#help-0
1 messages ยท Page 696 of 1
yes
I was wondering why isn't my answer correct
And what operators do i require to obtain the right answer and for what reasons do i need to use that oeprator for
Okay, well we know there are 8C4 different ways to seperate coats into two piles
You got that down good
Now we need to consider the total number of possobilities
Like wouldn't that be 2^8 -2
Our initial thought would be to just add 8C1+8C2+...+8C8, but there is one tiny problem: [ \binom{n}{k}=\binom{n}{n-k}.]
dackid (jump king +)
The only problem here is that you can have duplicates
But that was when i thought of dividing 2^8 by 2
So in regards to this problem, choosing to have 2 coats in the left pile and 6 coats in the right is the same as having 6 coats in the left pile and 2 in the right
,w solve ((8 choose 4))/ (2^8/2 -2)
Which still isn't the right answer
Yeah choose 2 on the left is the same as choose 6 on the left
Please be patient and let me explain
Okay, well dividing by 2 does seem like it would get you there, but there is a problem: there are exactly 9 different types of combinations if you have 8 items.
8C0,8C1,8C2,8C3,8C4,8C5,8C6,8C7,8C8.
So just dividing by two isn't going to give you 8C0 through 8C4 (which is what we want)
That all depends. Can we have 1 pile empty in this problem?
Also, 8C0 is 1, not 0
There are no division issues here
,w solve (8 choose 4) divide ((2^8-2)*(4/7))
You done trying random stuff?
Okay
Thank you. Let us assume we can have an empty pile (that is still two piles).
So we end up with the following probability [ \frac{\binom{8}{4}}{\binom{8}{0}+\binom{8}{1}+\dots+\binom{8}{4}}.]
dackid (jump king +)
And that will get you your result.
let me try that
If you can't have an empty pile, then just omit 8 choose 0
,w solve (8 choose 4) divide ( + (8 choose 1) + (8 choose 2) + (8 choose 3) + (8 choose 4))
Was wondering why can't you use 2^8 -2 but then add like some constrains
Well, this isn't 2^8-2 for one. Second off, why are you getting that in the first place?
I understand where you are getting 2^8 (which we have addressed has duplicates), but where you get -2 is beyond me.
becasue 2^8 includes the casess such as 8 choose 0 and 8 choose 8)
,w solve (8 choose 0) + (8 choose 1) + (8 choose 2) +(8 choose 3) + (8 choose 4) + (8 choose 5) + (8 choose 6) + (8 choose 7) + (8 choose 8)
Ah, okay. Well there are more duplicates than 2.
,w solve 2^8
I know that the sum of the combinations is 2^{number of items)}
I am aware of this
But we have already addressed there are many duplicates in here, so this is clearly not right.
Okay thanks
Happy to help
Hey, doing this quick probem for my homework
I'm not quite sure how to find the coordinate points for this.
Would very much appreciate some guidance here
I know how to find the terminal angle but not the coordinates
No it is the unit circle but
it'
is not one of the points that's on the unit circle explicitly
the question is asking me to calculate the coordinates idk how to
For starters, I'd use x^2+y^2=1
that'll give you coordinates *on * the edge of the unit circle.
but it's kind of unclear what coordinates you were asked to find
oh
I get it now
give me a sec
so the coordinates is (cos(pi-2.7),sin(pi-2.7))
wait you can do that
wait youre right
holy shit im stupid
i forgot how to do thsi LOL
yea
if your teacher was asking for points on the line, then there's more work to be done, but sounds like you got it from here
you're welcome!!
Someone pls help me understand z-scores
Sorry I wish I could but idk what that is
does anyone know how to solve this??
#3 and #4
Rationalize the numerator
Multiply and divide by sqrt(x+h) + sqrt(x)
You'll be left with h in the numerator which cancels out with the h in the denominator
After which you can substitute 0 as the indeterminacy has been removed
Mathematical induction
do you want to prove this for all integers n>0?
yea i did but i solved it
thanks anyways
you're welcome
49^n + 24^(n-1)
yeah showing $25|49^n+24^{n-1}$ for all integers $n>0$ is equivalent to showing the statement @slow silo wanted to prove
logician_pdx
What about it are you having trouble understanding
Whats an angle sector?
