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physicsrocks
now incorporate the fact that the line goes thru (4,0)
how
do you know what it means for a line to go through the point (4, 0)?
it means that if you put x=4 and y=0 into the line's equation, it remains true.
you should maybe review the whole topic of equations of straight lines after this
@alpine sable Has your question been resolved?
@alpine sable Has your question been resolved?
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Oh shoot mb
Npnp
Part d, I thought it was going to be an easy question but I couldnt figure it out
I got the derivative of (x^2 + x + 1)/(x + 1) = 0
First using long division to get x + 1/(x + 1) = 0
Then using quotient rule to get 1 + 1/(x + 1) = 0
x + 1 = -1
x = 0
Did I do something wrong?
how did you get that derivative
Using quotient rule
Oh wait I see my mistake
Its supposed to be 1 - 1/(x + 1)^2 = 0
f(x) doesn't have a maximum
i assume they mean a local maximum
oh
So x = 2, sub that in to f(x) and I have the coordinates? Thats the answer?
Wait no 1 min
still need to revisit that derivarive
i recommend simplifying the function first
x = 0 and x = -2
I assume this is my max and min
What do I still need to do with the derivative sry?
Nvm I think I got the answer
Thank you!
❤️
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\
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Oh ight
What's the full question?
You need to use a different formula, Area = pq/2 where p and q are the two diagonals of the rhombus
Each diagonal is the distance from one to the opposite point so for this example
p = Distance from F to H
q = Distance from I to G
Alright
and then multiply them and divide them by two
Yea
Np
Btw I suggest you look up things you don't know, ie area of rhombus, you can look up the formula and try it yourself
Yea it worked
Oh mb
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@upper whale yo sorry to disturb but I need your help
Please don't occupy multiple help channels.
Wym
Don't ping specific people and don't open multiple channels
What's up?
Repost your question
The opposite angles of a parellogram are equal
Yup
Yeah that's fine
That's fine
The angle can't be negative, but when you plug it back in you get a positive angle
ye i got 85 now
That website checks your answer so you can submit it to see if you got the values correct
Teachers can set it to only 1 try
And a penalty is fine, it just shows what you need to review
If you only submitted just the answer to y, that's the reason. I'm pretty sure you have to submit all of the parts at the same time
Yes
o
Ight
Okay i got 8
Do i put 8 inside 8x+7 to get the angle?
8(8)+7
Why are you looking for angles?
This question has nothing to do with angles
No
So 8 is X?
You already found it
Igh
That's it
Literally what was stated before
opposite angles are equal
Adjacent angles add to 180
Did you not read what I said?
Not exactly
The sum of adjacent angles equal to 180, how can you form the equation based on that
-3z-8=180
65
And the sum of adjacent angles, how would you write that?
-3z-8=65
That is not a sum
Huh
Do you know what sum means?
It means to add
So the sum of adjacent angles means, one angle plus the adjacent one
65+58
Where did 58 come from
58 is y
You have -3z - 8 and as you stated the angle adjacent is 65, what is the sum?
-3z-8+65
-3z+73=180
Good
Solve for z
Then apply the same process with x
You have -x + 1 and the angle adjacent is 65
And the sum of adjacent angles is equal to 180
Ye
ah
whjat
oh ye
i foprgot ot add negative
57
Honestly ima just give up
i got a 96
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Anybody know how to prove \bigcap {U_i:i = 1,2,…,n} = \bigcup {X-U_i:i = 1,2,…,n} ?
Given that \tau = {U \subset X:U = \emptyset or X-U is a finite set}
I’m having a bit of trouble visualizing this
Are you studying the cofinite topology 👀
[\bigcap {U_i\mid i=1,2,\dots,n} = \bigcup {X-U_i\mid i=1,2,\dots,n}]
eulerEMILYteristic
I don't think this is true?
Like it's not true for the case where n=1
I think you might've typoed
Lemee just send the proof and where I’m getting lost
It’s beating my ass.
