#help-0
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almost, that double counts the corners
it would be 9 + 9 + 7 + 7 = 32 which is none of the above I think
since you count the top and bottom, then count the sides but don't doublecount the corners
¯_(ツ)_/¯
now you're not counting the corners at all
oh well, it depends if the path is inside or outside the lawn
yeah i'm wrong
so I guess it would be 11 + 11 + 9 + 9 = 40 by the same reasoning, except the path is on the outside
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maybe factorise it?
that's completely different to simplify.........
idk
can you post the question verbatum then?
ok hang on
The actual question should be posted from the getgo as well
Function is undefined so no solutions?
not true.
"find the domain of the following functions"
Ok so what have you tried?
well.... do you know what the domain of a function is..?
that'd be a good place to start, understanding the question
tbh i have no idea what the domain is but i know what it does
yes, domain is similar to range
so google it.. or check your notes
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can someone help me on this problem? I don't know where to start nor do the problem!
ping me if anyone's gonna help
@broken pine Has your question been resolved?
<@&286206848099549185> please help!
where can I ask questions?
ty bro
np
main thing to note
the distance from any point of a triangle to its circumcenter is constant
https://www.cuemath.com/geometry/circumcenter/ this may help you
@bright swallow use an available help channel above
ty
@broken pine Has your question been resolved?
<@&286206848099549185> pleaaaase hellllppppp
.
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hi! would just like to ask help for this question on ideals of gaussian integers
my thoughts are i can do two things
which is correct? and if lcm, how do i get the lcm of two gaussian integers? tia!
<@&286206848099549185>
@jaunty onyx Has your question been resolved?
<@&286206848099549185> please sorry
@jaunty onyx Has your question been resolved?
@jaunty onyx still here?
hi yes sorry
still no luck
my thoughts now are
the lcm and the product are associates
so it doesn't really matter which one i choose
is this the right way to think about this problem @vale wigeon ? thank you!
the lcm and the product are not associates
this isn't even true in Z
just find the gcd with the Euclidean algo
then get the lcm by lcm(a,b) = ab/gcd(a,b)
at each step in the division process, do the division as in C, then round to the nearest Gaussian integer
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i tried to solve this problem, however my answer isn't the same as the one in the textbook
textbook answer
answer i got
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not sure how to do (a)
any help is appreciated
i see
thanks for helping
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Is the number of terms in an Arithmetic Sequence = ((First Term + Last Term)/Common Difference) + 1?
no it should be ((last term-first term)/common difference)+1
think about the equation un = u1 + (n-1)d
rearrange it for n
Shit that's what I meant.
I wrote that in the notebook and asked the wrong thing here 😂 .
Thanks.
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How do u integrate 1/(x+1)^2
You know how to perform substitution?
Yes
Is that how u solve it
So -(x+1)^-1?
Yep!
Thanks mate
+C at the end
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Hello, may I ask for help. how do I solve the equation for the area of this graph using integrals?
Is it safe to assume that both fuctions are sine waves rotated 90 degrees?
Are exact specifications given?
No
Then how could you even determine the exact area?
We don't need to determine the exact area, just find the equation for it
But you can’t assume this
hm... I'll keep exploring
You can write an expression though\\$\int_c^d(f(y)-g(y)),dy$
Euclid31415
I see, thanks, I'll watch thishttps://www.youtube.com/watch?v=kgg5Rspf1Js for further explanation
This calculus video tutorial provides a basic introduction in finding the area between two curves with respect to y and with respect to x. It explains how to set up the definite integral to calculate the area of the shaded region bounded by the two curves. In order to find the points of intersection, you need to set the two curves equal to eac...
I'll close this now
.close
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im not sure how i should approach this question
what i do understand is taht since we are finding the volume about the y axis, my interval would be [0,1]
but i get stumped from here, would i have to find the integral of y=1/4x^2?
i believe this comes into play but translating it to here is the problem for me
well i think im just supposed to find the integral of 1/4x^2
but ive tried and i got it incorrect
i used an online calculator
but i can snip it
and that gives me 3.9875
which cant be right if you look at the graph
oh yeah i include pi
but taht would make it an even greater number lol
It's the same shape if you rotate it about the y axis 
Third of all, we are rotating about y-axis and not the x-axis
I'm guessing the area will be = integral between (0, 2)
so when we rotate about the y axis, the bound would be like this ?
shouldn't it be this ? (after rotating) I might be wrong
Rotating y=1/4 x^2 about y axis gives a paraboloid
yeah so i would just have to find the integral of pi(1/4x^2)^2
over the bound [0,2]
It isn’t right
oh wait sqrt(4y)^2
Yes
oh let me try this
Its important to note you have to rotate the bounded region and also the graph of this parabola is symmetrical about the y axis.
