#help-0
1 messages · Page 625 of 1
x^2 + 4y^2 = 40
xy = 6
how do I find the value of (x + 2y)^2 ?
Can you expand (x+2y)^2 for me?
@visual fjord Expand
e x p a n d
@visual fjord it's simple just expand (x+y) ^2 then you will get answer
@visual fjord Where are you at?
the notation {a} means the fractional part of a
Dream what is the whole problem
nevermind i got it
the answer is apparently 64 because there was a formula that i never knew existed
your question was just expanding the brackets. .
yes and substitution was involved
Oh no, not subbing in stuff
bruh
nvm wait
{a} = a - floor of a
floor a means the greatest integer smaller than a
$a=\floor{a}+{a}, a\in\mathbb{R}^+$
Mosh
what is the context of this?
It's just a basic question
I mean I wanna plus plsu and minus it
Add 2x and 3x
ya
{(2x+3x-9y)-7z}
You get 5x - 9y - 7z
Oh ok thanks it's looking like my answer is ok then
Thanks
Yw
this some beta ass shit but can someone explain im in fucking 10th grade and i dont remember this shit from year 8 😭
Do you know what a denominator is?
yeah ofc
14*9
i just forgot how to work it out
multiplying the denominators (14*9) always gives you a "common" denominator
It isn't necessarily the smallest though.
you need to find least common denominator in this case it's their multiplication
so for the first one you will do 14*9 + 2 you can figure out for second one
wait wdym by 14*9 + 2
you need to find upper value for first one to i showed you the way
you really need to work on your explanation if that's what you meant
"do 14*9+2" doesnt explain anything you meant
didn't wanted to write him the solution but basically he need to find least common denominator for those 2 given values
bruh i just wanna know the fastest way to work it out cause my brain is dead
its like 4 am
and i havent slept for ages
14 and 9 are coprime so 14*9 is the smallest denominator
i
do you know how to calculate your numerator for the first one ?
$\frac{2}{14}=\frac{2}{14}\cdot\frac{9}{9}$
Mosh
x=23.43356414207485
yes
is it not tan opp/adj ?
yes
x=39/tan(59)
tan(59)=1.66427
in degrees, maybe you have your calculator in radians
39/1.66427=23.433
to cancel it out?
O
wait i can show you
can anyone help?
let me see
really easy problem
you know what a consecutive number is right?
like x and x+1?
yup
so just do the difference of those cubes
and thats equal to 1812
did you understand or should i write it?
(x+1)^3 - x^3 = 1812?
well
@dry berry yes solve it you will get answer
x^3-(x+1)^3=1812
if that doesnt work
try the one you put
or viceversa
just in case
so try this one
@dry berry don't use vice versa case it's given difference of cubes of two consecutive terms is 1812 which is positive if you use x3-(x+1)3 then answer would be negative
the weird thing is that it isnt in here the answer
you would get 24.07 and -25.07
and it also says integers
So use 24 as answer
ohhh
So consecutive term will be 25
man i've typed in wrong function 😳
is it free here already?
@alpine sable yes
can somebody help me with this question
😦
do we need to use differentiation here?
if yes is there any other method
?
i think we need to use defferentiation
is there any other method
since i haven't learnt differentiation yet
😦
@hollow ravine use formula pi (outter radius square - inner radius square) h
when it comes to tangent of a curve we often use defferentiation
fine the volume of the bigger one
fine the volume of the second one
and subtract them
nah nvm
im wrong
we have $y_{1,2} = \frac{-2 \pm \sqrt{-4x^2 + 12x +4}}{2}$
hmmm
gansta
@proud burrow I did it and I got it wrong so idk
that's ok dude
the answer is 0.1 if you needed
there is no answer
thats why
i mean no answer sheet provided
what about this 😦
ok I will try it now
but how do you get the height
since they only give the length
Length is the height
$-2h^2 - 6 =14$
gansta
why tho
i think there might be smtg wrong
cuz thats literally -14
@proud burrow this is what I got
there must be smtg wrong with the question
$-2h^2 - 6 =-14$
gansta
now is correct lol
this teacher is ridiculous
she simply sets question
and didn't provide us with any answer
D:
Find the quadratic polynomial the sum of whose zeroes are root2 and their products is -12 . Find the zeroes too.
