#Need help solving this second order differential equation
118 messages · Page 1 of 1 (latest)
@viral zephyr
ok i imagined something different uhmmm
is this a differential equation in terms of y with respect to x?
or even a differential equation system
Ru in uni ?
because i never learnt how to solve systems 💀 yet
yes
Which?
uhmmmmmm wdym which
Name ?
hustler's university
Isn't that Andrew tate uni?
Nvm I sleep 3 am already got school in 2.5 hrs
go sleep
Basically, you are suppose to change ax to d2x/dt^2
And change ay to d2y/dt^2 and that is how you form the equations. Then somehow get x in term of t and y in term of t. And maybe substitute t in x to y or the other way round to get y in term of x and theta.
i understand it's physics and a is the acceleration with respect to x and also another with respect to y
s'' = a
Yes.
$a(t) = -kv(t) \Rightarrow \frac{d^2x}{dt^2}= -k \cdot ucos\theta \
a(t) =-g-k(t) \Rightarrow \frac{d^2y}{dt^2}= -g - usin\theta$
what is k_y ?
or it supposed to be v_y?
How did you do that?
K is like a constant.
k_y ?
I completely do not understand what is happening here.
it's code haha
but i was unsure
Wow. Maybe this is correct?
Which part?
ehm i dont think so
adonhs
Oh I see. I put wrong.
Sorry. I did not see properly.
For Ky I meant K.
So basically just K.
Both k in both equations have the same value.
$a_x(t) = -kv_x(t) \Rightarrow \frac{d^2x}{dt^2}= -k \cdot ucos\theta \
\a_y(t) =-g-k\Rightarrow \frac{d^2y}{dt^2}= -g - k$
adonhs
How to continue? I completely have no idea.
since we have theta we gotta somehow convert the differentials
How do you even solve d2y/dx^2? I have never done this before.
$x''(t) = -k \cdot cos\theta$ and $y''(t) = -g-k$
adonhs
i think we could differentiate
$v_x = ucos\theta \Rightarrow \frac{dx}{d\theta} = -usin\theta$?
adonhs
if v_x is a function of theta
But I thought you need in function of t so that can substitute t later?
Because want y on the left side and x and theta on the right side.
ok so since i never done such thing, but i just watched a video it seems to involve linear algebra
so we are working with vectors and matrices
and x and y are components
I never learnt those. Maybe just tiny bits of vector.
can you tell what you know
or you do
For vector I onky know like the level of the person yesterday. I do not know about equations or planes.
Is that person called unknown?
are you a high schooler?
I saw in a worksheet and that is exactly the level I am at.
Yes I am.
i thought u were some engineer ok lol
Why did you think that?
As you can see I am pre university.
some people who study have pre uni and some who are high schooler have undergraduate role so cant tell
besides that i thought because it involves some physics lol
I would start off with this
adonhs
because v_x is basically the first derivative of x(t)
I am trying to understand it.
I would write it even simpler
From what I know to get x and y I have to integrate twice? But that does not seem correct?
Okay. This is rewriting equation?
yes to my understanding
it should make sense that v_x = dx/dt = x' first derivative
a_x = d²x/dt² = x''
I would try to do this with this video
so basically we have
actually
adonhs
In physics instead of ' we use dots if it's with respect to time
Maybe integrating both sides helps
Now this is the approach
adonhs
So we can rewrite the equation as
I am completely lost.
adonhs
You can watch the video I am just trying it on my own for the first time lol
It's just that I am familiar with linear algebra so I thought give it a try
So now we would for the Eigenvalues as this equation above reminds us of the Eigenvalues of a matrix
,w eigenvalues {{[//number:-0.5k//],[//number:C//]},{[//number:D//],[//number:-(g+k)//]}}
I am gonna use the lambda notation for the eigenvalues
The Eigenvectors look so complicated haha
adonhs
So basically the solutions should be
adonhs
Hmm I honestly, I can't tell, since we have too many constant variables, we already had g and k, but due to the integration of both equations we also got C and D and the vectors c1 and c2 are also "vector of constants" and a and b are constants of the linear combination (linear algebra)
You'd need some basic foundation in Linear Algebra and Calculus/Analysis, at least to know what Eigenvalues and Eigenvectors are but anyway
This is all I could do LOL
Here is the link again:
https://www.youtube.com/watch?v=E0YUvCqhr-c
You could check some videos out of him or so
How to find eigenvalues: https://youtu.be/hpE9Iom55N0
When we start looking at how multiple quantities change, we get systems of differential equations. What do we use for systems of equations? Linear algebra, of course!
Full dissecting differential equations playlist: https://www.youtube.com/playlist?list=PLug5ZIRrShJF-vOxStdHg1jyntiTKrAYO
N...
Oh no I forgot the square here, meaning it is not a linear differential equation, damn it
x² instead of x...
well it was all for nothing i guess
Maybe you can check out the other channels people who are more experienced than me
#calculus
#real-complex-analysis
#advanced-analysis
you can try it in those channels, i believe they are connected to this topic
#diff-geo-diff-top should also work too
Thank you so much. It is okay. I will try to understand.
I cannot type in that Chanel I do not know why.
I am so sorry. I am stupid. I just checked and realized that the equation was wrong. I forgot to put v.