#help-17
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Hello !
how to find derivative of this function at x=0:
Thanks !
woooow
so how to prove that it exists ?
if by any luck the exercise is assuming that it is differentiable ..then you hav already done
it doesnt 😦
and i couldnt reach any conclusion using derivative definition
you can watch the derivative at x=0- and x=0+
okay um use l'hospitals rule to calculate derivative of $e^{-\frac{1}{x^2}}$
Arnavutköy
It just goes around a loop
oh whoops
oh wait l'hospital rule helps you find limit
not derivative im trolling
no beacuse you do knothe derivative for x not equal zero
so you can do the limit
simply calculate the derivative of e^{-1/x^2} via regular derivation rules
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Consider an orthonormal reference system in space ( S ). Two planes are given, respectively:
[
\pi_h : hx - hy - (2h + 1)z + 2 = 0
]
[
\pi' : 2x - y + 3z + 1 = 0
]
where ( h \in \mathbb{R} ) is a parameter.
(a) Determine for which values of ( h ) the two planes are perpendicular.
(b) Given the value of ( h ) from the previous point, let ( r ) be the line of intersection of the two planes. Determine a skew line ( s ) with respect to the line ( r ).
jandro0103
@lethal heart Has your question been resolved?
<@&286206848099549185>
wdy m :"Determine a skew line ( s ) with respect to the line ( r )" ?
hint: any line perpendicular to either plane that doesn't intersect r is a skew line of r
Can we go through it?
no, skew lines never touch
i think he means to do the point with you
oh lmao you're probably right
Yes
i think to find r you have to solve this
jandro0103
but im not sure
it's what jandro said, just solve the system of equations
you can sum the equation !
since it has 3 unknowns and 2 Equations, you'll end up with a line
Task Bot
so x = -4z - 3
$x=-4z-3$
now you sub this into (1) or (2)
@hexed needle
do you understand how to get x and y here?
jandro0103
jandro seems to want to help so I'm gonna let them take over so as not to crowd the channel. if either of you get stuck you can ask me lol
@hexed needle But what should I do now?
im not sure how to continue here ... maybe z = t, but i dont know how to explain why
oh, alright. well that would be correct. the set of Equations jandro wrote down do indeed form a line, but it's easier to see if you set z = t. then,
x = -4t - 3
y = -5t - 5
z = t
that's your solution to the system
so that's the line that intersects the two planes
and t is some number. if you plug anything into t, you get a point on the line
And what should I do now?
you need to find a point on one of the planes that doesn't touch r
how would you go about doing that?
Mmm
isn't that what I said?
But do I have to try things out?
yeah trial and error basically. if you look at the first equation in the problem for example, (0,0,-2) is in that plane. is that point in r?
what did you get these from?
but does the point have to belong to a single plane, not both right @hexed needle ?
In r I substituted coordinates for x,y,z
which point did you substitute?
(0,0,-2)
okay, so you should have
0 = -4t - 3
0 = -5t - 5
-2 = t
Yes
Oh so I don't have to put -2 in the other equations?
the plane Equations?
I got 8=3, 10=6 and t=-2
that means (0,0,-2) is not part of the line, since you get nonsense if you plug it in
Right?
as long as s is not parallel with r, yes
well now you have a point on one of the planes that doesn't touch r.
you need to make a line going through that point that isn't parallel with r
then it is a skew line with respect to r
so we just need to take a different direction
the easiest way to do that is to make it normal to the plane
d = (1,1,1)
do you know how to do that @lethal heart ?
I can't use vectors
why not?
I didn't do them
like you haven't learned them yet?
Yes
oh, well that's fine. you just need to make sure that whatever line you create doesn't intersect r
if you take the line
x = -4t - 2
y = -5t + 1
z = t + 3
for example, that is parallel to r
since the "slope" is the same for each component
so you just need to change the "slope", then make sure it doesn't intersect r
does that make sense?
