#help-17
1 messages · Page 199 of 1
its not even a quadratic equation
i think there is a problem with this question
i asked 3 ai to do this
what
and no one got it right
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its solvable
✅
@digital lake ?
let me just
ok
how come
idk thats the answer
thats why
i think its not possible
i did this question like 4 times
@digital lake i think they wrote x squared by a mistake
?
oh
lets try without the x squared because i think its a mistake
nvm still not possible
im gonna do the verification
ok
mhm
what is the problem?
the answer
only 2?
1+1= 2
mhm
wdym
its should be a quadratic equation
ok i see
yea I just followed that to do verify
i think its just not possible
lets see
oh
to verify if the answer is correct or not, then you use verifications
and its got correct?
im doing x2
wtf
yeah
3?
$$\frac{1}{(x-3)^2}+\frac{4}{x(x-3)}=\frac{2}{x-3}$$
thats just the problem
yeah
try to replace 3 into x
now we do $$\frac{1}{(x-3)}+\frac{4}{x}=2$$
convergence
$now we get:5x-12=2x^2-6x$
convergence
yea
then its simple from here
convergence
mmh
uhhh
we already solved this?
alrihght then its done right
yeah
but his answer shows that it is x1 = 3, x2 = -4
its an error
💀
x cant be 3 at all
solved
how?
wdym
btw i tried doing it by replacing x into 3
this step is done assuming $x\noteql 3$
and it doesnt work
so its not possible?
yes
answer 3 shouldnt work
yes x cannot be 3
i see
get what?
like do u understand it
why it not x=3
no
if x=3 is a solution then we would have 0/0 case
epic
ok thanks guys for trying
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Draw the two lines in the same coordinate system
In the same coordinate system find an equation for a new line that is parralel with the x axis so that the area of the limited space = 12
2 solutions ofc
I got the answers im just stumped on how to set up an equation for it
hmm
correct me if im wrong
u wanna take this?
alr
so they gave u 2 lines
and asking u to draw a third line parallel to x axis such that area enclosed is 12?
@grand raven
Yup, 2 isoceles triangles both negative and positive
I got the answers graphically but i cannot for the life of me find an equation
wdym u got the answers graphically?
It wants an equation that can be reused lmao
thats it?
y = -5/3
simple?
I mean an equation that can be used for the same problem with different areas
thats fine
i think i have an idea
lemme try it on paper first
@grand raven is this the figure u got?
with this the area of triangle is the matrix determinant of (3+c/2,c) (3-c,c) and (2,1)
ah thats also fine
did u take variable line y = c or u just took for area 12?
with the points u can take half of det of the points and equate it to any area u want
and u can find the c accordingly
i think thats what u want
?
Yeah probably, having a hard time interpreting this, classmate got some insane set of equations
Yup hahaha
Yeah somewhat but idk if i have an equation for it
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Can anyone help me get started on this problem/give me a big hint? Been stuck on this for a long time
Need to prove QM-AM>=GM-HM for two positive integers
hmm
Maybe try making it so anything that has square root is on one side, and anything that doesn't is on another side. Then simplify it you can, let's see if we can get to anything from there
Yes, but the divisions become nice on numerator
Oh so square twice?
Or do they
after getting roots on one side
To fully get rid of square roots, but it'll be ugly
yes the correct word
im also wondering abt the signs of inequality
Here me out, I think the square root one side division one side, simplifying might be helpful
-2/(1/a + 1/b) = -2ab/(a + b)
You take the left one to right
is there a guarantee the values wont be in fractions?
You do the subtraction
then squaring will change inequality
That might be the case
So wouldn't ie be better if we simplify as much as we can before squaring? 
yes
I tried putting the square roots on one side and (a+b)/2 -2ab/(a+b) on the other and squared but things didn't simplify out
The inequality signs would also stay the same way
what was result of subtraction?