So basically, it looks like a cylinder with a paraboloid dent on it
i got this but im not sure if it is right
It would be\\$\int_0^1\pi(2)^2,dy-\int_0^1\pi(\sqrt{4y})^2,dy$
Euclid31415
let me try this out hold on
i got it!
but let me understand
so when it says we have to rotate about the y axis, we must make everythin in our equation in terms of y right ?
i think i may have forgotten to pi on the two before i came here ;/
but thank you for the help guys, appreciate it
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if i have a right triangle, will every median to the hypotenuse be equal the 2 parts that it created?
yes, because the circumcentre of a right triangle is always at the midpoint of its hypotenuse
Hello 👋, got a question about asymptotes, its been a while for me and I cant seem to work out how to find the vertical asymptote of (x^2+4x)/(x^2)
The Horizontal is 1 and the Vertical is the denominator set to 0 but it doesnt make sense as its just x^2
Please make sure to open a new channel instead of taking someone elses
But to answer your question quickly, you do just set it equal to 0 and so the vertical asymptote is x=0 because when you do x^2 = 0 and solve for x, you will get 0
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im cofused on it all pls help there is many questions i need help with
Say your questions then
Just replace the values in the expression
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hi i dont know how to do this, btw this is transformation of functions
ok sorry
If you want information on how to get help, feel free to see #❓how-to-get-help
Im not sure if im right but shouldnt it be something like 1 + 2/(x-2)
Desmos is for sure a good tool for learning how things change by what you put
For example, you want y=1/x to be shifted to the right by 2 units
Well that means that for example, the forbidden value 0 wouldn't be at 0 anymore, but at ...
2 !
That's why Davo wrote "x-2" at the bottom
Because 2-2=0 and that's a no no for your function
And same goes for left
If you got x
You add +1 to it
For each unit you go left
Think of it this way, if x intercept is at 10 for example
In a graph
If you move it 1 unit to the right
So x-1
The intercept is at 11
Since you need x+1 instead of x to intercept
And before the changes it was at 10
Like here teachers used to explain it that way for students who didnt understand, if you dont get it its fine
But remember when it says left, +1 right, -1
And when it comes to stretching the graph
When it says vertically
It means to the y axis
So for example if before stretching when you have x=1 y=10, and you stretch it by a factor of 2, when x=1 y should be 20, and if you stretch it by a factor of 0.5 y should be 5
Up down basically +-
@balmy zinc Has your question been resolved?
So like if in graph 1/x you got x =1 y =1 right
In the deformed graph
We got 1+ 2/(x-2)
@balmy zinc Are you still there ? lol
So it should be equal to -1
He prolly having a seizure after reading all my texts lmao
Yeah that's what I'm thinking lol
im a bit confused about vertically dilating and the difference with horizontal dilations on how you write it
Horizontal means length wise
Vertical - height vise
So if it says horizontal dilitation
If at Y value you have X
Then after dilitation
At Y value you should have 2X
If you dilitate
By 2
And this not your channel
im confusion
Not here
where then
Open help channel
k ty
thanks I understand it now
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Np
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Hey this is a stupid question but
??
What
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Hi, what is the greek symbol called in math that looks like a Q
Ω ?
σ ?
No
Not your channel btw
Okay but it isn’t open yet
well technically it's not actually inactivated yet
it's fine just go to another one and i'll be back
Okay
It’s okay just make sure u read rules because a lot of people seem to not be
-1 ?
yes
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Let $X=C^0([-a,a])$ be the space of functions continuous on $[-a,a]$ and let $T:X\to \mathbb{R}$ be a linear operator s.t. $Tf=f(0)$. Assuming $X$ has the $L^1$ norm, namely $||f||1 = \int{-a}^a |f(x)|,dx$ show that $T$ is not bounded.