Yes
this is ignoring the whole "point on the plane" thing, i was doing that bc i thought this involved vectors
what i just said is actually easier anyway
but since the direction of r is d = (-4,-5,1), isnt enough to take a different direction like d = (3,3,3) ???
that's what I'm saying, yes...
but you need to ensure they don't intersect since they could still intersect at a single point
even if the direction is different
well easiest first step is to change the slope.
take your line r and make all of the t coefficient different
Ok
that changes the direction of the line so it isn't parallel to r

x=-5t-3, y=-7t-6, z=2t
sure, that works
I finished ?
I have to equalize the parameters and a false relationship must emerge
👍
there ya go lol
so that does work
well no
that says t = 0
so plug t = 0 into the x and y to see what happens
if 2*t = t, the only way that can happen is if t = 0
.
so t must be 0
But in this way a true equality emerges
that's not true
-3=-3
jandro0103
well it works for x, I meant y sorry
you have to use this to build s
-6=-6
the line r has y = -5t - 5
.
look at the Equations for r again
I saw it
why did you use -5t - 6 for y?
Ops
Sorry
-5=-5
x=-5t-3, y=-7t-5, z=2t
Then it was wrong here too, now I've corrected it
I think
oh I see
well then if that's your line, it wouldn't work since they intersect at t = 0
so you need to change the intercept too
you only need one of them to be different
then they won't intersect at t = 0
just change the x intercept for example
then you're done
r:{ x=-4t-3 , y=-5t-5, z=t . r':{x=-5t-5, y=-7t-5, z=2t
there you go, that works
Now to see if they intersect
I didn't understand how to do it
Maybe
t=2t -> t=0
in order to intersect, the x, y, and z coords all need to be equal for some t
yes, true
exactly
and they're not parallel since they have different directions
so it is a skew line with respect to r
👍
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@hexed needle But what was the point of finding the point P(0,0,-2)?
that was only done bc I thought you were allowed to use vectors lol. it's an entirely different method
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I have this problem, would someone be able to help?
@sacred frigate Has your question been resolved?
@sacred frigate Has your question been resolved?
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bro, it's the same idea
no, how did you arrive at that?
in class we learned just input the y= into desmos and count based off slope
and I got 7 over 3
Can you elaborate the details?
you can just tell from the equation
how
wdym
the x coefficient in a linear equation is the slope
if you have y = mx + b
m is the slope
IM SO FUCKING STUPID GODDAMN
so its -6/7x?
lemme solve this rq
Hi
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A 3.1 kg ball moving west to east struck a 2.0 kg stationary ball. If the 3.1 kg ball slowed to
1.2 m/s and was deflected to 25º north of east and the 2.0 kg ball was deflected to 48º south of
east with a velocity of 1.06 m/s. What was the original velocity of the 3.1 kg ball? (4 marks)
so i know momentum before = momentum after
momentum of ball + stationarry ball = 1st ball + 2nd ball
v = inital speed of 3.1kg ball
3.1xv+2x0= before
and the first ball is went out in like a triangle like this
so the momentum of the first ball after is 3.72NS horizontally
oh i got my trig wrong somehow
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You should just show your work
ok
look
3 1/4 is 3.25 meters per sceond
x 60
is 195
then 2 3/4 is 2.75 x60 is 165
and in one lap they cross and 195/165 = 1.18
wait nvm
ok look
you do 195 x24 to find total distance ran
then divide by 180
to find laps ran
which is
26
and then (165 x24) / 180 = 22
then they passed 4 times
<@&286206848099549185>
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bro
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So I get that D and E are wrong since those are not concave down
Just not sure how to use f'(3) = 2
I used MVT, but it doesnt tell us the value of c where the derivative is 2
We just know the average rate of change is 2
<@&286206848099549185>
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show that x^3 - x + 1 is irreducible in Z/3Z[x] (this part i already did) and find all primitive elements of the finite field Z/3Z[x]/(x^3-x+1), which i need help
primitive element is one with multiplicative order 26?
yes
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Hi for sketching graphs, how do you know if there is a vertical tangent at a certain x value?
do you have a specific graph in mind you're talking about
or a specific type of function
@warped osprey Has your question been resolved?
