#help-0
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@steep pike Has your question been resolved?
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Could someone help me with this probability question regarding card draws:
You draw 4 cards, one after another from a 78 card tarot deck. What are the odds of drawing the Emperor card 3 times total? (Odds of drawing the Emperor in a single draw are 1/78)
Here's what I've got:
Number of 4-card hands: (78choose4) = 1426425
Number of 4-card hands with three Emperors: 77*4 = 308
Odds of drawing 4 cards with three Emperors: 308/1426425 = 0.00021592442 =~ 0.0216%
Does this seem correct?
where did 77 come from
multiplying that 4 doesn't seem to give you anything of sense
wait that's a bad explanation
so how would you get the number of 4-card hands that are 3 Emperors and 1 other card
also how can you draw 3 emporor when you have only 1
because you draw it and put it back and then re-draw
there's 77 different ways to have a 4 card hand that's EEEX, and then you have X in all 4 positions, so EEEX, EEXE, EXEE, XEEE; hence 77*4
E = Emperor
X = something else
oh yeah
just need someone to verify
seems good
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thanks
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Can you help me to see that this goes to e^-lambda ?
Well, it does not
mbb
Unless you meant -n in the exponent
if you mean this exactly as stated, then it goes to 1, not e^(-lambda).
Yes, this going to one makes sense applying the limit properties
as n tends to infy, lambda/n tends to 0
I'm actually looking for ^n
Just send the right screenshot then
Substitute for -n/lambda and recall the limit definition of e
Isn't this how we define e^{-\lambda} ?
so here x=-lamda ?
Yeah
To be honest, The definition I'm aware is e^x=1+x/1! +x^2/2! + .... +
are they same ?
Here, this is an interesting proof @barren portal
That's Taylor series
Taylor series requires basic of calculus, have u done that ?
I'm actually about to finish Calculus 3, but the college skipped power series and so
for last semester
Ah! Dw, there's an interesting video on Taylor series then, wait lemme pick it up from internet quick
https://youtu.be/3d6DsjIBzJ4
@barren portal
Taylor polynomials are incredibly powerful for approximations and analysis.
Help fund future projects: https://www.patreon.com/3blue1brown
An equally valuable form of support is to simply share some of the videos.
Special thanks to these supporters: http://3b1b.co/lessons/taylor-series#thanks
Home page: https://www.3blue1brown.com/
Full series: ...
Are u in university or something?
Yes, 2nd year.
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Can I ask some direction help with 2b ? Trigonometric identities
Try splitting the fraction up
And expanding from there or factoring to lead to an identity?
u wanna expand the left or right side?
Right side
2-2sin^2 = 2cos^2 so thats the denom
(1+cot^2) = csc^2
u can do the rest now?
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In a graph, is the clique cover number always greater/equal than the max independent set?
I have tried the following proof:
Given graph G=(V, E)
Let $C_{min}$ be the minimum set that contains the cliques which cover the graph G.
Let $U_{max}$ be a maximum independent set.
Assuming $|U_max| > |C_min|$:
We then have
$\exists v_i, v_j \in U^{max} : v_i, v_j \in C_i, C_i \subseteq C^{min}$
this implies that $v_i$ and $v_j$ are adjacent which then implies $v_i, v_j \notin U^{max}$
which is a contradiction.
Therefore $|U_{max}| \leq |C_{min}|$
this seems plausible but im not sure if i missed something
LanPodder
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how did the constant move out of the exponent
e^c is just a constant
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Hi if anyone can solve this with working steps i will send them 10 bucks on steam, Thank you so much
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Find the number of labelled trees on 5 vertices
i found three unlabelled trees
the first one i found was a path graph
so if i want to find the number of labelled path graphs on 5 vertices
is it the same as finding the number of linear arrangements of 5 objects?
@surreal lichen Has your question been resolved?