Still annoying, but looks better
Let's see what happens if we square
And take right side to left
So you'd have something bigger equal to 0
For now we don't need to expand (so like just keep in (a-b)^4 for example)
Let's see if it can be of any help
Well a^2+b^2/2+ab = (a+b)^2/2, idk if that helps
Oh I forgot about ab
So we'd have (a+b)^2/2 - (a-b)^4/[4(a+b)^2] - QM*GM*2 >= 0
What is QM, GM?
Also what is this, I didn't understand
Like left side fine, what is right side
sqrt[(a^2+b^2)/2]*sqrt(ab)
Oh ok
Since sqrt[(a^2+b^2)/2]^2+sqrt(ab)^2
You just added them
Yea
What we have now certainly looks like something
But like what thing is what we should figure out
Yeah
I was originally thinking of breaking things apart and simplifying them into squares/fourth powers, then move them all to one side to prove it must be >= 0 by the trivial inequality
I thought of that too, couldn't find an answer
I might just check the solution 😭
Let's try mixing the first two parts before QM,GM
Also valid
It'd be 2(a+b)^4/4(a+b)^2 - (a-b)^4/4(a+b)^2
What's this?
Oh okay
Yea
Trying to put the first two together
So like now let's see
If we can simplify the numerator
So we'd have
((a+b)^4 + 8a^3b + 8ab^3)/4(a+b)^2
I got a^4 + b^4 + 12a^3b + 12ab^3 + 6(a^2)(b^2)
sqrt[(a^2+b^2)/2]*sqrt(ab)
The QM,GM?
Yea
Oof
Yea
Let's look through that
Damn it's long af lmao
Ooooh
Ok ic
The first parts were good but instead of continuing to bash it we should've noticed/applied inequalities in our toolbox
I forgot this question is a proof...
We went well for like half of the way
Still good enough tbh
Yeah
İn these types of questions I feel like unless you've solved a similar question, it's not really achieveable to solve it fully
But if you can even do some part of it yourself and then learn from solution how it should be done, you'd progress
Or you do lots of experimentation
Yes that also
But like sometimes it needs a specific way of thinking
Mhm, especially in this case
Didn't notice the connection between the GM/radical and the left side
Anyways tysm for helping me 🙏
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when it says " the topology generated by the borel sets B " what it means ? The topology that make the colection of sets B, to be borel or the topology that the sets in B are open?
the second one is usually what you mean when you say generate
take the smallest topology such that every set in B is open
@rough pilot Has your question been resolved?
oh ok thank you
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Hi, Im doing a grade 12 mathematics investigation about waterslides.
Lol funny question
I need to optimise it so i need to use alot of decimals the maximise the accuracy
that is a lot of decimals
So just a linear function or what?
do you have the original problem with you
it must be in this form
I initially was going to use a interpolation calculator
but it wouldnt be in this form so
put this in Desmos and adjust the 3 sliders until it looks good I guess
That’ll be the fastest way without any calculation
this is solvable, just put the step to be 0.0001 or something :3
Just
guessed it xD
I mean the other thing u can do is use wolfram alpha to solve
So like
Forget about the t
U have two points that u can use (start and end point)
Put that in to solve for u and v and just take t as 1
Lol
If u want t just estimate another point on there
I’m pretty sure it’s doable with wolfram alpha
Unless ur teacher specified no tech
We can use tech
Yeah then just do that
would that find the values of u and v?
I mean, if u put in the value instead of x, yes
Like u know the start and end point from ur previous two functions
yes
(Also, I’ve never seen so many decimals in a function 
neither
Im gonna lose my brain
Would be easier if Ramanujan is around 😭
something like this?😭
Yeah
becz when x=4.79070543365, y should basically equal to = 10,
and vise versa
(Does it…solve? Or did it broke wolfram alpha
^ yep
I got two real answers
I guess ill try putting those values in and check if they actually work
Make sense cuz they r within a term that’s being squared
Okie
Ooooops
I shouldve assumed that would happen without the t
Pick another point
bahaha
I guess ur thinking process
Like
U picked points
"I kinda guessed through trial and error and guessed points"
So that u can solve the system of equations
im gonna fail lol
Noooooo
Like just say
Since there’s three unknowns
apparently its possible
We can solve the system of equations if we have 3 distinct known points
you have to cancel out the t though
And then go on to show process
I mean
Ud still need a third point I think
actually im not sure let me check
@wide olive Has your question been resolved?
