#help-27
1 messages · Page 380 of 1
yes, but i don't get how it relates to my question. it seems like an unrelated fact
it’s not at all unrelated
i can understand that, i just don't understand how
we first compute lim |a_{n + 1}/a_n| and after simplification we found that the limit equals
|x - 2|
do you agree with this so far?
yes
ok and the ratio test tells us that if this limit is < 1 then the series for a_n converges
since we are interested in where our series converge we should therefore set our limit < 1 to see what values of x make that inequality true
doing so leads us to |x - 2| < 1
we rewrite this as
-1 < x - 2 < 1 <—> 1 < x < 3
so we know for sure that the series converges in this interval then we check the endpoints to see if it converges there as well
you’re wondering why the radius is 1?
the radius is the distance from the center
the center here is 2
|x - 2| < 1 means all points within a distance 1 from 2
youll notice that for any power series we have some |x - c| term after our limit computation
and the limit will always be of the form L * |x - c|
we want this to be < 1 so we get
|x - c| < 1/L
1/L would be our radius
note that if L = 0 then
L * |x - c| < 1 always holds since 0 < 1 regardless of the value of x so our radius would be infinite in a sense
and if L = inf then L * |x - c| < 1 would only hold if x = c
every power series converges at its center (since we’re just summing zeros)
🔥
she hugged me and I got tingles from it
interesting
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How do I do number 5? I dunno what they mean by secant line 😭 😭
the line that goes through the 2 points
find a line of the form y = mx + b
that passes through the points (x1, f(x1)) and (x2,f(x2))
In the previous problem you already solved what is the value of "m"
yeah for the slope
do i have to do point slope form?
You can do that too, but its arguably easier to just find the value of b based on some of the two values of x1 or x2
$$f(x_1) = m x_1 + b$$
$$f(x_1) - m x_1 = b$$
And you already know what f(x1), m and x1 are.
you could do the same with x2, and prob you would be inclined to check with both just in case, both should give the same value for b.
go ahead
in the picture i included it showed a table at the bottom, for number 9
freak no
sorry number 6
the table is for problem no. 6
and questions 8 and 9 are:
-
Where is the rate of change constant?
-
Write the equation that represents the average rate of change
To be really honest, youre probably a few classes away from knowing about derivatives and these problems are more suited for it. But we can do it with the avg change of rate too
ngl, this is my final review packet 😭
oh, lmao.
yeah rip
Well, anyways, dont worry about it. We will work under the assumption that the avg rate of change is taken in ranges of length 1
mkay
I hope you see that all ranges go from a to a+1
yeah
Now, for 8, we would like a range that as a avg. rate of change of 0
wait sorry, what does that mean
im honestly so sorry, im kinda sick right now and all of this is a different language, i swear im smarter when unsick 😭
To be really honest, the question is a little ambiguous on words. I wont bore you on the why, but this function doesnt really have any place where the rate of change becomes actually constant.
for context, this is a first semester ap precalc packet if that helps?
But im mostly working in that they meant for a place in the function in where the avg rate of change is 0, aka, it says as is in the bounds of a range.
thats what im sayinnng, i literally dunno what they mean
yeah that would make sense
in another words, we would like the following:
remembering that all ranges go from a to a+1
$\frac{f(a+1)-f(a)}{(a+1) - a} = 0$
I wrote it with parenthesis to make it obvious, but the denominator obviously simplifies to 1
And since the only way a fraction is = 0 is that the numerator is also = 0, then we can ignore the whole denominator part even if it wasnt 1.
okay, im gonna ask my teacher on monday just incase but i think you have it right so far
yeah sounds right
knowing that our f(x) is 4 - x^2, you should be able to find a value of a that satisfies the equation.
remembering that here, a is the value that determines the range [a,a+1]
go ahead
do a screenshot prob
Well, first
Any given polynomial of degree "n" has n roots too.
Open to multiplicity
yeah i'm ngl i don't understand
yeah, the power right?
kind of
the biggest power
Nope, thats the degree of the polynomial
whoops
for example, x^4 - 4x^3 + 6x^2 - 4x + 1 is a degree 4 polynomial
yeah
There is a really important theorem literally called the Fundamental Theorem of Algebra
I wont bore you with the full detail
guys why did my teacher not teach me this 💔
But the tl;dr is that a "n-degree" polynomial will have n amount of roots. > down to multiplicity
So, here, this polynomial will have 4 roots.
oh yeahh, i remember that, we just did not get the name or anything
And just in case, the roots might be either real or complex.
yeah cause -3i is one of the roots
in this particular case (cause i wrote the polynomial myself) this only has 1 type of root.
x = 1
but this root has multiplicity 4
thats because, if we factorize the polynomial, we get (x-1)^4
ohhhh
so its the power the root is to when factored down
that makes alot more sense
so it would be like (x-4)^2
And you should remember that any n-degree polynomial can also be factorized into n-factors
Now, we want a 4 degree polynomial, so we are missing two factors yet
so 4 factors
One of them is already given to us, -3i
So we have:
$(x-4)^2(x+3i)(x-a)$ where a is our missing factor/root
You will agree that (x-4)^2 is entirely real.
