#help-49
1 messages · Page 106 of 1
And since there are 100 rooms the wise men should place themselves so that each room has at least one wise man
And that way no matter wich corrider she chooses she'll lose
So the number of wise men is 100? Isn't that logic?
Yes
So I believe the right answer is 100?
Btw it’s not just 100, it’s finding all possible values
Also you need to make sure that there are exactly 1000 corridors too
Develop?
Sorry wdym?
I asked u wdym here
Oh, it’s specified in the problem at the beginning. That there needs to be 1000 connecting corridors
oooh yep 1000 corridors and 100 rooms
Yes, and not only just that, but there are many ways to connect the rooms by the corridors which is why there should be more than one magic number that exists. Because there can be different constructions just with the same 1000 corridors and 100 rooms
Yeah..I get it now ..
why cant it be 99?
because then at least there is a room with 0 people, from which Merlin can definitely make a series of iterations such that there are two connecting rooms with 0 people
so for example when theres 3 rooms and 2 corridors
like a cherry
then the magic number has to be 3?
wait
mb
2
... can definitely make a series... are you sure?
Oh wait, I actually retract what I said before. 99 works I think
yes that should be it
I think it’s just a simple graph. that’s what someone else told before
for the win of merlin he must achieve such a situation:
then he could choose te connection AB and the wise man from B as to move to A.
yes ofc he can
yeah or similarly BC, so the wise men cannot act accordingly
so you do not need a wise man in every room
nope
so i guess the minimal number is much lower than 100.
the problem is that there could be more than one minimal number depending on your construction. ofc for smaller numbers like n=2 and n=3, theres only one, however for n=100 (this problem), there probably is more than 1 depending on the construction
ah
how should there be more than one minimal number?
its different every construction
there are 100 rooms and 1000 corridors
so depending on the construction of the rooms and corridors the minimum may vary
we actually would have to list out all possible minimal numbers
yeah
and what is the relevanz for my statement that i guess the mimimal number is lower than 100?
my guess is that its 1000 for any construction
i dont think so
honestly, idk, im still working on the problem
i think regardless of the number of vertices
the answer can be the number of edges
i think
thats what you can try to prove
i mean
its only a guess
and its true on sum smaller cases lmao
yeah i can see so far
i think this is true
@nova pike
is there a rigorous proof behind it?
idk
but hear me out
ive created an outline for the solution
you induct on the number of edges
assume that you have 100 rooms
and you just keep on adding an edge to an already existing graph
so the induction thesis would be that you need at least k wise men when theres k edges right?
so you would say if the castle has 4 rooms and 4 corridors (formed as rectangle) and you have only 3 wise man than merlin would win?
yeah
show.
yes, i would like to see how your idea works
how do i even begin
take a rectangle A, B, C, D assume the wise man are on A, B, C than show the moves from merlin to win.
no.
no. on A and B are wise men. if merlin choose AB, A could go to B or B could go to A, the wise men decide.
im saying if A goes to B
A and D would be empty
and merlin can simply choose AD
you said "has to go".
also the wise men decide tactfully
im saying that cuz if you dont, merlin would win
im pretty sure merlin wins here
ok, how does your induction work exactly?
i was thinking of doing something like
its so hard to explain lol
like
taking a subgraph where the number of men in that subgraph is less than the number of edges
but this idea kinda sucks
thats fine
you should do somethin like
if the minimum is k
and k men are placed in the rooms
then there exists a sequence of moves for merlin such that
he can empty a given room
this gotta be something
hmmm
@nova pike Has your question been resolved?
@nova pike Has your question been resolved?
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I don't think I'm doing this correctly 😭
And the question is
turning points of y = ... in said interval, and if they're max/min?
Analyze and sketch the graph
Label intercept relative extreme points of inflection and adymtops
Asymptotes
Ah so concave up down type stuff?
Yes
Ah
Im watching vids on how to sketch using concavity since its been a while
Brb
Help 😭 alr
I think (?) I derived it correctly
But idk how to find the points of inflection ans critical point
Check with the actual answer
Points of inflection i remember happen where the second derivative is zero
I did that but I think it's wrong
Y do u think its wrong
When i try to graph it it's not correct
But i got the critical point correct somehow
Dang this is hard. I was seeing what should x be at the critical points but idk if u can solve for it since we r dealing with trig functions
Im seeing if there are other ways
If another <@&286206848099549185> can help thatd be great
@glossy compass Has your question been resolved?