idk
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sorry i am coming back to this. if we dont have a topology how we define the borel sets ? So then we will have the topology generated from the borel sets
borel sets are for sigma algebras, right
Just think of any collection of sets which is closed under countable intersection and union, those can be borel sets
no theyre for topologies 
hmm
Borel sets are the sets who belongs to the sigma algebra generated by the open sets of a space, If I have understood correctly. But if I don't have a topology how I define them ?
then they're just sets which belong to a sigma algebra
ig
but you can have a topology
have it generate borel sets
and then take the topology generated by those borel sets and it's not the same topology you started with
you need a topology in the first place to talk about the borel sigma algebra
yeah the topology generated by the borel sets will be in general a larger topology
both, actually
borel sets always form a sigma algebra in any topological space
neat thing about topology is that you don't need to know you're using topology for most of it :D
I see. But I read about lemmas which start like let's take the borel sets of X and then generate a topology that do something etc. But it doesn't define a first topology to specify which are the borel sets and I am confused
theyre putting a different topology on X
Yeah a topological space. But I guess I need to know the topology? Or it means this lemma for example works for any topology and its borel sets ?
damn
they're saying "Take any topological space X.
Take its Borel sets.
generate a (presumably different, maybe larger) topology from those using some algorithm.
etc."
ie. the algorithm they describe works for any such X
you dont need to know the exact sets of the topology to work with it so to speak
its just given to you when we say X is a topological space
works for any (unless they specify otherwise, like "Take an X with this or that property")
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having problems answering this problem
this is what i have, i do not know how to get F1
if im able to get k i should be able to get the rest of the questions, any hints?
i also know that F1 would equal ma but where do i get the acceleration here?
@vast shale Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185> anyone know anything about springs?
Springs?
What kind of springs?
Hmm…
i do not know how to get F1 here, can anyone help me out?
Where did you get that you need F1 from? I cannot find a single mention of F1 in the question.
Unless you added it in.
its the force i represented when the box is pushed
and displaced by 0.05m
in theory it should equal the force of the spring, unless theres another way to get it?
I was never good at physical math and more mental math. I mean like I cannot do math with physical objects or word problems and have always been better at math without objects.
I cannot help, sorry.

I hope you find help!
I think you could use the first sentence of your problem to find k?
If I interpret it right. Then the spring is stretched 0.200m when 450-g mass is attached to it means the force of gravity affects it
So you could use that information to find k?
oooh, but question tho why does gravity affect this if its on a horizontal plane?
I think it has two parts
so fs would equal to mg, but im still confused why we would use g
F = ma but when force is because of gravity then a = g so it is F = mg
i see, so i would just use g then...
fs = -kx
-mg = -kx
k = mg/x right?
wait, we need to be careful here
oohh
because spring force will be opposite to force of gravity
so you need to choose whether your positive side is into the Earth or away from the Earth
If into earth then mg = -kx
Yeah, then it would be -mg = kx
i see i see, so k is always negative?
No
Actually, the sign of k is not important now
we just care about its magnitude
i see i see
with k here im pretty confident i can get the rest
thank you!! @placid spear

Just remember to plug it in the equation to test, though
In physics, most of the time sign is just for direction
so you can always choose if you should set it to negative or positive
depends on your problems
since fs is pulling the box to the left, it would be negative right?
if we set left as negative and right as positive?
Do you mean spring force or force that push the mass to the left?