Can anyone help with how youโll complete this with fractional powers ๐คทโโ๏ธ
By that you mean simplify?
try grouping the terms and then cancelling the powers
(27x^-2)^2/3 = 27x^-4/3 = 1 / 27x^4/3 no?
for example if you have $(25x^2)^\frac{1}{2}\implies(5^2x^2)^\frac{1}{2}$
ใใใ
then you can get $5^2$ and $x^2$ together and cancel the 1/2 power
ใใใ
so in the end you remain with 5x
let them try first don't give the answer directly
no problem
,w sqrt(3)sin(x)+2cos(x) = 1
the answer is a bit less than 2, so yes
but i dont rly know which part of it is wrong
a^2 != 3^2 to start with
The previous question hasn't been solved, this chat is occupied.
sorry
no, you are going in the right direction
your answer is correct
tho, thats not the general solution to sin(phi + theta)=1/sqrt(7)
In a packet of spaghetti, one-third of the strands of spaghetti are intact, but the rest have been snapped into two pieces. of all the pieces of spaghetti from the packet (broken and whole), what is the largest fraction guaranteed to be at least as long as half an unbroken strand?
can anyone help me?
oh you are solving for theta in [0,2pi]
then you still need the general solution
to figure it out
This chat is occupied, the previous question hasn't been solved.
like i said tho, you are going in the right direction
which general solution?
Since x is in [0, 2pi>, why do we need a general solution?
to figure out the solutions in the interval?
Right, but there are finitely many, it seems kind of redundant.
i mean you could also get two terminal angles and then add 2pi periods to it
either way is fine
i am confuse
We can probably use the fact that sin and cos are injective on this interval.
Calculate the surface area of everything but the slope and multiply by two.
do i need to calculate the slant height???
that doesnt really work, either way you would still be adding 2pi to the solution you get to figure out the appropriate solution
u mean to find the reference angle first?
yes
well not exactly
but yes
a reference angle by which you can add the periods to, to get the solutions in the interval
its inevitable whatever way you do it
but isnt my ref angle 0.3875
ohh thats not the working for ref angle?
do you remember that sin(x) = a for -1<=a<=1 has two solutions?
yea
those two solutions are x=a and x=pi-a
this is me not referring to the general solution btw
for now just take them as your reference angle
also next time, dont approximate your answer till the very end
we'd like to have the least error in calculation
you are still not getting my point
you are supposed to take the reference angle and add 2pi to them
until you exceed 2pi
the angles you get during the calculation that are in [0,2pi] are the accepted ones
Iโm not sure

Woah mate, atleast some of these lol
send answers priv
1st) substitute 3 in place of x , if you get 0 then that function is divisible by (x-3)
Send it here
I can tell you how to do it, won't send the answer ๐
You gotta try mate, otherwise you won't learn
This isn't an exam, is it?
Seems so
isnt this just a) x = 5 and b) x = 6
yes
bruh
He's having an exam lol
I prefer you to not help him now, not being mean or something... it's for his own benefit
most of the questions arent that hard
Yep
my point wasnt to help him
it was to say
how tf do u not know the answers to those quesitons
i mean not judging
Oh lmao, I get it now
but... grade 11
Hmm but on the contradiction the questions are too easy
I am in grade 11 myself
and I used to get these questions in exams when I was in grade 8th ๐
i j finished grade 9 and ik more than half of these
yep
Can someone explain me derivatives of function in easy language?
how familiar are you with basic physics?
Derivative at a point or the derivative in general?
The derivative at a point (x, f(x)) is the rate of change of the function f at that point.
Big number => function grows quickly.
Small number => function grows slowly.
Big negative number => function falls quickly
Small negative number => function falls slowly.
Zero => function does not change.
the derivative is basically the best linear map that approximates the function input around x mapping to the output around f(x)
I believe OP asked for a description in easy language.
well this is pretty easy considering the context in multivariable calculus
the op didn't mention if the function is a single variable function
i can teach you how to complete these questions (long division), however i do not see what gain anyone gets if i do them for you
if you wanna learn yourself what youll need to know is: factor theorem, remainder theorem, polynomial long division
are a and b parallel? what proofs can I input to justify my answer?
Yes they are both 180 degrees
is there, like, a proof for that? a theorem perhaps?
I forget what the angle is called
these proofs are the only ones that are given to us
and I don't see anything that fits
We know it's 180-69 so it it 111
but that doesn't prove anything, does it?
It's basically the Converse Of The Alternate Angles Theorem
Interior
but for it to be "alternate interior", both angles should not be adjacent, right?
and they're not even.. interior angles.
do you really know the topic
Ok
I was wrong about the interior bit
But they are parrrrl
If the angles remain the same
The lines will
wdym remains the same
Since we have the line intersecting the alternate angles then we know the angles are the same
yo not to be rude but
the things you're saying,, doesn't make sense
i mean, it's good that you're helping me but
don't just answer to questions that you don't really know
some kid might believe you immediately without asking for any reasons lol
and that could result to confusions
<@&286206848099549185> can someone help me w this
i'll just post the image again so u don't have to scroll up.... someone answered and just made me confused lol
"are a and b parallel? what proofs can I input to justify my answer?"
