#help-28
1 messages · Page 183 of 1
Hint says to show a sequence of D is not equicontinuous
Then use a modified version of arsela-ascoli for R^n

f_n(x) = x^n for A= [0 1]
Next
Suppose $A$ is a compact subset of $R^m$, $f:R^m \rightarrow R^m$, and $\mathscr{B} is a subset of continuous functions from $A$ to $R^m$ such that for each$ x_0$ and $\epsilon$, there exists a $\delta$ such that $d(x, x_0)< \delta$ implies $d(f(x), f(x_0)) < \epsilon$ for all $f$ in $\mathscr{B}$.
Prove Script B is equicontinuous
Ok so
I'm guessing I just take all the B(x, delta_x)
And take a finite cover
Wait hm
Guess there's more to it than that
Ok I dunno
<@&286206848099549185> i could use a hint im kinda tired
Uhh the current problem is the message at 10:06 AM
West coast time
Suppose $A$ is a compact subset of $R^m$, $f:R^m \rightarrow R^m$, and $\mathscr{B}$ is a subset of continuous functions from $A$ to $R^m$ such that for each $ x_0$ and $\epsilon$, there exists a $\delta$ such that $d(x, x_0)< \delta$ implies $d(f(x), f(x_0)) < \epsilon$ for all $f$ in $\mathscr{B}$. Prove that $\mathscr{B} $ is equicontinuous.
I figure we cover $A$ with $B(x, \delta_{x, \epsilon})$ and take a finite subcover of that, but im not sure where to go from there
992HallucigeniaEnthusiast
Gonna take a nap brb
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I need help
quick dm me
grade 7 linear equation and also inequalities
Why can't a game developer do grade 7 linear equations?
Also, why dm? Just post it here.
Likely a grade 7 game dev
maybe the game isnt math related.. somehow
you'd think hp systems and such would require nearly every game to be math related
Is it possible for a computer game to not be math related in terms of development?
@hardy vigil
Not really, no.
this seems like a great challenge but we'd need to define math related
no simple arithmetic? absolutely not, no complex functions, probably
Like, utilizing at least 1 algebraic expression in the code for example
but then logical statements also fall in math
hmm...
rendering the game would take math, i assume we ignore that factor
is num1++ allowed? are all forms of arithmetic allowed?
Y'all arguing over what?
seems like bored discussion
Damn what you upto
More like, I already know the idea of game development. And what it does use, is infact mathematics. I'd call it mathematics all day. So nothing left to discuss lol. But this isn't the right channel for it, so...
very good point
- Preeta watches an ant and a beetle crawl in a hole in the ground. The beetle is 3/4 inch below ground level. The beetle climbs 1/3 the distance the ant is below ground level. The beetle is now 2 1/2 inches below ground level.
(a) Let x = the position of the ant relative to ground level. What equation can be written to solve for x?
(b) Solve the equation from Part (a). Show your work.
(c) What is the distance between where the ant is and where the beetle is? Answer the question in a complete sentence. Show your work.
Show your work, and if possible, explain where you are stuck.
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
@hardy vigil Has your question been resolved?
<@&286206848099549185>
?
My questionn
Preeta watches an ant and a beetle crawl in a hole in the ground. The beetle is 3/4 inch below ground level. The beetle climbs 1/3 the distance the ant is below ground level. The beetle is now 2 1/2 inches below ground level.
(a) Let x = the position of the ant relative to ground level. What equation can be written to solve for x?
(b) Solve the equation from Part (a). Show your work.
(c) What is the distance between where the ant is and where the beetle is? Answer the question in a complete sentence. Show your work.
can u help
Ok am gonna see
i have only done till
3/4 + 1/3x = 2 1/2
3/4 + 1/3x = 5/2
Let's solve this problem step by step:
Given information:
- The beetle is 3/4 inch below ground level.
- The beetle climbs 1/3 of the distance the ant is below ground level.
- After climbing, the beetle is 2 1/2 inches below ground level.