Let's say we choose this as our frame of reference
The force that pushes 450-g mass to the left is negative
But the spring force is the opposite to it so it is to the right
Means spring force is positive
spring force here
pushing the box to the right
OHHHHHH
since the spring is compressed, it wants to decompress (to the right) so its positive
Btw, the original F = -kx still works here
We don't need to think that much 😂
because it depends on x
If pushing it to the left means x will be negative
so F will be positive
ah i see it depends on x
ok ok i got it
i just got all the values for the problem, thanks man
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\begin{problem} Determine a function for $f(x) = \left|(x-2)^2 - 4\right|$ without absolute values and graph $f$ . \end{problem} So, I graphed it, but how do you determine a function for it without absolute values? Do you just make it casewise defined?
what do you even mean with "determine"
well then I suppose piecewise
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,w graph |(x-2)^2-4|
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@sand ember Has your question been resolved?
you want all conditions $x>0$, $x\neq 1$, $x>1$ or $x<-2$, and $x<-1-\sqrt{5}$ or $x>-1+\sqrt{5}$ to be true at once, since else $x$ would violate at least one of these. This means that you most likely want the intersection of all of these.
Crystopher
If it is somewhat challenging to figure out their intersection you can draw the real line and each interval on this, then find the interval where all are valid.
the intersection should be $x>-1+\sqrt{5}$, as shown in Desmos
Crystopher
Here are 3 real parallel lines drawn, the blue segments are different intervals, the red is the intersection
upper is for $x>0$, middle is for $x<-2$ or $x>1$ and the last line is for $x<-1-\sqrt{5}$ or $x>-1+\sqrt{5}$. If you 'merged' all of them you would see that the red one is the intersection.
Crystopher
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hey, so i got this new topic and i was just wondering how do you solve this, like where do i start, whats not possible and and and (its about volume of a rotational body and i think this is the way to get the volume)
this is the root function
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<@&286206848099549185>
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.reopen
✅
@red finch Has your question been resolved?
@red finch Has your question been resolved?
what do you know about integration?
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Same thing again?
find factors of -20 such that f1 + f2 = -1
Q: How long do you think I've been stuck on this exactly?```
but...
that doesnt matter to me anymore...
it just is...
ive given up all pleasures
for me all thats left in this world is me and what i am trying to do
thats all that matters in regards to attention
A:
Q: I need to know what the function represents.```
if you're really unable to factor quadratics with integer solutions, you could just memorize the quadratic formula and then put in the values that way
or even better, factor it
(x - a)(x - b) = x^2 - x - 20
which means
ab = -20
a + b = 1
Q: If you factor the polynomial, it, apparently, gives you a lot of information relating to it. This implies that A: when graphed the only real reason it extends infinitely is because that would be the representation of the function repeated endlessly, and that the function itself is not infinite.```
how do you type the messages in this format?
3 `, both at the start and at the end
oh
ikrn
I need to know what it all represents, otherwise all knowledge presented will be repetitive, and or useless.
it represents what meaning you give it
Incorrect.
you mean what ax^2+bx+c means?
Keep your questions short and concise.
I need to know the structure of the function itself.
And why it appears the way it does in response to change or graph.
If I do not have the structure, then the numbers are meaningless, just like if I didn't know it was a function, this would be nearly impossible.
there is a coefficient of x^2, coefficient of x and a constant
,w graph x^2-x-20
damn sugar withdrawal symptoms... I swear that stuff is like drugs.
its very unclear exactly what it is youre asking here
he wants to know everything
Sorry, I did not see this.
Finally, for once in my life I can focus. I am finally truly perfect... I can resist temptation... I can cancel it before it becomes a problem... My mind can finally be clear of everything... And so now I can simply process without fault.
bro whatt
Just some personal information, ignore that. I worked for quite some time to achieve that.
what is the qs here
What shall be known by you?
So, relating to this, why is it that it does not start at -20 or lower and subtract? How are the numbers being interpreted?
Q: (question)
A: (answer)
G: (guess)```
you need to sit down and actually plot one of these for yourself if you dont understand why they look like that. take x^2-x-20, pick your favourite x values, plug them in and plot the corresponding (x,y) points on some paper
done
elaborate?
thats desmos, not you manually plotting points so see why they are where they are
for x =1, y = -20
x= 2, y= -18
x= 3, y = -14
x= 4, y =-8
x = 5, y= 0
so x=5 is a root.
after x=5, y=+ve
x= 6 , y = 10
....