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open a new ticket that's only for you
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Why can there be infinite many solutions to this question? I thought that any homogenous system of linear equations (SLEs) of form Ax=0 will always be consistent
Unless A is singular
"singular" is quite the misnomer, as it implies there are many solutions
Sorry, I don't quite get what you mean by "Singular"
If the determinant of a matrix is zero, then -by definition- is called singular
Oh okay
If a matrix is singular, it can have multiple solutions
Ah, I see
Been a while, so I can't remember if "homogenous" means "non-singular"
I think so
because if it's singular, then an inverse of A cannot exist
therefore, there isn't necessarily a unique solution to Ax=b (including Ax=0) (right)?
what is an "inconsistent system of equations"?
No solutions
i.e., in ℝ³, you can have 3 parallel planes that don't intersect eachother
ah gotcha
Yeah I don't know this one sadly. Guess I gotta review my lin alg.
Give it 5 minutes then ping helpers if no one comes
okay
at least one
And since we are only dealing with the ℝ³ case, we are dealing with planes
So consistency can only mean "a unique (set) of solultions" or, infinitely many (sets) of solutions
And there can only be 3 types of inconsistencies
Alright fair, so could you elaborate on what's confusing, sorry?
I don't get the written answer explanations that is provided to me
I thought the question is asking in terms of Ax=0, but to me, the answers seem to be answering in terms of Ax=b—as in it is explaining why Ax=b must have an infinite number of solutions
Oh fair no, they're assuming that Ax=b is inconsistent and then from that you can show there would be infinite solutions to the homogenous Ax=0
oh
Do you agree with this statement?
yep
Calm calm, does it all make sense now?
so they're first deducing restrictions on A
and then using the restrictions to find what must then be true on [A|0]
Yeah in particular you know A isn't full rank, else it'd be invertible and you'd have a solution to Ax = b as x = A^{-1}b
yep
Therefore when you REF the matrix A, you'll have somewhere "at the bottom" having a zero row
Then
couldn't you just directly answer by doing:
this is true
Thus for [A|0], we will have at least one row of 0=0 in REF
And since we already know that A0=0 is consistent
i.e. we know a single case
[A|0] must have infinite solutions?
in ℝ³
why then is it necessary to state* these properties of [A|b]?
That's pretty much what I think they're trying to say
This here in particular is saying you can't "fix" one of the coordinates
As in you won't be able to restrict one of them to be a fixed value
But how is that relevant for showing that [A|0] has infinite many solutions
let's say we have like something in $\bR^3$ that turns into $\pmqty{1 & 0 & 0 \ 0 & 1 & 0 \ 0 & 0 & 0}$ on REF
chartbit
Then that will tell you for the homogenous that x=0 and y=0
so then (x,y,z) = (0, 0, z) = z(0, 0, 1)
That's effectively what the statement is trying to say
Or for $\pmqty{1 & 0 & 0 \ 0 & 0 & 0 \ 0 & 0 & 0}$ in REF, we get that $x=0$, and so $(x,y,z)= (0, y, z) = y(0, 1, 0) + z(0, 0, 1)$
chartbit
I get it
thanks
I feel like the question
's wording is a bit confusing (to me)
Yea as you have like the hom and nonhom case and they're easy to confuse I guess?
Yeah
Anyways is all of that all good?
Perfect, have a good one! 
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how do i find the x intercepts of a vertically transformed equation
and they y for horizontally
In order to find the x intercepts, you'll need to use the standard equation
yea but they will change wont they
like i found the roots of the original
but they will change once u transform the function
how do i find the new roots
find the new function first
so -2x+12x-4
oh yea ok that works
that gets me the right roots
wait what if it was a horizontal tranformation
how would i find the new function then
@dawn dust Has your question been resolved?
<@&286206848099549185> ?
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can someone help me find (f/g)(x) as well as its domain?
is there anything to plug anything in?
no im just dividing the equations as it is
i got this as the answer and it was wrong
hmmm 🤔
Just write it with the root
√(49-x²)/(x+4)
Now for the domain the only condition is that x shouldn't be -4 and the whole function needs to be positive inside the root
So that leaves you with 2 cases, either both the denominator and numerator are positive of they're both negative
oh, i thought radicals weren't allowed in the denominator?