Aram
I proved this for the sup norm, but the L1 norm beats me
So you need to show that you can have an arbitrarily large value but still a finite integral, ie a finite area under the curve
i have a solution in mind, but i don't know how to hint at it
Okay, here's a hint : ||Use a triangle||
And here's a hint that's almost the whole solution : ||k*1/k = 1 yet k isn't bounded||
precisely
I actually thought about that, like a sequence of continuous functions that peaks at x=0 but is 0 everywhere else, but I figured the limit isn't continuous, idk if that's a problem
no
all you need to show is that Tf can get arbitrarily large
You're not trying to show Tf can be infinite
hm I see
peaks at x=0 but is 0 everywhere else
close, but the point of the triangle is to have continuity
yeah sure
so a function like 1-n|x|, |x|<1/n and 0 elsewhere basically
ah makes sense i guess
thx
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if i hv N amount of odd nums n M amount of even nums
Look at the even numbers first, does it matter how many you have? What is the parity of that sum?
Yes, you notice that the even numbers always sum up to an even number
so odd amount of odd nums would give ya an odd sum ig
ya
thx
tiz server finally has the help channel functions lmao, i hv been for such a long time
ask in an unoccupied channel man
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Hello how can I know the exact 'definition' of a real life curve ? I need to describe the following chair so that anyone can replicate exactly as it is, and as it has quite a lot of curvy lines, I don't know how to describe them.
sorry buddy
ask in an occupied channel 😂
Sorry, this channel is busy. Please ask in one of the channels directly under "Math Help (Available)".
@south kayak Has your question been resolved?
eh? xd
its a chair
not sure how i can describe that
OH
oh
you want to describe a real life curve? @south kayak
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@thorn kindle Has your question been resolved?
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The answer the book gave was 1:50000
What went wrong guys ?
hello , i want to understand math (algebra ) and using it. i am really good at math but i want to go deeper outside school can you recommend me some books i will really appreciate it and if you know about books to learn about functions (graph)
Kindly go to an available section and ask your question there, thanks
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The plane V has a parametric description (1st one) & The line L has a parametric description (2nd one)
How do I prove that the line L is parallel to plane V?
@slate kayak Has your question been resolved?
Equate both the parametric descriptions and see if there is a solution
You mean I should put the line numbers on one side and then put a “=“ and the plane numbers on the other side?
I assume they have given a,b,c linearly independent
Yeah i think so
Yes
Okay will do
We are basically looking for the position vector of the point of intersection by equating
And since a,b,c are linearly independent, we can equate the coefficients of each of those separately!
Ah
I have to go do some work now sorry
Okay bye
If we show intersection does not exist we have shown both are parallel
Thnx for the help
I sitll dont know how to do it
This exercise is different from the others the others dont work with base base they just give the R3 equation instantly
Idk what to do
Ok byeee
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Prove that $y^\frac{3}{5} \arcsin{\sqrt{\abs{x}}}$ is differentiable at $(0, 0)$
rept1d
$f(x,y)$ ?
TC159
yes
Ah, just to be sure
<@&286206848099549185>
show that (\underset{(x,~y)\rightarrow(0,~0)}{\lim}~f(x,~y)) exists
SubGui
since y and arcsin are continuous functions at (0, 0)
you may have no trouble in calculating it
yeah, i understand this is what i need to do
though i've trying to do that for a while, unable to succeed
how can I prove that this limit exists?
the side limits evaluate to the same value
and this value is the same as f(0, 0)
as f(x, y) is continuous

btw are you sure about the limit of $f(x, y)$ itself?
and not $\frac{f(x, y) - f(0, 0)}{\sqrt{x^2 + y^2}}$
rept1d
i'm not sure if the existence of lim f(x, y) is enough
if the function is continuous, then it may be differentiable
but I hope someone else can help you precisely
you mean in differential equations?
well, boundary conditions are used to find the constant from the general solutions, but it is not its only use
they define how the functions behaves in the neighborhood of the point
is it somehow related to my question?
not really, it's just that lil.flack0o got bored waiting in his channel and tried to hijack this one
Please do not interrupt question channels. There are several others available right now
i think we should start cracking down a bit more on interrupting help channels
they’re in a section literally called occupied
while in general this question may be pretty hard, for most well-behaved functions it's enough to prove that all partial derivatives exist in some neighbourhood of the point and are continuous at this point.