X^2
x
OOPS
x and x^2
wdywtk?
Why was X a combination of the x and y axis?
X was an unknown value, an input value, now what?
desmos is plotting the line y=x with blue and y=x^2 with red and y=x^2 - x - 20 with green
yeah i showed that earlier
so why are you asking this?
,w graph -x
,w graph -20
You do understand that the color of the line doesnt really have anything to do with the core concept right?
Which ive been asking for this whole time.
yes!
But nobody seems to know how to explain this probably because they forgot what it was like not to understand it so they dont have reference.
which is why teachers look insane most of the time.
because nobody bothers to remember its hard to remember e v e r y single problems points of confusion.
but who knows
that's just desmos.
please form your questions better, it's causing quite a bit of confusion
You are asking me to ask that which I don't understand myself.
I am asking for the core concepts behind how these numbers interact, are represented, and are formatted.
that does not appear in typical slang knowledge
"quadratic equations" are equations with a variable, most commonly x, with 2 as their highest power
they cannot go into negative powers of the variable, they can have coefficients attached to them
That isn't what I asked for.
I asked for
I'm sure you know what I'm talking about, you probably just don't understand the perspective of the question.
go to this to see how changing the coefficients effect the graph
try to understand it yourself
put some time into observing.
i also don't know much as i am in 9th. but i can help a little.
erm
Ok, one second
?
Does each variable take on a different representation depending on how many are added?
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can someone explain a point function using mathematical proof, that this particular certain quantity is a point function
I understood path function using area under curve. because initial and final positions are same but paths can be different.
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i tried to simplify first and then find the derivative instead of using the product rule. where did i go wrong?
You didn't send a picture
put a dot at the start
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thank u lol
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how to do this
someone help pewasse
Okay, let's do the first one
It wants you to find f(g(3))
Any thoughts?
??
Oh sorry. Was in another channel
Yes. You have it exactly right
You need to find g(3) first. Do you know how?
im not sure but i think like
3 is the input
and you find the output
yes
yes
yes. Precisely right
which is 6?
yup. good work
alr, imma do the next one on my own
g(4) = 2
f(2) = 5
is that righ
np
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it was all you
doesn't seem like it. You did that totally fine
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How do you determine which system belongs to each figure? (2 figures will be left)
by using the normal vectors i guess
Do you know what those figure means? in terms of solutions of a system of equations
Exactly, but that still doesn't help that much?
Yeah
You have equations of planes
well if the normal vectors are pairwise linearly dependent then it's figure 7 for example
They never are
Fig 7 will be left, probably
Pairwise they are
Where?
Well I don't know if we mean the same thing
I mean that in some cases two equations have linear dependencies while the third doesn't
Ah
Well I thought you meant all three are pairwise linearly dependant (thus all three linearly dependant)
Do you see how in (1), the second and third equations are basically the same, up to a displacement factor?
Ok, so figure 10 means that there is a unique solution, so is there any of the 3 systems that has unique solution?
Ok, now (2)
a solution to a simultaneous system of linear equations, by definition, has to satisfy every one of the equations. graphically, a point will be in the solution set if it lies on every one of the planes represented by the individual equations. the red sets in figures 8 and 9 do not depict points that lie on every one of the planes so they are not going to be the answers
as you seem to be starting to point out, the other figures depict situations where there are no, exactly one, or infinitely solutions, respectively, so you can calculate with those systems and see which of those possibilities you get
i guess i misspoke, the 'no solutions' case could "look like" either figure 7 or figure 8 or figure 9 graphically, depending on whether pairs of the equations have a solution or not
but the use of the red coloring in figures 8 and 9 just really puts me off, in suggesting that the red points are the solution set
Oh, true
They are just highlighting intersections, although figure 10 is inconsistent
Do you see anything?
