#help-0

1 messages · Page 592 of 1

alpine sable
full wasp
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i would say take logs of both sides but wtf is log10(500000) without a calculator looooool

alpine sable
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it's easier to divide both sides by 2000 first

muted raft
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2^(x/30) = 500000/2000 = x/30 * log(2) = log(500/2)

alpine sable
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log 2 and log 5 are 0.30 and 0.70, they r standard values u can learn

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but it doesn't say to use log5 as 0.7

indigo jetty
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lg 5 = lg(10/2) = lg10 -lg2

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u are given lg2 = 0.3

alpine sable
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oh

full wasp
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wtf i didnt think of that

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me and my electron-sized brain

worldly oxide
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@wraith locust is correct answer -5??

civic hearth
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I need help

worldly oxide
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How can I help??

civic hearth
civic hearth
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B. And C.

wraith locust
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@worldly oxide yes -5

dry echo
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Can someone help me visualize this?

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Don't solve it for me though, I wanna know what's happening

worldly oxide
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@wraith locust want soln?

full wasp
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hold on

olive fiber
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does anyone know how to do this

full wasp
dry echo
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man, this is great

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thank you so much!

dry echo
full wasp
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this is about the extent of my abilities with blender lmao

worldly oxide
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@full wasp you know any reagent which can reduce Fe+2??

full wasp
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idk maybe like Ag(s)

dry echo
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true

worldly oxide
#

@full wasp does Li work as it is strongest Reducing agent??

brave ice
dry echo
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those are way simpler yeah lol

brave ice
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oops

dry echo
tiny cedar
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if i have cos x = 5/6, then cos 2x will be 5/3 ??

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or it dosnt works like that

oak chasm
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@tiny cedar It doesn't work like that.

tiny cedar
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oh

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how can i find it then

oak chasm
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$$\cos(x) = \frac56$$

ocean sealBOT
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Chai T. Rex

oak chasm
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Take arccos of both sides.

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$$\arccos(\cos(x)) = \arccos\left(\frac56\right)$$

ocean sealBOT
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Chai T. Rex

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Chai T. Rex

tiny cedar
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uh fuck

oak chasm
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If you only want one solution, that should be enough to start you off.

tiny cedar
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i mean

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im supposed to do it w/o calculator

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so is there rlly no way i can do this

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this is the problem, its in spanish but i think the words dont rlly matter

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i found cos x

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wich is -5/6

oak chasm
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Sorry, I have to go.

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But here's something useful:

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,w simplify cos(2arccos(a))

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Oh, wait.

ocean sealBOT
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Chai T. Rex

oak chasm
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,calc cos(2acos(5/6))

ocean sealBOT
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Result:

0.38888888888889
tiny cedar
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oh

oak chasm
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,calc 2(5/6)^2 - 1

ocean sealBOT
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Result:

0.38888888888889
oak chasm
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But now I have to go 🙂

languid ore
worldly oxide
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@languid ore 400??

languid ore
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@worldly oxide How would you find that answer?

worldly oxide
languid ore
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where does the 45 come from

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we dont use cos in my class could you explain how i could solve it without cos @worldly oxide

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how?

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please

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okay

stuck kestrel
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yes

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x = 20

wraith dew
full wasp
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ah this isnt too bad

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although is this a test

wraith dew
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nono its an ungraded content check

languid ore
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my fault

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im not sure how ur getting 20

alpine sable
# wraith dew help!

U calc volume for both hemisphere and the cone, and subtract cone from hemisphere

full wasp
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cone volume is like 1/3 πr²h (h = r tho)

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and hemisphere volume is 2/3 πr³

wraith dew
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ok so i got the hemisphere volume

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but im just confused on the cone's volume

alpine sable
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Cone’s volume is given as 1/3 pi r^2 h

full wasp
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the height of the cone is equal to the radius of the hemisphere

wraith dew
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so the height equals the radius?

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ohhhh

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i got ot

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it

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tysm!!!

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ok i got 28.3 as my final answer

south stream
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Why is 9-(-13) = +22 shouldn't it be negative because the 13 is greater?

worldly oxide
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@south stream thats not 13 it is -13

south stream
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Oh

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So 9 became greater

worldly oxide
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Yeah

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And you're giving 13 extra to 9

alpine sable
#

ye a positive number is of course greater than a negative number if u think it like that

south stream
#

But...
(-63) + 49 = -14

worldly oxide
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Why dont you write it like 49-63

south stream
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The operation change then the negative sign of the first term

worldly oxide
#

When you subtract a negative term it is basically you're adding both digit

soft echo
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is this free?

worldly oxide
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??

alpine sable
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Yep

soft echo
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alright

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wait

worldly oxide
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Want area??

soft echo
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no

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what angle is this

worldly oxide
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Which??

soft echo
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the one in the ss

soft echo
limpid rock
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there are 4 of them

worldly oxide
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Which angle mention the quadrant

soft echo
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hw question

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i named the angle parallelogram is that correct?

soft echo
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oh

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alright thanks

patent hearth
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I'm struggling with part b can anyone help?

soft echo
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is this a test?

soft echo
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is that a test?

patent hearth
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No its hw

soft echo
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oh ok

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do you know the answer?

