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Yw
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Can someone explain to me how we got square root of 2
sqrt(2)^2 = 2
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Just started learning Matrix but Teacher wont explain things normally
i still cant understand how this
become this
factor out 10 from the first row
row operations
?
teacher didnt teach row operations? they are quite important
he is just speedrunning stuff
whole class is confused
oh shit i did not notice the other rows

this sounds like something that should be broken into several steps tbh
yeah , take common and then do row operations instead of in 1 step
https://www.youtube.com/watch?v=fvQ013dZb9c
this video helped me alot to understand what is matrix and how to find determinant
Детерминант линейной трансформации есть мера того насколько площади/объемы изменяются в этой трансформации.
Оригинал: http://3b1b.co/eola
Подобные видео финансируются сообществом через Patreon.
Там вы сможете получить доступ к новым видео раньше всех.
http://3b1b.co/support
3blue1brown это канал с анимированной математикой...
Teacher didnt even mention anything about using matrix in spaces
From all the classes in the University, math sucks as hell
а, так вы по-русски говорите?
Yes, but its a english only server
the rule is not strict
Makes sense
just read them, apparently no
так что, между этими двумя определителями что ли никаких промежуточных шагов не было?
тебе показать что в этом учебнике?
я ни слова не понял
из того, что тут написано
о так это ж совсем другое дело
так
элементарные операции над матрицами бывают трех видов:
- перестановка двух строк (меняет знак определителя)
- умножение строки на множитель (определитель умножается на тот же множитель)
- прибавление отной строки с каким-то коэффициентом в другую (определитель не меняется, каким бы ни был коэффициент)
вот это вам препод рассказал? или он проспидранил/пропустил/рассказал предельно непонятно (нужное подчеркнуть)?
Диктовал, но практики особо не было
У нас 2 пары по пятницам, Лекция и Практика, но там все в шоке на протяжении 3х часов
Я еще умер с того, что если поменять местами строки у матрицы, у которой и так нулевой определитель
сначала выносим 10 из первой строчки, получаем $10\vmqty{3&-1&12&8 \ -5&3&-34&-23 \ 1&1&3&-7 \ -9&2&8&-15}$
Ann
шта?
Я после пары сидел, общался с ней, она мне постоянно про какие то свойства говорит
тип
не поняла, о чем ты
если у матрицы, нулевой определитель
и ты поменяешь местами строки
то он будет отрицательный по свойству
ничего не понял
так я это понял потом
я еще не понял
вот есть допустим
тройная матрица
и 2 из 3 строк одинаковые
если их местами поменять, то определитель будет отрицательный
тройная в смысле 3 на 3?
да
определитель поменяет знак
Но как, если мы в итоге получаем ту же самую матрицу
ну тк
пусть D -- определитель исходной матрицы
после преобразования он станет равен -D, согласно свойству
это понятно, если бы были разные значения
но получили мы ту же самую матрицу, из чего следует, что D = -D
но если 2 из 3 строк одинаковые
ты меня хоть дослушай, пожалуйста...
пусть D -- определитель исходной матрицы
после преобразования он станет равен -D, согласно свойству
но получили мы ту же самую матрицу, из чего следует, что D = -D
ферштейн?
фраза D = -D меня убивает, учитывая что я на программиста иду
Прости если доставляю проблемы
если так не нравится привычка математиков не обозначать вещи так, как они пишутся в императивных ЯП типа си или джавы
эт False выдает. Тут получается что такая матрица находится в суперпозиции чтоли
нихрена оно не выдает false.
ладно, не будем усложнять
у уравнения D = -D решение есть
в твоем пониманииD = -D словами как переводится
определитель исходной матрицы (D) равен (=) определителю преобразованной (-D)
да глубоко нам пофиг на объемы и площади
ибо площадь/объем не могут быть отрицательными (в базовом понимании)
😭
а определитель как объем вообще берется со знаком, означающим ориентацию, так что вот это вот про "площадь/объем не могут быть отрицательными" идет лесом
ужас
(1) пусть D -- определитель исходной матрицы
(2) после преобразования он станет равен -D, согласно свойству
(3) но получили мы ту же самую матрицу, а значит D = -D
ладно, если я буду использовать определитель в уравнении или в функциях
скажи пожалуйста, какая из этих строчек вызывает непонимание?
вопрос поставлен слишком размыто, так что я на него ответить не могу.
Последний.