<@&286206848099549185>
so you need help with "show the function is odd"?
a)f'(x)=x^2/sqrt(x^2-1)+sqrt(x^2-1)
c)sqrt(x^2-1) is even function bc x^2 and sqrt function are even
but x is odd and odd×even is odd
Nah I need help with determining the shape of the graph in general
Mostly how do I know if there is a vertical tangent at 1 and -1
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which one is the one corresponding to a?, the (-1)n is throwing me off,
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I don't understand this example and its solution, could someone explain the problem for me? How can -3>0?
where do you see -3 > 0
i could just be blind
-3x<0 is what I saw.
its a rule in inequalites basically if x > -y then -x <y
so 3x> 0 ==> -3x<0
Oh shit its -3x<0
f(x) = 2-3x from R->R+
now y = 2-3x ==> x = (2-y)/3 (Rearrange)
Now x>0 ==> 2-y/3>0
2-y>0
2>y
Hence range = (-inf,2)
when you want to find range that the function as y
and bring x in terms of y
and then solve like you do for domain of a function
oh so ur transferring the negative to the lhs? I didn't learn the quadratic inequalities
ok so the signs change all together?
Understood, to find range, we need to bring it in terms of x and to find domain, it needs to be in terms of y right?
alright thank you
yes
wait I have another question
Sorry to take ur time, could you help me understand what f(x) = |x-3| means? I'm not sure what these brackets || mean
ok so
|any value| is the modulus of that value
y = |x| is defined as y = { x when x>0, 0,x=0 , -x when x<0
hence it is similar to absolute value
another way to define |x| is the distance of x from the origin
we have f(x) = |x-3|
f(x) = {x-3 when (x-3)>0, 0 when x-3 = 0 , -(x-3) when (x-3)<0
wait what is modulus? Is it just a positive number of a number, like modulus of 5 is 5 and modulus of -5 is 5?
not exactly
so ur function can be written as f(x) = {x-3, x>-3, 0, x=-3, -(x-3), x<-3
i hope its clear now
Ohh OK I understand now thank you!
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Let $G$ be an abelian group with neutral element $e.\$
Let $a,b \in G$ with orders $\operatorname{ord}(a) = m$, $\operatorname{ord}(b) = n.\$
Show [ [a] \cap [b] = {e} \Rightarrow \abs{U} = mn. ]
$\textbf{Proof.}\$
Let $u_1,u_2 \in U.\$
Then for $i_1,i_2,j_1,j_2 \in \mathbb{Z}$ with $0 \leq i_1,i_2 \leq m-1, : 0 \leq j_1,j_2 \leq n-1$ there is
[ u_1 = a^{i_1}b^{j_1}, u_2 = a^{i_2}b^{j_2}. ]
Consider
[ u_1 = u_2 \Rightarrow a^{i_1}b^{j_1} = a^{i_2}b^{j_2} \Rightarrow a^{i_1-i_2}b^{j_1-j_2} = e. ]
Because of the assumption $[a] \cap [b] = {e}$ it is $i_1 = i_2$ and $j_1 = j_2$ which implies every element of U is unique.$\$
Therefore $\operatorname{ord}(U) = mn.$
𝔸dωn𝓲²s
Is the proof correct
@bitter pilot Has your question been resolved?
what does that assumption have to do with the line before
[ u_1 = u_2 \Rightarrow a^{i_1}b^{j_1} = a^{i_2}b^{j_2} \Rightarrow a^{i_1-i_2}b^{j_1-j_2} = e \Rightarrow a^{i_1-i_2}=b^{j_2-j_1}. ]
They are only equal if both are the neutral element because of $[a] \cap [b] = {e}$.
𝔸dωn𝓲²s
i_1 - i_2 = 0 and j_2 - j_1 = 0
why is that the only way for them to be equal?
and why does a^(i1-i2)=e imply i1-i2=0 ?