Yep, you appeal to diff of squares to argue that you get no complex coefficients
depending on the problem, they will prob ask you to expand the factorization
Which, yeah, takes a bit.
alrighty, that twas my last question, tysm!
np, good luck
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This quesiton js tricky
For (c), I was able to obtain N11.9E however AI got a different answer
,rccw
I'm not sure if I'm in the right headspace to understand this rn, but any time you have a discrepency with another source, please show the full working of both you and the source
This question has a lot of steps you need to take, so please do what Hanako said and show your working
@limpid lance Has your question been resolved?
@limpid lance Has your question been resolved?
N12.9E sorry I forgot
AI’s answers
Let’s compute it cleanly and give the numerical bearing.
1. Resolve velocities into components
Take:
- East = +x
- North = +y
Athlete A: 3 m/s at N30°W
[
\vec v_A =
\begin{cases}
x_A = -3\sin30^\circ = -1.5
y_A = 3\cos30^\circ = 2.598
\end{cases}
]
Athlete B: 2 m/s at N10°E
[
\vec v_B =
\begin{cases}
x_B = 2\sin10^\circ = 0.347
y_B = 2\cos10^\circ = 1.970
\end{cases}
]
2. Relative velocity of B with respect to A
[
\vec v_{B/A} = \vec v_B - \vec v_A
]
[
\vec v_{B/A} =
\begin{cases}
x = 0.347 - (-1.5) = 1.847
y = 1.970 - 2.598 = -0.628
\end{cases}
]
So relative velocity points E and S.
3. Direction of separation at closest approach
At closest approach:
[
\vec r_{BA} \perp \vec v_{B/A}
]
Thus, the direction of (\vec r_{BA}) has slope:
[
\frac{y}{x} = -\frac{x_{v}}{y_{v}} = -\frac{1.847}{-0.628} = 2.94
]
So:
[
\tan\theta = \frac{x}{y} = \frac{1}{2.94}
\Rightarrow \theta \approx 18.8^\circ
]
This angle is measured from North towards East.
4. Direction athlete A must take to intercept B
Athlete A must run along the line joining A to B, i.e. along (\vec r_{BA}).
[
\boxed{\text{Direction} = \textbf{N }19^\circ\textbf{ E}}
]
✅ Final Answer
[
\boxed{\text{Athlete A should run in the direction } \textbf{N }19^\circ\textbf{ E}}
]
If you want, I can also show:
- A labelled vector diagram, or
- A short exam-marking version (3–4 lines).
S
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
I have provided my full working, can you help please?
@limpid lance Has your question been resolved?
@limpid lance Has your question been resolved?
!noai
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).
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Is this correct way to show? i havent done one in so long
yep
so even the arrow is right?
It's an inconsequential detail, no?
I mean sure? But I'd personally not format it that way
I write it more like a => than a ->, but oh well, I don't think it matters that much here
,tex \begin{align*}
\int_0^2 (x + 1)^{-1/2}\dd{x} &= \int_1^3 u^{-1/2}\dd{u} \tag{$u = x + 1$} \
&= \frac{u^{1/2}}{1/2}\eval_1^3 = 2\sqrt{3} - 2 \approx 1.464
\end{align*}
Can TeXit not do align environments lol
jewels!
(Looks better on a document)
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thanks
.reopen sorry, i wrote it like this . i believe its correct now but just wanna double check
✅ Original question: #help-27 message
looks good 
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Why is the chain rule being used here? Am I misunderstanding theorem 2?
Does it have something to do with the du/dx in part b? I get pretty lost with that notation
i see
the ‘u’ there is 2x^2 + 1
oh I see is it like d/dx * u = du/dx? maybe im dumb but i feel like that could have been more clear
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not sure about
Just plug in the point (3, 1/2)
Yes
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how can i find the coordinates of the red dot
Are there any measurements or is this more of a proof?
!xy
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
the angle that the y line makes with the blue line is 22,5
english is not my native language
do not call me "bro".
Yeah it wasn't about that
also yeah it wasnt about language
it's that you gave us only pieces of the problem and not the full thing
can we have a picture of the full problem? we need to be sure you didn't miss anything else.
im tryna design a centrifugal
for a jet engine
i have to put some weir angly things
i need the cordinates to do that
Did you find the problem in a textbook/worksheet?
no
i tried to do it like this 300x=22,5.360
im kinda dumb
What's 22,5.360
The angle that the y-axis makes with the dotted blue line. is 22,5
i tried to do it like that if 360 degress equals to 300 whats 22,5 equals to
yeah i have to ask this to my teacher
360 degrees equals 300
the circumference of the circle is 300 degrees
3.2.50
turkish
Can you post everything in turkish
Because the translations don't do much good I am afraid
çemberin yarıçapı 50cm ve kırmızı bir nokta var bu nokta bu çemberin 22,5 derecelik kısmına denk gelen şeklin ucunda yer alıyor pi sayısını 3 olarak alacağız kırmızı noktanın kordinatları lazım
I tried redrawing the graph based on the information given.