help
that's fine if you have wrong solutions, just how you do it
ful explanation
so polynomial will be x^2 - root2x - 12
btw why do we have to expand the equation
do u know abt vietas relation of zeroes and coefficients ??
nope bro
in india it's different
lol learn that that is basis of this question
but i forgot
cbse?
how does that work but i think thats correct
class 10 ncert 2nd chap
thanks ❤️ @dry berry
ik but which excercise
h is not only equals to 2 but also -2
search the chap godamn it i forgot
since (-2)^2 =4
i did i browsed but couldnt get the exact type of question
yea?
thanks
https://ncert.nic.in/ncerts/l/jemh102.pdf Pg 28 from bottom
see n understand coz vieta's used everywhere
thanks bro
cool bruh
: D
the graph show us it goes through the point (0;14) and (4;14)
i don't think so tho since the graph should only work under mapping x=2
so h must be 2
only
yea
since the graph has the function y=f(x) = -2(x-h)^2 -6
we can put the following two points into this function
(0;-14) and (4;-14)
ooh
it seems like i've missed the point (4;-14) earlier
it those two function has the same root "h" you can only choose that root i guess?
btw im done here
the rest is yours
Why is this solution wrong ?
I have checked multiple solutions online and none of them have considered that y cannot be 0
why would it not be 0?
@nimble mulch use second equation as whole numerator >=0
@muted raft if it's zero then it would be infinite
$\frac{0}{1+0^2} = \frac{0}{1} = 0$
zslya
apply log rules
@rustic hatch as base is 4 for both substitute both value equal then find value of x
wdym?
@hidden horizon yes that what I ment
what about the log
log will go coz its same both lhs and rhs
just like exponents when bases are equal
@hidden horizon yes
ohh yeah thx bro
thx bro
cool bruh np
use basic trig
is this open now?
I got this problem. How do I find for a, a that is not 0, a solution? I can not have the null-vector. The matrix on the right is the inverse of the one on the left.
So if A is the matrix on the left, then the augmented matrix [A, I] should produce [I, B] where B is the inverse matrix of A. I assume you can apply something like this here?
so 2x = 4x - 12
so x will be 6
got it ?? @rustic hatch
Since A is supposed to be invertible like you said
cool bruh
A is inverted and can be seen on the right hand side. I need to find solutions to T_a(x)=T_a^-1(x)
for a non zero "a" and non zero vector "x"
But I am not seeing an approach to the solution other than brute force?
Hmm I think I have an idea one sec
There is a term called involutory matrices which is what I think is here
@rustic hatch im goin 2sleep , so if u hv any more doubts , dont ping me , hv a great day
Okay no problem. I was thinking about that as well
If a matrix is invertiable, then a special property of matrices will help a lot, do you know what property I'm referring to?
if i simplify it, is it gonna be 4x instead of 2x^2
not entirely. Been a while since I took linear algebra. I am helping someone with the problem.
det is not 0?
nope
det is (a) and 1/a
I know that. I inverted the matrix which can be seen on the right hand side (since a is non zero)
Do you know how to find the det of a 3 x 3?
Yes. Found for both.
So set the det equal to 0, and find a
And a cannot equal that value, it can be any other value though
Oh wait this is just a question about invertible matrix theorem
Which means you can pretty much apply any of the properties in the theorem
AKA it must have 3 pivots, it must have nullspace 0, it must be linearly independent, it must have det = 0, columns form basis, etc
I mean I am not sure on what dldh06 is refering to? Both determinants are found to be a and 1/a (of course) setting them to 0 does not do anything is it is non 0 (of course since it is invertible)
Find the det of a 3 x 3
Yes that should work as well
This process
The LHS matrix
And like I said, for a matrix to be invertiable, the det cannot be equal to 0
But that has already been done. The determinant is equal to a and a is then of course non 0
So the solution to your problem, is a can be any value except for 0, so $a \neq 0$
dldh06
yep but that is not the problem though?