Im watching this rn hopefully something will click https://youtu.be/dIY86WqvGjw?feature=shared
We know how to graph functions, and we know how to take derivatives, so let's graph some derivatives! Many students find that this hurts their brain, but it's just about practice! Remember that the value of a function and the rate of change of that function at a particular point are completely unrelated! A function may be positive but have a neg...
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im a little confused how to go about finding a set of vectors that are linearly independent that span U
I know you need to set up a matrix, solve using gaussian elimination to put it in rref, then put the solution in vector form
but not sure what matrix to set up?
have you found some vectors in U?
@finite jolt Has your question been resolved?
As long as they're independent, yes
well if you polynomials are ax^2+bx+c then U contains all those with a+b=0. So they are of type ax^2-ax+c. It's a two dimensional space given by vectors (a,c). So you can take a base (1,0), (0,1) which gives polynomials x^2-x and 1. These are clearly linearly independent.
@finite jolt Has your question been resolved?
I would still need to set up a matrix though right
To get it in vector form
Also I thought the polynomials themselves were the vectors, not (a, c)? I think I'm missing something notationally
A vector is just an abstract representation of a polynomial. (a, b, c) is just an abstract representation of ax^2+bx+c
ok so I don't have to set up a matrix right because if I do x^2-x and 1, then a and b can be anything and will describe anything in U? unless I'm tripping
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i need a little help with part d
i thought that i could do this:
3P2 * 4! / 5!
3P2 is to select 2 vowels from the 3 in a particular order, then i group them
then I multiply by 4! which is the number of letters + group -1
but this gives me a probability of 6/5 which is > 1 and i dont know what I'm doing wrong
I reckon it's better to do the probability of 1-(no two vowels are next to each other)
oh do u have any idea why this isnt working?
@calm quest Has your question been resolved?
Because ur double counting 3 vowels together
how so?
Your 3P2 could be AE, AI, EI and your 4! Includes permutations where the last vowel is next to your other 2
So your over counting
Dawg can someone teach me two step inequalities I still dont understand it I'm literally crying I am a straight a math student in highschool somebody fucking help
but isnt that okay because it just needs at least two vowels
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can someone help me with d)
i dont know where to start
@calm quest Has your question been resolved?
search it up
take the number of integers you have and apply the formula (n-1)!
oh
so you have 8 integers, and so you want to do (8-1)! = 7!
Ya please don’t look it up. They’re probably just playing a prank or smth….listen to @agile cliff’s explanation
i only remember the formula, I can read and find an intuitive explanation for you
thanks for letting me know
If you would like
omg that i would really appreciate that
just do the math and dont rely on other people
you’re being a poor helper rn
give me 5 minutes tops and i’ll get back to you okay?
....
<@&268886789983436800>
thank you so much!!! :)
@calm quest basically you have to consider the odd numbers as one unit
Lemme draw that for you
do not say things like this here.
right so there's 4 odd numbers
but i only want at least 3 together
No not really. It says ATLEAST 3
So that means 3 or 4
ahh ok yep
so i need to find the arrangments where 3 or 4 of them are together
but no less
Now the easy thing to do is to add the permutations for 3
Add the permutations for 4
Add em together
Voila!
But can you see the problem here?
The problem here is that some permutations in 3 would automatically contain permutations where 4 of them are together
thanks for trying anyways, I really appreciate it!!
if you would like my help, feel free to message or @ me. but i have faith he can help you.
no problem, good luck!
ty!!
so does that mean we only need to consider the ones with 3 together?
Yes I think that should work
Since the permutations of 3 together automatically contain permutations of four together
okay so do i have to choose 3 of the 4 odd numbers, consider it a group and then arrange it around a table?
but the 4 is already considered in the 3 together?
But the one with 3 together should be ONLY 3 together and not cases with 4 together
oh but dont we want both of them together
Yeah but when we apply the factorial to inside the odd numbers unit, we would still be arranging using 3!