Ah you missed the X -
Oop my bad
[X\setminus\bigcap {U_i\mid i=1,2,\dots,n} = \bigcup {X\setminus U_i\mid i=1,2,\dots,n}]
eulerEMILYteristic
Sorry I typed that on a phone 💀
Showing that they’re subsets of each other?
okay so suppose
[x \in \bigcup {X\setminus U_i\mid i=1,2,\dots,n}]
we want to show that
[x \in X\setminus\bigcap {U_i\mid i=1,2,\dots,n}]
eulerEMILYteristic
where should we start?
Proving that x is also an element in the second one
Or am I missing something
Okay good
Btw this is just an example of ||demorgan's laws||
I was thinking that 😭
Assuming that x is an element of the second one and therefore x is an element of each X\U_i
Oh and then that x isn’t an element of U_i
I'm not sure what you mean here
We're assuming the first line and trying to get to the second line right?
So if
[x \in \bigcup {X\setminus U_i\mid i=1,2,\dots,n}]
eulerEMILYteristic
x must be an element of at least one X-U_i
yup perfect
So what does that imply
It implies that it’s also an element of the union?
Well we just did it's an element of the union => it's an element of at least one X - U_i
So we don't wanna just go backwards
Can you see anything that would help us progress towards the thing we want to prove?
That if x is an element of the intersection it isn’t an element of X\(intersection stuff)?
If x is an element of X - U_j for some 1 ≤ j ≤ n then can it be an element of \bigcap {U_i}?
No
At least that’s what I’m trying to say lol
Sorry I’m typing all this out on a phone so it’s kinda hard to do LaTex
So yeah do you see why x being in the first one implies that it's in the second one?
Oops wrong message
^
Yes
Yep okay that makes sense
Okay awesome
Is that it?
Yup it should be pretty clear how to go the other way too
But make sure you see how to do the other direction too
Also for future topology questions, #point-set-topology is a good channel to ask questions :)
Thank you!!!
I just got told to ask here 💀
Thank you for helping a high schooler with topology 🙏
Probably TTerra didn't think your question was that advanced so they directed you here lol
But I think you should be fine to post in #point-set-topology since it's from a topology book
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Can someone please explain how to solve this
can you show the whole question? :)
ah! this is classic example of the SAT trying to trick you into doing more work, the product of the roots of a quadratic is c/a :)
where c is the last coefficent, and a is the first coefficent
Oh
Vieta formulas*
Where are these things taught
My school just taught me how to do the quadratic formula
Is there any resource for this
Given a quadratic $$ax^2+bx+c=0$$ with roots $X_1,X_2$ we can say $X_1+X_2=-\frac{b}{a}$ and also that $X_1X_2=\frac{c}{a}$
the logic: $(x-a)(x-b)=x^2-(a+b)x+ab$ :)
no need for the messy expanding of radicals 
the SAT really likes to give of the illusion that questions are harder then they are, usually there's always a simple way, usually
There is more formulas of the same for cubics and quartics although idk if u need them I didn't do SAT
I remember a few of those curveball questions the first time I took it
How did you study for the math section
train for the tricks they may throw at you, manage time well, and get good at algebra, those are the methods I've learned :)
they also love to have tricks with systems of equations
I just looked online for some worked examples and applied those in some practice tests which you can find online https://satsuite.collegeboard.org/sat/practice-preparation/practice-tests/paper
oh wait sorry nvm just dumbed
yes there are plently of books 
sorry awful tired today
I have a nice 2021 edition
this one helped me with my reading a TON
@barren scroll Has your question been resolved?
@proven leaf thx so much
yw 
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Closed due to the original message being deleted
just trying to figure out how these channels work #sowwy 🥲
Arctic
not quite yet i havent taken a crack at it
ah
i just wanted to try out the latex and claim a channel
next time go here
and get a channel afterwards if you cannot figure out your problem
ahh got u! im sorry about that
its alright
the other thing; the channels always retain history?
this channel will close soon since you deleted og message
got u
ok nice! i will begin on these and probably be back soon
thanks!
oh actually just one more thing if its ok to ask u: is the forum appropriate for advanced mathematics
like analysis questions n such
i dont see a tag for those subjects in there
you mean #get-advanced-access stuff?
no like in the help-forum channel
the threads?
i never look at those lol
i bet you could ask advanced level questions there
yeah the threads
i think discord calls them posts but that
i see you can tag them by subject but i dont see any tags for advanced topics
i dont even know when they became a thing
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Closed due to the original message being deleted
you can also do .close to close
oh lit ty!