I need to find a vector x
that solves T_a(x)=T_a^-1(x)
(aka my first picture where the vector X=(x,y,z))
But you said to find an "a" that has a solution?
A solution is not an "a". A solution is the vector
worded poorly I see.
i. e I need to find a vector x
that solves T_a(x)=T_a^-1(x), for "a" that is non zero
So is the goal to find "a" or (x, y, z)?
(x,y,z), a not equal to 0 and (x,y,z) not equal to the null vector
The thing is, if $a \neq 0$, you'll have infinity many (x, y, z) vector solutions
dldh06
Yes. But which form do these vectors have. I need to argue for an approach and not just pick any random vector from brute force and show that it works
I would assume RREF would be the best way to do that part
but both would just be identity matrices in that case.
Symbolically, keeping "a" in there
https://www.wolframalpha.com/input/?i=rref+{{1%2C+-2%2C+-1}%2C+{2%2C+-3%2C+-1}%2C+{1%2C+-1%2C+a}}^-1
Where is this question from?
A pratice problem. Not from a book or anything special.
Hi there.
I know that if
F(x) = a cos(px) + b sin (py) [1]
Then
F''+pF = 0 [2]
But assume we don't know anything about F(x). How can we solve it from [2] to get [1]? What should i know first if i want solve it in reverse??
Something you created?
No not at all. A friend was given this in a cs lin alg class. I took lin alg last year.
Do you have the solution? And the full problem, with what it's asking to find?
<@&286206848099549185>
Hello vondarkness
Did you mean
f(x)= a cos(px) + b sin(px)
And
f''+p²f=0
?
Can you identify an "a"?
2
I'd say $a=x\sqrt{2}$
No
𝔙eryhappyperson
So am I.
I sis this so far
𝔙eryhappyperson
Easy 2
does that mean 15d = 3/8
no
5/18
because you do 7/9 - 1/2
how did you get 3/8
its 7/8
lol its ok
sure
so d = 1/40
but how do i figure out the first 3 terms??
now you plug the d in one of the equations to find a1
then you just go:
a1
a1 +d
a1 + 2d
what is a1?
sorry
sec ill re write it @alpine sable
its a system of equation
no

lmfao
Loool
in order to find ouut how much one thing cost
in this case M (Milk)
u would make the other variable (in this case bread) the same number
what i mean
a number that both 4 and 5 go in is 20
yes
12M+20B=44
20M+20B=50
now what we do is get rid of bread
so it is
kinda makes sense?
no
sorry did not even write properly
Ur goal is to find out what milk and bread cost
in order to do this u would make one factor in this case maybe bread the same
so u can figure out what milkk is
ohh
,rotate
Look where the 0s are on the graph, and the seek the one equation which is 0 at the same x values.
Is this channel free?
Probably.
Yess....but in reverse. How can i know
f''+pf = 0
Become f(x) = a cos px + b sin py
Without knowing what is f(x)?
Like how come a regular f'' somehow ended up as a trigonometric function??
If i start from f(x) to find f'', i can do that. But how about in reverse??
I think it's a bit too long to explain it here, please check out the wiki
https://en.m.wikipedia.org/wiki/Characteristic_equation_(calculus)
In mathematics, the characteristic equation (or auxiliary equation) is an algebraic equation of degree n upon which depends the solution of a given nth-order differential equation or difference equation. The characteristic equation can only be formed when the differential or difference equation is linear and homogeneous, and has constant coeffic...
Soo should i know complex number in order to understand it?? Since the example already used complex conjugate and i don't know a thing about it
Yea, you'll need knowledge of complex numbers to understand it
I already got this point but i dunno what should i do to get f(x)
Is any number divided by infinity defined or undefined
like -4/oo
is that 0
or undefined
bro
?
You can check the wiki site>>formation of the general solution >> complex root
hello uncle Rico you can say $$ \lim_{x \to \infty} \frac{-4}{x} = 0 $$
Biscuit
someone help explain this question please
<@&286206848099549185>
ping me when u can
wtf looks hard
Almost got it.....but still wrong. Can you help me?? Why still get sqrt(p)??