Well they didn't ask to simplify the function
,w domain √((49-x²)/(x+4))

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Can anyone correct these limits for me? I unfortunately don’t have a solution manual. If you can tell me where I went wrong and correct my mistakes, it would help me a lot. Thanks in advance 🙂
oh i see now
why is $\lim_{x \to 2} x^3 = (1)^3$?
♡Lex♡
I wonder with e)
Pip error no brain found
The way you did e) is weird
How do i approach those? I am confused
Why'd you plug in x = 1 into x^3 if x -> 2?
Ah true, so which x value can I pick? i mean I can’t tell from which graph it’s coming from. Since it’s f(x) I assumed it to be from the first graph
x = 2
this is not the slayest notation
Yeah that too
Ahhh so as x approaches 2 x^3 is 2… right?
x -> 2
x^3 -> 8
How can I correct that?
x^3 right?
I usually draw an arrow that the denom is zero and then say dne
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✅
What about the point on the graph, how will that be defined through notation?
Is it f(2)?
The red point or the white one?
The red
Ah okay, now that’s what made me write 1 in the first place, thankyou once again! 🙏
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what about the fraction?
simplify that fraction and you get your final answer for the fraction
how?
111/20 isn't final answer tho right?
yea it is
What about this?
We didn't get that in class, homework is totally different..
@woven plaza
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How do I find angle v?
Could you show me?
use the pythagoras theorem
Yes
It’s 3a^2
opp/adj
a/2a = 1/2
tan^-1(1/2)
,w atan(0.5), convert to degrees
Wolfram Alpha doesn't understand your query!
Perhaps try rephrasing your question?
Click here to refine your query online
Result:
0.46364760900081
,calc 0.463647*180
Result:
83.45646
,calc 0.46364760900081*180/pi
Result:
26.565051177078
yes that's how you convert radians to degrees
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Is this a compounding problem?
no
So it's a simple interest?
yeah
so A = (42, 500)(1 + (3/10)t)
is this what i graph?
,w plot y= (42500)(1 + (3/10)x)
get rid of the comma

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How do I solve this system
Wait I got it I think
x-3 or y-5 should be = 0
so x=3 y=5
x = 3 or* y = 5
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So I set x(t) to 0 and y(t) to -4, I got +3 and -3 for both x and y. but how do I know if its (-3,3) and (3,-3) or (-3,-3) and (3,3)?
Those are the t values you get right? As in the point in the “track” where you have the same point?
Yep, so you know that t=3 will give you that point, and also t=-3 will give you that point
But you want to find both velocity vectors for that point
Putting in those two t values will get you two different things I think?
Those are your t values, remember how there was a question we had and I said that from both you needs to get the same t values?
As in you solved x(t)=0 and y(t)=-4 for the t values
Hold up didn’t we do this question 
Yes im going over everything again im just stuck on this 1 part
But anyways, these will give you t values, and you want those to be the same, the ones that match for both are the t values you’d accept
So you get t=3 and t=-3
Those are what you’d use, if you get me?
ah so theyre not points
ok 1 moment I will try something
Ok I got the answer
thank you so much!!
❤️
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Obviously it’s “the theorem of three perpendicular lines” and im okay with it.
but what had me confused is the teacher says if the angle that were blue circled wasn’t perpendicular, then the other two arrow-pointed angles wouldn’t be perpendicular too.
That sounds like a bullshit to me, just some imagination in mind, you would know it’s not true
Even the blue-circled isn’t perpendicular, the other twos that arrow-pointed would still be perpendicular too
well it depends in what order and how you construct the various points
if the blue angle is not perpendicular, then at least one other thing also has to change. and depending on what you change, you can probably make the other two also not perpendicular
@cinder sundial Has your question been resolved?
yes that is one possible way to change it
maybe a better wording from your teacher might have been: if the blue angle is not perpendicular, then the other ones don't have to be either
imagine instead moving the black pen towards the camera
What I’m trying to demonstrate from the vid is, even I’d changed the “blue-circled” angle, the other twos (arrow pointed) is still perpendicular
So what the teacher is not true at all
no
maybe the phrasing of your teacher wasn't perfect
but the point is, if blue is not perpendicular, then the red ones aren't necessarily perpendicular either. they can be, but don't have to
so in a general situation you do not know anything about them
u mean a situation like this
that changes one of the red angles, yes
This is the true statement without any flaws, compared to my teacher that didn’t speak his word clearly and make me feel so confused
My problem is solved, Thank you so much
I luv u
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hi hi how do you start getting to learn calulus ?