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Is it possible to solve this question with this formula y=a(b)^x for this question
Yeah, what’s your working equation
Read the problem
55000(1-7%)=37000
93% of 55000 is not 37000
@fossil mulch Has your question been resolved?
@fossil mulch Has your question been resolved?
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So what I did was f' +2g=0
g' -21f + 13g = 0
But stuck on what to do next?
Right now I'm thinking of this objectively
for this you can note that g = -1/2 f'
and then plug it into the second equation
and then you have a single ODE just in terms of f that you can solve
Can you show me what you got?
This was what I got after solving the ODE
So what i did was g = -1/2f'
and then differentiate both sides again and got g' = -1/2f''
and then substitued into equation 1
-1/2f'' -21f + 13f'/2 = 0
f'' + 42f -13f' = 0.
@real gazelle Was my wokring out right?
yup that looks correct for f
and then did you figure out what g should be?
shouldn't g be the differentiation of- exp(-7*x)/2?
Well we konw that f is C1 e^-6x + C2 e^-7x
So it should be the derivative of that, times -1/2
oh huh, I think it should be +13?
this part should be - 13f' / 2 I believe
Ahh, yes
Yeah so -6x and -7x
@rich basin do you need any more help from there
I have to go now, but hopefully someone else can help you figure out the rest if so
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whats the difference between the two
is X1 + X2 not equal to 2X
no, imagine rolling two dice
X1 + X2 would be the distribution that is the sum of the two dice
2X would be if you took the first die and multiplied it by 2
so
thats why 2X has a higher variance
cause its like ur basing the value from 1 roll and multiplying it
yeah exactly
ok
while if you did 2 rolls you're more likely to be in the middle
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hello
I don't understand this part of how they went from
this to this
what happend to the xoi?
What xoi? You also shouldn't cropped it out like that, can create confusion when you just look at your screenshot.
What happened is x_o is a common factor of every terms in the sum, so they factored it out of the sum
xoi
X0i
Yes, and what's wrong with it?
The sunf of investments are the sum of each terms x0i for i=1 up to n
Since each invesment are computed omega_i * x_0. They just replaced x_{0i} with it
Eesh
(I think it's a w for "weight", not an omega)
Is it? Haven't seen this font before
yes
wait how can they interchange it like that?
They didn't interchange anything, it's just substituting one for another.
I guess you could call that an interchange
ok can you show me some examples of where you do that? I don't know much about summation.
Well if it's confusing you why, what you are doing is essentially replace every x_{0i} term with its corresponding w_i*x_0
I.e, we are having (im replacing x_{0i} with x_i for easier typing)
x_1 + x_2 + ... x_n=w_1 * x_0 + w_2 *x_0 + ... + w_n * x _0
As you can see, both sums are equivalent to each other
@broken needle
thanks
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A logics question: If a predicate P(x) is negated, and the predicate contains logical connectives such as a disjunction or conjunction, would the connectives remain or switch as well? (Sorry if this is a beginner question)
they would switch (de morgan's law)
Alright thanks!
so if P is A OR B then NOT P would be NOT (A OR B) which is equivalent to (NOT A) AND (NOT B)
I see
alright yeo it's de morgans laws
I didn't knew it apply to that as well
Thanks!
you can't just negate every connective in a proposition directly though to negate it
you have to use de morgan's laws in layers, if it has nested connectives
i don't quite understand??
I understand that it only needs two statements and a connective
i you have a bunch of connectives like, A and B and C or D and (not B or A), etc
(for example)
you can't just negate every and into an or
and every or into an and
what would be the action then?
you'd have to bracket everything out and use de morgan's laws on each part
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I have basic question
Square root 27 is equal to 3 square root 3
Yes
but my question is why is it actually +-3 square root 3
show the original question
I know that the square root cannot be a negative number
one minut then
the question is numbered 19. and the rest below the answer I marked inside a rectangle is unrelated
Write so we have to state our restrictions first.