Not sure how you can reason stuff about line b without assuming b is parallel, since FCZ patterns require them to be parallel
hm
i think we just need to prove that a is parallel to b and vice versa using these proofs. but since i don't see anything that fits, do you think it means that they're not parallel?
no they're clearly parallel.
why do you think they're parallel?
i mean a might be 1 degree slanted towards right
like, the main task is to determine whether they're parallel or not
and we didn't tackle about FCZ patterns so that might.. not be it
Im aware it is...
however like I said, FCZ stuff requires they be parallel
is it, like, the only way to prove that they're parallel? the FCZ stuff?
Not sure, I only know FCZ patterns for angle congruence
hm
oh wait.
this satisfies one of the proofs now
i used the vertical angle and alternate interior theorems
what do you think
since the two lines are intersected by a transversal, and the alternate interior angles are congruent, then they are parallel?? bc of Converse fo the Alternate Interior Angle Theorem??
not sure lol idk what im doing
How do you know this is true without assuming the lines are parallel?
Yeah, you cant deduce anything about b's relation to a from only knowing stuff about a
dlkfjdal it's an error maybe, i'll ask my teacher tom... im tired wanna sleep :()
That sounds like a good idea.
Yeah I got the same thing
express x in terms of p, given the fact that p = ln(x), do the same for y
Need to keep applying log rules
Specifically there is one about products and one about powers
Apply the product one first, then the power one
What is I?
Please send a picture of your steps
It looks like you are assuming it's equal to 0. This is an expression you are simplifying. Not an equation.
I understood it thank you.
ln(1) is not 1.
ln(1) - 13ln(x) - 16ln(y). Very good. But, where does the equals sign come from??

Okay
And you can simplify ln(1)
Then you are done
What is your favorite geometry channel on YouTube?
i tried looking at the answer but i dont understand it, can someone help?
the assumption here is that a and b are vectors in general, which means they can potentially be non-parallel
oh, okay(?
cause i tried solving by the rule of, if they are multiples of the same vector then i could find k but, uh, didnt work-
can you show the answer you looked at & point out the part you had trouble understanding?
i dont understand where the 5/8 comes from
it's to make the a components match up
5/8 = k/2
one of the vectors is a scalar multiple of the other
@coral cosmos this does not answer linglingbee's question
oh
so it would be 5a + kb = 5a + 2b?
no
Ok yes, two vectors are parallel means the vector 2 is some multiple of vector 1
so a1 + b1 = x(a1 + b1)
= xa1 + xb1
If you match components then
a / xa1 = b / xb1 = 1/x comes out to be constant
if you scale a vector by 5/8 you scale the whole vector by 5/8, not just one component
8.795 - 2.485 : 35 = 8.724
Because We divide it first
Is that true?
Sorry, Is that okay if I'm asking my question like this?
also I think what Ann was saying that
8a is some multiple of 5a
you need to find the multiple {which in this case is 5/8} and then multiply it with 2
oh i see
thanks!
Thank you
No prob : )
No prob : )
I have 5 1/2 ๐ and 6 3/4 ๐
After few days 1/7 from both apple had Rotten
It's mean
5 1/2 + 6 3/4 - 1/7
Or โ 1/7?
what do you want to find? how many apples have rotted, or how many apples didn't rot?
Ohh
Sorry,How many Apples didn't rot?
then that'll be $\frac{6}{7} \times \left( 5 \frac{1}{2} + 6 \frac{3}{4} \right)$.
Ann
Wait
I Will write my answer
...is english not your native language, by the way? you sound like you're struggling.
Yes, sorry ๐๐
i know it's unlikely but it may be worth trying anyway: what is your native language?
(if you don't want to answer, you don't have to)
Indonesia
okay nevermind
I want to fall in love with math and try to do some elementary school question and i have forgot a lot.
Then want to ask someone to ensure my answers
you want someone to check your answers?