The radius of the circle is 50cm, and there is a red dot at the end of the shape that corresponds to the 22.5-degree part of this circle. We will assume the value of pi as 3. The coordinates of the red dot are needed. (I guess this is the translation)
||you lost me at assuming pi = 3 :(||
"assume the value of pi as 3" yup, definitely building a jet engine alright
im just tryna find the right solution also im not even an university student what do you expect me to do
I was joking, don't worry about it. anyway you're on the right track
Yes, this feels like a geometry/trigonometry problem to me.
ty i kinda lied im not designing a jet engine but this is a assigment that my teacher gave me
what do i do
:(
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✅ Original question: #help-27 message
i guess
i have to translate that
this thing?
Yes
don't worry about it
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I’m a second-year student at an Italian scientific high school.
Our math teacher gave our class this geometric riddle to solve. Almost nobody really tried to work it out, but I solved it using similar triangles.
At the end of the lesson, I showed my solution to the teacher, and he asked me how I managed to find the result without explicitly using the horizontal distance between P1 and P2.
The point is that I did use it implicitly, but it cancels out because of triangle similarity.
From similar triangles, I wrote:
x / 4 = (6 - x) / 6
Solving step by step:
6x = 4(6 - x)
6x = 24 - 4x
10x = 24
x = 2.4
At first I was confused because swapping the terms gives 6 - x = 3.6, but that is just the complementary height, not a different solution.
I believe the solution is correct, but I would really appreciate it if someone could confirm it and explain clearly why this method works.
also the right angle (looks like it)
oh are you talking about the one formed by the person in the middle
There is a right angle (as stated by the teacher), and the two triangles also share the angle at the intersection, so they have two equal angles and are therefore similar.
icwym
those arent similar
yeah because the right angle is no longer present
but in any other triangle I don't see the equal angle at intersection
doing it algebraically with equations of the lines on a graph, the distance between the heights cancel out
So, the only thing that wasn’t clear to me was why, if I swap the denominators, I get one value in one way, 2.4, and another value, 3.6, in the other way. And if I then subtract 3.6 from 6, I get 2.4. That’s the only thing I didn’t understand
ig what if we extend the 4 to 6, the connect it to D and extend x to that
maybe then geometrically it'd make some sense
wdym swap denominators
Here’s a photo of my calculations and how I tried to solve it
god I don't want to make a diagram, but I kinda get it
It's basically like if you extend the x to as high as 6
and x could be either the x we have, or the 6 - x above it
then the value of x you'd get is 2.4 and 3.6, which would depend on which distance you found (the height of the man, or the extra distance above him till it's 6 metres)
ooh ok so that’s how it is, i get it now, if this is the solution, thanks, didn’t get how the two proportions worked before, sorry if i stressed you out
IG it's almost like, the ratio between the 4 and the height of the man, is equal to the ratio between 6, and the height above that man till 6 metres
I can't exactly prove how though, although I do kinda see how that might work
yeah i got that, actually i realized it right away when i saw the exercise, that’s why i did the proportion, it’s just that i didn’t understand why putting the denominator one way gave one result and swapping it gave another, thanks a lot
Ahhhh no problem man, happy to help
Thanks !
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During a collision between two objects, momentum is conserved if there is no loss of energy. Thus pt = pAi + pBi = pAf + pBf , in which pt corresponds to the total momentum (in kg·m/s) and ( pAi, pBi, pAf, pBf) represent the initial and final momenta (in kg x m/s) of objets A and B. Even more, p = mv (p and v are vectors) in which p corresponds to the momentum (in kg x m/s) of an object, (m) its mass (in kg), and (v) its velocity (in m/s).
The diagram illustrates a curling throw, where stone A, with a mass of 18.8 kg, collides with stone B, with a mass of 17.5 kg.
What is the magnitude and direction of the velocity of stone A after the collision?
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Super quick question, for euler's and fermat's theorem in discrete maths, is the y != 0 always, or just for positive whole numbers, etc.?
so as in, i don't know how to define y in it, should it be "y is a positive integer", y € N, y != 0, y € Z_+, or something else?
(and is it the same across both euler and fermat*)
this page says it's positive integer for both
my lectures (swedish tbf, but still*) are saying for fermat's it's y != 0 and im not even sure for euler's
Ah little theorem
You take a prime, and smth that the prime doesn't divide
Which, by the nature of primes, means that the gcd is 1 as cooly said
so y€Z?
