

forget that

#

i have 3*sqrt(x^2+16) - 3x^2/(sqrt(x^2+16))

#

over x^2 + 16

leaden ginkgo
#

yes

faint ore
#

so here is where i have trouble

#

where could i go to further simplify

timber island
faint ore
#

what do u mean = u

wooden marten
#

declare a new variable u

timber island
#

U substitute u for sqrt (x^2 + 16)

faint ore
#

why would i do that?

wooden marten
#

simplifies the fraction, ig

faint ore
#

you cant just multiply by the denominator or something

timber island
#

I can send a pic of my simplification procedure if u want

faint ore
#

sure

#

well actually let me try it out first

#

3u-3x^2/u

#

over u

#

like that?

#

hello

timber island
#

Yeah

timber island
#

In the 3x^2 term

faint ore
#

nevermind

#

i figured it out

#

thanks for the help

#

.close

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#
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night lotus
#

Calculate the double integral with A limited by x^2=4-2y

warm shaleBOT
night lotus
#

So far, ive graphed it

#

Dont understand what limits you fill in for what integral :\

open forge
night lotus
clear condor
#

!help

obtuse pebbleBOT
clear condor
#

you get help

night lotus
#

Calculate the double integral with A limited by x^2=4-2y

#

Need help with the limits of integration

obtuse pebbleBOT
#

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gusty tartan
obtuse pebbleBOT
gusty tartan
#

tryna solve this differential

#

i think the best route is sub but im not sure

clear condor
#

what would you sub?

gusty tartan
#

y=xv(x)

#

got an idea brb

#

.close

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gusty tartan
#

.reopen

obtuse pebbleBOT
#

gusty tartan
#

yep

#

still stuck

#

question said use sub

#

y=xv(x)

#

<@&286206848099549185>

clear condor
#

so what is y' in x and v

gusty tartan
#

thats where im up to

#

well the confident up to

#

i did stuff past that but i have no idea waht i was doing

timber island
#

U can divide both sides by x and integrate

gusty tartan
timber island
#

Mhm

#

U can treat as x as a constant, then integrate (btw not sure if this turns into a double integral)

#

@gusty tartan still stuck?

obtuse pebbleBOT
#

@gusty tartan Has your question been resolved?

gusty tartan
#

used sub

#

:P

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timid silo
#

what will be the explicit form of this?

obtuse pebbleBOT
drifting wraith
#

is that multiplication?

timid silo
#

yeah the dot symbolises multiplication

leaden ginkgo
#

weird dot

#

$i \cdot j$

warm shaleBOT
#

! saad

royal shard
#

Isnt that factorial?

#

Oh no

drifting wraith
timid silo
#

my first thought was that its the product of i and j taken two at a time (i not equal to j) subtracted from the square of the sum of the first n natural numbers

timid silo
drifting wraith
#

i didn't i asked wolfram

#

i don;'t know the method

warm lark
#

Who can help me pythagorean theorem

obtuse pebbleBOT
timid silo
warm lark
#

Anyone?

#

Who can help me?

warm lark
timid silo
#

could u tell me what is the exact question is? i can try to help

warm shaleBOT
timid silo
#

ahhh i see

#

this makes a lot of sense

jolly ginkgo
#

Try it first cuz I'm not entirely sure

#

You must be knowing the last two sums

#

I assume

cobalt plover
timid silo
jolly ginkgo
#

Alright

jolly ginkgo
timid silo
#

yes i got it

timid silo
jolly ginkgo
#

Alrigh

#

You're welcome

timid silo
#

thanks a lot!!

jolly ginkgo
#

❤️

#

Lots of ❤️

timid silo
#

.close

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mental cosmos
#

can someone put me in the right direction?

obtuse pebbleBOT
mental cosmos
#

its supposed to be solved with graph theory

obtuse pebbleBOT
#

@mental cosmos Has your question been resolved?

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toxic hollow
#

Just to double check. {h(1),h(2)}={1,2}

obtuse pebbleBOT
toxic hollow
#

Means all the pairing between the two sets right including h(1)=2

sage geode
#

That implies h(1) = 1 and h(2) = 2 or h(1) = 2 and h(2) = 1

#

So, no, h(1) = 2 is not impossible

#

Oh I read that as "excluding" catThink

#

Yeah, anyways, h(1) = 2 is possible

obtuse pebbleBOT
#

@toxic hollow Has your question been resolved?