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I am not sure

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but lets see

alpine sable
# patent hearth

men and projects are directly proportional, men and hours are directly proportional, hours and projects are inversely proportional

soft echo
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lol

alpine sable
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(m*h)/p=constant

patent hearth
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I dnt get it lol srry

soft echo
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which grade are you in

alpine sable
patent hearth
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Yes

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But not this kind

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Ik that sound stupid

alpine sable
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ok, first lets imagine we keep the number of hours constant

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so for example lets say we fix the time at one hour

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more men = more projects completed

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less men = less projects completed

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#men and #projects are directly proportional

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does that make sense

patent hearth
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Yes it does

alpine sable
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now let's imagine we keep the number of men constant

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for example we fix it at 2 men

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if they have more hours, they can complete more projects

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if they have fewer hours, they can complete fewer projects

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so #hours and #projects are directly proportional

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do you follow

patent hearth
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Yes

alpine sable
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ok now imagine keeping the number of projects constant

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more men will finish the projects in fewer hours

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if we have less men working then they will take more hours to finish th eprojects

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so #men and #projects are inversely proportional

patent hearth
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Yes

alpine sable
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so now we have mh/p=constant

patent hearth
#

Ohh
I think I got it
Thanks
This should make solving other qs easier

alpine sable
#

np

soft echo
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can you tell me the answer

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I did the maths another way

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lets see if it works

patent hearth
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I haven't solved it yet

soft echo
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after solving it

patent hearth
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Sure ill send it

soft echo
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l

patent hearth
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I got 32
What bout u?

soft echo
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k

soft echo
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Lol I somehow got 135

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LMAO

patent hearth
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K lol

alpine sable
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32 is correct

soft echo
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yes ik

elfin lynx
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Can someone explain b. I having trouble seeing how you get to that number

alpine sable
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Ok, quick simple question. Is >18 greater than or less than? Debate in another server

elfin lynx
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greater than

lone vapor
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none

alpine sable
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If it is greater than, then is 0>18 true? No...

alpine sable
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Hmmm

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Well it is just a symbol referring whether something is greater or less than

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In that case, I am wondering why people think it is greater

muted raft
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Yes which is why >18 does not make sense

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there is no quantity on the left

alpine sable
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Yes

muted raft
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18 does not make sense but i guess people might assume it as numbers greater than 18?

covert glade
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Can someone please help me

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I came across this question and idk what to do

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A Norman window has the shape of a semicircle atop a rectangle so that the diameter of the semicircle is equal to the width of the rectangle. What is the area of the largest possible Norman window with a perimeter of 47 feet?

Be sure to realize that the perimeter is just the outside of the window.

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please lmn asap

alpine sable
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first step draw a diagram if you haven't already

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so let's say l is the length of the rectangle and w is the width of the rectangle

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find an expression for the perimeter in terms of l and w

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then find an expression for the area in terms of l and w

covert glade
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Okay

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what should we do after?

alpine sable
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then substitute that into the area equation

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now that you have the area functon in 1 variable, find the critical points of the area function

gleaming granite
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kinda weird lmao

bold token
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is this available?

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i guess it is

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what does this mean?

noble bolt
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y" means double differentiation of y

alpine sable
#

is there a channel on this server to help with a math course ill be taking in a months time , it kicked my ass once before and i know ill need help with it

bold token
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so at y' do I use dy/dx?

noble bolt
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That is d^2(y)/(dx)^2

bold token
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oh wow

noble bolt
bold token
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then after dy/dx?

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the first derive

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what do I do next?

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derive the next equation and discard the dy/dx at the left?

noble bolt
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Differentiate dy/dx again

bold token
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wdym

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oh I use dy/dx as the equation I derive?

bold token
noble bolt
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I'll explain from start

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First take everything except y to rhs

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Find dy/dx

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Now replace dy/dx with y'

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Now find dy'/dx

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@bold token

bold token
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so it would be 8yy'?

noble bolt
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No..

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Wait I'll solve and send you

bold token
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oh didnt really need that, but thx

tranquil matrix
#

Can anyone help I’m doing past papers but I don’t know how to do this

coral pagoda
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At least for the 4y^2 part

bold token
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hm

coral pagoda
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What is the derivative of x^2?

bold token
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2x

coral pagoda
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And the derivative of 4?

bold token
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y' would be 2x+8yy'=0?

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that's what im thinking

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but my teacher didnt explain that further xD

coral pagoda
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No no, this is not what y' is equal to

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However, we can solve for y'

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[ 2x+8yy'=0\Rightarrow 8yy'=-2x] Finish the rest

noble bolt
#

We have to find y" so there should be no y term

ocean sealBOT
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dackid (jump king +)

coral pagoda
bold token
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um

noble bolt
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F I was wrong it seems

bold token
coral pagoda
bold token
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so 2x/8y?

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then I get its derivative

coral pagoda
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You forgot the negative, but yes

bold token
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so it would be y''?

grand kelp
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$x^2 + 4y^2 = 4$ is an equation of an ellipse

ocean sealBOT
#

NickPro

coral pagoda
bold token
grand kelp
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So the value of y clearly matters

bold token
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then I derive -2x/8y to get y''?

coral pagoda
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So we have $y'=-\frac{x}{4y}$

ocean sealBOT
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dackid (jump king +)

bold token
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wait somethinglike that

coral pagoda
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Now you need to differentiate again

grand kelp
#

Yes, then you differentiate this fraction

coral pagoda
#

As we see, the chain rule will come in to effect again

bold token
#

yeah

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so what do I use next now?