One important point, btw. This theorem only proves sufficient conditions, and there are some differentiable functions that don't have continuous partial derivatives. Luckily, I don't think this is your case.
- Find all partial derivatives analytically. 2. Prove using your favourite definition of continuity that they are indeed continuous at (0, 0)
Am i allowed to find partial derivatives before I know they exist?
If you can find them, they exist.
You have a nice analytical function, not some horrific specifically-crafted monster, like Weierstrass's function, it should be alright
Although this absolute value does make it slightly harder
You can make your life simpler and just rewrite your function in two branches for x<0 and x>=0, for example
Is there a name for these sufficient conditions (a theorem or something) so that I can mention it in the proof?
proof of differntiability in multivar typically follows the following process iirc:
Find the partials
Compute the tangent plane
show that the tangent is a good approximation
Then find the derivatives for each branch and prove that they are continuous using limits, for example
I don't think there's an epic name for it
not an epic name but just something so that i can google more if i need
You can call it something like A sufficient condition for the differentiability of the function
in terms of partial derivatives
ok thank you
Or at least that's what it's called in almost every textbook I've seen
The main problem you will encounter is trying to prove that multivariable limits exist, but it shouldn't be too hard either.
@rapid nova Has your question been resolved?
ok, so for example
[
\pdv{y} \qty(y^{3/5} \arcsin{\sqrt{\abs{x}}}) = \frac{3 y^{-2/5} \arcsin{\sqrt{\abs{x}}}}{5}
]
but according to WolframAlpha
[
\lim_{(x, y) \to (0, 0)} \frac{3 y^{-2/5} \arcsin{\sqrt{\abs{x}}}}{5}
]
does not exist
rept1d
i know WA can be wrong sometimes but i'm not sure
well, it looks right to me. Lemme look into it quickly
Are you sure that you need to prove that the function is differentiable and not to check if it's differentiable or not?
yes
i only need to prove it for (0, 0)
too bad
Although wolfram happily tells that there are some points where it is differentiable
It's just that this amazing domain doesn't contain (0, 0) unfortunately
can it be that WA is wrong?
Extremely unlikely
But everything is possible. Your best bet will probably be (dis)proving the differentiability using the general definition
Which is something like this: 1. $$ f(x, y) - f(0, 0) = f'_x(0, 0)x + f'_y(0, 0)y + \alpha(x, y) \sqrt{x^2+y^2}$$ 2. Find $$\alpha(x, y)$$ analitically and show that $$\alpha(x, y) \sqrt{x^2+y^2} \neq o(\sqrt(x^2+y^2))$$ at $(x, y) \rightarrow (0, 0)$ or something like this
Dmytr
If your teacher is a troll, proving that the function is non-differentiable will be a sufficient counter
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need some help on a standard deviation question
@alpine sable Has your question been resolved?
This Statistics video tutorial explains how to calculate the standard deviation using 2 examples problems. You need to calculate the sample mean before you can calculate the sample standard deviation.
How To Calculate The Standard Deviation Using Excel:
https://www.youtube.com/watch?v=k17_euuiTKw
Ten Side Hustles For College Students
https://...
try watching this
TC159
$= \sum_{i=1}^{N} x_i^2 - 2\bar{x}\cdot\sum_{i=1}^{N}(x_i) - N* \bar{x}^2$
Could I have some help soon as you are done helping the other person?
TC159
yes
this is a little complicated
uhhh
all I know is the normal formula
yup
$(x-u)^2 =x^2 -2xu + u^2$
TC159
for every x, right?
yup
therefore $\sum_{i=1}^{N}(x- u)^2$
TC159
$= \sum_{i=1}^{N} x_i^2 - 2u\cdot\sum_{i=1}^{N}(x_i) + N\cdot u^2$
because we sum the square of every x_i
because 2xu factors as 2u(x)
so the sum of 2ux_1 + 2ux_2 .... = 2u(sum of all)
yup
TC159
oh ok
you have N which is the number of archers right?
lmao
it just randomly came up
N is 20. you calculated u and have the sum of the squares
you can substitute everything to get
$\sum_{i=1}^{N}(x- u)^2$
TC159
yes..