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gloomy glen
#

Hello,
I am currently watching 3b1b's video on eigenvectors and values, but my question is regarding change of basis matrices.
In the video he uses the new basis vectors directly as his change_of_basis_matrix, but isnt it needed to first setup a system of linear equations with the ( new basis on the left | old basis on the right ) and solving that as shown in the second image?
Im still not a 100% percent sure on how to obtain the transformation matrix needed.

warm canopy
#

sure but in the 3b1b video his "old" basis is the standard basis and the eigenvectors are already written in this standard basis so you're skipping that step because there's nothing to do

obtuse pebbleBOT
#

@gloomy glen Has your question been resolved?

gloomy glen
warm canopy
#

in 3b1b vid its the standard basis and the eigenbasis

gloomy glen
warm canopy
#

(-1 1) but yeah

gloomy glen
#

yes

gloomy glen
#

if
(1 0)
(0 1)
already is the old basis

warm canopy
gloomy glen
warm canopy
#

once you fix a basis, the columns of the matrix are telling you what happens to those basis vectors under the transformation

gloomy glen
#

Yes.
So I use the current basis and the new basis to calculate a transformation Matrix B.
Then I multiply the current Matrix A:
B-1 * A * B and get the Matrix A' for the new basis, right?

warm canopy
#

a couple seconds after that screenshot he'll say that product is equal to (3 0 ; 0 2) which is precisely telling you the eigenvectors (a basis now) get scaled up by their eigenvalues

#

correct

#

B will take you "from the new basis to the old" (this at first seems kind of backwards but it is the correct way)

#

this makes sense, B takes you back to your old basis, A is the matrix of the map in terms of the old basis, and then B^-1 takes you back to the new basis

gloomy glen
#

This topic is a lot to keep in mind and connect haha
but thank you

warm canopy
#

change of basis is notoriously one of the hardest things to get your head around in linear algebra

gloomy glen
warm canopy
#

the order they're written

#

B^-1AB

#

(because transformations get applied right to left)

gloomy glen
#

so first B * A? and then that * B^-1.
The last thing im struggling with atm is:
"B takes you back to your old basis, A is matrix in terms of the old basis, and then B^-1 takes you back to the new basis"

warm canopy
#

appplying the matrix X and then the matrix Y is the same as applying the matrix YX

#

things are applied from right to left

#

multiplication is associative so it doesnt matter how you actually compute ZYX as long as its in that order

gloomy glen
#

One last question 😅 .
The way i understood it in lectures was actually this way. With B^-1 we transform coordinates from the new basis into the old. Than we put these values into the matrix "from the old basis" and then we use B to turn the old coordinates into the ones in the new basis

gloomy glen
warm canopy
warm canopy
gloomy glen
warm canopy
#

ehh this is subtle

#

it depends on what you have defined B to be

#

either its "the new basis vectors written in terms of the old" and then what I said is correct

#

or its "the old basis vectors written in term of the new" and then its what you said

gloomy glen
#

Now what I want to do is:
TA->B * L * TB->A = TA->B * L * TA->B^-1

warm canopy
#

your issue here is that A and B are not bases

#

in R^3 you need 3 vectors for a basis and then your change of basis matrix will be 3x3

gloomy glen
#

Lets think of it as R^2 then. I just want to know about my concept

#

Maybe I should just stop for today and take another look tomorrow

#

.close

obtuse pebbleBOT
#
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azure anchor
#

do you know what g'(x) and g''(x) represent?

#

you have to know general behaviors of square and cubic functions. and also the general patterns that derivatives follow.

#

whats the derivative of f(x)=x^3

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

azure anchor
#

do you know what the graphs of x^3, x^2, and wave (trig) functions look like? this should be pretty recognizable if you are familiar.

#

and if you understand the pattern that derivatives take and what they represent, it just takes a little bit of thought to imagine what the derivatives would be with just these graphs.

#

you really don't know what b could be?

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

obtuse pebbleBOT
#

@magic goblet Has your question been resolved?

crystal solstice
#

Thus is mostly correct. Look at a.iii and c.i again

#

Not sure what #4 is asking you to do

crystal solstice
#

0 isn't an option. You have to say if it's a min/max/inflection

#

Is the function going up or down for ci

#

Increasing or decreasing?

rustic harbor
#

I think he was talking about at the point

obtuse pebbleBOT
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stone gorge
#

f(x)=2x^3+1/x

find f(-x)
find -f(x)

obtuse pebbleBOT
obtuse pebbleBOT
#

@stone gorge Has your question been resolved?

stone gorge
#

<@&286206848099549185>

rigid crystal
#

for the first one, plug in -x to f(x)

stone gorge
#

-2x^3-1/x?

rigid crystal
#

yeah

#

and the second one is similar

#

just find f(x)

#

and then negative of that

stone gorge
#

is it the same?