Exactly
We have to do
ONLY 3 + ONLY 4
so what is the difference between 3 and 4 TOGETHER and ONLY 3 + ONLY 4
We miss out on the in-unit arrangements
wait sorry could u explain that?
what is a in unit arrangment
Inside the block we are considering as one unit
ohhh ok let me try it
(block),remaining odd,2,4,6,8.
This is what I mean by exactly 3 together
Now the remaining odd number has to be kept AWAY from the block
yess i see
Edmund Cloudsley
To select the items in the block
ah!! yes i see
i saw similar notation. this is indeed true
okay so for just 3 arrangement i did this:
,w 4C3 * 5N2 * 3! * 4!
4C3 * 3! * 5! - 4! * 4!
,w 4C3 * 5N2 * 3! * 4!
Cheers thanks mate
hey cold te!!
Hello
,w solve \binom{4}{3} * 5N2 * 3! * 4!
4C3 × 3!
wait so is this correct for just 3 arrangements
,w 4203!*4! + 4! *5!
@calm quest
yes
Is this the final answer
yes
Now I’ll explain it to you
wait hang on
Okay
,w solve 4!*5!
<@&268886789983436800> i’m not sure why no one pinged for this
ugh i missed that ty
you’re welcome
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i am very confused...
@blissful drum Has your question been resolved?
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How to simplify this?
am i right that it's like this
i am trying to get a general expression for V
but i need help i am stuck
in cartesian the laplacian operator is very simple and im able to get this
iam stuck with this i dont know what to do
can anoyne help me
someone did this
how did he get this last line
dv = A dr/r^2
like huh?
please @ me if you know
@bright grail Has your question been resolved?
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help how do i solve this
y=a*b^x what are the variables
the data table is all the questions given
What I mean is in this expression a and b are constants and y and x are variables right?
yeah, sorry
So let y be thousands of transistors and x be years since 1980 and find a and b
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could someone help me start no. 6 and no.8
it'll also be great if u can check my induction for no.7
also im completely lost for this
@gaunt nimbus Has your question been resolved?
no 7 looks good
Thank u 🙏
ah for question 8, can't you do $F_{kn + k} = F_{kn + 1} F_k + F_{kn} F_{k - 1}$
south's secret twin brother
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so by the induction hypothesis $F_{kn} F_{k - 1}$ already divides $F_n$
south's secret twin brother
Huh
kn + k = (k + 1)n
Ok
Then don’t u have to prove that the remainder is less than F kn + 1
Too?
IDK yeah this approach seems not to work
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where can i find proofs of calculus rules/theorems? (like definition of integral, derivative rules, limit rules)
any real analysis book
hmm, any online stuffs? cause real analysis books in my country are hard to find
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for deriving pi^x
e^ln(pi) = pi
is it rly outside the brackets i.e. here
$\pi^x = (e^\ln{\pi})^x $
cuz then u move the pi^x to x * ln(pi)
so it is this
yes, this
$\pi^x = (e^\ln{\pi})^x$
Quequog
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
$\pi^x = (e^{\ln{\pi}})^x = e^{\ln{(\pi)}x}$
MæthIsAlwaysRight
woudlnt the derivative of e^(ln(pi) * x) be ln(pi) * pi^x
why this?
yes
ln(pi) * pi^x = pi^x * ln(pi)
it's the same thing
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how do i do "c" and "d"?
Upper or bottom?
bottom
When you have something like $\frac{a}{b}x = c$, multiply both members of the equation for $\frac{b}{a}$ and simplify the left member
cristorenzo99
So, in the first one, multiply both members of the equation for $\frac{11}{6}$ and do the multiplication in the second member
cristorenzo99
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I wanna learn how to calcculate minecraft stronghold coordinates via just 2 ender eye.
Lmao
okay
you'll need the x and y coords of both throws
Ok
make one throw, record x and y coords and the direction of the pearl
@dreamy lichen can you explain me with example like i am nuub in math ;-;
okay
you can make a throw at e.g. (0, 0)
then you'll need to record the direction of the throw
does minecraft show you your orientation?
or not
okay, cool
Yea i got it like ik the basics like have to press F3 and take a ss of direction in F3
so there will be some triangle like this one
2 points with known coordinates
the third point will be the stronghold
so you'll need to calculate its coordinates
for simplicty, move only in the x-direction.