U_m is the group of units Modulo m
So
glow$U_m = {, y in \Z_m \mid gcd(y,m) = 1,}$
That automatically excludes y = 0
クーリー
so can I just say y != 0 and then sgd(y,m)=1 => Y^phi(m) =_m 1? (where the = is actually the triple equalsign for kongruent)
wikipedia says "any integer a" (a is y in their case) for fermat's and for euler's "a positive integer"
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combine the 2s in the numerator and denom separately first
have you tried this at least? ^
I’m doing it now
Tysm
Is it always lien this though?
wdym
I mean, yes? I don't see why not unless you wanna show the question
after all, all I see here is multiplication and division, and they are commutative
Ty
orz u 
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is the teacher wrong or what
,w increasing -x^3-3x^2+5
its increasing as long as x is negative
oh
bruh
wait i factored wrong
lol
mb

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any ideas on how to find primes $p_1,p_2,p_3$ (not nessicarily distinct) such that
$$p_1+p_2+p_3+7=p_1p_2p_3$$
ihave<skissue>
i mean a cubic (RHS) should grow much faster than somethinng linear (LHS), but how can i formalize that idea?
parity seems more promising imo
ohh
same with one 2 and 2 odds
so either all of them is 2 (fails) or one of them is 2
so that leaves you with 2x 2
wlog its p_3, so p_1+p_2+9=2p_1p_2
nah, one being 2 makes the sum odd and product even
yeah? whats wrong with that
you will get sum+odd=product
odd+odd=even right?
odd = even is wrong
what? if only one of them is 2, then p1 + p2 would be even
and even + odd is odd
yea
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Trying to get good practice in, while I understand how to solve radical equations that are like. By themselves (an example being the square root of 19+X is equal to 1)
However when you combine two radicals I start to struggle. Here’s my work and truth be told I’m just a little uncertain if I’m even progressing the first step correctly
${(a+b)^2 \neq a^2 + b^2}$
k
js for simplification, id use u = 3-2x, maybe?
yeah, it would be easier to solve $\sqrt{2u + 1} + \sqrt u = 1$
south
How did you guys transform the problem into that
use this and you'll see
and I'm assuming this is where I messed up originally? I did A^2+b^2 instead of (a+b)^2?
yes, and many other mistakes
if you don't mind I'll list them out one by one
Also is u just filling in the variable for X?
we define u = 3 - 2x
then you want to get 7 - 4x in terms of u
Yes please do. I don't mean to be a lot, but I can't understand what to do right. if I don't know where my misunderstanding starts
hi is this the help channel for high school math?
- first line should be 1 - sqrt(3 - 2x)
- even if you forget the middle term when squaring [1 - sqrt(3 - 2x)], you should get 1 + (3 - 2x)
when you square root something then square it, you get back the original expression
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
can I help?
sure thing
alroghty
i just realized i wrote the problem down wrong
okay okay and the reason I'm doing 1-square root of 3-2x is because thats the easiest thing to get rid of?
wait I can write down the sol to explain
yes, it's easier if you start squaring from $\sqrt{7 - 4x} = 1 - \sqrt{3 - 2x}$
south
don't give them the full solution though!
otherwise they won't learn anything
where did they specifically go wrong
think about what your middle term would be if you didn't rearrange it first
you'd get $2 \sqrt{7 - 4x} \sqrt{3 - 2x}$
south
@restive river
noted. I'm volunteering to teach a kid so I need to learn a few ways to do so 😭
i want it to be known that I'm still here, i'm just rewriting the problem and putting notes between each step. That way you can guys can not only see my work but track my thought process
hey so, south's method will get you there. but in general, when you're solving two radical terms, you must and must get rid of the radical by squaring the RHS and LHS. then you use simple algebra to move ahead
okay wait, sorry. I'm looking at this problem of
If you let y=3-2x, it becomes sqrt(y+1)+sqrt(y)=1. Furthermore you let y=(tan(t))^2 you will obtain (1+tan(t/2))^2=1-(tan(t/2))^2
did you forget the middle term while expanding (a+b)²?
Maybe overcomplicated but first thing entered my mind
letting y = tan^2 t..
@proven oriole are you familiar with trigonometry?
no
Then forget what I said
and now theres like 3 people all saying a variety of things
okay, then go with the remove the radical at any cost method
lemme try your way
r we serious...
where'd sqrt(y+1) come from
sqrt(1+2y), I was so dumb
So if I put in this format. Not a lot changes in my head about how to attack the problem. It’s reorder but for what? Now I’ve done a similar problem where there was a number outside of the square root sign
Anyway y=0 seems an obvious solution
Like this, and that’s how I handled it for the correct answer
So I’m a little lost on what the point of moving this one is supposed to be. And how I’m supposed to eliminate it
sqrt(1+2y)+sqrt(y)=1
your original problem has right-hand side 1 though
but okay, let's start with this easier question first
get rid of the radical
if you have 2y - 1 = 3, then surely 2y = 4
the idea is to have one side be a constant
after $\sqrt[3] {2x + 6} = 4$, cubing both sides gives $2x + 6 = 64$ as you've written down
south
right, i follow this. But why can't I just simply cube both sides for my original problem as well?
or does moving the 1 to the left, make me able to cube?
why would you cube both sides when you have square roots?
If you cube both sides then you cancel out the square roots. Which would take the problem from Sqrt of 7-4x + sq 3-2x=-1 down to
7-4x+ 3-2x=1
no
to undo cube roots, you cube both sides
to undo square roots, you square both sides
i'll write that down
\textbf{cubing} ${x}$' means you are doing ${x^3}$, whereas \textbf{squaring} ${x}$' means you are doing ${x^2}$
k
so in this case instead of cubing I'd be squaring both sides
so the problem would look like
Oh
,rccw
you must square
Sorry
${(\sqrt{7-4x})^2 = (1-\sqrt{3-2x})^2}$
k
this is what u envision, ya?