Because [a] and [b] are distinct sets without e and it is a^0 equals the neutral element
I would have liked to hear something like "the left side is an element in [a], the right side is an element of [b], so in total that element is in [a] cap [b]"
is 0 the only solution to a^k= e?
Isn't that obvious
How far does one go into explaining
no offense but there are some other obvious things you havent seen. so I wasnt sure whether you just claimed what you wanted or whether that was actually the argument you have in mind
So what do I change
I will add this
the left side is an element in [a], the right side is an element of [b], so in total that element is in [a] cap [b]
i_1 - i_2 = 0 mod m
j_1 - j_2 = 0 mod n
you havent used 0 <= i1,i2 <= m-1
(with that condition it is obvious to say that the only option is 0)
i_1 = m-1 = i_2 then i_1 + i_2 = 2m-2
What I am trying to say is with the sum
Won't get out of that interval
No
you are right
If i_1 and i_2 are in that interval
i_1 = i_2 = 0
Then I showed every element of U is unique
Can you give me a hint on
[ \gcd(m,n) = 1 \Rightarrow \abs{U} = mn ]
I started with $V := [a] \cap [b]$ is after some theorem a group and therefore a subgroup of $G.\$
Then $V \subseteq [a], [b]$ it is $V$ is also a subgroup of $[a]$ and $[b]$
𝔸dωn𝓲²s
The intersection of arbitrary many groups is a group
let c in V, so c=a^k and c=b^ell and then some playing around with that. and bezout probably also helps
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I have a question
I wanna know if you can reverse the derivatives ?
Like how to reverse a derivative?
that happens to equal 1/[dy/dx]
dx/dy that is
That just doesn't seem right
well, you know implicit differentiation?
,rotate
!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.
@placid crescent Has your question been resolved?
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i dont know how to do this
think about the angles, maybe you will spot some similar triangles...
Triangle OMN and OQP are similar
just take care of order and implement their properties
so MO = 19.4 and PO = 6.5?
is that correct?
^
thank u
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I just asked this question but actually I’m still lost
I’m not understanding when you flip the sign of the answer and when you don’t
are u asking when to flip sign of x^2
For the answer of -6 and 5
you need to find values of x using factorisation
you need to make factors
for eg (x + a).(x + b) = 0
now first consider x + a = 0 which implies x = -a
and next consider x + b = 0 thus x = -b
and x = -a, -b
the first part is the factorisation / simplification
factoring out the -1 leading to
x^2 + x - 30 = 0
regardless of whether you have that = 0 there or not, the factorisation of the bolded part will still be
(x+6)(x-5)
Where did the -1 come from
the original equation they gave had a leading coefficient of -1
its usually easier to work with a positive leading coefficient which is why they factored that out
-x^2-x+30=0
Implies a -1
what?
see you don't necessarily need to remove that negative sign of x^2
but it is generally done to ease factorisation
simply consider it multiplying LHS and RHS by negative 1
wdym
if you could do factorisation with the negative sign infront of x^2
you can proceed with it
I wouldn’t have to change the problem to
X^2+x-30=0
I could leave it as
-x^2-x+30=0
Right? Or wrong
So if I see -x^2 I should reverse the signs at the beginning of the problem to make it easier?
I’ll write down my thought process and take a pic and you tell me where i go wrong.
if there is a RHS you can multiply LHS and RHS by -1 and proceed with it
if there is no RHS then you take -1 out from equation like say
-ax^2 + bx + c
-1(ax^2 - bx - c)
and then factorise it but -1 will remain like
-1.(x + alpha)(x + beta)
I see the problem
yes, bc x² + x - 30 = 0 has the same solutions of x as -(x² + x - 30) = 0
Now
-6 and 5 don’t get to positive 30
And 2 negatives don’t get to -x
How would you do the problem without factoring -1?