So make your throws e.g. at (0, 0) and (500, 0)
then the angles will be just your orientation
the way speedrunners do it is they either use a program to calculate this stuff or they look at the difference in angle and use a table to tell them how far to go https://www.reddit.com/r/MinecraftSpeedrun/comments/lkthsk/navigation_tips/
but yeah this is the basic idea
they move perpendicularly to it?
interesting
that's one way yeah
that's probably the fastest way to get accurate result
one needs to calculate the point in perpendicular direction tho
i know some people can get an estimate in their heads
it means you only need to care about the difference in angle
yeah
there's also some weirdness with chunk boundaries
if you moved perpendicularly to the direction of first throws like this (for x blocks) and the difference in directions was A, then you would need to move x / sin(A) blocks in the direction of 2nd throw, from the place of the 2nd throw
this looks pretty estimate-able actually
https://docs.google.com/spreadsheets/d/1h4v5rhDopz4VFgpq2DQ4vZ10wNpYThr6y0yRzXST7Yw/edit?gid=0#gid=0
Here is a calculator btw
just make a copy of that
so you can edit it
A PC Minecraft Stronghold Triangulation Tool.
here is another one
this one is probably even easier to use
the math behind it is just making a triangle and then using some trigonometry
Btw i also thought that same graph
@dreamy lichen i have mod to find and calxulate automatically but i wanna learn the calculations
As i am noob
hmm well you probably should learn some basic trigonometry first, this will be a good goal but probably not the best way to jump into it
ninjabrain bot is way faster tbf
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why is the allowed values of the statement(?) (a^b)(c^b) = (ac)^bhold for only a,c >= 0 is there a proof why?
wait... are you sure it only holds for m,n >= 0
it holds for negative values too right
????
wrong thing lmao help
you could have (-1)^(1/2) for example
and that's complex number territory
changed it
also you need to change m, n >= 0
ive studied a little of that, is there a proof?
yeah then (-1)^(1/2) still applies
$\sqrt{-1} = i$ is the definition of $i$
south's secret twin brother
yeah
should be a,c >= 0 btw
exponents can be negative no problem
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(a to b) integration of floor(x) + (b to a ) integration of floor (-x)
a to b integration(floor x - floor(-x)
a to b integration (x-{x}+(x+{-x}))
(a to b integration)(2x-({x}-{-x})
so I am stuck at this part what should I do for integartion of fractional part (x) or (-x)
Rest it will be (b^2-a^2)
@wise bough Has your question been resolved?
You're basically finding the area of a rectangle and since it's a piece wise function I'd recommend you break the Integral into multiple pieces wherever it changes definitions (at every integer between a and b)
Can you send an image of what you've done, it's really hard to read the typed out version
That fractional part thing will evaluate to 1
They both offset each other (you can see that if you use some random numbers)
xd_senBugha
Can you show me how it gives 1?
Do you meant....1/2-(-1/2) =1?
if it is true then integration will be ....x^2/2 .....(b^2-a^2)/2
????
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Literally saying that v-3 = v+ 3
so how would we approach this
Let me read rq
Ive no idea tbh
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sorry i just really wanted to do that
lucky
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How does one prove that a given function is not a tangent for another given function?