I don't understand what you are saying
Sometimes when we solve radicals they can be arranged such that we get an extraneous solution, which means we solved the problem correctly however the answer we found does not hold true for all of the radicals in a certain question, thus its extraneous.
Our restrictions are what x cannot be. But here we observe that sicne there is an x^2, x can be any real number and the solution will be true.
Where is the +-3. Why do you have just 3?
its +-3 square root 3 that is the answer
I just want to understand the +- sign here
I'll explain it you in a second give me a second to verify the algebra
thanks
Alright the algebra looks fine to me. Now lets tackle your question, so your wondering why is x + and - in this instance as you say a square root cannot be negative right?
yes
and its not 3-+ square root 3 because than its not multiplying right
I understand that to get 9 you can do 3^2 or -3^2
The working in here is wrong.
Uhhhhhh no Dudev thats wrong.
Because if we integrate +-3sqrt3 we see that its true
@ebon torrent Let me point out a simpler example
how is it wrong?
,,x^2 = 1
What are all solutions to this.
-1 , 1
= +-1
That's what you shouldve done here
The other thing I should point out however
Is when you are solving equations
you need to check the answers you get by plugging it back in to the original
Certain steps can yield extra solutions which were not part of the original like squaring both sides.
thats what im suppose to write?
theres a missing +-in each of the boxed steps
sqrt27 itself is positive as you identified earlier
sqrt(anything) is always not negative
yes
Yeah and if you plug it in to the solution dudev we can verify that its true because it will be 0 for either positive or negative
can I ask another question ?
I got a solution for question 20.
but it says that the solution is that there is no solution
what I did was wrong? or is it that I just didn't do this part ^ checking if its correct by plugging the nunber for x
This ties back to what I said about extraneous solutions
A good way to avoid your confusion dudev is to always plug your answer back into the original question and see if its equal on both sides. If it is then is true, if not then its not true.
so I put 39/36 for x
I already messed up actually I noticed
should have been -6 on the third line
actually it doesnt matter here
gimme a second
solved it.
I don't know how but I'm constantly fucking up on every question here
Its alright take a deep breath. We have all been there. You just don't know the process, and that is why you are constantly messing up.
Before we even proceed on any other question. Stop what you are doing. This right here will change all of the problems you are facing. Trust me.
thanks, but if I look at your sheet of paper I don't process every thing I see the way you do
A few minutes and you will not mess up on other questions, because you will know the way.
I don't expect you to, not that I thought any less.
That is why I am going to explain it to you.
thanks
Alright. So first order of business we know no matter what that a square root can never be negative correct?
yes
With this said, with any radical equation the first thing we always do is state what x cannot be. It is quite simply x can be anything as long as ensure its not negative, and we have to consider all numbers, so we use an inequality. In simple words, we use things called restrictions that says what values x can be and can't be.
I know that usually x cannot equal to 0 in my questions so far
The reason this is SOOO IMPORTANT. Is because in nature when we solve radical problems for x, we sometimes get "extraneous" solutions (A solution that does not exist). What it means is that we have solved for it correctly, but when we plug in the value that we found into the original equation both sides of the equal sign are not equal to one another which means it does not work.
did I solve it correctly then?
here
The way you verify if you solved it correctly is if both sides are equal for the x value that you solved and plugged in,.
You ALWAYS do this.
ALWAYS.
plugging 39/36 is a bit of headache
I have an interesting problem for you
Don't overthink this duvdev just simply think why is this wrong. There is no secret trick or anything. Just look in front of you.
I dont understand this part
mhmmmmmmm.
you can trust the algebra, but check if you like
I dont understand it
see this
Okay I will hint you. Just what we were discussing above. What should you do for any solution you find?
But which part exactly doesnt make sense
check if its true
if x is 1 then the solution would be 3
Does 3 = 0?
if x = 1, then we need 3 = 0
no the solution is wrong
Exactly
The mathematical explanation for this is how we define the word 'solution'
if it was 0 = 0 then we know its right because that is true
the solutions to an equation in x are all possible x values that solve the equation
Right.