like as in -x^2 - x + 30
if x² + x - 30 = 0 in factorised form is (x - 5)(x + 6) = 0,
then -x² -x + 30 = 0 in factorised form is -(x - 5)(x + 6) = 0 or (5 - x)(x + 6) = 0, you're getting mixed with the signs
but the -1 in front technically doesn't matter
consider m and n to be factors of the equation
then m + n = -(-1)/(-1)
and m.n = 30/(-1)
ur just finding values of x that satisfy the equation to be 0
Thanks
Yeah I get it now
yeah this is right
The part that didn’t make sense to me was factoring out -1. I also see you do this if you had something like -3x^2….
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How do i do that
Factor 12d
What does that meaj
Do u know how to factor?
what can multiply together to make 12, for example?
Wronskian! 👻
6x2
12x2
do they share anything in common?
They can be multipled by 2
so you can take 2 out to the front
Wym
2(12d^2-6d)
Axe
we can factor more stuff
that's not the final answer
Oh shit
they share more factors
Thhen what i do
^
Im getting it
Why
in other words is 24 divisible by 12
Thas 2
because if it is then we can factor it
i’m aware but i think it’s clear that you can factor more from the beginning
instead of factoring each prime one by one
Wait wym by that
yeah 24 is 12*2 and 12 is 12*1
so they share 12
so factor out 12
so you can take 12 out to the front
then deal with the d after if you can’t spot that immediately
nah just go from the start
24d^2 - 12d
Oh shit i was teyna makdena brwxket
Wtf does ^ dis mean
to the power of
Ohh
d squared
Why did we factor 12
to get a polynomial multiplication expression
Thats the answer?
there's more we can do
my guess is your teacher would want you to do more
we're done with the numbers but
now the d's
d^2 means d*d
so you can see they actually share a d
How would do that tho one is d^2 and one is d^1
because d^2 is d*d
Show the equation
Axe
good job
So thats final answer?
yeah
Aii appreciate it bro i got this retest
Tmr
It fucked up my grade so badly
96 to a 92
Can i dm u if i need help?

Wha tha mean
Helpers are just people volunteering their time to help you. Be polite and patient.
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why is it 2.5m/s to the right?
i got 0.5m/s to the right
using conservation of momentum, i have m_1v_1f = m_2v_2f
so thats 1.5 * 0.5 = 1.5 * v_2f
No, 1.5 × 3.0 = 1.5 × 0.5 + 1.5x
Technically there are 4 terms
But 1.5 × 3.0 + 1.5 × 0 on the left hand side
Before and after, two pins
oh
so it's m_1v_1i + m_2v_2i = m_1v_1f + m_2v_2f
oh yeah that does output 2.5m/s
thanks
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can someone help?
well we gave you some pointers last time, where did u get up to with those?
7^n=1mod3
well as in you should always remember that squares can only take a limited value mod n
so if k is a multiple of 3, what can you say about k^2 mod 3
similarly if k is 1 more than a multiple of 3 etc.
k^2=0mod3 if k is multiple of 3, k^2=1mod3 if k is multiple of 3 +1 and k^2=1mod3 if k is multiple of 3 +2
yep
so that tells us k^2 = 2 (mod 3) is impossible
so what can we say about n?
7^n-2^n= multiple of 3 or multiple of 3 +1
7^n is a multiple of 3 +1 for any n
2^n=2^n(mod3)
i think ur a little bit confused
we've shown that 7^n - 2^n - 9 = k^2 reduces to k^2 = 2 (mod 3) if n is odd, and k^2 = 0 (mod 3) if n is even
we've said up there that k^2 = 2 (mod 3) is impossible
so what can we say about n?
yep
i'm going to make the substitution n=2m for now
we now want to know when $7^{2m} - 2^{2m} - 9$ is square
LY
now i was saying yesterday, we know $7^{2m}$ is square right?