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dy/dx?

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y'?

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or y"?

coral pagoda
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Take the derivative of -x/4y

noble bolt
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Ans should be in terms of x from what I have learned

bold token
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yeah whats the derivative of 4y?

grand kelp
#

It's generally not a good idea to change the system of notations in the middle of your solution

coral pagoda
bold token
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4(dy/dx)?

grand kelp
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4y'

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Yeah

coral pagoda
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You have a quotient of two functions -x and 4y

bold token
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yes i know qouteinet rule

coral pagoda
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So you need the quotient rule here to take the derivative

bold token
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jsut the 4y im worried

grand kelp
noble bolt
smoky barn
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How did you understand the importance of variables for data analysis?

can someone help? im stuck on this question

coral pagoda
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Well y is a function of x, so you use the chain rule. And you are correct since the derivative of 4y is 4y'

grand kelp
#

So you would have to add plus-minus in the front

noble bolt
#

What's wrong with this?

bold token
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Im not following

coral pagoda
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y is not a function

bold token
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let me clear

coral pagoda
#

Please ignore them Yogurt

bold token
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with -x/4y,

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i do the qoutient rule

coral pagoda
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Yes

bold token
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now what would be the derivative of 4y?

coral pagoda
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You mentioned it earlier

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4y'

bold token
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4dy/dx?

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why 4y'?

coral pagoda
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They are the same thing

grand kelp
#

That's the same thing

bold token
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oh xD

grand kelp
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Just in different notation

bold token
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so now if I get the equation

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I get y' in either sides of the equation right?

coral pagoda
#

This will not be an equation this time

bold token
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so I just disregard y' on the left?

coral pagoda
#

You'll have $y''=\dots$

ocean sealBOT
#

dackid (jump king +)

coral pagoda
bold token
#

oh so y''=blahblah with y'

noble bolt
#

Why can't we take y as a function here ?

bold token
#

right?

coral pagoda
#

That is the definition of the 2nd derivative

coral pagoda
#

But if you recall the vertical line test, that means y is not a function

noble bolt
#

Ohh....

bold token
noble bolt
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Ok thanks got it 👍

coral pagoda
#

Its yogurt, take the derivative of -x/4y

bold token
#

aight

noble bolt
#

Didn't think of verifying whether it's a function or not

coral pagoda
#

You are asking questions you'll know the answer to if you just take the derivative

coral pagoda
noble bolt
#

I see

grand kelp
#

They can also still be functions, but with no clear analytic expression

coral pagoda
#

Also true

bold token
#

i feel

grand kelp
#

Like inverse to a degree 5 polynomial

bold token
#

that my ans is wrong

noble bolt
#

So we differentiate y^2=4ax the same way right implicitly?

bold token
#

is (-4y+4xy')/16y^2 wrong?

coral pagoda
#

Okay, recall the quotient rule [ \left(\frac{f}{g}\right)'=\frac{f'g-g'f}{g^2}]

ocean sealBOT
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dackid (jump king +)

coral pagoda
#

In our case f(x)=-x and g(x)=4y

bold token
coral pagoda
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Okay, so it looks good

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Now the catch: what is y'?

bold token
#

dy/dx?

grand kelp
#

You calculated the derivative of y like 3 minutes ago

bold token
#

y' is

grand kelp
#

Why not just plug that in

bold token
#

-x/wy?

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2y?

coral pagoda
#

-x/4y

bold token
#

4y

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something

coral pagoda
#

Yes

bold token
#

so I plug that

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in the y'' equation

coral pagoda
#

You replace y' with -x/4y

grand kelp
#

Yes

bold token
#

aight on it

noble bolt
#

Ok so you replace y' in the end

coral pagoda
#

Yes

noble bolt
#

Can this be done for functions too?

grand kelp
#

Indeed

coral pagoda
#

Sure, but if we can write y=f(x), then the question becomes pretty straightforward

noble bolt
#

Nice this makes differentiation a bit easier

coral pagoda
#

Nothing special here

grand kelp
#

This can be done for any curve given that it's differentiable

noble bolt
#

Ok

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Gotcha

bold token
#

[-4x-4x^2/4y])/16y^2?

grand kelp
coral pagoda
#

Simplify, but yes

bold token
#

welp thx everyone

noble bolt
#

I see

coral pagoda
#

You bet

noble bolt
coral pagoda
#

\begin{align}
y=\ln(x) \Rightarrow x=e^y
\end{align}
\begin{align*}
\dv{x}(e^y)&=\dv{x}(x)\
y'e^y&=1\
y'&=\frac{1}{e^y}\
y'&=\frac{1}{x};; (\text{Recall equation 1})
\end{align*}

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There ya go

ocean sealBOT
#

dackid (jump king +)

coral pagoda
#

Also, there is your proof for the derivative of ln(x)

noble bolt
#

But I found itzoomEyes

coral pagoda
#

The derivative of a^x makes use of the chain rule

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Note $a^x=e^{x\ln(a)}$

ocean sealBOT
#

dackid (jump king +)

coral pagoda
#

And so by the chain rule: $(a^x)'=\ln(a)a^x$

ocean sealBOT
#

dackid (jump king +)

noble bolt
#

Oh

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I did it the long way

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I am nubPepoG

coral pagoda
#

Nah, it's okay

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Try finding the derivative of $\log_x(a)$

ocean sealBOT
#

dackid (jump king +)

noble bolt
#

Give me a min I'll solve it

coral pagoda
#

Alright. This one's a little tricky at first

noble bolt
#

Yes it is indeed

coral pagoda
#

Keep in mind the variable is the base of the logarithm

noble bolt
#

Yes

tribal geyser
#

Hey guys I need help with 12

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Like I did the working and I got the answers however the answers only have two of the answers I have

grand kelp
#

Look at the question

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They only asked alpha and beta

tribal geyser
#

Yh

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So?