Already followed that wiki method
As I have said here, there might be a typo
Ahh yeahh....should be p^2
Okay....then i almost understand
Soo if it's 2 dimension, the sin px can be changed into sin py without anything to do??
I don't think so, I think it's just a typo
Ahh okay....after checking my book, i got misunderstanding.
However now i get it why it become like that. Thank you very much @Biscuit#5208
$7\ =\ -1.79\sin\left(\frac{2\pi}{365}\left(x-79\right)\right)+6.3$
Břāđ
how do you solve the multiple angles for something like this without graphing it
sin
Sorry for the easy question, but I'm not good at math:
Enter a number between 1 and 100:
Enter a number between 1 and 100:```
What are the chances to win?
<@&286206848099549185>
@chilly night 1 in 100
@rustic finch take everyhing to the other side and write it in the form sin(...) = (some number)
then take arccsin on both sides
but three times
did u enter 3 numbers?
hello, what is -i squared
complex numbers?
yeah
(-i^2) = (-1)^2 * (i)^2
i start with 60x and 3000y
every time i gain 100y
i lose 1x
how do i put this in equation format
but like the supplemnetary one. like sin120 and sin60
can someone help me solve this
@silver baytry #multivariable-calculus
60x+3000y +a(100y-x) ?
just put it there, thanks
thx will check if worked
@quasi scarab 176?
yes
Thank you bruh that made it so easy
is this channel free?
yes bruce
sorr
how would i find the two points the line y=4.2 through the parametric curve
sorry for the bad drawing
it was (60y-x)(3000y+100x) not 60x +3000y + a(100y-x) @quasi scarab
? then u shouldve told us what the question was in detail
i did i needed the numbers in equation format
1/100 * 1/100 * 1/100 = 1/1000000 = 0.0001%
u said this: i start with 60x and 3000y
every time i gain 100y
i lose 1x
how do i put this in equation format
and u got this : (60y-x)(3000y+100x)?? how
no
i didn't think i assumed
u didnt pay attention to the rules, so i advised u to read them, i didnt go around telling ppl what to do
wdym
can someone help me with these
im not too sure if this is math or physics
but its in my math class
its rotational kinematics right
but basically math
which problem were you having a hard time with @silver bay
do i just use the equation for simple harmonic motion of a pendulum
id imagine so
but im not sure if its right because i dont know gravity, should i just assume its 10 m/s^2
usually yea whatever convention you use for your glass
sorry class
usually for problems like this i think youd just use g
we haven't really done this before
or if you all are using 10
and i dont have a teacher :/ so i have no clue
youre lucky theres a lot of resources for physics at this level
at least lecture-wise
if you can wrap your head around simple harmonic motion really
this is just a subset of that
this isnt even physics 😭 its for my diffeq class and im not sure whether im supposed to do something different for that
oh
idk id just answer it however you can figure it out
math class
idk at that point id just pick the easiest way
since theyre not really clear
you can state/solve the SHM equation
which is uhh
2pi sqrt(L/g) right
oh nvm i found it in my book
ye
i mean yea
its not really exactly clear what youre supposed to do
but it seems like youre on the way
idk if you state the original one, then the small angle approximation
maybe if you feel like solving it
so solve the IVP on that solution, then use calculus to maximize it
thats probably overkill for what this problem is asking but i guess thats the mathy thing to do
since they give you an initial position and velocity
ummm
ok ok makes sense
then whatever procedure you typically use for maximizing things
so i just use the equation, plug in a value for length, and solve?
i would state the equation, state the small angle approximation
without subbing in anything
then for part 2, use the given length, IV's state the specific SHM eq for that situation
then do calc stuff to maximize
or whatever handwavey 'it is known' blah blah stuff youre allowed to do for periodic functions
does that all make sense
which part seems confusing
so
Hi guys, im using excel and im trying to represent a large amount of data, i thought a line graph might be the best option but im struggling to create it on excel, would anyone be able to assist me? Thanks
say this equation but with a sin(theta) instead of theta
then i say because its a small angle, sin theta~~theta
idk thats probably overkill but i would state it just for shits and giggles
i mean they're constants so you can leave them for as long as you want but whatever works
id solve it fully with all constants just left but thats just me
oh okay
okay makes sense
😄
lol im gonna have to review
yknow how differentiating velocity gets acceleration and differentiating that gets displacement, what does integrating velocity get you?