Mhm. In my head square is 2 because it’s 2 dimensional and cube is 3 because it’s 3
I just have to make sure I put the correct numbers when I do this
I apologize again for being slow to pick this up
Where's the domain restriction 😠
What is a domain restriction?
Domain restriction of $\sqrt x$ is $x \geq 0$
1 divided by 0 equals Infinity
Basically values that makes the function defined
yes, here's a quick tip why. \textbf{squaring} ${x}$' means you are multiplying ${x}$ with itself, thus the exponential representation becomes ${x^2}$, the same way the square root of ${x}$ becomes ${x^(1/2)}$ and the CUBE root of x becomes ${x^(1/3)}$ so when you square ${x^(1/2)}$ exponentially the 1/2 is multiplied with 2, which gives 1 and you end up with ${x}$ which eases your expression by a 100!
smithereens
omg why won't it type 😭
My way btw, y=tan^2(θ)/2, missed ^2, and in the end =-2sqrt(2) contradiction, I always make lots of errors
I’m not understanding where I need to define or input this. I understand what it’s saying I don’t understand how to relate it to my problem
Saving this to write down later
In some problems, you might need this to eliminate some values of $x$
1 divided by 0 equals Infinity
that only applies when you find the solutions to x
there will be a value of x which makes 3 - 2x or 7 - 4x be negative, and you can't take the square root of a negative number
you really should expand both sides first
what I mean by x^1/3 is
same goes for sqrt
lemme try
I think I got it?
Also the notes on the bottom is for something entirely different ignore that
no, you're still making the same $a^2 + b^2$ mistake
south
where's the middle term 2 * 1 * -sqrt(3 - 2x)
and why are you dividing everything by 2
where'd 1+2y coem from? if we're to write ${7-4x}$ in terms of ${3-2x}$ it'll be $sqrt{y+4-2x}$
What’s the difference between these two functions? Because if (X+Y)^2
Don’t I have to take everything inside the parenthesis to the second power anyway?
smithereens
$(x + y)^2 = x^2 + 2xy + y^2$
7-4x=1+2(3-2x)
south
what? how so?
To try and isolate X. I divided 2x by 2 and what you do on one side you have to do to the other. 4x/2x is 2x. Then I repeated it to get X alone
nvm got it
Did he really squared the whole thing?
Going to erase and back up
@steel sage that's very smart 😭 I kinda need help with high school math these days, could I dm for help?
Sure
is ${y=(tan{theta})/2}$ an assumption?
smithereens
I really like this visual but I’m having trouble understanding it. So
And I’m going to drag this question away from everything else for a moment
You do know you are in other person's channel
Do another question first
dude, do you know binomial into binomial multiplication
it's the same question tho
Still, someone's in a channel for an algebra question, and you are doing a trig one, i suggest opening a new channel and then linking your old convo into the new channel, or continue the convo there
Sorry, you are right
my bad
hey could you make the other channel? I'm kinda persistent on understanding this
How do I apply that middle part of 2XY
That’s the part that’s messing with my brain
do yk binomial and binomial multiplication?
Uhm, gimme an example problem of binomial and binomial multiplication
I don’t know what that is by name alone
for eg
${(1+x)(2+x)}$ as such
smithereens
@proven oriole
xy is x * y, you are almost there
also, you forgot a minus in the middle
I’m answering it, so you can see how I’m going about tackling it
you can use the distributive law on this
so that would be $1(2 + x) + x(2 + x)$
south
it's like how (1 + x) * 5 = 1 * 5 + x * 5
remember if you want to use FOIL, you should get 4 terms
well FOIL works cause of the distributive law
This is how I’d answer that question off my memory. But I feel like I’m neglecting a X (sorry I had to blur out mail)
where's $x^2$?
OKAY
1 divided by 0 equals Infinity
this implies that ${1(2+x)+x(2+x)}$ the same way
${(a+b)^2}$ is ${(a+b)(a+b)}$
Like I said I thought I was missing something with a X
smithereens
How does this multiplication thing tie into the division? Or the A^2+2ab+b^2
1 divided by 0 equals Infinity
fractions are basically division
you don't need to divide
when you expand,
So are you saying
instead of doing A^2 +2AB+B^2
I could do A (A+B) + B(a+b)
In my case it would look like
if you expand it fully, it's stil $A^2 + 2AB + B^2$
1 divided by 0 equals Infinity
nope, that was an explanation on why ${(a+b)^2)}$ is ${a^2 + 2ab + b^2}$
smithereens
?
expand further
Oh
@proven oriole are you understanding why we squared it?
I assume it’s -4x because the 4x is negative
And when I took it out for some reason I made it positive
hon idt you're grasping the basics of this
I’m not understanding why, but I’m understanding what is being asked of me when I see A^2+2ab+b^2. And I understand a format that I know how to solve
okay but to simplify $(\sqrt{7 - 4x})^2$ you don't need to do that at all
if you want to expand ${(7-4x)^2}$ then your first step is ${(7-4x)(7-4x)}$. tell me why.