you might have to be more careful depending on whether the red coloring in the figure is just there, or is intended to represent points in the solution set
The first and second lines look really similar
I edit some messages
You can also see that by taking the normal vectors
If the normal vectors are colinear, the planes are parallel
the more interesting interpretation of the problem would be to assume that the red coloring has no meaning
2 is either figure 9 or 11
why
Oh sorry I added a - sign in my head somehow
Might be a misprint tbh
in the case of 9 or 11 the normals all lie on some plane, therefore they are linearly dependent
No I don't think it is, it gives a different figure for each system
but since none of the normals in 2 are pairwise linearly dependent it can't be fig 8
Hm
Can you elaborate?
look at the picture and imagine the normals for 9 and 11 (and also 8)
in the more interesting case, you would look at the system with no solutions and see if every choice of pairs of equations has solutions (figure 9), only some pairs do (figure 8), or none of them do (figure 7)
you will see that they all lie on some plane, and are therefore linearly dependent
the red intersection lines are orthogonal to the plane spanned by the normals
Assuming these intersection lines are parallel (which they are, otherwise these figures would be equivalent to figure 10)
True
Yes
fig 10 is the case where all normals are linearly independent
Why "therefore linearly dependant"
I see how the red line is perpendicular to the plane spanned by the normals
because you have three vectors in R^3 spanning a 2 dimensional subspace
But I don't really know how you conclude the linearly dependant thing
They span a plane instead of the whole space
They aren't completely linearly dependent, as in all colinear, but they are linearly dependent in the sense that you cannot form all vectors with a linear combination of them
How do you know they span a plane
by the usual definition of linear dependence, a nontrivial linear combination that's equal to zero, they are linearly dependent
by looking at the picture and seeing that the red lines are always orthogonal to the normals
That's just how the figure looks
i don't have a rigorous proof in case you want one
in figuring out the picture for the 'no solutions' case (which is one of 7-9) looking at the normals is one way to do it. 7 is all the normals are multiples of one another, 8 is a pair of normals are multiples of one another, 9 is the normals are not multiples of one another, but all lie in a plane. 11 is like 9 in this last respect, but those are distinguishable based on the solution set (nonempty in 11 vs. empty in 9)
Oh
Some intuition: if you take a random set of three planes in space, you'll get figure 10
That's the general case
Wait let me just pull down the picture:
Ok, yes
Figure 9 has fewer degrees of freedom, figures 8 and 11 even fewer, then figure 7
(I think 8 has fewer than 11 but whatever)
Are there any other doubts?
When you have linear dependency, you basically lose a degree of freedom
So for 9, all normals lie in a plane
How do we deduce which system that is
Or atleast the possibilities
you take some point of intersection of two planes and check if it's contained in the third plane
So in the end, we can't say which belongs to which by just observation?
We have to do some calculation?
Might as well just solve all the systems then..?
Well, for (2) and (3), if you ignore x1, the normal vectors are all colinear
That means figure 9 or 11 depending on whether there are solutions or not (or 8 or 7 but we ruled those out)
Well but we can't just ignore x1 can we?
you don't need to solve all the systems tho
Well ok for (1) we know it's fig 8
We can just solve (2) and (3) quickly
Isn't that the "best" thing to do here
We will have to do some calculation anyways
I mean you can if you just want to build intuition
But yes you would need to actually do calculations to verify
Well then I find it's better to right away after concluding (1) belongs to 8, just solve (2) and (3)
And we will probably right away know to which they belong
Sure
Without having to argue about anything with normals or anything like that
Maybe we can "headsolve" (2) more or less
2x1 = 3 will be the second line
x1 = 3/2
The whole exercise can be answered by just solving systems of equations (of 3 or 2 equations)
Ok now -3x2 + 2x3 = -3.5 and this means (2) will have no solution
It can't be 7 nor 8
well in the case of 10 checking for linear indepence of the normals would be easier then just solving, no?
I think it's basically the same amount of effort
but the right side would just be zero
I guess but you can stop as soon as you know there is a unique solution, you don't need to compute it
It's more or less the same process
No
Why?