Let x be the position of the ant relative to ground level.
(a) Equation to solve for x:
The beetle starts at 3/4 inch below ground level and climbs 1/3 of the distance the ant is below ground level. After climbing, the beetle is 2 1/2 inches below ground level.
So, the equation can be written as:
3/4 + 1/3x = 2 1/2
(b) Solve the equation:
To solve the equation, we need to find x that satisfies the equation:
3/4 + 1/3x = 2 1/2
Convert 2 1/2 to an improper fraction:
2 1/2 = 5/2
Now, solve for x:
3/4 + 1/3x = 5/2
1/3x = 5/2 - 3/4
1/3x = 10/4 - 3/4
1/3x = 7/4
x = (7/4) * 3
x = 21/4
x = 5 1/4 inches
(c) Distance between the ant and the beetle:
To find the distance between where the ant is and where the beetle is, we calculate the absolute difference between their positions:
Distance = |x - 3/4|
Distance = |5 1/4 - 3/4|
Distance = |5 - 3| = 2 inches
Therefore, the distance between where the ant is and where the beetle is 2 inches.
Let's continue solving the equation:
3/4 + 1/3x = 5/2
First, let's get a common denominator for 3 and 4 on the left side:
3/4 + 1/3x = 5/2
3/4 + 1/3x = 10/4
Now, combine the fractions on the left side:
3/4 + 1/3x = 10/4
3/4 + 1/3x = 10/4
Now, subtract 3/4 from both sides to isolate the term with x:
1/3x = 10/4 - 3/4
1/3x = 7/4
Multiply both sides by 3 to solve for x:
x = (7/4) * 3
x = 21/4
x = 5 1/4 inches
So, the position of the ant relative to ground level is 5 1/4 inches.

??????
I solve it what?
so this is the answer?
Yeah
sure?
Yeah
Your welcome
<@&268886789983436800> this cant not be chatgpt
Bro what is wrong with you?
what is wrong with you
do you think we can't go to chatgpt ourselves?
provide value or leave.
alot
we need human help
since youve gotten the answer from chatgpt i think you can follow along, do you have any specific questions about the solution i can help you with tho
i dont get the answer
i think it contains an error
i would like it if you could resolve it
im sorry but i cant just provide the answer for you, i could try guiding you im not exceptional at helping people though
no problem just guide me
alright so you have finished a) right?
alright, now we can start to solve it, do you know how to solve a linear equation?
its alright, just try to write it step by step and ill try to correct you if you go wrong
x = 21/4????
could you write it step by step?
3/4 + 1/3x = 2 1/2
3/4 + 1/3x = 5/2
1/3x = 5/2 – 3/4
1/3x = 10/4 – 3/4
1/3x = 7/4
i did it till here
i dunno what to do further
yes exactly
21/4
for multiplication i recommend using * as it doesnt cause confusing with the variable x
k
great so now you have x = 21/4 so you have solved b)
Preeta watches an ant and a beetle crawl in a hole in the ground. The beetle is 3/4 inch below ground level. The beetle climbs 1/3 the distance the ant is below ground level. The beetle is now 2 1/2 inches below ground level.
(a) Let x = the position of the ant relative to ground level. What equation can be written to solve for x?
(b) Solve the equation from Part (a). Show your work.
(c) What is the distance between where the ant is and where the beetle is? Answer the question in a complete sentence. Show your work.
copying it down for accessibility
What is the distance between where the ant is and where the beetle is? Answer the question in a complete sentence. Show your work.
do you have an idea how to approach c?
yo
alright so how would you go about calculating the distance between for example 2 items where one of them is at 1cm and the other is at 3cm
to calculate the example what do you think the best option is
how????????
if you subtract the 1 cm from the 3 cm you get the difference between the distances, the difference is the distance between them
2
ya
now you can apply that to the distance of the ant and beetle
are you talking bout my question or the example
bro....
we found x
which is the value of the ant
knowing the beetle is 2 1/2 inch under the ground, and the ant is 21/4, or 5 1/4 inch under
and the beetle is 2 1/2
oops yeah
so..
now we can use the subtract we used in the example with this situation
we would 2 1/2 - 21/4
almost
since the 5 1/4 is bigger we subtract the 2 1/2 from that instead,
5 1/4 - 2 1/2
21/4 - 5/2?
yes
thanks man you are the best!!
np, now just formulate it into a sentence and ur assignment should be completed
btw what is ur instgram
i dont have it, why
nah just wanted to be friends:)
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what have you tried so far?