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I found alpha and beta

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and I have plus or minus 1/2 and 2/3 or 3/2

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The answer gives me only 1/2,2/3

noble bolt
tribal geyser
#

@grand kelp

coral pagoda
#

[ \log_x(a)=\frac{\ln(a)}{\ln(x)}]

ocean sealBOT
#

dackid (jump king +)

grand kelp
#

That's honestly a very strange way to solve a quartic equation

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Lemme look at this for a moment

noble bolt
#

I didn't think of that sheesh

coral pagoda
#

It helps quite a bit weSmart

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,w plot log_x(a)

grand kelp
#

@tribal geyser First, you lost the 18x^2 term in your equation

ocean sealBOT
coral pagoda
#

Nice job wolfram -_-

tribal geyser
#

@grand kelp it’s using sum and products lol

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so if u could explain that’ll be great

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@grand kelp I didn’t lose it lol I wrote in at the top

grand kelp
#

You didn't

coral pagoda
#

So I know the product is equal to -6, but what about the sum?

grand kelp
#

The sum is 52 / 24 afair

coral pagoda
#

I don't know what the sum of the roots are for higher polynomials

tribal geyser
#

yh

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If u put it on a calculator it also gives u what I got lol

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I got plus and minus 1/2 and 2/3 3/2

grand kelp
#

It just works the same, since you have $(x - x_0)(x - x_1)...(x - x_n)$

ocean sealBOT
#

NickPro

noble bolt
#

Is this right?

tribal geyser
#

But the equations gives 4 solutions

coral pagoda
#

Well anyways [ \beta \cdot \frac{1}{\beta}\alpha\cdot -\alpha=-\alpha ^2]

tribal geyser
#

How did u know which one?

ocean sealBOT
#

dackid (jump king +)

tribal geyser
#

Channel taken sorry

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@alpine sable

alpine sable
#

no worries

coral pagoda
#

And [ \frac{1}{\beta}+\beta +\alpha-\alpha=\frac{1}{\beta}+\beta]

ocean sealBOT
#

dackid (jump king +)

tribal geyser
#

Yes

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I’ve done all of that

coral pagoda
#

So $\alpha=\sqrt{6}, -\alpha=-\sqrt{6}$

ocean sealBOT
#

dackid (jump king +)

tribal geyser
#

Like if u try solve it u will get 4 solutions

noble bolt
#

Dackid give me more of those kinds of questions if possible

coral pagoda
tribal geyser
#

I’m lost

noble bolt
#

Yes

tribal geyser
#

Can anyone help?

grand kelp
#

@tribal geyser What's your problem once again?

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You don't know what solution to choose in a pair?

tribal geyser
#

Yes because I figured out alpha which has two solutions and beta which also has two

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So which one am I suppose to use

grand kelp
#

It doesn't matter because if you change the sign of alpha or replace beta with its reciprocal the solutions would stay the same

tribal geyser
#

Are u sure because why would the answer only state 2 then?

grand kelp
#

Well, there isn't a valid reason to say that either of these answers is wrong so I assume the authors just gave one of the options

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@coral pagoda It's not sqrt(6) since you have to divide that 6 by 24

torpid hazel
#

sry

jovial mica
#

can someone help with this question?

autumn timber
#

idk

alpine sable
#

Less of a problem question but more understanding. When I have a taylor series, am I evaluating f(x)^n by the value of a?

Lets say ln x centered at a = 1. When expanding it, am I evaluating ln(x) and its derivatives at the value of a?

So it would be ln(1), 1/(1), -1/(1^2), 2/(1)^3....

livid crypt
#

can someone help me with this problem?
how do I start it

jovial mica
#

Alright thanks.

strong furnace
# livid crypt

are there any particular instructions (integration by parts / integration by substitution) to solve this problem?

alpine sable
# livid crypt

i don't know what techniques you know, but one boring way I see immediately would be to expand the fraction by sqrt(25+x^2) so that you get rid of the root in numerator.

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Could you proceed from there? Then you'd have to use an algorithm for such integrals.

livid crypt
strong furnace
#

adding to that you can also substitute x = 5sin(theta)

alpine sable
livid crypt
#

wait why would you substitute x = 5sin(theta)

alpine sable
#

i suggest you to try it and see for yourself what happens

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if you are still confused then ask again

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it's something that you have to see once or twice to be able to think of it

hollow owl
#

hi I need help with how to solve this

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I dont know how to start solve when there is sin and cos

strong furnace
#

did you use the hint?

hollow owl
#

I put the hint instead cosx and what then? how do I continue

strong furnace
#

have you learned about this limit ? sin(x)/x

hollow owl
#

equal to 1

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yes

alpine sable
#

expand by (1+cosx)

strong furnace
grand kelp
# livid crypt

This particular integral is actually pretty easy since this is a semi-circle centered at the origin with a radius 5

#

What you need is the top-right quarter of the circle

iron swift
grand kelp
#

It would be 25pi/4 I believe

alpine sable
#

how would u determine that 12a starts at 1?