Я вижу эти вещи так
- Была матрица
- Преобразовали и получили такую же матрицу (Матрица = Новая Матрица)
С такой логикой, раз они одно и тоже, то и определитель должен быть одним и тем же
я новерное доведу щас кого-то до убийства.
но "определитель после" отрицательный, тогда получается что до образовния он был(?) отрицательным тоже?
??
не путай, пожалуйста, понятия "что-то отрицательное" и "что-то, у чего спереди торчит минус".
всю жизнь для меня это было одно и тоже
не знал, что у минуса есть и такие понятия
-D есть произведение -1 и D
скажем так
если у переменной отрицательное значение, то, поставив перед ней минус, ты получишь положительное число
например, если x = -9, то -x = 9
так, это понятно
вроде классе в шестом проходят, что минус на минус дает плюс
то есть -D ни в коем случае не надо воспринимать как что-то точно отрицательное
тоесть, сам D может быть чем то отрицательным
само D может быть каким угодно вещественным числом -- хоть положительным, хоть отрицательным, хоть нулем
-D есть произведение -1 и D, ни больше, ни меньше
безо всяких там додумок
правильно, получается ложное утрерждение
значит, D ≠ -9
уравнение D = -D можно и нужно решить, причем для этого не требуется знаний больше, чем школьная алгебра класс этак за шестой
интересно
и тогда ты получишь, чему равен этот несчастный определитель
алгебру из школы знаешь/помнишь?
да
ну вот реши мне уравнение x = -x
погнали.
x - (-x) = 0
x + x = 0
x = 0
браво
естественно
то есть ты только что доказал своими усилиями, что если у матрицы две строчки совпадают, то ее определитель равен нулю
я в шоке
почему ты не мой препод 😭
хороший вопрос
надеюсь, что моими силами у тебя случилось просветление, хоть и на небольшом масштабе
Ладно, вернемся к первоначальному вопросу.
Операции над строками
таки да
Я понял достаточно много на самом деле
скопирую то, что раньше написала
элементарные операции над матрицами бывают трех видов:
- перестановка двух строк (меняет знак определителя. или, что то же самое, определитель умножается на -1)
- умножение строки на множитель (определитель умножается на тот же множитель)
- прибавление отной строки с каким-то коэффициентом в другую (определитель не меняется, каким бы ни был коэффициент)
да, и ровно таким же образом.
в твоем скрине колдуют только со строками
пишут что сложили строки, но размер матрица не поменялся
он и не должен
ага
я так понимаю, коэффициент в таких вещах, обязательная вещь?
оче удобные операторы присваивания с операцией += и -=, чтобы как раз вот эту операцию объяснять, особенно программистам и иже с ними
твоя правда
конечно. но можно и "без" коэффициента -- тогда он просто будет равен единице
все равно определитель от этого не меняется никак, так что пофиг. но и как отдельный вид операции выделять не надо.
угу
получается, то, что мы прибавляем, не трогаем
в матрице оно остается таким же
строка, которую прибавляем, да, остается как есть
понятно
так вот, как бы написала я: сначала выносим 10 из первой строчки, получаем $\Delta_4 = 10\vmqty{3&-1&12&8 \ -5&3&-34&-23 \ 1&1&3&-7 \ -9&2&8&-15}$
а уже затем колдуем с прибавлением первой строчки ко всем остальным (по-хорошему надо делать поочередно, но в данном случае пофиг в каком порядке)
Ann
то есть затем делаются вот такие операции (запишу на си-псведокоде):
row_2 += 3 * row_1;
row_3 += row_1;
row_4 += 2 * row_1;
и делаем это очень аккуратно, ибо к 24 арифметических действиях, выполняемых в уме, легко по неосторожности ошибиться
коэффициент вообще обязателен тут?
в смысле?
ну то что мы умножаем на 3, 1, 2
можно все коэффициенты взять за единицу, и это все равно будет допустимо
а то, что мы берем их именно такими, как написано, это не из-за того, что ТАК НАДО, а имеет мотивацию
чтобы красивые циферки получить?
точнее, удобные
типа того
немного точнее: наша цель -- очистить один из столбцов (в данном случае второй), т.е. следать так, чтобы в нем был ровно один ненулевой элемент
затем, когда мы раскроем определитель по Лапласу вдоль очищенного столбца, будет только одно слагаемое
не слышал об Лапласе
э
забыла, как по-русски называется, сек
по-английски Laplace expansion, сейчас поищу
Теоре́ма Лапла́са — одна из теорем линейной алгебры. Названа в честь французского математика Пьера-Симона Лапласа (1749 — 1827), которому приписывают формулирование этой теоремы в 1772 году, хотя частный случай этой теоремы о разложении определителя по строке (столбцу) был известен ещё Лейбницу.