/ prove it is not
im guessing you need to have a point a where f(a)=g(a) and f'(a)=g'(a)
I have two functions
if one of these conditions cannot be satisfied th functions aren't tangent
!xy
I need to prove that it isn't a tangent/is a tangent at any point
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
yea, i believe you need to show that f(a) = g(a) or f'(a) = g'(a) cannot be satisfied for any x = a
How does that work
if f (a) = g (a) that means that they have the same point
and f'(a) = g'(a) shows they have the same slope
this is how it works
cant be any clearer
so if they have the same point and same slope they are tangent
if they have the same slope but not the same point they aren't
Sure, but I'm not given a point
and if they have the same point but not the same slope they aren't tangent either
can you please show us the functions
you show there exists a point such that either of the conditions isn’t satisfied
the negation of it being true for all x, is it being false for at least one x
f(x)= 9x
f1(x)= x^3 -3x^2 +3x+18
what did you get for f’
we could also just choose any point where the functions are equal, such as x = 0
f'(x)=9 and f1'(x)=3x^2-6x+3
i don’t need you to tell me man
but yes
^
tangent means it only touches at 1 point as far as I know
So I can't just take any point
as oak dining table said earlier, for one function to be the tangent line of another function, the two functions must be equal at that particular point, and their derivatives must also be equal
what point in particular are they asking for
And is equal to the derivative at that point
or are they saying for all points
if it is one, yes
or do they ask you if it is at a particular point
they don't
yep
alright give me a second
in the future please just take a picture of your question
it leaves out the ambiguity
It's not in english
Sure
I'm gonna be back in a sec anyway
With something that has to be translated
x is
two solutions here right
$3x^2-6x + 3 = 9$
knief
$x^2-2x-2 = 0$
knief
what’s up gigagoat
Wassup
marties doing calculus
cool
did you get this @olive herald
yes
and what did you get
$x = \frac{2\pm \sqrt{12}}{2}$
knief
x = 1 \pm \sqrt{3}
yeah
yea
now you evaluate each function at those points
if they are equal, then it is the tangent line
sure, but if it is 2 solutions
Doesn't that mean
This isn't a tangent
Since like it touches at 2 points
no, this just means the slopes are equal at two points
it will touch if the functions themselves are equal at these points
How do I make sure it doesn't touch at any other point though? Are tangents allowed to do that if the slope isn't equal?
no
if the slope isn’t equal it may intersect sure, but it won’t be a tangent line
So it is allowed to intersect
if the functions are equal yea
Alright getting to check the functions now
🦆
13,803
a bit large
13 thousand?
Not true
or is that 13.8
ahh
I get -6.5
,calc 9(1+sqrt(3))
Result:
24.58845726812
So checking for positive now
,calc (1+sqrt(3))^3 - 3(1+sqrt(3))^2 + 3(1+sqrt(3)) + 18
Result:
24.196152422707
,calc 9(1-sqrt(3))
Result:
-6.5884572681199
,calc (1-sqrt(3))^3 - 3(1-sqrt(3))^2 + 3(1-sqrt(3)) + 18
Result:
13.803847577293
two functions "touch" at a point if the functions are equal at that point
well it isn’t tangent at either point
because the functions are equal at those points
so it isn't tangent?
But why
The functions are not supposed to be equal for that?
suppose f(x) = 9x and g(x) = x^3 - 3x^2 + 3x + 18
yep
then there does not exist a value of x such that f’(x) = g’(x) and f(x) = g(x)
you can also see this graphically
yes
And this isn't the case because if I put 1+root of 3 into the derivative function
The Derivative isn't the same?
value* ig
Because we solved for Derivative
well, the slopes are the same at those points, but the functions themselves aren’t equal
we need both to be true
one being true is insufficient
next one
I need to translate
Will take a second
oh btw
Does this way always work?
the one we just did
yes, though you could’ve also done it in reverse, first find the values where the functions are equal, then test if the derivatives are equal at those points
just show it
Movable Pedestrian Bridge
To allow for smooth passage of ships in the harbor basin, a movable pedestrian bridge was designed in Duisburg. When needed, it can curve to varying extents, forming an arch. The pylons (pillars of the suspension bridge) are pulled further outward by four hydraulic cylinders, which tensions the two main suspension cables, raising the footpath connected to them. The structural support and the footpath each form parabolas with different curvatures.
When the bridge is positioned at its median height, the vertex of the footpath reaches approximately 4.50 meters above the normal level. At its maximum height, the vertex reaches 9 meters, with the slope angle α\alphaα of the footpath reaching nearly 45°.