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without calculator?\

lament wyvern
#

what is sin(pi/4)

alpine sable
#

nvm i got it

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thnaks

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anyway

grand kelp
#

$\sin\frac{\pi}{4} = \frac{\sqrt{2}}{2} = \frac{1}{\sqrt{2}}$

ocean sealBOT
#

NickPro

hollow owl
#

I just get to 2sin(t)^2/x^2

grand kelp
#

Notice that $\frac{2\sin^2{\frac{x}{2}}}{x^2} = 2(\frac{\sin{\frac{x}{2}}}{x})^2$

ocean sealBOT
#

NickPro

grand kelp
#

Now you can replace x/2 with t and get $2(\frac{\sin t}{2t})^2$

ocean sealBOT
#

NickPro

grand kelp
#

@hollow owl

hollow owl
#

wow very nice text bot

#

ok I understand you cuz 2*x/2 = x. thank you

grand kelp
#

no problem

hardy geyser
#

Is there an easier way to do this on the calculator instead of guess checking

lament wyvern
#

xy = 36
find all the factors of 36

#

1,2,3,4,6, 9, 12, 18

hardy geyser
#

how about on the calculator

lament wyvern
#

not everything needs to be done on a calculator

hardy geyser
#

I’m trying to make the act faster im on time crunch

grand kelp
#

This doesn't have to be done on calculator

hardy geyser
#

but if I did it on the calculator it would be faster?

lament wyvern
#

no

grand kelp
#

1 + 36 = 37
2 + 18 = 20
3 + 12 = 15
4 + 9 = 13
6 + 6 = 12

#

All the options

#

@hardy geyser I don't know how you can find the divisors of a number on a calculator

hardy geyser
#

so guess check would be the fastest way

grand kelp
#

I mean, 36 isn't a very large number

#

You can even check all the possible options, of which there's not too many

hardy geyser
#

what if they give me a larger number

grand kelp
#

There are some techniques that you can use like estimating the numbers you can get, checking the remainders, etc.

#

Not sure the remainders would work but who knows

#

For example we have just found that all the options are 12 or larger

hardy geyser
#

nvm I found a YouTube video I got it ty

grand kelp
#

Okay

leaden hill
#

guys

#

how can I solve this

#

it want A degree

grand kelp
#

Is that a pyramid?

leaden hill
#

are u kidding?

woeful pulsar
#

so it's flat?

grand kelp
#

I'm not, it maybe a triangle or a pyramid

leaden hill
#

triangle

#

ABC is a triangle

grand kelp
#

Okay

carmine lion
#

48??

leaden hill
#

how did u guys solve it

carmine lion
#

because the triangles are the same

grand kelp
#

This can't be true

carmine lion
#

the sides are equal

#

why cant it be true

grand kelp
#

Because you're getting that the sum of angles is 144 degrees, not 180

leaden hill
#

ye

#

nick is right

#

what u say for this question @grand kelp

grand kelp
#

I'm thinking

#

That's a weird question

woeful pulsar
#

yeah you have a triangle and the circumcenter

#

but it should be determinable

leaden hill
#

I agree its damn weird .d

#

but I have to solve it

woeful pulsar
#

tho it's definitely solvable

leaden hill
#

@woeful pulsar can u solve and explain if u can

woeful pulsar
#

there are lots of isosceles triangles

#

try marking down all the equal angles

#

see what relations you can make too

grand kelp
#

Ah, yeah

#

If D is the circumcenter, then BAC is half of BDC

#

So it is 66 degrees

leaden hill
#

u sure?

grand kelp
#

Yes

leaden hill
#

what u mean with circumcenter

carmine lion
#

64?

grand kelp
#

@leaden hill You can draw a circle around the triangle

#

Have you studied things like that?

leaden hill
#

no kinda

#

new in thesethings

#

and what u say about that

#

ise means if

#

ABC is a triangle

#

it want how much is the X

grand kelp
#

Ever heard of Menelaus's theorem?

leaden hill
#

yeah

grand kelp
#

You can apply it for ABE and the line CD

leaden hill
#

I am gonna try

#

wait

coral ridge
leaden hill
#

yetiyo mu

#

thales

#

emin misin

coral ridge
#

yep

#

2/5=x/(x+9)

#

bunu yap

leaden hill
#

aga

#

o oran altta geçerli ama

coral ridge
#

cevap 6 değil mi

leaden hill
#

o oranı

#

altta şey yapıyor ama

coral ridge
#

ef/fb oranı de/bc oranı demek zaten

#

de/bc = ae/ac

#

thales işte

#

@leaden hill anladın mı

alpine sable
#

How would I approach this problem in a time effective manner?

woeful pulsar
#

is it some sort of taylor series?

alpine sable
#

Whoops, sorry

woeful pulsar
#

firstly you can ignore the x^10 and just differentiate ln(1+8x)