вот
как так
учебник 1990 года
определители старших порядков без нее считать -- геморрой
разве что к треугольному виду приводить
но тогда дофигища циферок за собой приходится тащить
есть удобная ормула для вычисления определителей 3 на 3 (и только 3 на 3), в честь него названная
можешь показать, что там за равенства (1.6)? мб что-то знакомое
щас
или вообще скинь-ка сам учебник. он же у тебя скорее всего пдф
@wooden python Можно попросить об просьбе? У меня математика только первый курс, каждую пятницу. С текущим преподавателем я не думаю что смогу осилить математику. Если ты не против, могу ли я иногда писать тебе и выделять пару минут твоего времени?
да пожалуйста
Потому что я сам потом ребятам из группы обьясняю щас все что ты пишешь
я по возможности буду отвечать ессно
рада была помочь
вот тут как раз не складывали, а разложили
по 2-му столбцу, который мы только что очистили
у нас пусткой был
чтобы вот в этой сумме только одно слагаемое было
знаки сигма, я ни разу не использовал, понятия не имею что оно означает
это сумма
в качестве совсем на пальцах объяснения можно ее записать как цикл for
опять же через си язык
то есть типа
да да
double sum = 0;
for (int i = m; i <= n; i++) {
sum += a[i];
}
после выполнения этого кода в переменной \verb|sum| будет храниться значение суммы $\sum_{i=m}^n a_i$
Ann
чтобы не писать каждый раз многоточия
их вычеркнули
так, надо обдумать
понятно
знаки минус и плюс идут от (-1)^(i+j) в определении алг. дополнения
я заметил
я иногда это представляю себе как шахматную доску, у которой верхний левый угол окрашен в "плюс"
Приму к сведению
это я постараюсь сам сделать
ибо концепцию работы с этим понимаю
@verbal hound Has your question been resolved?
так что в итоге
я кушал ((
но получилось
сошлось
спасибо, я если что, буду обращаться @wooden python
закрываю вопрос на сегодня
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Completely lost on this problem, I think I could go about this by brute forcing pdf's but that calculation is going to get impossibly hard to do and the hint that the problem gives makes me think that's not the best way to do it anyways
I know we can rewrite P(X2>X1) as P(X2-X1 > 0), but I don't think that actually advances my ability to solve this at all
P is the probability, right?
yeah
and N(0, 1) its any number from 0 to 1 like 0.15123 and so on
No, N(0,1) is a Normal distribution 0 mean STD of 1
@autumn bear Has your question been resolved?
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@autumn bear Has your question been resolved?
<@&286206848099549185> After stepping away for a couple hours and not hearing back from an email to my professor, I'm still completely lost on this problem, looking for anyone who can nudge me in the right direction
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can anyone explain to me how to find the great common denominator? in a problem like this
it makes sense to me when I'm adding two fractions together but I haven't done it with 3 or when they're on opposite sides
kind of confuses me
the screenshot I sent is the instructional video I was watching. I'm not sure how they got 6(x+1).
Just find "x" in this?
is that the question
yeah
my thought process for finding x here is
multiplying both sides by x+1
or subtracting by 1/2 then multiplying both sides by x+1
but it gives me junk when I try that
$1/(3x+3)$
ahaan
we have this
6x + 6 is the lowest denominator they can all share
do u see anything common in the denominator?
if you care and dont know, you can do $\frac{1}{3x+3}$ for formatted fractions
I don't understand
teach me how to use this bot fr xD
@next sonnet I got the LCD as 6(x+1)(3x+3).
- Multiply the entire equation by the least common denominator (LCD) of (x+1), 2, and (3x+3).
- The LCD in this case is 6(x+1)(3x+3).
in my head I'm thinking
hm
weird
lcd of allthose
wouldn';t that just be
6x + 6
because they can all multiply into that
multiply the 1/2 by 3x+3/3x+3
Simplify the equation:
- Distribute the LCD to each term in the equation to eliminate the denominators.
- This will result in a new equation without fractions.
I don't get how you get the lced
lcd
here lemme try again
so I look at this and I think
ok let me make 3/x+1 have the same denominator has 1/3x+3
Just multiply all the denominators
Multiply the entire equation by the least common denominator (LCD) of (x+1), 2, and (3x+3).