LY
you could try that, but then we can't factor x^2 + 3^2
(well u could work in some different ring but that's uni and let's try to avoid that)
ok
what i was saying last time was this thing is intuitively a little bit smaller than 7^2m
so we expect it to be bigger than (7^m-1)^2 and smaller than (7^m)^2
what's the issue now?
no as in let's suppose we prove that most of the time
(7^m - 1)^2 < k^2 < (7^m)^2
what's the issue?
remember that (7^m - 1) and 7^m are consecutive
so like if i have a number between 7^2 and 8^2, can it be square?
oh
yes, so k^2 is a perfect square between two consecutive perfect squares
so it doesn t exist for m>1
so that means there's only one possible value of n which might work, n=2
does n=2 work?
yes
so that's the answer
thank you very much!!
nw!
^^
btw if ur done, type .close or .solved
yh
@brisk monolith Has your question been resolved?
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@dense eagle
i have a question
can we proof that (7^m)^2-2^2m-9 is bigger then (7^m-1)^2 ??
wait i thought u proved it
uh you just expand
then stuff happens
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i need help with experiment number 2. I don't understand how to answer number 2-4.
okay
so basically, when they mean the "existence of a limit" for question number 2
this means that as we plug in x and x gets closer and closer to 1
the value gets closer and closer to - infinity or positive infiinity
yes
but there's a hole at 1
so the limit can't be 0
i'm very confused with all of this
sorry 😓
okay so there is a difference in the "calculation" of a limit, which can be done at any point, and the "existence" of a limit, which implies an asymptote
specifically, the asymptote is the line this function is approaching
when this line is vertical
we say that the x-coordinate represents the limit
so why would you think there might be a limit at x=1?
well, the denominator goes to 0
and the numerator over a very small number might be very big right?
so like, if we got 1 for .9 and then like 100 for .99 and then like 10000 for .999, we see that the number is growing bigger and bigger
this would indicate that there is an asymptote at x=1
because the value just keeps on increasing more and more
but since there is simply a hole, there is no limit in this case
or wait
in this case, sorry there is a limit
so the limit DNE?
i recommend just looking at the graph
the limit simply is x=1
but why?
okay basically, the "slope" of the line as x approaches one is inifnity
think of a limit as in, if we look at the graph of the function when x=1 locally, it basically resembles a "vertical" line
right
so we see in your graph that for a minimal change in x (like .009 or .09, we are seeing a 'lot' of relative change in the y-coordinate
this indicates that the function is nearly vertical at that point
which indicates that it is a limit
does that make sense?
umm
kinda?
if there's an asymptote there is it just hard to see the change in the graph because it's minute?
like usually when there's an asymptote it's easy to see so because the graph doesn't touch it
but if there's a asymptote at x=1 then why is the graph going through that point?
why not just stop there?
it is possible for a graph to go through in asymptote
it is???
yes, although most examples you see don't do that
okay
the point is that the function is almost "tangent" with that asymptote
right
okay
one more question
so when the question asks for the existence of a limit at x=1 what does that exactly mean?
You have to make sure that left-sided and right-sided limits at 1 exist and they are equal
If this happens, then the limit at 1 exist
i'm aware of that
The function might be undefined at 1, yes
The limit can't approach something, maybe you mean the function?
i mean the left and the right hand side
if you look at the data it's approaching 1 but doesn't equal it.
Yeah that's totally fine
does that mean the lim x-> 1 = 0?
.
it's the second one
@civic otter
Oh then yes
@vast shale Has your question been resolved?
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And using the graph makes more sense to figure this out than a table value right ?
@vast shale Has your question been resolved?
@vast shale Has your question been resolved?
Usually yes, but in this server I've seen people struggling with graphs and preferring tables 🤷♂️
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<@&286206848099549185> please and thank you 😭 💀
Please tell me Lexi
yes?