#

this should give you 8/(1+8x), which you should be able to write the taylor series for easily, which you can integrate

alpine sable
#

I will write down my work and see how it goes

#

Thank you for the help

carmine lion
#

i don't quite understand how im going wrong for this question

#

if sin(a)=-4/5 pi<a<3pi/2 and cos(b) =-5/13, pi/2<b<pi, evaluate tan(a+b)

alpine sable
#

Thank you so much!

west nimbus
#

How would I solve this on a graph?

autumn timber
#

idk sorry

twin pebble
#

how does the determinant of (m-lambda*I) make the eqn 0?

fading zephyr
#

the idea is that v is not zero, and neither is M - lambda*I

#

the only way you can get zero out of that matrix-vector product is if the columns of M - lambda*I are linearly dependent

round raven
#

if im given f'x and f(1) how would i find fx

twin pebble
#

integrate

round raven
#

thanks

fading zephyr
#

you integrate and find the integration constant using f(1)

round raven
#

so like just substitute c for f(1)

fading zephyr
#

no

#

you have f'(x), let's call its antiderivative F(x)

#

this F(x) is equal to f(x) + c

#

you know f(1)

#

so F(1) = f(1)

#

for example, say f'(x) = 1

#

and f(1) = 10

#

the integral of f'(x) is x

#

and 1 is definitely not equal to 10

#

however, there's also the integration constant in there, so that F(x) = x + c

#

then we say F(1) = f(1)

#

so 1 + c = 10

#

or c = 9

round raven
#

thanks

rich basin
#

I'm going to need some help with this mathematical problem

woeful pulsar
rich basin
#

I managed to get to when i got it to +- 2

#

what do you mean by products of all 4 roots?

woeful pulsar
#

hold on while I think what to say

rich basin
#

you mean a + b +c +d = -b/a

woeful pulsar
#

though you can try factoring it into two quadratics

rich basin
#

So do I make ab = 2 and cd = -2

#

and then swap around with ab =2 and cd = 2

#

as well as ab and cd = -2

woeful pulsar
#

actually there are just two cases

rich basin
#

oh yeah, my bad

#

so why acn't ab and cd be positive 2

#

and only can be negative 2

woeful pulsar
#

$6x^4-11x^3-26x^2+22x+24=6(x^2+Ax+2)(x^2+Bx+2)$

OR

$6x^4-11x^3-26x^2+22x+24=6(x^2+Ax-2)(x^2+Bx-2)$

rich basin
#

My friend and I were wondering why it can't be negative 2

ocean sealBOT
#

Element118

woeful pulsar
#

just need to find A and B

rich basin
#

can't really see the image

#

@woeful pulsar I mean why it can't be positive 2

woeful pulsar
#

erm

#

you have to try both cases

#

$6x^4-11x^3-26x^2+22x+24=6(x^2+Ax+2)(x^2+Bx+2)$

OR

$6x^4-11x^3-26x^2+22x+24=6(x^2+Ax-2)(x^2+Bx-2)$

ocean sealBOT
#

Element118

woeful pulsar
#

hopefully it renders this time

#

if you can't see the image, try reading the LaTeX

rich basin
#

I don't think I have LaTeX

strong furnace
#

if you start by evaluating the condition for the sum of 3 roots taken at a time you will get k=-2

rich basin
#

what are the conditions

strong furnace
#

-22/6 = abc+bcd+cda+dab if a,b,c,d are roots

rich basin
#

yeah

strong furnace
#

assume ab = cd = k

rich basin
#

I mean is it possible if you can prove it with when you sub ab in into abcd

#

where ab becoem +- 2

#

but +2 for some reasons was rejected

strong furnace
#

we cannot make a conclusion from just abcd

woeful pulsar
#

yeah

#

so you need to use the rest of the polynomial to figure out

alpine sable
#

Hey I'm really confused with this question could someone help?

#

This is part of my working out l and it shows where I got stuck

#

I'm pretty sure this question makes a 4x3 by 4x1 order

#

Which is not defined

#

Ahh I'm so confused

lament wyvern
#

a looks about right

#

but for AX=B, X is your variables

#

i.e. x y z

#

@alpine sable

#

A should be n x m where n = number of equations and m = number of variables, X is then m x 1, forcing B to be n x 1

alpine sable
#

Whaat

#

Wait so how should I put it?

#

@lament wyvern

lament wyvern
#

so AX = B

#

if X = the column vector (x, y, z)

alpine sable
#

Hmmm?

#

Ahh yes

lament wyvern
#

first row of A times X gives you

#

$\Sigma A_{1j} x_j$

ocean sealBOT
#

PrettyPrincessKitty FS

lament wyvern
#

which is ax + by + cz

alpine sable
#

Ahh alright

lament wyvern
#

if you write out A to be [a b c // d e f // g h i] and X to be [x // y // z] and multiply it out

#

you'll see it

alpine sable
#

So is question c just asking inverse of a

lament wyvern
#

C wants you to find x, y, z

alpine sable
#

Hmm

#

Its still not working though

#

It says dimension error...

fading fern
#

math is tough

alpine sable
#

@lament wyvern

lament wyvern
#

why is A a 3x4

alpine sable
#

Oh wait is that wrong

#

So it was right the way I had it before...

lament wyvern
#

each row corresponds to 1 equation

alpine sable
#

Yes

#

And x

lament wyvern
#

you have 3 rows, yet 4 equations

alpine sable
#

Is corresponding to x passengers

#

See on the question it has three rows

lament wyvern
#

I count 4 rows

alpine sable
#

Opos I mean four

#

Yep

lament wyvern
#

so your matrix should have 4 rows

alpine sable
#

And I don't see how column can rep the corresponding equations

#

Ok so I was right like this:

lament wyvern
#

yes

alpine sable
#

Then why isn't it working

lament wyvern
#

because it's AX=B

#

not XA=B

alpine sable
#

On my CAS inputs

#

Wait..