A question better off in one of the general channels, like #discussion or something tbh
True
oh sorry idk how this server really works sorryyy
But I'd suggest you understand the idea of super zooming into graphs
And the idea of infinity
How to tackle it
Don't worry about it
these channels here are for like homework/exercise questions, just so you know 
And understand the idea of observing behavior of functions
hmmm okay thank you!!! :D
Also
oh thats good to know thank you for telling me ! :D
There are some good lecture series on yt
To tackle calculus, you need to master Algebra
Because most mistakes that happen in calculus is because of the algebra
oh thats fun!! i love algebra ! thank you for telling me that
is there?? do you know any good channels are is it easier to search it on yt?
More advanced topics will cover slopes of tangent lines, derivatives, max/min, concavity, optimization, area of unfamiliar shapes, anti derivatives, etc...
Channel name - Organic chemistry tutor
He's got the BEST pre calc, calc 1 and calc 2 series
Also you will tackle series and sequences
thank you so much ankit!! :D ill start watching his videos soon thank you!!
okay okay!! :D
Okok gl
You can check out 3 blue 1 brown for more visual intuition into Calculus
okayyy thank you Vulcan for all the help!! 😁
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How does one express a constraint on the signage of a variable with the simplex method ?
like:
x1 >= 0
into the simplex's matrix
well that's assumed for the simplex method
that all the variables are >= 0
if at some point one of the variables is smaller than 0 then you are out of the feasible region
but you can fix that with the dual simplex method
it means that there is no solution ?
not necessarily, no
I'm new to this stuff, so what I basically did is write down my equations on my problem
Problem: Given a list of crops (with their selling price per unit and required fertilizer per unit) and a list of stored fertilizer, find in what quantity each crop should be grown for the season
x1..x5 the quantity of each type of grain produced
p1..p5 the selling price of each type of grain
f1..f4 the amount of each type of fertilizer available
ax..ex the amount of the x fertilizer the crops needs
Maximize Z = x1*p1 + x2*p2 + x3*p3 + x4*p4 + x5*p5
Subject to:
a1*x1 + b1*x2 + c1*x3 + d1*x4 + e1*x5 <= f1
a2*x1 + b2*x2 + c2*x3 + d2*x4 + e2*x5 <= f2
a3*x1 + b3*x2 + c3*x3 + d3*x4 + e3*x5 <= f3
a4*x1 + b4*x2 + c4*x3 + d4*x4 + e4*x5 <= f4
---------------------------------------
Objective function:
x1*-p1 + x2*-p2 + x3*-p3 + x4*-p4 + x5*-p5 + Z = 0
y1...y4 the slack variable (the unused fertilizer)
Subject to constraints:
a1*x1 + b1*x2 + c1*x3 + d1*x4 + e1*x5 + y1 = f1
a2*x1 + b2*x2 + c2*x3 + d2*x4 + e2*x5 + y2 = f2
a3*x1 + b3*x2 + c3*x3 + d3*x4 + e3*x5 + y3 = f3
a4*x1 + b4*x2 + c4*x3 + d4*x4 + e4*x5 + y4 = f4
x1 x2 x3 x4 x5 y1 y2 y3 y4 Z C
a1 b1 c1 d1 e1 1 0 0 0 0 f1
a2 b2 c2 d2 e2 0 1 0 0 0 f2
a3 b3 c3 d3 e3 0 0 1 0 0 f3
a4 b4 c4 d4 e4 0 0 0 1 0 f4
-p1 -p2 -p3 -p4 -p5 0 0 0 0 1 0
--------------------------------
Entering constants:
x1 x2 x3 x4 x5 y1 y2 y3 y4 Z C
1 0 1 0 2 1 0 0 0 0 f1
1 2 0 1 0 0 1 0 0 0 f2
2 1 0 1 0 0 0 1 0 0 f3
0 0 3 1 2 0 0 0 1 0 f4
-p1 -p2 -p3 -p4 -p5 0 0 0 0 1 0
and I get the right answer sometimes
but sometimes I get negative amounts of crops to grow
well you need to add the contraints x_i >= 0
do I need to introduce more slack variables then ?