That is why we always have to verify, because otherwise we are gambling essentially.
so can I ask again did I do it correctly here ?
Let's label the set of solutions $A$.
Then we want
$$x\in A \iff \text{$x$ is a solution to your equation}$$
We are not going to tell you. What do your logic tell you according to what we have just said.
if I put 39/36 for x
We will help but you have to show your train of thought even if its wrong atleast you are thinking
Right so stick that in
The implies arrows not only have to go forwards in a proof. But backwards. To show x=1 is a solution.
plugging x=1 back in is the backwards
and tell me what you get.
Squaring both sides is one of the steps that cannot be reversed with a backwards implication.
It can introduce new solutions.
I get square root ( 39/36 - 3 ) - 3 = square root (39/36)
(that was your line 2)
mk, so is that right or wrong?
so it can't be correct because on the left I have the same number - 3
Exactly
So lets analyze what went wrong
drop your image down here once again, and instead of just solving it again.
Look at process as to how you got 39/36 think about the algebra and just analyze it.
See if there was an error made
couldn't I spot that this is a trick question right from the beginning and instead of solving it just outright say that the solution = is there is no solution?
And how would you exactly do that?
this?
Yes this is the image, now observe your algebra and tell me your thought.
Observe how you got to 39/36
and then I'll give you my two cents on it.
so we have x = 4
Now how do we know thats true though?
Because we solved for it, but do keep in mind in nature when we solve for an x value we have to stick it back in to verify.
Right, so then what does that tell us for this question?
that there is simply no real solution for this problem
Because we algebraically solved it and got only x = 4 that fact will never change
Exactly there is no solution for this problem.
Lets do another problem to ensure you have the steps together
may I ?
But dudev although you algebraically solved this problem just fine. There was an easier way you could have solved it in less time.
this is my last question for this subject before I move on to the next one and I got it wrong too
if I just put any value I wanted for x that is?
Before we move on to the question, just on minute.
Observe my image do you see how I brought the 3 over to the other side and then solved for it?
what I can see I will say it in steps
What was my first order of business?
correct. And why is this important?
because the number cannot be negative inside a square root
Exactly, but also because when we solve for a solution
otherwise it wont be a real number is what I understand
Lets say we had an insanely large radical
I dont know what a radical is stil
I see that you moved the -3 to the other side of equation making it a +3
so it already wouldn't make sense in mind that this equation has a real answer
No no.
I simply just algebraically reduced the amount of work it took for me to get to x = 4
because you have the same number one is subtracted by 3 and that some how equals to the same number added by 3
what you did is correct and perfectly fine, but what I am saying is that there is an efficient way of solving these problems vs an inefficient way where you will get the right answer, but efficiency is the goal.
No you are overthinking it.
We are just speaking in terms of algebraic manipulation.
but actually the left side the -3 is inside a root
so what am I looking for just the process?
I brought that over the other side
and then just algebraically solved it for x = 4, just like you except it took me less work.
The point is being efficient what you did is perfectly fine, but when you algebraically manipulate something there is an easy way and a hard way of doing it. By knowing a few tricks like this it will save you time.
is there a meaning behind the 3 dots where you wrote no solution?
is it a math sign?
Its a shorthand for therefore mathematicians and many people use it
yep
its a math sign
alright forget about algebraically manipulating it just know what I did was an efficient way of solving it which saved time. What you did is perfectly fine my friend my point was there is an easy way and a hard way of solving it.
I understand it up to here
Good its simply just a property in algebra. Duvdev you are smart, and you don't know it. Think about the process and don't panick. Take your time to think.
not the right side as much
Okay don't worry.
So what we are doing is we are simply plugging x = 4 back in to the original question to see if both sides will be equal, and IF both sides are equal then we know the solution we found is true.
But if not then its not true.
What I did was I plugged it back in and I determined its not true. Remember for any x we find we always want to verify.
3sqrtx + 3sqrtx
yes
Well let me ask you where does x^2 + 2ab + b^2 come from?
are you confused on sqrt x multiplied by sqrt x ?
first im confused with x^2 + 2ab I learned its a^2 + 2ab
We are stating the same think, but the thing is we have different coefficients
a and b are not unique values they are just random variables we chose to display a^2 + 2ab
mk so 3 multiplied by sqrt x = 3sqrtx
What do you not understand?