I need to do (7-4x) (7-4x) because that's that squaring is. I'm doing multiplying that equation twice. Is that answer too simple am I missing something?
idt they're quite grasping the why behind it. you can't rely on a method to solve always if you don't know why you're using it in the first place
if i wanted to expand (7-4x)^5 I would do (7-4x) 5 times
yes, good. it is because ${x^2}$ is $x$ times $x$. you got that. now tell me when you have two terms i.e; 7, $4x$, what happens?
smithereens
i'm not understanding what's being asked here. When I have two terms, what happens? What happens when what? What am I doing with the two terms? Two terms on their own don't mean a lot.
(^ represents exponent btw not multiplication), you're almost there! in this, you're doing 5 times of 7 and 5 times of 4x and subtracting it, right
I'm saying $(7-4x)(7-4x)$, here you have two terms unlike 1 term in the eg ${5(7-4x)}$. so now that yk what to do with the latter, tell me how you will solve the former
smithereens
did you get my question
@proven oriole ?
which grade are you in btw
I'll have to leave in a few mins @proven oriole :((
@fossil locust take over
Yes, and I'm just solving the equation. I don't want you to think I don't know how to do things that I do know, because I struggle to word/explain math. Then if i show a picture of me doing the math you'll know if I understand or not.
and then I'd answer that equation
$(16x^2)$ *
smithereens
the last term
12th im trying to graduate
OH
yep and i understand why it's squared
and i understand why its positive
i rushed
in which country?
america?
ahh
the edu system is different here
12th is the last year
for us
idk how it works there lol
its the last year for highschool here too
yeah..?
no more school years?
whattttt
😭
that's the math we did in 6th grade here 😭
im in 10th rn
ok well
I can't find someone who's good with their stats :((
im happy you got it really early on, you can make fun of the dumb american sterotype in your off time. Please dont do it in front of my face
@fossil locust are you?
can you not ping me
I don't want to be involved
oh I'm sorry
you can just close this channel, open another one and show your working out
.close
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i have a quistion
how to divide (2x^3 - 4x^2 + 4) by (x-2)
do you know how to do polynomial long division in general? Y/N
ok, what's troubling you with this one
start by writing it as 2x^3 - 4x^2 + 0x + 4
i did that
$\polylongdiv[stage=1]{2x^3 - 4x^2 + 4}{x-2}$
two wuggen in a trenchcoat
after the first step, 2X^3 is cancled, but -4X^2 is also cancled
sure
im stuck here
ok then just keep going
$\polylongdiv[stage=3]{2x^3 - 4x^2 + 4}{x-2}$
two wuggen in a trenchcoat
your goal at each step is to kill the highest-degree term @flat willow
if more terms get killed, all the better, right?
you just move on to whichever one would be coming next
how did you got positive 4X^2 ?
(well, except all that remains would be 4. and you're kinda just done)
-(2x^3 - 4x^2) = -2x^3 + 4x^2.
how did you do that?
do what, exactly...?
all i did was explain how @winter torrent wrote down her first step of the polynomial division
which should result in much the same thing as what you did
multiplying 2x^3 - 4x^2 by -1
how did you get that $\LaTeX$?
i tried in $\LaTeX$ testing but i can't do it
?????
well... we're subtracting it, which is the same as multiplying by -1 and then adding
it's just easier to read that way
do you mean:
- "Why are we multiplying 2x^3-4x^2 by -1 at all?"
- "I get why this would be done, but I don't understand the execution of it."
but when we mulitiply 2x^2 by -2 we get -4X^2
-4X^2 - (-4X^2) = 0
correct
@flat willow Has your question been resolved?
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yes, Thanks
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I don’t understand where I’m supposed to go from here.
In case my hand writing isn’t clear enough. The problem is The square root of 8x+1 is equal to x+2
$\sqrt{8x+1} = x+2$, find x?
Nel
Yes I’m trying to find X
line 8 you should have 0 on LHS
What does LHS Stand for?
From 7 to 8, you did -8x
8x - 8x is not x
Gotcha
Sorry in my head since “x” is undefined it might as well equal Zero. So I don’t ever remove X because it could be literally anything
That's not at all how you should think about it
x is not undefined, it's unknown (for now)
Saying it might as well equal zero is just incorrect
What’s the difference between undefined and unknown, idk if that’s a dumb question
hii im new
1/0 is undefined
So is 0/0, 0^0, or just "infinity"
Those are not numbers
x is a variable, it is supposed to have a value
Now if the expression you're working on leads to x = 0/0 or something like that, you can conclude that x is undefined
But before that, x is simply just unknown: you don't know its value
Got it, I never had someone correct me on calling X that before
3 , 1 ?
But I can see the difference between 1/0 which isn’t possible or infinity oppose to unknown
Right... first things first: your first step was squaring both sides, but that only keeps the equivalence if both sides have the same sign
So before you do that step, you should at the very least state what range of value x can take
You do know that sqrt(x) is only defined for x >= 0, right?
I did not, no. So how would writing that down look like?
Writing what down exactly?