Check the given statements about the angle a(alpha) through own calculations
have you tried anything
So
9m is in the middle
Half of 73,72m
something about trigonometry
not rlly
Idk what this is even saying ngl
Hold up
I'm actually on to something, no?
just make a triangle at that point
well you’ll need more than what you had
the tangent line doesn’t touch the vertex
so you cant just do tan(alpha) = 9/36 ish
The following error occured while calculating:
Error: Parenthesis ) expected (char 6)
:(
i meant can’t
have you tried finding the equation of the parabola and setting up a coordinate system
the tangent on the right side drawn
where alpha is
Oh
you should know that tan(alpha) = slope
yep
I only know ax^2 + bx+ c is the parabole formula
I don't even know what a b c are in that formula tbh
knief
sure or lowest
ahh
turning point for parabola
(h,k) is the vertex
what is k and h?
^
^
^
So how do I find out what a b c are
The best way to visualize this is by playing around with desmos for a while, so I'd suggest doing that. C is where the y-value where the line crosses the x-axis, or (0, c); b affects the slope by whatever magnitude its value is, and a essentially tightens it even more quickly than b
Is there any other information given in the problem
No
I'll get back to you in a minute, then. If there's an answer key or something you could find, that would be cool; if not, I'll play with the numbers & stuff and see what comes of it. It seems that it's just asking you to prove that a(alpha) is nearly 45°, and I don't know what else. It doesn't seem like you actually need to worry about the parabola, though
Well, I don't think there's much to learn from it; the question is intentionally very vague, just complex problem solving
In the end
It's just a parabole with like a couple given values and the rest to calc ig
yeah, I don't know how to do this. Sorry
use the coordinates of the vertex
36 ish and 9, yeah
,calc (73.72)/2
Result:
36.86
h and k
basically a(x-36.86)+9?
we can say the left point is (0,0)
Oh yeah
knief
don't know where
brother
i’m not going to hold your hand
pick one
73.72= a(x-36,86)^2+9?
what about x sir
ah
you didn’t substitute a value for x
yep
wait so how do you express larger numbers
if you use , for decimals
do you use .
you mean coordinates?
no like
13,808 to me is 13 thousand 800 and 8
how would you write that
if not with a ,
yeah, we use . if at all
Germany
🇩🇪
you like flammable maths?
hans get ze flammenwerfer
i don’t speak german
Anyway, a= -8.9457
,calc (-9)/(36.86)^2
Result:
-0.0066241757685295
hmm
how’d you get this
you have to subtract 9 first
or no
this should be 0
oh lol
instead of 73.72
-9/73.72^2
^
yup
knief
differentiate
find the slope at x = 73.72
then tan alpha = slope
alpha = arctan(slope)
why differentiating though
ah ye
^
nono
arctan is its own function
1/tan is cotan
hence why i didn’t use the shitty notation
$\tan^{-1}(x) = \arctan(x)$
knief
it’s the inverse function of tan
what
And if it is just for the point, why does it let me get the angle
the derivative is a function that tells us the slope at a particular point
because $\tan(\alpha) = \frac{\Delta y}{\Delta x}$
knief
yeah...because sinus= x or y and cosinus equals x or y, right
ok this might sound stupid but
how does one differentiate this? I've never done it with numbers
I mean it is like
power rule
yeah
I know that rule
differentiating as I know is
doing it for every x in f(x)
but now we don't have x
🤔🤔🤔
huh
am i going to have to put you on my shoulders
🍼
i’ve essentially done the whole problem for you
maybe x^2 - 2x36,86 + 36,86^2 first ig
now we got like -0,0066241 * x^2 -73,72x + 73,72
-0,0066241 * 2x - 73,72 is f'(0)?
where x= 73,72
so like -0,0066241 * 73,72
$f’(x) = \frac{-18}{(36.86)^2}(x-36.86)$
knief
$f’(73.72) = \frac{-18}{(36.86)^2}(36.86)$
knief
,calc (-18)/(36.86)
Result:
-0.488334237656
,w arctan(-0.488334237656)
it shouldn't be negative though
,w arctan(0.488334237656)
anyway, mind explaining why this works
That is the exact solution from the solution book lol
they said 45 degrees?
yep
oh so it’s right
this is correct?
hmm this isn’t 45 degrees though
I think because it opens up downwards
oh ok
I get confused about radiants
why did it say 45 degrees?
ok so we found the equation of the parabola
We use the formula for vertex calculation
you’re fine with this yea
wdym
like you know why we found the parabola equation
and you’re fine with how we got it
no