displacement
oooo so its like a cycle
yeah
thank u
should i solve it with a laplace transform
because thats my current unit
i have no clue whether that makes any sense though
if you know how yea
haha
random square roots and stuff
will anyone be able to help on statistics?
I need help. What is 1+5
yall can u not see were having a conversation
no
please use a channel that doesnt have a active ppl in it
Bruh
hahaha me too i did it last sem but i forgot everything
broo i have a physics ap test tomorrow 🤯
damn i forgot how involved solving these things can be
can you say what you got for the first one once you finish
because i did it
like the easy way
but i have absolutely no clue if its right
so
you use
characteristic polynomial
you have imaginary solutions
but the imaginary part falls away when you determine the coefficient?
i mean you know the answer
idk if its 19 or 38
because
like
it says returning to original posiiton
not a full swing
oh
wait
thats what makes it tick
that or its mirror image
so wouldnt that happen twice in one period

were getting the position function arent we
so it should be positive, become negative at the bottom, be maximum negative on the other side, then positive again when it comes back
i am dumb so grain of salt but i dont think this function is giving vertical displacement
i think its angular displacement
?
thats true but i didnt use the diffeq at all
i just used the equation for period
you can use whatever you want
unless the question is specific
which is the time for a right swing and a left swing
i mean you can do it however you want i think
if you are not comfortable with that way find the roots of the velocity equation?
which is gonna be the same thing but longer
how do you get the velocity given a position equation
you solved the diff eq right
ah shoot gtg can i ask again in like half an hour
if you just want the first derivative
i think
just define the first derivative as a function
idk im being dumb
but i wanna review how to solve it now
just lazy

the way they do it in introductory physics is multiply left side by dx/dx or d(theta)/d(theta)
you get a variable seperable ODE I think
and you use the relation to solve it
how does the first equation turn into the second equation?
<@&286206848099549185>
you shouldnt ping right away
oh sorry
its a two step algebraic process
you should try to track it, its good practice
but its division and exponentiation
this is pretty much the biggest hint outside of the answer

divide both sides by 10
then turn the log into something like... little to the power of right equals middle
thanks 🙂
😄
I have N=20, k=4 (m1=4, m2=8, m3=12,m4=7) and SSB=22. How do i find the value of SSW? I tried SST=SSB +SSW. And MSB=SSB/K-1 (4) but i'm stuck.
Help pls I’ll give you a 🍪!
Which of these looks like an area formula?
????
hey, can someone help me with this question
why does 0^0 equal 1
bro how
Zero to the power of zero, denoted by 00, is a mathematical expression with no agreed-upon value. The most common possibilities are 1 or leaving the expression undefined, with justifications existing for each, depending on context.
In algebra and combinatorics, the generally agreed upon value is 00 = 1, whereas in mathematical analysis, the expr...
sorry i just saw this
how would that work?
@gilded gazelle i think we want some system of equation to solve for how many weeks it takes to make 10,000$ correct? EDIT: make 10,000$ more than its expenses
so it's linear, and linear relationships have form $y = kx$ right?
EL145
furthermore, the average weekly income is roughly 4,500, the average weekly spend is roughly 3,200.
ah ok i get it now
i knew the answer but i couldnt figure out why
i didnt use averages
i am studying, this has an answer sheet and once you mentioned averages i solved it by just getting both and doing simple math
spending + 10000 = revenue
so this
well that's not what i was thinking
did you try doing it ?
i'm not sure what you meant tbh
i know it's the same thing bigweld, but my thought process was 4500x-3200x=10000 hence 1300x=10000
i'll drop out the channel
sorry t o interrupt.
ok so you have a second order differential equation in x right?