This range thing
Nel
That's perfectly fine to write
Now in your case it's sqrt(8x+1), so for what range of values of x is that defined?
Sorry I saw you typing and didn’t want to interrupt, but the square root of x must be greater than or equal to one in this case..? Is that a proper range? I don’t think it could be 8 because whatever X is must be multiplied by 8 but regardless of its outcome it will be added by one
If it’s being added by one it can’t be zero
You're not quite thinking about it correctly
Whatever is inside the sqrt must be greater than or equal to zero
That means 8x+1 >= 0
Can you solve this inequality?
sorry to interrupt you but i think that x may be 3 or 1
im in 10th grade and we have been taught about this
You're not the helpee
!nosols
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
I don’t want the answer, I want to know how to get there
It’s okay, you didn’t know lol
actually, you can square both sides and then use Discriminant formula
use discriminant formula to further solve it
Are you solving it? I'm not sure what you're waiting for here
btw in which grade do u study
Oh, sorry I blanked out for a moment. The answer to that is -1/8 which makes the equation not true
what?
Ok but you should write the full thing
By just saying -1/8 nobody knows whether you mean x = -1/8 or something else
In this case it's x >= -1/8, right?
Could you stop interrupting?
Sorry, yes the statement
8x+1>=0 is untrue because X equals -1/8’s
No, that's still incorrect
what the heck is this server for?
Dog just read all info channels
Why are you saying "8x+1>=0 is untrue [...]"? That's not what solving means
I don’t know what you mean by solving, I assumed you were asking me to break down the equation further. So I broke down 8x+1 then found out it couldn’t be right because if it simplifies to a negative it’s below zero
But 8x+1 >= 0 is clearly true if x is 2, for example
Let's take a step back
You are given the equation $\sqrt{8x+1} = x+2$, and asked to find its solutions, that is the set of values for x such that the equality holds
Nel
I can do that, want me to write it out and show you how I do it?
Sure go ahead
Awesome give me a moment as you gave me 3 numbers to punch in
Hello
If you want then I can help you
In simple way
?
Or I am going to sleep
Alright I don’t know how I’d punch in zero tbh. I also don’t know how this relates to what the original problem is asking
But I did it
Go ahead and sleep, it’s okay 👍
Hold on, you wrote sqrt(8 - 1 + 1) ?
Yeah
The expression is sqrt(8x+1), not sqrt(8+x+1)
Well im putting -1 in for x right?
8 and x are multiplied together
Ohh that explains why I struggled to get a similar concept
This is very basic algebra, no wonder you're struggling with this exercise
When you have an expression and you want to plug in a specific value for a variable, you need to think of it as replacing the variable with that value in parentheses
So sqrt(8x+1) becomes sqrt(8(-1)+1)
8 and -1 are still being multiplied
I thought about that but second guessed it and decided to just go super literal. I’m a little rusty as I haven’t touched math in quite some time
Just remembering a lot of rules to actually do things
Okay I can do that though
Sqrt 8(-1)+1 but would it also be Sqrt 8(-1)+1 =(-1)+2?
Yes, the other side is (-1)+2, but here the parentheses are less useful
Okay sorry for the pause
Obviously the last one is also false
Also to be super clear, I didn’t wanna take up too much paper space. So since it was real simple multiplication I then added the one each time
Oh I forgot to put on the square root over them all
Ok but the sqrt disappeared
Also be careful what the sqrt contains, here it looks like the +1 is not included
I’ll draw the lines thicker so I don’t confuse you or my future instructor
My fault
Well it also doesn't help that the line is on top of the paper guide line
Anyway, sqrt(9) does indeed equal 3
Yeah, but uhm 1 is true 0 and -1 are not.
Right, for x=0 you get sqrt(1) which is just 1, but the other side is 2, so the equality does not hold
While that’s a good skill to have in my tool box it doesn’t exactly inform me how to continue this equation. It doesn’t however REALLY help me understand what and why I’m doing this
I don’t want you to think I’m sassing you or nothin
Mhm! 📝
You're missing fundamental knowledge so I'm trying to go over it quickly so that solving the actual exercise makes sense
I appreciate that greatly
Now, when x = -1, can you tell me what happens?
Yes, and you end up with sqrt(-7)
What does this mean?
Is sqrt(-7) something you can work with?
No you can’t, there are no whole numbers that like square root to -7
If that’s what you’re asking
Right
So we say sqrt(-7) is undefined
As soon as anything in an equation is undefined, you can stop and say the equation doesn't hold
OHHH
That's where -1/8 comes in
wait that’s so sick
sqrt(8x+1) is only defined when 8x+1 >= 0, so when x >= -1/8
Do you understand that?
Now you can start solving $\sqrt{8x+1} = x+2$
Nel
You can square both sides, but you must keep in mind that:
- x >= -1/8, otherwise one side is undefined so the equation no longer holds
- both sides must have the same sign (you can go back and check this later by plugging in your solutions into the original equation)
For the second point, in this case, you can also just say that the left side is always >= 0 since it's a square root, and so x+2 must also be >= 0
That means x >= -2
But you already have x >= -1/8 so this other condition x >= -2 doesn't matter
So far so good?