It's now tan(2arcsin(lsinxl+lcosxl))
If we use tan 2theta
It becomes complicated
<@&286206848099549185>
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oh weird
why is that there?
New discord feature
.reopen
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You probably have to sign up to see all the help channels in here
use id:customize and select "i need help with math" to get access to all help channels
wroked
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Is there a quick way to work this out without having to do a lot of working out?
My first thought is let A be the first matrix. 2 * column 1 of A + x * column 2 of A -3 * column three of A = column 7 of A
and solve for x
I'd just reduce "as much as needed" to get the final answer
You don't need to reduce the bottom 3 rows. You don't need to include any of the numbers outside of the first 3 columns
You do want to keep the -13 in the ? spot, and keep track of it, though
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how so?
how did you get the last inequality?
Say n is 5
We r assuming log n to be base 2
oh
Oh
i still don't see how the last inequality is true
@elder cape you gonna explain how you got the last inequality?
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i have a vector and an axis
how can i get the magantude of the vector on the axis
dot product the vector with the unit vector along the axis
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Hey there! Got a physics question on wave interference
This is the question
and this is our work so far
Using desmos, we found that the answer should be 2, but we're having trouble finding the answer symbolically
(that is, that the position should be at 3or 7 meters from the left source, which is 2 away from the midpoint between the sources)
You can also ignore the "k" part
The main confusion I'm running into is calculating the phase difference deltaPhi. Honestly the whole thing is really confusing too
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Let's say the wave by source1 is Asin(kx-wt)
What would the wave equation for the wave released by source 2 be ?
Asin(kx-wt+phi_0), no? But we're taking a picture of the wave at an arbitrary time t, so can't we just get rid of the wt term by assuming we're starting our time at t = 0?
Though i guess the wt terms would cancel?
well technically both waves have the same initial phase, so it wouldn't be phi_0, it would be delta_phi, right?
that is, the phase difference. Since both waves have the same initial phase, I just assumed phi_0 = 0
Anyway, that's what I've written on the whiteboard, after dividing out the amplitude
the issue is I'm stuck on how to represent delta_phi symbolically, since the equation relies on delta_D, which relies on the distances from x to the sources
So the expression I get at the very end is circular, like its saying "x depends on x"
Thanks for replying btw, been here a minute lol
I wish lol, this has taken me hours
I mean, if it makes it easier, we could ignore my work and start from the initial question
The idea is we want to solve the equation 0 = Asin(kx - wt) + Asin(ks - wt + delta_phi) for x, right?
Yes
Wait a min
The wave from the second source is travelling towards negative x axis
Yeah
So it would be kx+wt
That makes sense, and would explain why it cancels if we move it to one side and take the arcsin
So we should be able to get rid of the t term
What you are saying is right,but will that help us in anyway?
It reduces the equation to one variable. Unless we just let t=0, which also takes care of that
What should be the phase difference ?
That's what I'm trying to find
it should be equal to k times the path difference delta_D
0 = sin(kx) + sin(kx + delta_Phi)
-sin(kx + delta_Phi) = sin(kx)
-kx - delta_Phi = kx
- delta_Phi = 2kx
Mb
no worries, its a dense problem lol
does the above look correct to you so far?
i forget big delta notation lol
Yes
?
$$x = - \frac{\Delta \phi}{2k}$$
Rafzekael
there we go
Oh
so since delta_Phi = k*delta_D, and delta_D = |d_1 - d_2|
we should get
$$x = - \frac{\abs{d_1-d_2}}2$$
Rafzekael
the issue with this is that both d_1 and d_2 depend on x...
and that's where I'm stuck
(also it depends on where you define your orgin which makes things even more confusing lol
idk lol. this phase difference stuff is hella confusing to me
Say origin is at source 1
What would the wave equation be?