Yes
okay, post the problems and your answers here and people can check them
if possible, you could upload a picture
Is that okay?
thank you sm
yes, that's how this server works
you post a problem, you show what you've done so far, and people check it to see if you made any mistakes, and point you in the right direction or highlight your mistakes (as appropriate)
Awesome
$$f: \real \to \real$$
f is a continuous function. Find functions f such that:
$$f(xy) + f(x + y) = f(xy + x) + f(y)$$
what substitutions have you tried
substituting y with 1 might be useful for calculating f on integers
can you perhaps find enough relations to calculate f on integers?
like spam lots of small numbers to see if you can force a system of equations
But how will it help me on reals?
if you can solve it on integers, you may be able to extend it to rationals
displace to get f(x+y)-f(y)=f(x+xy)-f(xy) this should help probabl
you can get a differential from here ()
My fundamentals are really weak, sorry. My teacher is really bad at explaining. Everyone except a few gifted people could understand it.
if you set x to be a large integer while y to be a+k/x you might be able to do something to lift integers to rationals
;-;
though it's not symmetric hmm
so you might want to swap x and y and see what you get
left hand side is symmetric but right isn't
to expand on this if you take y to be the derivative variable which tends to 0 you get a differential equation
lim h-> 0 (f(x+h)-f(h))/h=x(f(x+xh)-f(xh))/hx
f'(x)=xf'(x)
is this about my differential form thing?
more like the original functional equation given
Why is part (c) not just the integral of x from 0 to 4?
integral of velocity only gives displacement, you need to integrate |v|
and it doesn't really make sense to integrate position
I'm integrating position though
Why not?
Is there a way to do this without computing $\int_0^2 x' - \int_2^4 x'$?
n/c
For y>10?
I dont understand can you please draw one of it for me
It says we need to draw straight line
Shaded region is what y cannot be
Anything above the line drawn is a good solution for y
Owhhh OK thank you
So on the y axis is where you look
y values above 10
Shaded region is values below 10
Oh I understand can
Makes sense? Do the next one and I will check for you
The question ask about straight line
Should i just draw the straight line
And should I color the part below y
I dont know what convention you use
An altenative way can be this
The idea is to show the 10 is not included
But all values above are
However, I like the first way more. Because it shows that we can only look at the values above 10 regardless of x
Oh I understand now thank you so much
A jumbo jet needs to reach a speed of 360 km/h (๔ฐ 224 mi/h) on the runway for takeoff. Assuming a constant acceleration and a runway 1.8 km (๔ฐ 1.1 mi) long, what minimum accel- eration from rest is required?
Please check my working: The jet has at most 1.8/360 hours, so y'(1.8/360) = a_x * 1.8/360 = 360, and so a_x = 72000
But the correct answer is supposed to be 36000, where would I need to divide by 2?
I started with y''(t) = a_x, and so y'(t) = a_x t + y'(0), and y(t) = a_x t^2/2 + y'(0) t + y(0)
So It should be right, but I am getting 72k, not 36k
I think you need to use physics to solve this problem
By using a kinematic equation
@hazy dome But that's what I am doing?
I have y''(t) = a_x, and then I integrate to get y'(t)
Since it is from rest, y'(0) = 0
So we are left with y'(t) = a_x t
Try using (final velocity)^2=(initial velocity)^2 +2ad
Idk where ur getting derivatives from
What about my working though?
But where did you get derivatives from?
What do you mean?
Your work above is just derivative stuff
But it wonโt help in answering the question
How will it not? I am calculating the velocity at the last possible second
The physics reference table
lol
I donโt have the ability to prove it, itโs just a kinematic equation
Hmm
Well you kinda stated the elementary concepts of rectilinear motion above
But that wonโt lead you anywhere
You said that the second derivative of the position function is acceleration, which is true, but doesnโt help because we arenโt given a position function
We have enough info to use a kinematic equation though
Hmm
Can you please send a pic of the original problem?
I think that will clear things up
Hi, can someone please check my work??
channel in use.
Yea no youโre not given a position function
I built one..
Doesnโt work in this case because you lack the info
What info do I lack?
You need to use physics
??
Data points
the channel is in use, #โhow-to-get-help
Positions at certain times
Alright thank uuu
Like which?
It's at 0 at t = 0, and supposedly at 1.8 km at t = 1.8/360
Well youโre only given the length of the runway and the final velocity
You donโt even know how long itโs gonna take for the airplane to reach the end
Of course I do, it's 1.8/360
Thatโs not true
And why not?
$x=1800m \ v_i = 0 \ v_f = 100m/s \ a=?$
Mosh
I am using physics lol.
so what kinematics equation are you using?
Hey guys I have a function that goes from R ---> R
how can I draw a non motonic function ?