It's not linearly independent
If you solve it you get an infinite number of solutions
Well I guess its enough to get it to REF
Then conclude it's 11
Since free variable
It can be 10 or 11 anyways
Nothing else
Sounds right
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its the determinant of the matrix
yes
this is the determinant of a 3x3 matrix
if you want to prove it then you can use the leibniz formula for determinants
@tropic plume Has your question been resolved?
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The white is the question the green is the solution
How come in the first step they put everything over y? What is the thought / purpose behind doing that
multiplying numerator and denominator by y gives (x+xy)/(x-xy)
which gives x(1+y)/x(1-y)
which gives (1+y)/(1-y)
which can be written as
(1+y)/-(y-1)
or
-((1+y)/(y-1))
there is a easy way my friend
why complicate stuff
I understand all of that, but im just trying to figure out why did they change x/y +x to (y-1)(x)/ y
And the denominator too
Oh wait
I see what youre saying
oh ok
You did it a different way
i got it
multiply second term's numerator and denominator by y
so
x/y + (xy/y)
x+xy/y
x(1+y)/y
did you get it?
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Is my solution correct? N(x) is a function and you have to find derivative N(x)'
You can't use the product rule ?
Product rule is the right call, only went wrong when differentiating (8x+9)^2 and (6x-7)^3 separately
I did differentiate them separately. I left the power outside the bracket alone and differentiated the inside terms. Should i do anything with the power term like multiply it outside + reduce -1?
But for the derivative of (8x+9)^2 you got (16x)^2 which is not correct
I did differentiate (8x+9)^2 wrt.x and 8x+2 wrt.x separately. Does it seem correct now?
Looks good now
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Given three-dimensional space with a cartesian coordinate system xyz containing the plane v with equation x + y + z = 1 and the plane w with equation x - y = 0. The line l is the intersection of the planes v and w. The line m is the line through the point P(1, 1, 1), parallel to the line l.
Which of the following points lies on this line m?
(A) A(0, 0, 0) (B) B(0, 0, 1) (C) C(0, 0, 2) (D) D(0, 0, 3)
so i did v and w together and then i got z = 1-2x and x=y
but for the 'direction numbers (not sure if its the right translation)' i thought you could just fill in 1 for example and then you'd get (1,1,-1) but this wont work for the final answer??
parallel to m? Uh maybe you meant l here?
Yeah ur right mb
ok so you probably want to parametrize this right?
as its maybe not obvious what the the direction vector here is
yea
So if im not wrong, i think we want a line of the form (x,y,z) = Q + Vt
where Q is the starting point, and V the direction vector youre after
and t some real number
so hm can we maybe just let t = x = y ?
The line of intersection would be perpendicular to both the planes right ?
?
the line of intersection of the planes
why can’t we just let x=y=1?
Yeah how does that imply that
i dont see directly why not, but its best if you can argue why
Oh yeah thats true, we can just find two such points on the line
you just need the d.r's of l so why not just do the cross product of dr.'s of normal's of both the planes
and then we're done
so let say x=y=0 and also maybe x=y=1
then you have two points on the line
then take their difference and voila you have a direction vector
why do we always need two points
?
I keep forgetting to do it but sometimes I swear we only used one ?
If you just had one point, how would you know in which direction the line goes?
nice!
how would u do this?
you can find the dr.'s of the normal to the plane from the plane equation
cross product seems alot messier than just doing one substraction
agreed
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how do i prove rigorously that for every $a_n \geq 0$, that is converging to $a \geq 0$, i.e $a_n \rightarrow a$, that it's also true that: $\sqrt{a_n} \rightarrow \sqrt{a}$?
Ayanokoji
@manic lance Has your question been resolved?
.close
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hi
i need help
just send the question, and your attempt
that is wrong
Okay
well the arrow mark says what to do ?
rearrange the terms such that it looks like
tan(x)tan(y)=1+tan(x)+tan(y)
oh
oh
im confused
nvm
tan20 = tan 90-70
on second thought