#

So my a is my x and my x is my a?

lament wyvern
#

A is a 4x3

#

X is a 3x1

alpine sable
#

Ues

#

Hmm

#

Could you please show me visually

lament wyvern
#

if you write out A to be [a b c // d e f // g h i] and X to be [x // y // z] and multiply it out
you'll see it

alpine sable
#

Like as in draw it Because I can't understand it sorry

#

I'm sorry, I just can't visualise that.

lament wyvern
#

AX=B
you have your A
you have your X
idk how else to explain it

alpine sable
#

Draw?

#

Pls.

lament wyvern
alpine sable
#

Yes but I can't just do xyz

#

What do I put in there?

lament wyvern
#

you can, though

alpine sable
#

Woohoo.

#

Wait

#

So then

#

Where does the 20240

lament wyvern
#

so I've drawn it
if you do the multiplication, you'll get ax + by + cz

alpine sable
#

So where does the total taking ls go?

lament wyvern
#

where can it go?

alpine sable
#

So like this

#

?

#

@lament wyvern

#

Wow I'm so confused

#

@lament wyvern

lament wyvern
#

why are you inverting it

alpine sable
#

Because it wants a^-1

lament wyvern
#

I mean you don't need to throw it in a calculator

alpine sable
#

I'm though because it goes against what I have been learning, usually the x,y,z is just for reference and then you times the other two and invert the equation matrix

#

Here I'll show you

lament wyvern
#

yeah I mean maybe you've been taught different

#

but usually you put it in an augmented form, row reduce the matrix, read off the solution

alpine sable
#

Ignore everything above the r ed line

lament wyvern
#

ah okay, so what you're doing there is you have AX = B
A^-1AX = A^-1B
IX = A^-1B
X = A^-1B

alpine sable
#

And there's the question

#

Yes but I'm pretty sure that's what it's asking

#

Not only thAt but it's a 3x3

lament wyvern
#

yeah, how you get from AX=B to X=[thing] is c)

#

are we on c) now?

alpine sable
#

So idk

#

Yes this c

lament wyvern
#

then you know what A is

#

oh my bad didn't see the thing asks for a calculator opencry

alpine sable
#

Np

lament wyvern
#

yeah you know what A is

alpine sable
#

Yes

lament wyvern
#

idk how to use a CAS to find the inverse

alpine sable
#

I do

#

Its just the matrix

#

Then

#

^-1

lament wyvern
#

okay, so you should be able to put that A matrix in

alpine sable
#

Matrix a ^-1

#

Yes

lament wyvern
#

just the A matrix, nothing else

alpine sable
#

Wait and is that it??

#

BRUHHH

lament wyvern
alpine sable
#

I asked thAt

#

BRUHHHHhhhHhh

lament wyvern
#

sorry, I got confused by what you were asking

alpine sable
#

Ok

#

Brb

#

Ummm

#

Its still NOT WORKING

#

@lament wyvern

lament wyvern
#

yeah sadly I have no idea how to solve that, it seems like a calculator problem

alpine sable
#

I think

#

Its because it's not a square matrix

lament wyvern
#

nonsquare matrices can have inverses

alpine sable
#

Therefore Its undefined

#

I don't think so

#

Because all the calculators online are asking for perfect square matrices

#

And wont let me modify it to 4x3

#

Oh well

lament wyvern
#

or rather, it has 2 inverses (if it's not singular)

alpine sable
#

Thank you anyway for your help

#

Oh yes true

lament wyvern
#

oh wait, no

alpine sable
#

Much appreciated

#

Oh wait

lament wyvern
#

yeah because the commuting makes no sense

alpine sable
#

What

lament wyvern
#

A-1A = I = AA-1
doesn't make sense for nonsquare

#

so then you have (A-1L)A = I = A(A-1R)

#

for the left and right inverses

alpine sable
#

So i was right

#

?

lament wyvern
#

I've gotta be honest, the question is confusing me

#

because A cannot be square

#

and yet it wants an inverse

alpine sable
#

Yes

#

Thats what I was getting at

#

Maybe it has something to do with the question

#

Or maybe ijt doesnt

#

Maybe it's an absolute giga brain equation

#

Anyway thanks again @lament wyvern

lament wyvern
#

np, sorry Icouldn't help more

alpine sable
#

Your time and all the other helpers is much appreciated

#

Np

whole palm
#

3 plus 1?

lament wyvern
#

I mean yeah you could just ignore one equation

#

then A is a 3x3

oblique plinth
#

btw was wondering if anyone could help me with this. unsure what where this 3/5 come from

lament wyvern
#

uh, looks like they've multiplied the entire thing in the step before by 3/3

#

so you get $\frac{3sin(3x)}{3.5x.cos(3x)}$

ocean sealBOT
#

PrettyPrincessKitty FS

lament wyvern
#

then you can pull out the sin(x)/x => 1 bit

alpine sable
#

\cdot ,\sin and \cos

lament wyvern
#

ty

pine lake
#

Can someone help me with this question?