@glass lichen You agree with me that y''(t) = a_x, right?
sure
So y'(t) (acceleration) = a_x t + y'(0)
But y'(0) = 0 since it is from rest
So we're left with y'(t) = a_x t
ok but how do you find the time?
time is relative, so just write down any answer
it's not
@glass lichen Why not 1.8/360 hours?
it is
it's not since the speeds are well below .1c before relativisitc correction is even needed
Because thatโs distance divided by final velocity
anyway
Which is... time
depends on the observer
ill be blunt, shut up if you dont plan on helping.
no u
Ok so we have time... now what???
We now know how long it takes the plane to reach the end
So now we just solve y'(1.8/360) = 360
But we donโt even know y
Yes we do...
You canโt derive something you donโt even know
y'(t) = a_x t
What you're saying doesn't make sense
I start with acceleration and then I integrate to get velocity
I am deriving the velocity equation
Ok cool... but now what?
what n/c is correct, but it's not really using physics persay, just calculus
What do you mean now what???
It comes out to a_x = 72000
But the correct answer is 36000
I'm asking why
Yea but it feels like n/c is kinda restating what we already knew
@hazy dome You can't derive your formula
Using kinematics, I got 2.7777777
You have to be able to derive it
You can derive it
M/s^2
ok, who gives a shit if he cant
Bro I just finished my first physics course XD
Chill
Because we haven't learned how to derive it
I just know what they teach me
So I shouldn't be using something we haven't learned how to derive, just because I got it from Discord
Here letโs think about this logically: if the acceleration is 72000, do you know how fast the plane would be moving???
Yes, twice as fast as it should be.
Because acceleration is the rate of change of velocity
So that's what I am asking, where do I need to divide by 2?
Weโre gonna assume that this acceleration is in m/s^2, thatโs WAYYYYY too fast for any airplane
guys, everything is relative, theres no wrong answer here
@hazy dome You're wrong.
Yes there is. Just stop
Write out your full work and send it in this chat
Via a pic
I already did, but I will do it again
8f +4g is correct
it isnt
$y'' = a_x \implies y' = a_x t + y'(0)$, however we know that $y'(0) = 0$ as it is from rest. So then $y'(t) = a_x t$, and we wish that $y'(1.8/360) = 360$ as that is the final velocity and the most amount of time we have, so $y'(1.8/360) = a_x \cdot 1.8/360 = 360 \implies a_x = 72000$
n/c
Except itโs actually 4fg
depends if f is a function or just a variable
you multiply 4 by 2f and 2g by 2f
<@&286206848099549185> I wrote the original question like 20 minutes ago so I will ping now
where are you getting 1.8/360?
1.8 km/360 km/h
yeah but why are you doing that?
1.8 km is as far as we can go
yeah
Why wouldn't I do that?
are you sure tho because wouldnt you only multiply the number not the variable
We want the minimum acceleration
cause it's wrong
you multiply everything
Iโm telling you you gotta use physics
it means the vehicle is travelling at 360 for the whole 1.8
Correct
bro
THATS IT
@dire pilot replace the variable by a random number like 2 and it might make it clearer for you if you have real numbers instead of letters
๐ญ
@leaden lily @dire pilot the channel is in use, stop posting
Thatโs what I was forgetting
sorry
Ok @alpine sable so where you went wrong is by dividing 360 by 1.8. By doing that, you assume that the plane is traveling constantly at 360 km/h the whole time, but thatโs not true at all. Itโs accelerating, the speed is always increasing
IN USE
I appreciate your effort @alpine sable , but the only way to solve this problem is by physics
@alpine sable I got 2.78 m/s^2
Same
Have you taken physics yet?
Yes, this is from the second chapter of a physics book
Perfect
So what you need to do is write down the givens and then consider the 3 kinematic equations
Only one of those equations will assist you in getting the correct answer
No
Hello.
I don't know how to read those
I think your main issue is youโre staying centered on Calculus
Which is fine, but it wonโt always help
I've decided to create my own mathematical theory or mathematical model which will describe geometrical objects and nature. Is there anyone who'd be interested in this?
Ok here are the variables: vf is final velocity, vi is initial velocity, a is accel, d is distance, t is time
Also deal with SI units only, so that means meters, seconds, and meters per second
Otherwise you will get an incorrect answer
So v_f is just y'(t) = y'(0) + a_x t, like I was saying
And distance is simply y = y'(0)t + a_x t^2/2
Also like I was saying
Yea, but donโt think about it through a Calculus lense
No youโre right, but I think youโre attempting to apply TOO MUCH Calculus to this problem. Just think about substitution
Anyway, the last equation we have not derived yet
Yes these problems are derived from Calculus but they need to be used algebraically
So we can't use it
You derive it from the first 2
Via direct substitution
Excuse me,
3 ร 14/4
Am I could multiply immediately or Should i simplify it first ?