rigid crystal
#

yeah

#

👍

stone gorge
#

alright thank you so nova

rigid crystal
#

you're welcome

#

happy to help

stone gorge
#

.close

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little lava
obtuse pebbleBOT
little lava
#

help with part a)

#

im having a hard time finding which method to use

#

.close

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karmic reef
obtuse pebbleBOT
karmic reef
#

how do you find the tangent line of y^2(y^2-1)=x^2tan(y) at (0,1)

#

tangent line equation

#

y-y1=f'(x1)(x-x1)

teal turret
#

what have u tried @karmic reef

warm shaleBOT
#

Stephen

karmic reef
#

I mean ill try implicit differentiation

#

D/dx(y^2(y^2-1))=d/dx(x^2tan(y)

Left hand side product rule

teal turret
#

nah dont do product rule on the left, just distribute the y^2, makes it easier

karmic reef
#

Oh lol

#

I didn’t think to

#

D(y)^2/dx =d/dx(x^2tan(y))

#

Right hand side product rule

teal turret
#

can u do the whole thing on paper so i can just look it over all at once

#

or using latex

karmic reef
#

Can u refoward ur latex but using back ticks

#

Or a way so the bot doesnt embed it

#

So i can copy the syntax

teal turret
#
$y^2(y^2-1)=x^2 \tan(y)$

karmic reef
#

$\frac (dy^2) (dx)=d/dx(x^2 \tan(y))$

warm shaleBOT
#

HeccinTech

karmic reef
#

Lol im just gonna write it down

#

This is wrong

wooden marten
warm shaleBOT
#

zfnQRZJT

wooden marten
#

?

karmic reef
#

No no

#

I mean

#

Yes

#

But i mean this is wrong in context of the work i posted like with my hand writing

#

Not what i posted

#

Thank u though

wooden marten
#

alr

teal turret
#

do u still need help?

karmic reef
#

Yeah

#

Im still working on it

#

Sorry

wooden marten
#

take your time

karmic reef
wooden marten
#

it seems you lost a y^2 - 1 on the left side

#

also for implicit differentiation d/dx of something that involves y remember you need the chain rule

karmic reef
wooden marten
#

y^4 - y^2?

karmic reef
#

Yeah

wooden marten
#

well you just
didn't write that

karmic reef
#

To do it that way

wooden marten
#

(also, just a notational thing, dy^2 usually means (dy)^2)

#

as in the denominator of the 2nd derivative operator

karmic reef
#

Ok

#

Wait was i supposed to do chain rule

teal turret
#

yea by distributing the y^2, i meant to do y^2 multiplied by y^2 -1, which is y^4 - y^2

karmic reef
wooden marten
teal turret
karmic reef
wooden marten
#

you still aren't getting the y^4 - y^2 on the left

teal turret
karmic reef
#

Oh i thought they simplified

wooden marten
#

wh

karmic reef
#

Sorry

#

Monkey brain kek

wooden marten
#

yes this is right

#

differentiate on the left side as well

karmic reef
#

Thanks

#

Wouldnt i write it as

#

No wait

#

Why would I differentiate the left side again

#

I dont think u can differentiate y with the derivative respect to x as in apply any rules besides it being dy/dx

#

Im only taking the first derivative

#

So its already differentiated

wooden marten
karmic reef
#

Oh i see

#

Wait

#

I donr

#

How ru getting rid of y there

#

Are u

wooden marten
#

you aren't

#

you're just finding the derivative

karmic reef
#

Is it dy/dx *4y^3

wooden marten
#

mhm

#

math is magic that way

karmic reef
#

Ignore the dx^2

#

Oh wai

#

There we go

wooden marten
#

yee

karmic reef
#

Now how can i get dydx on its own side

#

My guess is subtract the x^2sec^2(y)*dy/dx and factor out dy/dx and divide by the inside on the other side

#

But that still leaves me with ys on one side

#

Can you plugin ys

wooden marten
#

at the point

karmic reef
#

Oh ok

#

Since anything * 0 =0

wooden marten
#

now you can finish

karmic reef
#

Thank u

#

.close

obtuse pebbleBOT
#
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obtuse pebbleBOT
tiny seal
#

lets look at c first

#

gimme one sec while i write it out

#

+2e^x

#

wait

#

forgot to distrbute the -, whoops

#

there is a continuation of ibp, the di method

#

it makes these repeated ibps faster

#

integrals?