I am assuming you are using a program?
that should have a documentation
the standard form of linear programming is "maximize c^Tx subject to Ax <= b and x>=0"
so I would assume that an implementation of the simplex algorithm would assume that
how can I express that x_i >= 0 constraint explicitely
so I shouldn't be ending up with negatives in the C column
and I messed something up
is that right ?
I am not too familiar with this specific notation of setting up the matrix
if you start in the feasible region then you shouldn't leave it
so you made a mistake there if that happens
@thorny bough Has your question been resolved?
@thorny bough Has your question been resolved?
@thorny bough Has your question been resolved?
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Find the elements of order $6$ in $\mathbb{R}/\mathbb{Z}$.
isomorphism
$\mbb{R}/\mbb{Z} = {g + \mbb{Z} : g \in \mbb{R}}$
isomorphism
in other words, the real numbers that you have to add 6 times to get an integer
yes
what else though
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@remote heron
lets pray i did this right because im way too tired to fix it now 
right, lemme make a field
Awesome_Ruler_007
for horizontal one, I solve for $\frac{dv}{dt}=-kv$ as is the norm
Awesome_Ruler_007
oh geez theres directions 
i may have stepped in it
okay so you want to start from the differential equation
and get to some equation for s that shows what youre expecting
ya, well drag should apply to both direction, but vertically the acceleration due to gravity focks it up
where you go back to 0 as long as you start positive
$$
\text{Horizontal drag:} \frac{dv}{dt} = -kv \implies \frac{dv}{v} = -k\
\implies\int{\frac{dv}{v}} = \int{-k.dt} \implies \boxed{ln(|v|) = -kt+c}\
\text{Using initial conditions,} ;v=u;;t=0;;s_x=0\
\implies \boxed{c=ln(|u|)}\
\text{Thus,}; ln(|v|) - ln(|u|) = -kt \implies ln(|\frac{v}{u}|) = -kt\
\implies \frac{v}{u} = e^{-kt} \implies v = ue^{-kt}
$$
But we need it in terms of $s_x$, so we integrate it again:
$$
\frac{ds}{dt} = v \implies \int ds = \int v.dt \implies s_x = \int ue^{-kt}.dt \implies s_x = u\int e^{-kt}\
\text{Integrating:} \implies s_x=u\frac{e^{-kt}}{-k}+c;\text{, again with the same initial conditions}:s_x=0,:t=0\
\implies 0 = \frac{u}{-e^{-0}k}+c\implies c=\frac{-u}{k}\
\therefore s_x = \frac{-u}{ke^{kt}}+\frac{-u}{k} \implies s_x = \frac{-u}{k}(\frac{1}{e^{kt}}+1)\
\implies \boxed{s_x=|\frac{-u}{k}(1+e^{-kt'})|}
$$
Awesome_Ruler_007
This is how I solved that differential equation for $s_x$ incase it helps
ill probably just look at the vertical
im not into physics
but differential equations 
the second term looks great, its just the first one that's a bit odd
eq. is $\frac{dv}{dt}=-a-kv,:a=g$ for a reminder
Awesome_Ruler_007
I was given this eq. so it might be wrong
,w y''=-g-ky

damn
,w y''(t) = -g-k*y(t)

,w \frac{dv}{dt}=-9.8-kv
$s(t) = A\sin(\sqrt k t) + B \cos(\sqrt k t) - \frac gk$
jan Niku
$s(0) = s_0 = B - \frac gk$
jan Niku
methinks wolfram alpha is treating g as a variable
nope
which is why your solution looks a bit wonky
wonky?
ya, see this
is y'' double derivative?
yea
lets do one order at a time 😅
its not necessary
,w y''(t) = -9.8-k*y(t)
it leads to a lot of extra constant wrapping
fair
either way the theory for second order linear differential equations is straightforward enough to plonk through it IMHO even if youre clumsy with diff eqs
like me 
,w y''(t) = -g-k*y(t), y''(0)=0
okay, solving for constants
you can give it init conditions like this right?