So what you're saying is I could've used calculus this whole time
All I needed to do was solve for t
You saying not to use Calculus was entirely wrong...
Iโm saying to use physics equations derived from Calculus
Also to be a little more open-minded
What you are saying does not make sense
I was using the physics equations derived from calculus
Physics and Calculus overlap but there are problems that lie exclusively in their own fields
I was deriving them in front of you
Iโm not saying thatโs wrong
That. Does. Not. Make. Sense.
I was deriving the acceleration, position and velocity equations
Look, why are we even arguing about this?
They cannot be different
What about you spend some more time in your physics class until you get to kinematics
So that you can learn it from an actual qualified individual instead of some stranger in Discord
I am reading about that, but we need to derive every equation we use
Instead of using a "physics reference table"
Like you told me to
I encourage you to wait and learn for yourself
Wait for a professional to introduce these topics
lol
We've been going over kinematics
But like I've said 20 times now, we can't use random formulas without showing their complete derivation
Look, the 3rd one is derived from the first 2, which weโve already proven to be true
Try it out via direct substitution
Wrong ask
I know?
My point is you kept saying not to use Calculus
Even though I solved the problem without any reference tables
But your solution was incorrect
The problem was I didn't realize I was assuming the velocity to be a constant 360 km/h
Because you assumed the speed was constant
Right, but that has nothing to do with calculus
Nor does it have anything to do with deriving formulas using calculus
Which is what you were arguing against doing
<@&286206848099549185> umm a little help please...
Anyway, it's simple to solve now: y'(t)/y''(t) = t, and so 1.8 = y'(t)^2/y''(t) * 1/2 implies y''(t) = 360^2/3.6 = 36000
km/h^2

Notice how I didn't assume a single formula
I derived them all myself
This dude confusing
You did assume a formula
Which?
That v = d/dt x
No, that's how we're taught. If we define y(t) to be the position at time t
Then y'(t), is, by definition, the change in position at time t
How do I apply for tutor in homework help server
good question
Check dms
yeahh ;-;
It's could use for all numbers in fraction?
I mean, the answer will still same?
Yea
Because itโs just multiplication and division
Theyโre interchangeable in terms of order
Great,
Thank you!
Youโre welcome!
I finished everything in the practice test but i'm not sure what they are asking me to do in 1. b)
Basically substitute k into f(x) then do a little algebra
Write f as a function of k instead of x, and multiply the entire function by -2, then set it equal to 2
Yes
Np
How is the domain of this graph [0, inf)? what about at x = 3?
it's bc it drops down
jump discontinuity
but u can see that at (3, 2) it has an open hole
but at (3, .5) it has a closed hole
indicating that the function drops from 3, 2 to 3, .5
so technically 3 is part of the domain
closed circle indicates it includes that point
and open circle means it doesn't
yeah g(x) is still defined at x = 3
can anyone tell me how to proceed with this type question, I am new to probability
@gusty hinge is this your first intro to formal probability theory, with formal arguments involving measures and all that fun stuff? or is this your first introduction to probability in general?
or to put this another way, have you taken any basic probability classes such as those which would have you compute probabilities for dice or card games?
I know just very basic probabilty
Interestingly enough I've seen this question like 3 times in the past couple of days 
how we take example for p(Aintersectionb)=p(A).p(B)
that's only true when A and B are independent...
well you can start by drawing some pictures
both parts 1 and 2 have many different possible answers
so you can try making pictures to represent the sets you're choosing for your events
A worldโs land speed record was set by Colonel John P. Stapp when, on March 19, 1954, he rode a rocket-propelled sled that moved down a track at 1020 km/h. He and the sled were brought to a stop in 1.4 s; see Fig. 2-28. What acceleration did he experience? Express your answer in terms of g (๔ฐ 9.8 m/s2), the acceleration due to gravity. (Note that his body acts as an accelerometer, not a speedometer.)
How do I find the acceleration he experienced?
I found that -202 m/s^2 is the acceleration of the sled (I think)
But how do I find his acceleration?
he's literally riding the sled
so it's the same
But what does it mean to express in terms of g?
oh Hahahahahahaha
,calc 202/9.8
Result:
20.612244897959
Lmao, okay thanks
about -20.6g
can anyone help me with this question. Its
2x+5y=7
x-3y=-2
I have to like solve for y and x so I can get a coordinate. Thanks guys.
,rotate
trigo
??
what is 9+10
21
<@&286206848099549185>
use the fact that if the base angles of a triangle are congruent, then it is an isoceles triangle
Alright thank you, but I have to find the x value and when I equal them to each other the answer isnโt right
what value of x are you getting?