I was taught that ( sqrt x + 3 )^2 = (sqrt x)^2 + 2 * sqrt x * 3 + 3^2
Alright I see let me show you something cool then okay?
ye
it might be just how im suppose to solve these equations now , and that I will learn other more efficient ways later
I have just one final question here which I got wrong as well a few minutes ago
my math teacher is an online preparation course for now
I think I understand it but not this
because you get the same number twice essentailly in the parantheses and you add them together
but shouldn't the 2 * effect the square root x as well?
nope it doesn't.
let me think of an example
then it just effects the 3
yea you just take 3 square roots of some thing and you multiply it by 2
I understand it now
that is 9 square root 9
right.
which is equal to 27
9 * 3
which is?
27
right so what I just showed was an example of why it works.
Solve it the way you know how to solve it. There is no point in spending a few hours teaching a lesson I just thought it would be nice to show you for your own understanding.
Lets tackle question 21.
thanks a lot
this is the question
Ahhhh! A big question. How exciting.
the test will be in 5 months from now roughly and I will need to learn far more complex things than this
where do you live?
Israel
Mk, how old are you?
26
no, I will be 27 by the time I do that test
No worries. Everyone has their own path to achieving success.
I'll have 2 more tests to do along side it in 2 other subjects unrelated to math
Anyways.
so far you explaining it better than a 16 year old that helped me yesterday , but he was very helpful too
he just took longer
My goal is for you to understand and although I am taking a lot out of my day to help you. I love helping others.
I appreciate it , it will probably make you better in math yourself
Thats why I do it.
Alright so it seems you have found a solution
Now what is the first thing you do when you find a solution?
I check it , but I did cheat and looked for the actual solution and saw that both of these are wrong
Mk, so look over your algebra and tell me what you think is wrong.
Think about it.
Just analyze.
Im gonna solve for it really quickly so give me a second in the meantime analyze
alright give me a second
Alright.
So is the answer just -3. Pretty sure I just want to make sure there are no problems with your textbook.
the answer is +3
double check.
where did I go wrong ?
this looks right to me I glanced over it multiple times
Honestly, I find making people solve equations with idiotic numbers to be bad teaching most of the time
so where you went wrong
is (-22 +- sqrt16) / 6
you forget to take the square root of 16
your algebra was fine.
so far every piece of this course has 50% trick questions and im suppose to get it after only solving 10 equations and then move on to the next subject
Stupid teacher. Honestly.
oh man... I keep doing that
its okay, just be careful!
I saw that it was equal to 16 and how convenient of a number it was and kept it
how could I look for it so many times and not see that
No worries
its alright, just look and think. Don't just look.
so we have x1,2 = (-22 +- 4 )/6
now write out the two possible solutions
alright.
@ebon torrent what you could do is improve the way you lay out your solutions
it helped me in hs with these issues ur having rn
So
Good advice.
-3 means its 0 = 0
See how I used the => sign on each line to say there is an implication
Right so what does that tell us?
(lmk when ur done)
well then -3 is correct
Right!
but it says its 3
The solution is wrong
100% wrong 3 is not correct.
Again the instructors of your course baffle me.
and we know that 3 is wrong how?
lets try integrating 3 into the original equation and see what integrating just 3 tells us.
I'll do it right now
kk.
exactly
now lets try plugging in the second possible solutoon we found 4 (1/3)
Of course, it happens. There are wrong answers in answer key sometimes.
alright plug in 13/3
We see that its not true, therefore x = -3 is our only solution.
yes
they messed up on that one
from like question 10 to 21 I couldn't solve a single problem on my own
I will take all I learned today with me
thanks a lot to you
coming back to math at 26 when I have a full time job and so many other things is not ideal, but many people do it so will I
lmk if ur interested - you can ping me another time/day if you want
Save this screenshot for future reference write this down on your notes.
Its alright we all start somewhere.
Atleast your are starting which is good.
yes I would love to
now?