For source 2
(I don't know)
I think it was this
to simplify, sin(kx + delta_Phi)
That's the phase difference between two waves
^
The waves have the same initial phase, but that's different from phase difference
because they are offset by position
Man,I am getting confused
Nah, no worries at all! I appreciate any help
Simple
how so?
hahah, yeah if only lol
I think I'm missing an equation
cuz otherwise i feel like i'm really close to the answer
Ahhh
Y2 I.e wave from second source
Is 0 at x equals 10
We get delta phi from that won't we
We can, but the issue is that the question wants us to solve it symbolically first for full credit
so without any numbers lol
I suppose we could say it equals zero at x = d...
I am taking origin at source 1
And I am done
lmao
Out of my league
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Is this correct?
Absolutely corrrct
But u need to do one more thing
The surface area for the top is (21x12)-(8x4)
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how should i proceed with question 2?
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How to find the average speed for the whole jounrye?
Average speed is total length travelled over time
Average velocity is total displacement over time
Well for distance you just need to add how much it went up and how much it went down
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i dont understand how to do this question
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you can use trigonometry for abd and e.
how tho
for the first one, BC is adjacent to the angle of 40 degrees and the length of the hypotenuse is given (18m). as we have the hypotenuse and are looking for the adjacent we must use cos(θ) = adjacent / hypotenuse. substitute in the values: cos(40) = adjacent / 18 . Now rearrange to have the adjacent equal to 18 * cos(40) = adjacent. This is BD
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how would i do this question? I cant seem to apply the approximation
For a quantity $$Z= AB,$$
$$\frac{\Delta Z}{Z}= \frac{\Delta A}{A} + \frac{\Delta B}{B}$$
Sulphur
(Delta A)/A, for example, is the relative change of A
Similarly for the other things
Yeah coz you have to find change in V, not v
so I rearrange to V=v/(kA)
and because its a division would it become -5%-(+4%) = -9%?
You could do that, yes
okay thanks alot
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@royal kettle Has your question been resolved?
Ohh, got it, thanks!
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Hi, sorry I don't know how to use the math bot
but I have this problem here
I solved this by doing ln to the expression
and after simplifying and all I get 4
but by doing it the way outlined in the other solution, I obtain e^4, which is the correct solution
was just wondering if anyone could let me know how I could get e^4 using the method i solved by (and why)
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yeah that's true
guess it was that simple
didnt think about other side
thanks for your help !
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"Linearize the function
...
around the point A = (6, 5). Then use it to calculate an approximate value of f(B), where B lies on
distance 0.17 l.e. from A in the direction (8, −15). (Please compare with f(B) calculated with a mini calculator).
Also state the equation for the tangent plane to the surface z = f(x, y) at point A."
i dont really get how this is solved
i start by putting in A(6,5) into sqrt(228+x^2+y^2) and get 17
Now you need the normal of the tangent plane of the curve at that point
hmm okay can i not calculate b first by doing a + h?
Sure
okay then we get (6.08, 4.85) right
but then my teacher does f(a) = f(7,5) = 342 + ln(1) * 17 = 342
and i dont understand why
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How do i solve this
part (b)(ii)
65
How?
there are only two possible arguments for an imaginary number (which ones?)
Based on the argand diagram?
yes
Sry i dont really understand this part
a purely imaginary number must lie on the imaginary axis
||+- pi/2 ?||
As it has to lie on the imaginary plane?
Is it positive or negative pi/2? now
Well based on the argument it is in the third quadrant
So i assume it is negative
??
idk cus its purily imaginare it can be positive or negative axis right ?