$\sqrt{\frac{\sum_{i=1}^{N}(x- u)^2}{N}}$
TC159
yes..
I didn't zoom in, looked like a 3
3452360 - 2*434*8280 + 20* 434^2
but am I correct about the mean
oh ok
google says this is 32440
yup
wait
Am waiting
all I do is 32440 divided by 20
lamme try
I already did
oh nevermind
so 40 is the answer
yes
what about the squares of their score
ohh ye
it's the $\sum_{i=1}^{N} x_i^2$
TC159
do u know how to do the second part
what second part
I've already done everything xD
Let's go over again, alright?
you want to calculate this
but to calculate this you need to calculate this
You know that $(x-u)^2 = x^2 - 2xu + u^2$
TC159
you do that after
putting the first value
that's the second exercise
ye but how I lost myself trying to
so do I take away that value from the 8280
yup
TC159
$\sum_{i=1}^{N} x_i^2 - 2u \cdot \sum_{i= 1}^{N} x_i + \sum_{i=1}^{N} u^2$
TC159
first sum is the sum of the squares
second sum is the sum of all scores
third is a constant sum so it is equal to the itself times the number of times it repeats, in this case N
therefore giving you
$\text{Sum}{\text{squares}} - 2u \cdot \text{Sum}{\text{Scores}} + N \cdot u^2$
TC159
You know all of these values so you can just substitute
after all this it says: "One archers score is incorrectly recorded as 349. They actually scored 369"
alright, but first do this exercise ok?
that's the next one
or have you done this one?
anyway substitute to get $\sum_{i=1}^{N}(x_i- u)^2$
TC159
and then substitute in the formula to get the standard deviation
wdym?
then how do I calculate the new mean
yup
yes...
what this is saying is that basically the archer scored 20 more points
so the total number of points is the original + 20
that is 8300
8300/20 to get the mean
415
so the mean is 415 and the sum of scores is 8300. HOWEVER
you do not know the sum of the squares
correct
How do you calculate the new sum of the squares? simple, since he had 349
you simply add (349 + 20)^2 - 349^2
which is 40*349 + 400
14360
3452360 [old number] + 14360 [difference] = [new number]
3466720
okay so now you have
the mean, the sum of squares, the sum of the scores, and the number of archers
considering u is the mean and N is the number of archers, are you missing anything in this formula?
so we do square of the new number divided by the n of archers?
what?
I meant square root
No, first we substitute here...
oh
do you not remember?
I got confused
we have this
and since we can't calculate this directly, we tried to change this part:
and got this:
u is?
oh ok
Anyway, are we missing anything?
No, so lets substitute
3466720 - 2*415*8300 + 20* 415^2
which is 1374377720
so now we have:
$\sqrt{\frac{1374377720}{20}}$
I copypasted into google
yo wtf I made a mistake somewhere
wdym
k
$\sqrt{\frac{22220}{20}} =33.331666625$
TC159
rounding to nearest whole is 33
If you feel confident I got everything right.
I can tell you for a fact that the mean is correct
alright
damn ur a geniua
genius
but
the first standard deviation is 35
still ur intelligent af
why is this muyltiplication allowed
this is some context
pls ping me if u figure it out
ima close the room so u can have it
oh wait
no worries we r done
oh sorry i didnt reralize u guys changed these
dont worry lol
sorry
Closed by @waxen axle
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Needed some help with this question
I've been stuck on this for awhile.
I know that the car 70 feet away (y)
and the distance the light travels is the variable I'm searching for
Do you know the speed of light?
I do
isn't this a physics question?
Calculus
Its very similar to some physics questions ive seen though.
Do you have the full question?
Never mind
oh wait
I made it a bit bigger
i am horrible at interpreting questions
sin(70/x)
what does it mean for the light to move across the wall
Derivative
So tc159 it doesnt mean the speed of the light itself it means the speed at which the police light rotates
ie the wall
are you calculating the limit of the variation of the position right part of the light beam in respect to delta t or the left
Should I find the derivative of sin(70/x)
Not sure how to answer that question.