lament wyvern
#

you get 2 simultaneous equations

pine lake
#

Oh

nocturne summit
#

write the first equation in terms of powers of 3 and compare powers

pine lake
#

Correct?

nocturne summit
#

2x+1=3y i think

pine lake
#

Uh

#

How

nocturne summit
#

3x3^2x=3^2x+1

pine lake
#

What

#

How

low terrace
# pine lake

Umm... I'm new to this server, saw this question and I hope this helps you... (Pardon the handwriting plz)

nocturne summit
pine lake
#

But i found the ans

#

Appreciate ur help

naive plaza
#

Can chi-squared test use the value 0 (zero) as the frequency?

glass lichen
#

is it an ideal gas?

#

If the gas is assumed ideal then the calculation is simple, if it's not assumed ideal you need the van der waals

#

Ok so you can assume it's ideal?

#

$PV=nRT\implies V=\frac{P}{nRT}$

ocean sealBOT
#

moshill1

glass lichen
#

Yeah that's the ideal gas equation

#

ok so .09atm is 9.11925kPa

#

so then plug in all the numbers

#

$V=\left(\frac{9.11925}{(7.7)(8.314)(56)}\right)^{-1}$ cba to tex in the units

ocean sealBOT
#

moshill1

glass lichen
#

realized I messed up the re-arranging

#

Im getting ~393L

harsh zodiac
#

How many meters are in 279 inches?

#

My bad

glass lichen
#

,w calculate (7.78.31456)/(9.11925)

glass lichen
#

Yeah but you got on the order of 2000L, when it should be around 1/5 of that

#

Im saying im shit at sig figs LOL

#

try scientific notation?

#

$390=3.9\times 10^2$

ocean sealBOT
#

moshill1

glass lichen
#

Yeah well math says the answer is 390 so I'd talk to your teacher / prof about it

strong furnace
#

significant figures play a role in approximation i don't know how exactly but you can read about it

glass lichen
#

try 400

#

cause i cant recall if .09 is 1 or 2

#

Ok so it was to 1 sig

#

Yeah you had 2, 1 and 2, so division takes the fewest

#

Yeah sig figs are just a thing you do

strong furnace
#

they help in error propagation; I think

glass lichen
#

I mean I'd want the most accuracy in error prop not a sig fig value

#

then round off the average and deviation

strong furnace
#

the intention is to give the most accurate approximation keeping the error propagation in mind

#

iirc

alpine sable
glass lichen
#

My 2 cents is just round appropriately / that's what I plan on teaching

#

yes

#

keep to 4 sig figs

#

That's my guess, yes

#

Well yeah, the answer is ~.301 so the answer bank is probably wrong catshrug

brave fossil
#

how do i approach the first one?

#

do i try get it into reduced row e form with the variables

tough hatch
#

existence of free variables means the solution isn't unique

#

yeah it helps to get M_2 into RREF

#

so you can see what the leading 1s and therefore what the leading variables are

brave fossil
#

right i'll try do that

high gate
#

Help pls

winter bay
#

Which means whatever number is in the tenths place is divided by 10

brave fossil
tough hatch
#

any progress?

brave fossil
#

i have been trying to rref it but i feel im doing smthing

#

wrong

#

is the first step to do r3/ 9-k?

tough hatch
#

did u do gauss-jordan elimination?

brave fossil
#

nope

tough hatch
#

do u know gauss-jordan elimination?

brave fossil
#

i dont know what is exactly

#

i might but i dont know the name

tough hatch
#

it's a method of reducing a matrix to its RREF

brave fossil
#

oh yea ik that

#

i just looked it up

tough hatch
#

can you show what you did

brave fossil
#

so basically first i divide R3 by 9-k to get a one in the bottom left

#

and i work my way to get to the rref and have values with k and h in the augmented part

#

umm

#

if i try get the ref for m1

tough hatch
#

nvm

brave fossil
#

that just gives me m2

#

any other ideas?

tough hatch
#

yeah

#

well

ocean sealBOT
#

!superficialsicko

tough hatch
#

because otherwise there is no solution

brave fossil
#

i think i can give the solutions in terms of k and l

#

yeaa

tough hatch
#

assume that condition

#

then find the rref

#

so u can divide R3 by itself

brave fossil
#

by itself u mean 9-k right?

tough hatch
#

yeah

#

and divide 10-h by 9-k as well

brave fossil
#

and then i get z=10-h/9-k where k isnt 9

#

right i see

fossil meteor
#

take lcm from the lower most term

tough hatch
#

so you should get

#

what @brave fossil

fossil meteor
#

come in Q3 or some other which is vacant

brave fossil
tough hatch
#

what's the rref

brave fossil
#

im still doing it

tough hatch
#

ayt

#

tell me when u're done

brave fossil
#

just to make sure im on the right track, i should get x y and z in terms of h and k right @tough hatch

#

after rref

tough hatch
#

x y and z are the variables you are going to classify as either leading or free

#

then if one of them is free

#

no unique solution

brave fossil
#

right gotcha

#

i'll try finish it hold up

tough hatch
#

?