Yea but z = -5pi/9
From i) did you get positive or negative i?
my imaginary numbers are not my best so im asking as well
i is a show qn
well just from the fact that it's purely imaginary it must be either +/- pi/2. and we know that z has a negative imaginary part, therefore its conjugate has a positive imaginary part (which we are subtracting)
yes
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Hi I need help setting up this double integral
The double integral of (x-y)DA over the region R who is defined by the inequalties y <= 2x -1, y >= -x, and y <= 4 -x^2
Try drawing the region R and figure what your bounds should be
So where i'm getting at is that the domain of x ranges from 1/3 to (1+sqrt(17))/2?
and y is bounded by the 2x- 1 and -x? but I don't think that is correct of the parabola of 4-x^2
Can a number 44...41, whose decimal representation consists of an odd number of digits 4 followed by a digit 1, be a perfect square?
I need help pls msg me
this is also an in use channel, you want to pick one from the Math Help (Available) section
ah ok
Sorry to bother you again but how else could i approach this problem?
Consider dividing you region by this line AB here
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A 9200 USD investment grows to 12000 USD in 4 years. What is the annual interest rate?
So i did 12000 = 9200(1+- r)^4
then 12000/9200 = 1.304347826
1.304347826 = (1 +- r)^4
square root both sides by 4
therefore
are you sure it's not simple interest
i get +-1.068681656 = 1 +- r
nah it's for math 2 extended
10th grade math class
so listne
idk i dont study econ
because basically
if we can have it as -1.068681656
= 1 - r
we subtract both sides by 1
and then divide both sides by -1
that isn't a valid solution
why 1+-r?
$\frac{12000}{9200}=(1+r)^4$
kheerii
t being years in some cases, such as this
correct
you're not given any information about how the interest compounds
whether it's per annum, twice per annum or so on
you're assuming it compounds once per annum
yes
because that's how the information is given here
again
we're following this formula
but how else do we solve
that formula assumes that the interests compounds annually. do you KNOW that that assumption lies behind that formula?
the +- doesn't really matter, r will just come out to be negative
ok
we are coming out to the fact that there is an annual interest rate, and we are trying to find it after
and you shouldn't take the negative 4th root here
that gives you a ridiculous value for the rate
im not doing the -4th root, but doesn't it come out to be +- whatever the 4th of the root that is
the rate of interest can't be -2.07, that means you lose 207% of your money every year
i.e you go into debt
so we don't take that solution
we are given and before and after numbers
just 1.06....=1+r
9200 before, 12000 after
so r=0.06...
but if it's under 1, doesn't that make it go down
if it's negative, that is what makes it "go down"
no, it is exponential decay if the rate is under 0
you're confusing two different things
(1+r)<1 implies exponential decay yes
in other words r<0 is exponential decay
yeah. and in this case the base is (1+r)...
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i got the answer but
i dont understand how differentiating g1 with respect to t finds f_xy
you could write it with (y) instead of (t) as [g_1 \colon y \mapsto f_x(0, y)]
Invariance
does that help?
yes but i dont understand why differentiating wrt to y would still find f_xy
cz like
if you took the partial derivative of f_y wrt to x then u wold get f_xy
well i i dont understand the significant of making the x component 0 basically
it doesn't matter
*significance
you can set x = 0 before or after differentiation
either way you treat it as a constant
so it doesn't make a difference
why tho cz wouldnt setting x = 0 get rid of some y terms too
wouldnt that give u an entirely different expression
eg the 4x^2y^2
in f_x
You'd get rid of those anyway. Using that example, if we set (x = 0) first, we get
[\frac{\partial}{\partial y} 4 x^2 y^2 \to \frac{\partial}{\partial y} 4 (0)^2 y^2 = \frac{\partial}{\partial y} 0 = 0]
and if we set (x = 0) after, we get
[\frac{\partial}{\partial y} 4 x^2 y^2 = 8 x^2 y \to 8 (0)^2 y = 0]
the order doesn't matter because partial differentiation by y treats x as a constant
so if we have a specific constant in mind, it doesn't matter if we set it before or after partial differentiation
it would matter if we were differentiating by x, though, for the reasons you state
it's only because of this property that we get away with it
Invariance
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hi
i have issues
with the formula
with y-axis and x-axis
on a rotation
what the diffrent and whats the formula for both when its about the volume
and rotation area?