4.6
RS = RT, so 9x - 13 = 4x + 2, use that to solve for x
Alright thank you sooo much!!
np
hello im trying to understand how to check if a specific matrix is in the span of other matrices
i have those 3 and im trying to see if the bottom M_1 is in the span of the other 3
i found a video that explained it slightly, i put the vectors side by side and did guassian elimination
im just trying to understand if this is what im supposed to do?
What does it mean to be in the span?
for M_1 to be in the span it should be expressible as a linear combination of A, B, and C
so for each entry of M1 you have a three variable equation
three variables four equations
they got help already...
Can you simplify 2xy + 2 = 6y dy/dx -2x dy/dx?
bruh how am i supposed to know
Iโm not sure what you mean, but if you want to find dy/dx just factor out the RHS and then divide
RHS?
Right hand side
6ydy/dx -2xdy/dx=
dy/dx (6y-2x)
then now that you have it factored just divide by 6y-2x on both sides to get dy/dx isolated
So it would then be:dy/dx = 2xy+2/6y-2x?
Try applying ibp as well as the integral of the inverse theorem.
Does anyone know how to do 12?
discriminant of a quartic
... how about no?
i mean
i guess it's the only way, but if it really is that that's bullshit
I guess you can also do it using calculus
Find the local maxima and minima, and then set k appropriately
For using Integral of inverse theorem I need to know the antiderivative of f
Idk if thatโs allowed because this problem came under the factor theorem/remainder theorem chapter
or do polynomial division
But anyway after finding the local extrema what would have to be done?
how would it work in this case
what is 2 times x, is it 3x or 2x?
5x
what?
2*x = 2x
ok, ty
why would it be 3x lmao
itโs very likely theyโre trolling
because im stuck in a problem and im breaking my head to see what am doing wrong
go to a different channel i can help you in a bit
ok
ohh i see. make sure that the maxima are greater than 0 and the minima are less than 0
Finding k such that the values at the local extrema alternate from negative to positive to negative
yes
$\frac{2x^2}{\sqrt[4]{5}}$
TheMane3
can someone help me figure out how I would get the radical out of the denominator?
12x^3 + 12x^2 - 24x = 0
the nth root of z is z^(1/n)
x(12x^2+12x-24)= 0
x=0, 1, -2
what to do then?
actually
then I should just find the maxima/minima
yes
-5 is a minimum, 0 is a maximum,
-32 is also a minimum
@thorn kindle what would I do now?
Then you need 2 negative minimums and one positive maximum, which gives you -5 < k < 0.
@thorn kindle i was told to do something like this: $\frac{2x^2}{\sqrt[4]{5}}\cdot \frac{\sqrt[4]{5^3}}{\sqrt[4]{5^3}}$
TheMane3
im not sure why...or how that would work\
because if i cross cancel all it does is leave me with had i originally had, except the 5 is cubed
<@&286206848099549185>
?
4throot(5) times 4throot(5)^3 = 4throot(5)^4
is thi lane open
asking a question rn lol
you got your signs mixed up
0<k<5
Hey, a quick question. What if the end of pi were to be found. Would it be rational and would it change any complex operation, afaik people just use it up to the 20th digit.
it has been proven that pi is irrational
so you cant find any last non zero digit of pi
it's litteraly impossible
When doing numerical computations, perhaps people use 20 digits or so. However, when people use it within math, they usually use the exact value.
@nocturne mirage i mean regardless hes asking what if
in some alternate universe where it could be found, would it have any impacts like he asked
Exact, as in?
exact value means without decimals
it has stuff like pi and square roots and other constants
The exact value of pi, as a real number.
essentially, no approximations/rounding
3.14 is an approximation of pi but ฯ is the exact value
0.142857... is an approx for 1/7 but 1/7 is the exact value
Can someone explain to me how $x^{\frac{1}{5}}y^{\frac{1}{5}}=\sqrt[5]{xy}$
TheMane3
ik that $x^{\frac{1}{5}}=\sqrt[5]{x}$
TheMane3
but does the y in there not change anything?
like wouldnt the y also make it $\sqrt[25]{xy}$
dackid (jump king +)
Happens to the best of us :)
@warped phoenix it's kind of like how $n(x+y) = nx + ny$
visual of Petter's ascendance
I don't think this particular exponent rule is one of the typical ones you see when doing exponent laws.