Are we calculating the speed that the right part of the beam or the left..
that's my main question
The x is the distance
so the left?
Yes
I'm not sure where to start here.
y = tan(theta) * x
Should I find the derivative of that
v_theta = 28rev/m
1 rev = 2pi
v_theta = 56pi/m
v_theta = dtheta/dt
@wary stream how do you suggest solving this, partial x, partial theta?
why would it be partial derivatives
that's my first guess
oh wait y is fixed...
nevermind
I'm pretty stupid
You keep trying to overcomplicate things
you realize this is probably a calculus 1 problem right
I have no idea, at what level of education people are
anwayy
post the question again and i can attempt to help
i suck at these problems though
(what is calculus 1 by the way, I never used that naming )
there are different calculus classes, it’s 1, 2, then 3, partial derivatives are 3
Differential calculus
so calc 1 is like limits, derivatives early calculus?
I see
yeah i can’t help with this, i’m terrible at setting these up sorry
No problem 
The way I'd solve it is probably too complicated sorry...
these kinds of problems are called related rates if you wanna look into them
Will watch some youtube videos on it in the mean time. Do you think I should be able to ping helpers?
I would probably solve it like this $\theta(t) = 8* 2pi/60*t, x(t) = 70 \frac{\cos(\theta)}{\sin(\theta)}$
yes
you can definitely ping helpers
so you can get a purely time dependent formula for x
just post the problem again if you do
@harsh belfry
$\tan(\theta) = \frac{x}{y} = \frac{x}{70}$
TC159
yes?
uhh
$x = 70 \cdot \tan(\theta)$
TC159
mind telling me how you got there?
38
have you learnt radians, by the way?
what the fuck, this involves the derivatives of trig functions
how could you not have learnt radians xddd
I mean I personally am not at all experienced with them
anyway basically a revolution is a single turn which corresponds to the perimeter of a circle of radius 1, aka 2pi
I just know they have to do with angles
basically radians are a unitless way to describe angles
If an angle has x radians, then the angle of the arc of radius 1 and length x is x radians
basically radians relate to the arclength of a circle of radius 1
anyway
since it spins at 38 rpm
it does 38 revolutions, aka 38 * 2pi
per minute
38*2pi/60 per second
$\theta = \frac{76\cdot \pi}{60}t$
TC159
38*2pi got it
anyway
substitute in the equation for x to get
$x = 70 \cdot \tan(\frac{76\cdot \pi}{60}t)$
TC159
derivative on both sides
$v_x = \frac{70 \cdot 76 \cdot pi}{60} \cdot \sec^2 \left(\frac{76\cdot \pi}{60}t\right)$
TC159
now all we gotta do is get the corresponding time for the corresponding time
which isn't hard since that is exactly theta we have that inside secant squared
$v_x = \frac{70 \cdot 76 \cdot \pi}{60} \cdot \sec^2 \left(\theta \right)$
TC159
I need to re-read this a couple of times give me a moment
I might've messed upif you have an r
oops sorry it was a typo
Based on previous discussions, they struggled a bit in trig. So they learned, but probably forgot about it.
I see
TC r u currently busy
y
ok nvm
ok
Currently watching a video on related rates to hopefully get better at this.
If you wonder why I've gone radio silent
Will be closing.
.close
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hi
What's your question?
how do i do it'
Do what exactly?
everything.
That's more helpful then saying " how to do it "
With respect to x or y?
Probably y
idk it just says differientiate
Probably gonna find dy/dx xd
Implicit differentiation
Start by differentiating both sides
is this better? tf
It is
Left side is correct but you also have to differentiate right side, which can get annoying expanded
I suggest using chain rule
You didn't differentiate the right side
so i do product rule 2 times?
Yes
Product rule works too
ok
It’s just less ideal
implicit on sin(x+y) is going to be much easier and more efficient btw
^
That too
$\frac{d(\sin (x+y))}{dx}=\frac{d(\sin (x+y))}{d(x+y)}\cdot \frac{d(x+y)}{dx}$
3_n
Not quite.. you missed the dy/dx’s
Where do I put them
anywhere you differentiated y
So wherever I see y
Mosh
⛓️ 📏
XD
Idk what that is supposed to mean
chain rule 