Where are you getting volume?
What volume?
of the rotation figure
Let Ω denote the area in the first quadrant between the line y =
16 and the curve y = x^4. When the curve Ω is rotated one revolution around y-
the axis forms a body of rotation. calculate about the volume of the body.
like this
Ah so early calculus
There's different formulas based on the axis over which you are rotating
yes i know
i want all of them
but the rules
is typed
diffrent
online
iam confused lol
Where?
Where
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Can someone please explain to me the Tan, Sin, Cos A and B things? How do I know for future reference how to know which side is the opposite/adjacent?
This is taken directly from yesterdays notes from my class.
A is one of the angles on your triangle. You can see it notated in black ink
The "opposite of A" is the side that isn't touching A.
The "Adjacent of A" is the side that is touching A, and isn't the hypotenuse
The hypotenuse is the longest side of the triangle.
[in your picture, the red is in reference to the angle at A, and the blue is in reference to the angle at B]
Oh, alright. I was a little confused because in the previous page it was just explaining how to use Sin Cos and Tan, and then it just immediately jumps to this. It felt like a huge jump.
Thank you :D
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I have a vector in R4 and I want to find the basis of this vector.
The vector is {[a b c d] | a+b+c+d = 0, a = -c-d}
So, Ive been having some problems checking on how to find the span of this vector. I did b = -a-c-d and for a = -c-d, i plugged that into [a b c d]. But when i try verifying with other values i get different outputs
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.
It was a quiz so i cant really show it... i dont have the paper
what was the original question though?
.
Looks like a subspace of R4 and asks for a base for the subspace, ig?
yea
how i do it is:
apply the constraints, seperate the variables, factor out the variables, write the span and then check for linear independence
But im getting stuck on applying the constraints. Not sure if im doing it right
you just row reduce the matrix for those equations
Yea i know but im stuck on applying the constraints like i said
what constraints?
no, you just solve the system of those 2 equations
Those are rules that the vector needs to follow, in order to be a member of the subspace
yea thats what im doing no?
yea i got the same thing
Lemme fix that
that's not right
but then i somehow got 0
It is isn't?
so ik i made a mistake
no, b = 0
-(-c-d)-c-d = 0
so we should have 3 vectors right?
if we do c = -a-b-d and a = -c-d and then expand and simplify a we get a = a+b
so we have 3 variables a,b,d
Thanks for catching the miss btw, much appreciated
what am i doing wrong here
why is b 0 for this case
It is. You cannot find a vector satisfying all constraints with nonzero b
im just not sure what im doing wrong
If you solve the first restraint for b
And than plug in the second restraint
It will give you b=0
yes im talking about if we solve the first one for c
Well you have to chose 2 of the components as parameters, since with two constraints in R4 the subspace is 2-dimensional
Can i actually show you how I would do it when solving the first one for c?
It doesn't matter which two you chose, as long as it isn't b (because it's zero)
Sure
So c = -a-b-d and a = -c-d
Is the correct that the vector now will look like:
[ -c - d
b
c - b
d]
Where did you get the c-b from?
I see
But that immediately gives you b=0
Since in c=c-b you can simply subtract c from both sides
well could i not also just write the augmented matrix of the 3 varibales and solve to see linear independence
Sure
all 3 cols have pivots
unless im doing something wrong.. it seems as we have different answers
Can you show it?
I'm not sure if I know what you are trying to do here. Where did you get the matrix from?
You can try solving it your way because it’s the same way you did it when solving for b
I can't follow
Like just try solving it yourself and see what you get
I get the exact same thing as above with a different matrix.