How can I help
Ok
because my friends say its 8x2 which i think isnt correct
cuz its not a vertical line its slightly slanted towards the side
and yes diameter of a circle inside a square is equal to the side length of square but the circle is outside of the square
As per the diagram and as per the question just given that circle inscribed inside the square having the radius 8 cm
Which means the total length of one side of a square is 8 x 2 means 16
Actually it is outside but you can see the dots
Mathematics and in engineering if we see those dots it means we just imagine that's structure but don't work on that
Yes Circle is outside but the margin is negligible that it doesn't matter we can neglect that value
what in the physics
scrollup
Means
dude u fr?
🗿
give me a moment
i dont think it should be neglected ngl 😭
we cannot neglect that value 😭
Yes you can
how?
you really just cannot
yea
Calculators are allowed?
we can neglect and if you want to calculate that value it doesn't even matter because it's so small that when we add this it will just change a fraction of that value
duh this isnt 1980s
imagine using a log book counting trigo
no you cannot neglect it
hell
ok but usually questions ask for the exact answer 😭
yes
exactly
😭
Ok then assum it and add .
That won't affect anything
my answer is 14.78
why are you assuming anything
Like pie =3.14 and so on
which is like 1.22 off
But in my world we take 8 digits after decimal
what
first you say that this smidge of a circle is negligible
but obviously 8 digits after the decimal isnt
show your working so we can check
sin 45/2 is not that
i just use formula thats abt it
ignore what i did and what would u do
🗿
i would find the perpendicular distance from O to the square
yea thats what i did
🗿
because idh the vertical line
and bottom line as well
the formula i used was formula for chord in circle
where did uou get 3.062 from
@worldly otter Has your question been resolved?
2(8) sin 45/2
@worldly otter Has your question been resolved?
I got 8*sqrt(2-sqrt(2))*(1+sqrt(2)), which is indeed about 14.78
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perpendicular distance from a eqn is zero to center
are you ai
no?
!original
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.
exactly what an AI would say
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<@&286206848099549185> find the shortest distance between two points and it should touch a line and let the points be a,b and the let the line be ax+by+c=0.
the question isn't clear
which is normally an issue when questions are paraphrased which is why i asked
@young plank Has your question been resolved?
Not yet
not sure what this is tring to say
could you be clearer
what should touch what line
if youre looking for shortest distance its just rhe distance formula
That's why this is the question that is amazing everyone
$d = \sqrt{(x_1-x_2)^2 + (y_1-y_2)^2}$
ashy!
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I need assistance with this.
have you found the components of v already?
you can visualize this with @twin meteor
,tikz
\draw[->] (0,0) -- (220:2);
vin100
In the above command, \draw[->] means to draw an arrow. In (220:2), 220 is the angle that the arrow made with the positive x-axis, and 2 is the length of the arrow.
to scale this vector, you can simply mutiply the 2 in (220:2) by a constant, like
1 moment
,tikz
\draw[->] (0,0) -- (220:2);
\draw[->,yellow] (0,0) -- (220:2*2);
vin100
I'm just having trouble finding c.
I know that the magnitude of vector v is 2 and since it's magnitude changed to 1/2, c must be a scalar of +/- 1/4.
I just don't know which.
I know that the angle changing from 200 degrees to 40 has something to do with the positive/negative factor.
if you have difficulty in one way of thinking, transforming your doubt into another way of thinking can often provide you a solution
it's like when you're stuck in one pathway, you choose another pathway
if you're stuck at numerical calculations, you can think of drawing them in graphs
you can test with @twin meteor, which will reveal the answer
you can also draw grid quickly to measure the lengths
,tikz
\draw[opacity=0.5] (-3,-3) grid (3,3);
\draw[->] (0,0) -- (220:2);
\draw[->,yellow] (0,0) -- (220:2*2);
vin100
.close
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why is he allowed to flip from o to inf to from inf to 0
afer the u sub?
nvm
its because
when x is 0, u apraoches inf
and when x is inf, u approaches 0 right
i am pretty sure he just took out the negative and that allowed him to flip bounds
i meant this step
yeah
its just replacing the x values with u right
no
then here you just take the negative and flip bounds
well yes but that would still be infinity to 0