,w y''(t) = -g-k*y(t), y''(0)=0, y'(0)=u
lol
jan Niku
and we let $s'(0) = v_0$
jan Niku
to get A
Hi guys. Can anyone give me another example for the second question please?
how to get help
I get $s(t) = \frac{v_0}{\sqrt k}\sin(\sqrt k t) + \qty( s_0 - \frac gk) \cos ( \sqrt k t) - \frac gk$
jan Niku
I already read the rules and on the picture a person send is post my question on help-0
no you need to create your own channel
go to #help-1
Check the ones with "Math Help (available)"
so this is what we want, right?
That's wolframalpha's solution. Now, it if only gave a step-by-step solution in full latex...
eh i got a small sign error in mine
i cant help you with the actual typing haha
do you understand the steps to solve
So you mean like if any channel has someone’s name on it, then I suppose to pick any channel that doesn’t has a name yet
What amazes me is that I took 1'st order solution, solved for constants, but it back into wolfram alpha, and still got it wrong
oh where the hell is math help open
oh im so tired
yea you got it khai
#help-1 is now your channel, since it has your name on it
i love the pauls notes
have you worked with these before
the process is uhh
intimidating if you havent
ODE's? I've just started using them recently
but its very well documented
high schooler
you have a second order linear differential equation with constant coefficients
theres an inhomogeneity, but its a constant
hm? what's an imhogenity
jan Niku
I think I solved them correctly - since wolfram alpha and I get the correct eqn.
maybe I'm fucking up the constants?
ah then youre fine
the constants are just some more work
i wouldnt do them with a bot
a bot will guess what you want
start with your general solution
so no solved constants
that's the exact initial conditions I use
jan Niku
y''0 = 0 😌
ya, the constants were solving out much neater
lmao where am I going wrong? I'll prolly post the whole thing here (dw its quite short) and you can take a look ig
that makes a whole part of your solution fall away
which is nice
no no its easier to start over
I meant starting over, by scratch, myself and my solution
this entire process can be completed on half a sheet of paper if you do it carefully
I did it in less, but multiple times cuz things were going to shite
let's hope for the best ig 🤞
i will solve it too
idk if you wanna see my solution
or if youre trying to do your own thing
just lmk
as long as the solution is simple and doesn't use some otherworldly tricks, I'm more than happy to learn
Just to get on even ground, we're solving for:
$$
\begin{align}
\frac{dv}{dt} = g-kv, v(0)=u, s(0)=0
\end{align}
$$
Awesome_Ruler_007
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
s(0) = 0?
i thought your intention was to see this thing fall to 0
this is too many conditions either way
ya, $s = \frac{dv}{dt}$. I guess I could write it 2od
Awesome_Ruler_007
yep
but position is the derivative of velocity?
jan Niku
that's what I mean
okay
oh, I wrote it wrong above. mb
youre good
here is what im going to solve
$\dv[2]{y}{t} = g-ky$ with $y(0)=y_0$ and $y'(0) = v_0$
jan Niku
$\dv[2]{y}{t} = g-ky$ with $y(0)=y_0$ and $y'(0) = v_0$
mostley equivalent
ya
ya well that was the eq. given to me
jan Niku
that's correct
you would, but there isn't any s term in the RHS
jan Niku
ya, so its an integral of a derivative
$\dv[2]{y}{t} = -g-k\dv{y}{t}$ with $y(0)=y_0$ and $y'(0) = v_0$
does this seem right
looks ugly
jan Niku
nothing to it but to do it
y(0)=0 no
does it?