Could you show your work?
It'll probably be sideways again, tho... : <
It’s all good lol
Since c and d don't have pivots I can choose them freely.
b does have a pivot and must be 0 since the last line is 1b = 0
a does have pivot, so it isn't free either it is determined in the second to last line by the chosen values for c and d and the calculated value for b:
a+b+c+d=0, where b=0 and c and d are a chosen.
Give me a minute
ok
You went from (-c-d, b, c-b, d) as a vector, ig?
yea
I think the problem here is, that b shouldn't exist at this stage anymore
how tho
Hm! Sorry : (
ita ok hah
: )
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Using Rieman Sum approximate the double integral of x^2 + 4y Da
Where the integral D is region inside the upper unit semi circle centered at the origin (inside the circle, above the x-axis). I want you to approximate this using a polar Riemann sum, dividing theta into 6 sub divisions, and dividing r into 3 subdivisions (so there will be a total of 18 pieces). Use the point with minimum theta and maximum r in each subdivision piece as the point you put into the function.
So far i got:
delta theta: pi/6
delta r: 1/3
lim (m,n goes to infinity) i= 1 sigma m = 6, j= 1 sigma n=3 of F(rj, thetai)
I'm not sure what to do for this part of the question:
"Use the point with minimum theta and maximum r in each subdivision piece as the point you put into the function."
I'm assuming that I go from pi/6 to 5pi/6
and for r I go from 1/3 to 1 for every pi/6 upto 5pi/6?
@royal crest Has your question been resolved?
I'd consider drawing the division. It's definitely not easy to keep track
@royal crest Has your question been resolved?
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can someone tell me why or how this is even wrong?
can u show working?
Remember to use absolute values where appropriate
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Hii js a quick intro - I've started calculus and I've realised how abysmal my algebra skills are 💀 could you please help 🙏
How in the world do you get
(1/2)x^(-1/2) = 1(2sqrt(x))
its 2sqrt(x) or 2/sqrt(x)?
this?
Ohh ok Ty
I’ll defo be back for more 💀
How do I differentiate this
give me a second
You can do this because there is nothing above in function of x, because otherwise you should use the formula for divisions in the derivatives, I don't know if you understand me because I am using a translator.
nothing as a function of x in the numerator,It would also work with constants since you can take them out from the derivatives.
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Ty
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The polynomial P(x) = ax+ 3 satisfies the equation P(P(P(x)))−3P(x) = −2x for all real values
of x, find all polynomials that satisfy this equation.
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im really confused
if the following equation doesnt have an x intercept
in abs only positive value are the outputs
wha
absolute value
yea...?
so how a function that has only positive output values have a negative value?
OHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
omg i love you so much thank youuuu
welcome
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Given is a rectangle ABCD. Let a = AB, b = AD. On the side AB is a point E, on the side AD is a point F and let AE = 2/3a and AF = 1/2b. Where on the line FE should we choose the point G so that the rectangle inscribed in the pentagon DFEBC with the intersection at G and the sides parallel to the sides of the original rectangle, will have the maximum area?
i think its c
...
Draw a diagram
yeah I wanted to send but this guy sent his question like its his channel
Looks like he’ll be banned soon anyway
so like this
Im guessing I need to form a function for something and then find the maximum right
I thought maybe it has something to do with ratios of the sides
Yeah I believe you need to describe the area of the inner rectangle in terms of a and b
The BC side of the inner rectangle will be the difference in y component of G and E subtracted from b
You can do something similar for the adjacent side
@stray rock Has your question been resolved?
@stray rock are you still stuck?
I am
I had to eat in between also, so thats why I was gone sorry
but yeah idk how to do this
Can you do me a favour and redraw the diagram with A and C swapped
you want me to flip the whole thing?
Lets call the area you want to maximise A=L*W
yep
L is gonna be the horizontal side
We can describe L in terms of G and a
Since L is just a - Gx
Where Gx is the x component of G
Right?