Yep I’m following along
So here you got to 8x = x^2 + 4x + 3, which is correct
Then you tried to subtract 8x but did it wrong
Because I said 8x-8x=x instead of 0
Or did I misunderstand 4x-8x?
The former, yes
hi 
Hi
Gotcha
Gotcha gotcha gotcha
But even when I do it properly and 0=x^2-4x+3
How would I break this down further?
Wait actually
I can take that 3 away
Because it doesn’t have a X on it
No, you can't
Dang it
If you do that you need to take 3 away from the 0 as well
So -3 = x^2 - 4x ?
Mhm!
Ok but that doesn't really help
This is the point where you need to know how to solve quadratic equations
There are many ways to do that, one systematic way is simply to apply the quadratic formula
Another way is to "complete the square"
Yet another is to factorize, which is a lot easier when you already know one solution
What’s the quadratic formula? Formula’s are pretty simple once you remember which one you need to attach to what
,, x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
Nel
For any equation ax^2 + bx + c = 0, this gives you the x values that satisfy it
That’s a +- sign right? Meaning it can be either?
Yes, there are at most two solutions
If the thing in the square root is negative, there are no solutions, if it's zero, there is exactly one, since the plus-or-minus doesn't matter
If it's positive, then you get two, one for the plus, one for the minus
Gotcha
That thing, b^2 - 4ac, is called the discriminant
(it discriminates between the number of solutions: 0, 1, 2)
So beforehand you gave me really
Simple questions for me to break down. Can you do the same with this quadractic equation? That way I know how to properly plug in numbers into it
I can also then put it down on my note page of quadratic equations
Well you have x^2 - 4x + 3 = 0
You need to identify what a, b, and c are
Such that if you plug them back into ax^2 + bx + c = 0, you get your equation back
Okay so
Sorry let me finish writing this part down and I’m I’ll try to plug in what’s what
Now if this formula makes any sort of sense. Then A B C is the exact order the numbers appear in. Which is also why it’s so important to rewrite my equation from left to right. Something I didn’t do until now lol
Which makes me question is the X part in the A B C formula literally supposed to be X in the equation or am I missing something?
Yes it is
So in that case
Okay so that means in order to find X. I need to plug in the letters I just found into this here.
Now before I go through the effort of painstakingly do the math. Do I need to convert numbers over as is? What I mean by that is:
for example. B for me is -4x. But according to the Quadratic formula B must be negative. Do I need to make my -4x positive since I’m mashing together two negatives? What if my B just so happened to be 4x? Would I make it negative to match the equation?
Secondary question. It messes with my brain when formulas do stuff like “4ac” or “2a” but thanks to you I know that when formulas put variables tightly together like that they need to be multiplied right? With paranthesis around them at that
Ok first of all, a,b,c do not contain x. They are the values you can plug into ax^2 + bx + c = 0 to get your equation x^2 - 4x + 3 = 0
Oh that’s weird but I get it
If a was x^2 like you tried to do, you would get (x^2)x^2 + ... = 0, which is not the same as your equation x^2 + ... = 0
Then, you say "b must be negative", but that's not the case at all
Are you saying that just because the formula starts with "-b" ?
Mhm
b can be any real number
I was asking in fear of taking this far too literally
-b is just that number, multiplied by -1
So when plugging in -4, because I don’t bring down the X. I’d be doing -4*-1 to place it in that first slot
That would make it a positive 4
Yes, if b = -4, then -b = -(-4) = 4
Is my “A” (x^2) an exception to this rule or not bringing X’s into the equation? If not then what would I put in its place
Typing out my thought process here
I want Ax^2 to =X^2
But x is unknown. My gut reaction says if I want something to not change I plug in 1 because 1 copies whatever it’s raised to or multiplied.
But 2 (which is 1^2) ≠ X^2
So I just put in X by itself and drop the exponent??
Because X^2=x^2
But 2 (which is 1^2) ≠ X^2
Not sure what you mean
Okay so I want Ax^2=X^2
If I plug in 1x^2
Oh
Sorry I think I’m just wrong
I was going to say 1x^2 wouldn’t equal X^2
But I mistakingly did 1^2 instead of just leaving it at 1x^2
Am I finally ready to solve this?
c = 0 ?
Also, -4^2 is not the same as (-4)^2, careful
You do, but once you get used to it, you can skip a lot
For example you really don't need to write the (1) factors, since they don't change anything (in a product)
I’ll get to that level after a few drills of solving radicals right now I gotta stay to the basics 💪
Okay I’m not gonna send another picture of the same equation but! I did parenthesis every single thing I plugged in
This is the easiest part, now I’m not trying to find out what I’m solving. Now I’m doing the fun part of actually solving lol
If you add you get positive 3
And subtract you get !
1
@drifting sierra holy hell. I got the answer right. Here’s my work for the addition the subtraction is on another page. (As you can see I ran out of space)
But! I want to say you were great
And thank you so much for dedicating so much time to me. Not once did you make me feel bad about not knowing this or like stupid or anything
Good job 