yeah, its just theta'' = -g/L theta
but this is a first order differential equation in v or dx/dt
and you know condition at some point
yeah i think
wait
can i check number 1 with you
because i think i dont need the diffeqs for that
but i also dont know if i did it right
sure
oreo
if you are allowed to use this
then that is alright
but this result requires differential equation
so if this is a result you're allowed
I'm not sure if im allowed to use it
you have the time period of oscillation
so i should probably use a differential equation
if this is an introductory physics course
they probably don't expect you to solve the diff eq
its a differential equations coures
*course
like a really intro level one but we've covered the things i should know to solve it
like 2nd order linear
you can solve 2nd order differential equations?
i think? i dont really remember 😭
general solution Ae^(a_1x)+Be^(a_2x)?
yeah
okayy, so
my equation is
$$\theta '' = -\frac{g}{L}(\theta)$$
i think?
or that should be a sin(theta) on the right but im using small angle approx
i should probably just keep it as sin
nah they use theta to get the result
oh okay
oreo
im confused about how id solve that though
should i just plug in numbers and then try>
but then i get like
okay if i plug in numbers
i get
$$\theta '' + \frac{10}{0.6} \theta = 0$$
oreo
and to factor that i get like imaginary numbers right
yes
sooo
uh
$$(D+\sqrt{\frac{10}{0.6}}i)(D-\sqrt{\frac{10}{0.6}}i)\theta=0$$
oops
no
oreo
okay that
yes
oreo
theta in this case but yes
to get it in the desired form you need to actually do that
okay sounds good, so itll be
wait what is my dependent variable here
oh nvm
theta is dependent, t is independent
wait would it even be theta then
because theta is the dependent variable
$$\theta=c_1 cos(\sqrt{\frac{10}{0.6}}t)+c_2 sin(\sqrt{\frac{10}{0.6}}t)$$
does that look right? im not sure if i did the euler thing right
oreo
does not look right
e^(wit) would be cos(wt)+isin(wt) right?
i think so
don't you think there are two terms missing from your solution ?
you c1.exp(iwt)+c2.exp(-iwt) right?
yeah
so i think what i have is right
wait no
uhhh
wait
no
i need to check again
ok yeah i think what i had is right then
i think the other two terms cancel out or something?
I am really tired
i think so
i have the equation for theta
so i have to find out how many times it equals 0 between t=0 and t=30
i have no clue how to do that
you can use something called R-method to convert this into a single sinusoidal function
so you would get a sin function with the same period
that makes sense but at the same time we have like constants right
and i dont knwo what the constants are
the constants affect the phase and amplitude of the sinusoid not the period
oh okay makes sense
so after you have theta as a function of time with period this
you can use that as time period
and now you have a simple arithmetic problem with time period total time and number of ticks
for?
the R-method you mentioned
the idea is to divide by sqrt(c1^2+c2^2) and you'll have terms similar to he terms in sin(A+B)
but here's a link for more info
The trigonometric R method is a method of rewriting a weighted sum of sines and cosines as a single instance of sine (or cosine). This allows for easier analysis in many cases, as a single instance of a basic trigonometric function is often easier to work with than multiple are. The R method is most often used to find the extrema (maximum and mi...
why would you think that?
well
its nowhere in our textbook
and i really dont know how im supposed to solve this but theres no way its supposed to be this long
because i have 10 of these as 1/10 of my assignment
also R-method is trigonometry so precalculus that would be a pre-requisite, no?
yeah i guess
i dont think ive ever seen it though
in precal
but i could be wrong because i took precal like
3 years ago
almost 4
how would i do this though
because my constants are really arbitrary
theres no given values
these are my questions
you have to use the condition
like they say it is released from rest
at an angle of .1 radians
so that is your initial conditions
for 1 the constants don't matter
since the time period does not depend on the constants
you need to differentiate to get all the information from the initial condition btw
yeah i understand
im confused, differentiate what?
the equation i got?
I know this is a math channel but can someone help me in my english please?
#discussion might help
okay so id get the angular velocity equals something right
since the left hand right now is theta
4?