Feel free to ping me as well dudev but save the screenshot I just sent you and apply it whenever using a problem and eventually you will be able to recall all those steps on your own.
Shuri. Duvdev he is determined and a hard worker, but learns in a certain way. The manner his instructors teach the material is taught to him is appalling. He learns in a special manner according to the content he is taught. So I had to find ways to work around and help him understand.
can we do it later today?
If you want Duvdev ping me later today as well.
I will try to help, but I think I did help a fair bit.
Now save that screenshot I sent you, and take care. Take a break and come back to this later. You deserve it.
thanks I did save it , I dont know why its explained like this. It's kinda what you get as an external student
The content you are taught or what I wrote in the screenshot?
how I'm taught
Don't blame yourself. But make sure you watch all the videos and material and think about each and every step. But lastly, learn the process. Don't do problems without learning the process of solving a problem and then jumping to another.
use the image I sent you when solving these problems and eventually the steps will be able to recall without referring to the image.
I would believe you are 14 just by your math skills , but the way you conduct yourself is impressive
I was told at my workplace that I wont be able to learn math again at my age 26, but I want to prove em wrong
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sry this seems dumb but u cant take the inverse cosine of a negative number right?
Don't worry its okay.
Its all down to how you define the inverse function
You can [-1,1]
Do you know the unit circle?
Ahhh we are seeing if the function is invertible
ye ive seen it
The issue is, that blue line is not a function.
Oh I'm high, this is completely wrong
that way it passes horizontal line test and we know we can find the inverse of a function therefore its invertible.
Yeah you can definitely take the inverse cos of anything between -1 and 1
yeah.
nope
thats undefined yes
(unless you use the extended definition of cos as a complex function)
cus cos must be -1 <= x <= 1
do you know the unit circle?
sorta i tocuhed on it
So in order to make arccos a function, this is the usual thing we do
We only let it output angles between 0 and pi radians (which is 0 and 180 degrees)
Im gonna let Shuri do the rest. Gl taro. Ping me later if need be.
okok
mhm im following
So the arccos function is a function which has domain
the closed interval [-1, 1]
and range
the closed interval [0, pi]
We could choose other ranges
but the default is [0, pi]
Like for example, the range being [2pi, 3pi] 'works' as a function
but yeah - its sensible to have a default, and thats what your calculator does too.
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Draw a near-linear space with three points.
what is a "near-linear space"?
Definealinearspacetobeanear–linearspacein whichanytwopointsareonaline. A linearspace isanincidencestructure I=(P,L)suchthat AxiomLS1:anylineisincidentwithatleasttwo points,and AxiomLS2:anytwopointsareonpreciselyone line.
whyareallthespacesgone?whatwentwrongwiththecopypaste?
there are not actually that many options for which subsets of your 3 point space you get to designate as lines
what have you tried
if you draw 3 points and try to satisfy the axioms, you should be able to get an example...
@neat void Has your question been resolved?
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REPORT
<@&268886789983436800> (spamming in multiple channels)
.close
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I'm trying to graph [
\map g t = (t-1)\map{u_1}t -2(t-2)\map {u_2} t + (t-3)\map {u_3}t ]
For which I get [
\map g t =\begin{dcases*} 0, &if $0 \le t < 1$ \ t-1, &if $1\le t < 2$ \ (t-1)+(-2(t-2)), &if $2 \le t < 3$ \ (t-1)+(-2(t-2))+ (t-3), &if $t \ge 3$\end{dcases*}]
As a piecewise representation of $\map g t$. Would that be correct?
what are these u_k(t)
Unit step functions defined as [
\map{u_c}t = \begin{dcases*} 0, &if $t < c$ \ 1, &if $t \ge c$ \end{dcases*}]
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if d(2)/dx = 5 and y = x^2 + Kx + 5 , get the value of K
is this question even right?
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is that supposed to be
$$\dv[2]{y}{x}=5$$
ℝam()n()v
$\dv{y}{x} \bigg|_{x=2} = 5$
ℝam()n()v
that?
yes
so K=1 ?
the question is correct
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.
well how is the value of K = 1
yes
did you find dy/dx