The LCD in this case is 6(x+1)(3x+3).
oh
so
to find
the
LCD
multiply all the denominators together
that's the lowest possible denominator they can create
right
then I multiply all th terms by that LCD over 1 to cancel out the denominator?
it's weird in the video they say greatest common denominator
so whats the difference
I mean i use this way
Simplify the equation:
- Distribute the LCD to each term in the equation to eliminate the denominators.
- This will result in a new equation without fractions.
- Solve for x:
- Simplify and rearrange the equation to isolate the variable x on one side.
- Combine like terms and move all terms involving x to one side of the equation.
makes sense
do u understand that
yes
if u do ill send lvl 4
does this always work
if there's 3 fractions
I can multiply all the denominators together
that gives me the LCD
multiply all the terms by that to cancel out the denominators
gives me a new equation no fractions
solve for x
@next sonnet did u get it?
yep
sorry for late response am solving a chem question for myself xD
ok I'm lost again
when I get the LCD
should I multiply the numerator by the other denominators as well
so the 3 in the first numerator
gets multiplied by 2 and 3x+3?
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I am having trouble calculating the angular and linear velocity given this information only.
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how is it not .00056
lemme get my work
20 - .005 = 19.995
19.995 = x^2 - x
x=5.0005555898
5.0005555898 - 5 = 0.0005555898
0.00056
@sharp zephyr Has your question been resolved?
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@sharp zephyr Has your question been resolved?
omg slice
wat
Result:
5.5552126623581e-4
Result:
5.5558985334248e-4
for this maybe you have to round it down (?, so f(x) doesn't exceed the limit
,calc (5+0.00056)^2-(5+0.00056)
Result:
20.0050403136
,calc (5+0.000559)^2-(5+0.000559)
Result:
20.005031312481
this value of x is in |x-5| < 0.00056, still the function exceeds 20.005
Well that's something to consider, it's a new thing for me with respect to limits 🤔
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how to solve #6
!status
What step are you on?
1. I don't know where to begin
2. I have begun but got stuck midway
3. I got an answer but I'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
1 for me
what are the properties of tangent lines
one more
wait what thats the only one ik 😭
their slope is the same for a point
Find the derivative of f(x) then equate it to the slope of y= -(3/4) x + 3
you can solve this either by derivatives or using the concept of determinants.
(quadratic equations)
we havent learnt that yet 😭
which one?
oh alrr
wait how do i find the derivative of k
comcept of determinants
k is just a constant
It's a constant
so it stays k after being differentiated?
ig quadratic equations are taught before differentiation but alr
😭
k is a constant.
oh so it becomes 0
Dyssrupt
ohhh okayyy thanksks
and d/dx 1/x is equal to 0/1 after being differentiated right?
no
oh huh
yes
-1/x^2
uh i have no idea 😃
why did you diff the function?
im just following what they told me above 😭
...
i dont know why we have to differentiate it to get k
i would but its like 1 am and im just tryna finish this so i can sleep. ill like figure out whats going on tmrw morning ykykyk
concept
cause i have more of these to do so might as well learn it nvm
they two sentences you just said contradict each other LMAO
💀 yeah ik
so diff'in gives you the slope of the tangent
ohh
at "x" point
so the slope is -1?
so you diff it and got -k/x^2
did you get -1 ?
after diffing it?
-k/x^2
the question is asking for a line to be the tangent at some point
yeah
so if we just equate the slope of the line to be the slope of the "tangent" we just got by diff'ing
we might get our answer
what
😭 wait what do u mean by equate
y=-3/4x+3
=
the slope, babe.
😅
not the eqn
OH HELP -k/x^2
thats the slope of the second function
oh
im asking the slope of the line
yes.
yaaa
idk
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hello one more problem im so confused on
probably not
oh wha 😭
take the derivative, set it equal to 3. is there a solution?
also hii again
oh
lemme check
set x = 3? or like the equation i get after differentiating equal to 3??
set the equation equal to 3
x does not have to equal 3
if f'(x) represents the slope of the tangent line at point x
set f'(x)=3
if there is a solution
then at this x-value
the slope of the tangent line is 3
oh wait what
okk one sec
i just checked on a graph it doesnt work
oh
yeah it doesnt give me any real number solution
OKOK TYY 🙏
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hello
what is biomial theroem guys
Lecture 01: Derivatives, slope, velocity, rate of change
*Note: this video was revised, raising the audio levels.