if y is displacement
i thought you wanted to see this thing fall
ya, but it hasn't moved in t=0
oh displacement from starting
ya, its a projectile going up in an arc - not falling down
well then shooting off to infinity is what you want, isnt it?
going up in an arc
okay
so here's the tricky bit: its $a=-g-kv$ when the object goes UP, $a=g-kv$ I guess when it goes down
Awesome_Ruler_007
but we won't worry about that for now
the solution should be looking like this - object moving in arcs
,w \frac{d^2y}{dt^2} = -g-k\frac{dy}{dt}, y(0)=0, \frac{dy}{dt}(0) = u
,w y''(t) = -g-k*y'(t), y''(0)=0, y'(0)=u

hmm?
some kinda stupid sign error or something 
k is positive right?
i get a reasonable solution with negative initial velocity
which dont make sense
but it is what it is
@naive leaf Has your question been resolved?
but that wouldn't be correct

I guess I'll just stick with what I have (this project's due tmrw)
many thanks for the help though
,w y''+ky'=-g, y(0)=0, y'(0)=m

I tried it here
i should just use matlab but it takes so long to boot
nah, leave it. don't destroy your sanity over this :berk:
matlab is a hell that I wouldn't wish anyone
lmao its an emoji. nvm
haha. well, if you can solve it then sure - but it isn't mission critical
(g + k*v0)/k^2 - (g*t)/k - (exp(-k*t)*(g + k*v0))/k^2```
$y(t) = \frac{g+kv_0}{k^2} - \frac{gt}{k} - \qty( \frac{g+kv_0}{k^2} )e^{-kt}$
jan Niku
jan Niku
honestly, I have no idea
you are intended to solve this right
Not really - You can use an online calculator (this is for a modelling project) but I'd wanna learn how to solve them myself
okay
theres a lot of theory that does the heavy lifting in these
have you taken a course in diff eq? or just seen them
its not completely un-straightforward but also day before a project IDK
you need to know i guess just
particular and homogenous solutions
principle of superposition
and the weirdness of
i mean unfortunately you also have independence of solutions here too lol
so its a lot to learn the day before
well, I guess that's a bit above the standard High school stuff
I do wanna learn this stuff though. any resource you recommend??
say you used matlab to get to here
then solve your initial conditions by hand
thats some work on its own
IMHO you really need a course, or at least to heavily follow a syllabus
its a very large topic and a motivated teacher is really helpful
hm. I don't think my uni would cover this
self-study and all
any self-respecting uni will have a course on diff eq
I don't think its a module
well you can self study too
its just not ideal but
you can ask in #book-recommendations
im sure theyll give you some impossible book
theres quite a few just straight up free books, too
id lean into whatever youre most comfortable with and find a resource with a guided like
list of topics
as in like, if you like physics, find one that uses a lot of physics and applications
i like coding, so theres quite a few books that take a more numerical approach
or if you are just into raw math
etc
here it is: https://rentry.co/foa5s
no, I like deep learning mostly. So yea, math in general
if you want to site something
% it was created in collaboration between YOU and N. Michaels
% declare variables symbolically
% g - gravitational constant
% k - drag coefficient
% v0 - initial velocity
syms g k v0
% declare symbolic solution and differential
syms y(t)
Dy = diff(y);
% specify initial conditions
cond1 = y(0) == 0;
cond2 = Dy(0) == v0;
% specify differential equation
ode = diff(y,t,2) == -g-k*diff(y,t,1);
% solve
s(t) = simplify( dsolve(ode,[cond1 cond2]) );```
s(t) =
(g + k*v0)/k^2 - (g*t)/k - (exp(-k*t)*(g + k*v0))/k^2```
this is basically an online solver
IMHO
if youd rather solve the constants yourself
remove the initial conditions, and replace the last line
s(t) = dsolve(ode)
C1 + C2*exp(-k*t) - (g*t)/k```
which site is this?