#

you can learn them rn, its very easy actually

#

just an area function

#

i highly recommend khan academy if you want to

#

well, if you know derivatives, you can already solve integrals with the fundamental theorems of calculus

obtuse pebbleBOT
#

@timid silo Has your question been resolved?

tiny seal
#

that one is

#

i deleted the one with the mistake

obtuse pebbleBOT
#
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timid silo
#

Can someone help with this one?

obtuse pebbleBOT
timid silo
#

You don't have to solve the entire problem, I just need a procedure or hints

tiny seal
#

what is z in this context?

#

this looks like a typical line integral, so we can just parameterize C

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what i dont get is why we do a . on a scalar

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z=(x,y)?

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there has to be some context about z somewhere

timid silo
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This is problem is from Complex Integration

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(Please ping me when you reply)

tiny seal
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@timid silo
heres a hint, we know (a(theta-sin(theta)) , a(1-cos(theta)) goes from (0,0) to (2pi a,0)
it is not too hard to solve for theta here and find bounds a and b, we are also parameterized
let z=x+yi, then we may use the following picture with u(t)=x(theta), v(t)=y(theta)

timid silo
tiny seal
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yeah

timid silo
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But

tiny seal
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you do d theta

timid silo
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It becomes very lengthy by doing that

tiny seal
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its an integral theta dtheta, sin(theta)dtheta, dtheta, cos(theta)dtheta, these arent that long
the only lengthy one is solving for theta's bounds

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but we are given 0,0 which is easy to solve, only solving the upper bound will be lengthy

timid silo
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I think upper bound for theta is 2pi

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Maybe that wasn't the lengthy part

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Expanding z^3 then substituting x and y in it goes long

tiny seal
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yeah

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but thats the fun of contour integrals

timid silo
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I tried writing x = sin alpha = a(theta-sin theta)

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But it doesn't work

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Such alpha doesn't exist

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<@&286206848099549185>

obtuse pebbleBOT
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@timid silo Has your question been resolved?

obtuse pebbleBOT
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@timid silo Has your question been resolved?

obtuse pebbleBOT
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@timid silo Has your question been resolved?

obtuse pebbleBOT
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@timid silo Has your question been resolved?

obtuse pebbleBOT
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@timid silo Has your question been resolved?

glacial obsidian
obtuse pebbleBOT
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tardy epoch
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Takes like 3 times

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x^3 to 3x^2 to 6x to 6

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Keep at it

obtuse pebbleBOT
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@timid silo Has your question been resolved?

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tall bramble
obtuse pebbleBOT
tall bramble
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this is solution idk from the red line how they set up that equation

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<@&286206848099549185>

trail musk
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Define collinear

tall bramble
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same line

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parralell

trail musk
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What does that mean in terms of the arithmetic

tall bramble
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there will be a konstant where ab will equal cd

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cb

trail musk
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Ok great!!!

tall bramble
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so CB = kAB

trail musk
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Or in other words, the RATIO between components is constant

tall bramble
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or otherweay round

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yh

trail musk
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So like how about this just to show you what I mean

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Lets say we have the two vectors (1,2) and (2,4)

tall bramble
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1:2

trail musk
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Wouldn't any collinear vector satisfy:
y component is ALWAYS twice x component

tall bramble
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how is it always

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cant the konstant differ

trail musk
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The constant cancels

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Any vector on that line is (c,2c)

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2c/c = 2

tall bramble
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ok

trail musk
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So then

tall bramble
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so even if the graph looks way off cb = 2ab

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interms of my qquestion

trail musk
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No

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Thats not what I'm saying

tall bramble
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ok

trail musk
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I was just using the (1,2) as an example

tall bramble
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alight

trail musk
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(a component of CB) / (b component of CB) =
(a component of AB) / (b component of AB)

tall bramble
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ok

trail musk
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Plug in the numbers now

tall bramble
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how did u get 2 values for cb tho

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this is proper confusing me

trail musk
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Do you know what I mean by components?

tall bramble
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no

trail musk
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don't vectors in 2D have to be described by two numbers

tall bramble
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a nd b?

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a and b?

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is that what u mean by 2 numbers

trail musk
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in this case we're treating a and b as our basis VECTORS

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So what multiplies the a is the a component, and what multiplies the b is the b component

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The a component of CB is -3k

tall bramble
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how is it over -2

trail musk
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The b component of CB is 2-9k

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Trust

tall bramble
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yes i understnad that

trail musk
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Now that you hopefully understand what the word component means

tall bramble
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still dont understand the 2 and -2

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i undersntad the numerators now

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but denominators

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dk

trail musk
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What are the a and b components for the vector AB

tall bramble
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2- 9k and -3k

trail musk
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Nope

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I said for the vector AB

tall bramble
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2b -2a

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?

trail musk
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what multiplies the a is the a component, and what multiplies the b is the b component