View the complete course at: http://ocw.mit.edu/18-01F06
License: Creative Commons BY-NC-SA
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More courses at http://ocw.mit.edu
the junk part is confusing to me
do you know the binomial theorem? it says (x + deltax)^n = x^n + nx^(n-1)*deltax + other stuff
he is just calling the other stuff “junk” and not writing it out
ok
yeah i don't know i didn't like math that much as a kid now I love it so yeah
thanks btw
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The length contraction equation does show that the distance gets shortened
however, the first statement is confusing me
I was thinking that time dilation affects the time taken
@clever pecan Has your question been resolved?
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in the case i want to calculate the force of 2Q and Q on q, i will calculate the force of both charges on q and add?
Subtract rather since the forces have opposite directions
add them as vectors
@dire jolt Has your question been resolved?
how do you know that?

Clearly, the 2Q and Q charges are located on different sides of the diagram
With q being in the middle
i am stupid
n the figure, if Q = 30 C, q = 5.0 C, and d = 30 cm, what is the magnitude of the
electrostatic force on q?
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Show or disprove the logical equivalence:
a -> (b -> c) <-> a ^ b -> c
The biconditonal <-> is another way to denote logical equivalence
So we can take the two sides and show they're logically equivalent using truth tables
Yeah I was just about to ask
I asked gpt and it gave me one but one of them was T and one was F
Specifically when a is T and b, c is F
Is the second statement (a ^ b) -> c or a ^ (b -> c)?
There is no order of operations defined for logical operations, so a ^ b -> c doesn't make sense. It's possible that (a ^ b) -> c and a ^ (b -> c) are logically equivalent and the statement is being renamed a ^ b -> c, but we can't take that for granted
@twilit spoke
Don't forget to close the channel using
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can anyone give me a hint? im so stuck with this
i tried v = 4pi/3 r^3 and calculating dv/dr but no help
and you need a more complicated eqn than that because the water isn't in the shape of a sphere
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how do you show that something is a basis for r^3
Yes sorry
but to show that something is a duck you show that it satisfies the definition of a duck
trying to do this
do you have a definition of basis on hand
or was your teacher cruel and incompetent to you by withholding it from you
i have my other friends notes from another school
i feel like my teachers notes are not amazing and we really only briefly touched this
verify the linear independence of all the vectors v1-v3
let V be a vector space
linear independence means that all the coefficiences are equal to 0 rigt
in order for a subset B ⊆ V to be a basis for V, two things must happen:
- B must be linearly independent
- B must be a spanning set for V, i.e. every vector in V must be expressible as a linear combination of B
no bad
linearly independent means that only the trivial solution is a valid solution to that equation
so like one point of intersection?
you must digest the definition of linear independence as a whole.
if you try to regurgitate only bits and pieces of it, you will choke.
and it will be unpleasant for everybody involved.
so i need to find the basis?
no
why not
you're not "finding" a basis
that isn't your goal
your goal is to prove that {v1, v2, v3} is a basis
this consists of two big steps, each of which can be broken into some sub-steps, as follows:
in what follows, S := {v_1, v_2, v_3}, the set you are looking at.
- verify that S is linearly independent:
a. write down the equation x_1 v_1 + x_2 v_2 + x_3 v_3 = 0, where x_i are real-number variables.
b. rewrite the vector equation as a system of three linear equations in three variables, and solve it
c. verify that the ONLY solution of this system is the trivial one, i.e. x_1=0, x_2=0, x_3=0. - verify that S spans R^3:
a. take an arbitrary vector u = (u_1, u_2, u_3) ∈ R^3.
b. write down the equation x_1 v_1 + x_2 v_2 + x_3 v_3 = u.
c. solve the system for x_1, x_2 and x_3.
d. verify that your solution exists no matter what u is.
thank you sm
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If a fair coin is tossed 50 times it gives 50 heads
Are next 50 tosses as likely to be heads as the first 50
that sounds like a rigged coin
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✅
hey
I just realised that Probability of getting X heads after getting X heads is dependent on X
;-;
So a longer sequence of heads is less likely to repeat after occurring than a shorter sequence of heads
However a sequence HHH is less frequent than a HHT
Expected number of tosses before one gets 3 heads is 14
Expected number of tosses before one gets 2 heads and a tail is 10
Sorry but anyone can help me?
I then understood that two sequences can be equiprobable but different in terms of their rarity or surprise or entropy
So a Head Head Head is more surprising than Head Head Tail even though both are equally likely to occur
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I don’t know how to do this
do a substitution (should be obvious what it is) and then perform integration by psrts
looks great so far!