sorry, not site
cite
this is matlab code
i wrote a script that solves either the general or entire thing
you can cite it as an online solver or give the code, if you want
impressive, seems like matlab isn't so bad
its nice
nah, I think I'll pass on that. I don't think adding this level of complexity is a good idea the day before
but nice to know I can solve ODEs
if you dont have to solve it yourself
yep. do want to learn it at some point
technically, we're taught fundamentals of ODE's at school
no i mean
well thats the usual process of solving these kind of equations
you find two solutions
nah, I get what you mean - like solutions imposed on to other?
and then add them together
right
so yea you may be able to solve this its just a pain in the butt
focus on the project
im gonna go back to reading
feel free to dm if you run into something
my last day off before semester so im gonna drink tea and doze off

sorry for the whole thing. and thanks for the offer! I've sent you a FR
youre good gl
👍 technically, I didn't need to do diff eq. (all my classmates chickened out) but I've learnt a lot about ODEs by solving the same one in 50 different ways
well the theory builds up nicely
all the way up to solving systems of linear diff eq's
you can get into nonlinear diff eq's and dynamics/control/stability analysis
which is where the real fun is 
or pain if you dont like analysis
and pain, where I'll die solving anything
I've heard horror stories for solving PDEs
you dont generally solve them
nonlinear diff eq's dont generally have solutions
you analyze them as objects in their own right
you heard from losers
PDEs are fantastic
I've never done any analysis - looks like I'll have to find out
if you ever get a chance to take a PDE course even if it adds some time you should jump on it
its a beautiful course and has the potential to change the way you see the world
tbf, I'm quite conflicted between taking an undergrad in math vs. Data science. I know I wanna research in Deep learning later on
says everyone. I don't know how much I'll like it
but you will learn what you need to know to do anything
its a short period of your life
if youre willing to put in the work to specialize yourself it will pay off
I find math beautiful, but that sort of elegance isn't really present in uni
but its more work than a normal degree
you will probably gain mostly the same abstract skills
like problem solving time management etc
if you do math your specific skills like the things you pick up from classes will generalize better
but youll probably see mostly the same topics, too
like core of datasci is all stats right
so not much of an option there
yea, but that stats isn't really that deep
atleast what's employed in DL. In practice, simpler stuff works - occam's razor
that's an idea
majoring in stats or applied math is a move for sure
mathematical sciences?
yea although idk who would call it that
applied statistics is a super marketable degree
challenging though
it is very data science-y though
if thats what youre into
you may look at #discussion or
dont take my word for it theres a lot of ppl in secondary here
I'm just into deep learning
but if you are into machine learning and data science an applied statistics degree will satisfy you for sure
ya. but I wonder if a CS+data science degree is better
up to you
reach out to more ppl
i can say
dont mull it too much
its a short period of your life
and your degree doesnt define your job etc
it is fun aesthetically but you will ultimately get to define what u get out of school ya know
anyways 
ya, but a good course can surely accelerate my undergrad research and get better schools for masters
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I am stuck here, I have solved it 2x and got 2 different answers and now I am confused
Can you show your work?
My answers were the following:
y= 3/x+5/8
and
y= -45x-225
yes
one second
its hard to read because I did it on a little note pad but should be good enough
if not let me know
they're both wrong
@junior blade can I get fucked up at your wedding
When two lines are perpendicular, $m_1=-\frac{1}{m_2}$
HPH_Bulko
m = (y-b)/x
and m 1 in this case is -x/3 correct?
the x is not included, it's just -1/3
so it would just be 3
yes
which means the second lines M is = 3
Now you know m and the point through which it passes, so do you know the formula for this?
no
You actually wrote that formula at the top here
oh the y - y1
HPH_Bulko
(P as in Point)
so we would have $y-1=3(x-8)$
Synx
substituting them in
yes
and then we just solve for y
which would give us our equation
right
which would be y = 3x-23?
im guessing that is the answer
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✅
hey @alpine sable would you be free really quick to double check over another problem
i can help if u dont mind
all good I just wanted to double check my answer
mhmm go on