So don't beat yourself up too much
ah ok ty โค๏ธ 
How do I get started solving either the vector $\bar{a}$ or $\bar{b}$ from the equation $\bar{a}\cdot\bar{b}=|\bar{a}||\bar{b}|cos\theta$? I know both sides are equivalent as that's just a dot product, but if I only treat $\theta$ as the variable and solve for b, I'd expect two answers, but I can't get either of the vectors out of the dot product ๐
jetp250
Oops, that's small text
so you want to reconstruct a and b given the dot product?
I have either a or b and want the other vector given the angle, the lengths of both vectors and the other vector
Ok so you can get a generic b vector using the other definition of dot product
then scale it up to be the correct length
since any vector on span(b) will give the same dot w/ a, you just need the one with correct norm
actually I think you can only know a plane of vectors, then get a circle as a subset of said plane
$b=\begin{bmatrix}x\y\z \end{bmatrix}\implies a\cdot b = a_xx+a_yy+a_zz$
Mosh
or whatever co-ordinate space you're working in
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Perhaps try rephrasing your question?
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I'm doing this in 2D to keep it simple, but my initial attempt was to break down the vector into its components and solve for each dimension separately
ok so yeah, $a\cdot b=a_xx+a_yy$
Mosh
that is an inadequate explanation, but I don't see why I have to re-scale it, and I'm not getting two results so it's probably not right to begin with
$a_xx+a_yy=\norm{a}\norm{b}\cos(t)$ is a linear equation, so you can get a vector whose span is the line
Mosh
Seems like having actual linear algebra classes could be handy, I'm not even familiar with spans ๐ Maybe I'll do some Googling on that and it seems like I could be able to solve it
span of a vector is the set of scalar multiples
The equation is not hugely complex anyways and now that's a scalar form already
span of a set of vectors is the set of linear combinations of the vectors
Yeah I'm hitting a total wall with terminology. It's better I look up all the terms and try again
can i post?
Fine by me
,w solve (1/2)(n)(n+1)(n^2+n+1)=(100)(1/6)(n)(n+1)(2n+1)-(1/2)(n)(n+1)
why cant i cancel the factor of (1/2)(n)(n+1)
so im left with just a quadratic
if i do that then i get the bottom two solutions but not the top two
i was just wondering why i cant cancel the common factor
(as in divide both sides by it)
@plucky crow You can, but if you divide by something, going on past that assumes that what you divided by wasn't zero.
oh
So, you can divide by n and n + 1, but then you have three cases:
- The case where those are divided out.
- The case where n = 0.
- The case where n + 1 = 0.
oh
You handle all three cases separately.
You find all the solutions.
You check whether each one makes the original equation true.
Just because you divide by something doesn't necessarily make what you divided by equal to zero a solution to the original equation.
That's why you have to check each solution.
im a bit confused
so what do i do with the information that n=0 or n+1 = 0
to find a solution
You solve those equations for n as well.
what does check mean
Then you check them in the original equation.
oh so i sub n=0 in the originak
Yes.
and n=-1
well 0 it is yes
yeahhh i think it may be easier instead of plugging the radicals into that massive eq
to just
not divide by those things
lol
Then you have to find the roots of a quartic.
yeah. but then again, how can we know that this is true without assuming that the liens are parallel right
if the first derivative of a function is abs(x), would 0 be considered a minimum
no because the derivative would never change sign
wait doesn't the slope change from -1 to 1
you said the derivative is |x|
yea
it means the 2nd derivative isnt defined there if it's a corner 
you need to bring all the w's to one side @worldly coyote
6w-2w=-16-36
4w = -51
w= -51/4 = -12.75
why do people still have school
My book asks me to take the first 5 derivatives of f(x) = xยฒe^x and then find a formula for the derivative of number N of the above function. Here is my demo, is it correct?
Looks good to me
Nice job
help please???
Assign a variable to represent the number
A number X that divided by X+6 = 10/11, X/(X+6)= 10/11 -> 11x= 10x+60-> x=60
Then go from there
When you read try to write the equation as you are reading
okay thanks
$y=\sqrt[3]{x-1}+7$
TheMane3
The domain would be all real numbers greater than 0, and the range is all real numbers
for the above function
right?
No, all real numbers
What is one property that cubes have that squares don't?
if we were to graph these two, they would never intersect, right?
right
I'm not sure if I got it right
If one of the sides shown is head there are 3 possible cases
A) hh coin, it gives H
B) hh coin, it gives H
C) ht coin , it gives T
The probability of getting H is 2/3 = 66.66666...%. But I'm not familiar with calculating probabilities
This conceptually makes sense , but I might be wrong
i vaguely think this is one of those ambiguous problems
nah nvm i just ran out of brainpower today
It's more about comprehending the text than math , so maybe this is not the right server to post it