Yeah, which would be?
b - Gy
Yeah
Now as for G, it lies on the line connecting F and E
So we can describe it as (Et, Ft) = (2/3 at, 1/2 bt)
oh so like multiplied by a factor t
Yes
alright yeah
then we rewrite A with the new G
so we replace Gx and Gy with those?
okay wait I have a slight doubt
with this step
so you just described G with those coordinates?
Yeah though, you may be right in spotting something dodgy there
You are right, it is wrong
well
Give me a second to think about this
in your case
t just has to be <=1 then right
for it to work? or is it completely wrong
ohhhhh
no but is it really wrong?
Yeah, it wouldn’t be lying on the line, it would be a region
oh yeah true
I think instead it should be G = F(1-t) + E(t), taking a and b as vectors
Then when t = 0, G is at F
t = 1, G is at E right?
okay but cant we do it without vectors?
if EB is 1/3a
and FD is 1/2b
that means both of those are being stretched right
one is being stretched, and one the opposite
I’m not sure I can see where this is going
well when G is at F
the sides of the rectangle are 1/2b and a
when its at E the sides are b and 1/3a
maybe something with that? sorry im just kinda bad with vectors
Yeah that is the L and W we had earlier
It may be possible to get the equation of the line FE in terms of a and b
Under the assumption that A is fixed at the origin
Then l_FE would be given by
y = mx + c
y = (1/2b * 3a/2)x + 1/2b
Hang on
okay wait no just quickly I actually dont understand, how did you get m?
okay
[ y = - \left(\frac b2 \cdot \frac 3{2a}\right)x + \frac b2 ]
shsgd
It’s a bit hard to describe G with this though
Which is why vectors work better i’d say
Because we have this as G= (b/2)(1-t) + (2a/3)t
= 1/2 b - 1/2 bt + 2/3 at
Hmm
Vectors may make this a bit weird since a and b now have 2 components
there has to be a way to just do it geometrically
The only problem is describing coordinates of G
well
what about what we did before, with the t right
if you stretch 1/b with t
if t is 1
then you stretch 2/3a with
like it has to be something like (a - 2/3a*ct)(b - 1/2t) where c is some number?
yk so that then it wont be a region like you said
That would just be this, no?
Where t is in the range 0-1
yeah but lets do that for this
Well what would the coordinates of G be in terms of a, b, c and t then?
(a - 2/3a*ct, b - 1/2t) this?
yk what I mean like if you stretch 1/2b you ahve to stretch 2/3a by the same amount no?
so can we use that then?
1-t as c
or I mean like as
a - 2/3a(1-t)
and then b - 1/2t?
if not then im out of ideas
That would be this
yeah so why cant we do that there
here
It changes a bit since length and width are scalars
G = b/2(1 - t) + 2/3 at
= 2/3t a + (1-t)/2 b
A = l*w = 2/3t * (1-t)/2 = t - 3t^2
This is why I initially said it may be better to flip the diagram, since then A = Gx * Gy
A’ = 1 - 6t = 0 iff t = 1/6
Then we would get G = 1/6 * 2/3 a + (1-1/6)/2 b
= 1/9 a + 5/12 b
Possibly
I have the answer here if you want it
Yeah, go on
Can you send the diagram again
I need to go get some paper, can’t do this in my head give me a min
@stray rock can’t seem to get it and don’t see where i’m going wrong
it's alright
i didnt get the question
oops ok
really?
Yeah
Since G = 2/3ta + ((1-t)/2 )b
Then t = 1/4
G= (2/3)(1/4)a + (3/4)/2b = 1/6a + 3/8b
So A’ = 1-4t
okay tysmm
A = t - 2t^2 + c
If you backtrack a bit and don’t mess up the vectors, you’ll be able to get it
Again, I think it would help to flip the diagram
Sorry I couldn’t fully help, but hopefully you get the idea
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yes using calculator machine
Hit the cos button and type in the angle
you see that cos button in the middle
oh
also make sure your calc is in radians mode
ohhh