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is my answer correct?
no, just to help you visualize the image and demonstrate piecewise functions
Ah. Then why are you excluding those points in the domain?
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Im confused as to how answer for this question is positive infinity
What do you think it should be?
Wait sorry let me explain
If i find the limit from the right side it makes sense that its positive infinity
but when i calculate limit from the left side
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the denomitor would be negative when foiled
Would it be? Look again.
The (x+7) factor is what's making it go to positive infinity. Think about the value of x+7 for values of x close to 0, from both sides
Also -.99 is close to -1
yea I was just using it to calculate the left side of 0
but now the squared make sense as to why its positvie
You should choose a point closer to zero. -0.01 woule be a better candidate.
You can do it analytically. For any value of x in a close neighbourhood of x = 0, x + 7 and x^2 are both gonna be positive
will do
thank you guys
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1 more attempt at getting help. Is this graph correct? here is the instruction
Domain: [-3,5]
x-intercepts: (–3, 0), (5, 0)
f(1) = –3
f(x) has a relative min of –3 at x = –2 and a relative min of –5 at x = 3
f(x) has a relative max of –2 occurring at x = 0
f(x) is increasing on the interval (-2,0)∪(3,5)
f(x) is decreasing on the intervals (-3,-2)∪(0,3)
(1,-3) isn't on the graph
should it be?
@proud schooner Has your question been resolved?
@proud schooner Has your question been resolved?
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What are your answers? Can you show your work
A is 2^8 right?
yes
How did you arrive at that?
That's not quite correct
there are 3 coins that are always head, and the rest are either going to be head or tails
Ah okay I see your confusion
so the variability is in the 5 coins
It says "exactly three heads" so if 3 coins are heads, then the rest HAVE to be tails
But the trick is that it might not always be the same 3 flips which are heads
So for example maybe flips 1, 2, 3 are heads and 4 through 8 are tails
Or maybe 1, 5, 7 are heads and the rest are tails
Do you see what I'm saying?
8P3
sorry for the ping, but ur dang good at explaining stuff, Aight imma head out, dont wanna flood the channel
Isn’t it just 8 choose 3?
Let them figure it out
Yup, so b will be 8C3
C is a bit harder
Yeah it is haha
yup that's correct!
there's a trick you can do which makes it so you don't have to calculate 6 different 8Ck terms though
do you want to hear it?
ofcourse
okay so how many possible outcomes do not contain at least three heads?
8C1+8C2
Don't forget 8C0 :)
but yup!
So the possible outcomes that DON'T contain at least three heads is 8C0 + 8C1 + 8C2
the total number of outcomes is 2^8 like you said before
subtract them from the total number of outcomes
there is symmetry
i know this isnt my question but Im so confused 💀
so you can WLOG
about ?
this is basic combinatorics
it's still a bit hard
which grade is that 😭
what do you mean by that?
its undergrad
without loss of generality
i am actually mixing up different concepts
so forget about it
Yeah there's no need to invoke that here
it's undergrad for any compsci major
you are going to have to take discrete math if you do compsci
nvm I have a B+ in compsci :exit:
you have a degree ?
I think I learned this in Algebra 2 class in the US
But yeah it's totally reasonable for a question like this to show up in a computer science class (probably a class named Discrete Math or something) in college
combinatorics is a college level topic IIRC
As someone who took discrete math, why the hell is it needed for Computer Science?
it shows up a lot in algorithms
this sort of stuff is a basic tool you need if you're trying to calculate stuff like runtime
also it's good to know various tricks to simplify stuff mathematically
it has applications in encryptions for example
number theory is important for that
Interesting
And I’m just tryna learn more statistics (someone please help me with my problem)
@hearty socket Has your question been resolved?
Why is linear algebra so important in cs?
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new to this so bare with me
I understand to set it up into 2 cases and solve
I got x<2 and x>2 but I dont understand why my final answer would be x<2, x>4. the book says why but im just not getting it
I don't understand how this can be shown on a number line as well
@haughty tendon Has your question been resolved?
wait figured it out
i think
can i send u a pic of my number line
2 sec
this is for seperate question
if you just want your answer checked you should use desmos
no no its just that im using a number line to find which x's satisfy
i wanted to know if the method im using is valid or im just making stuff up in my head
any method is valid if it leads to the right answer
i dont understand what youre doing
yes neither do i actually
okay just help me out
so yes
we can split into two cases
pls and thank u
not just can but its necessary
you must split
step #1 is multiply by a quantity you dont know is positive or negative
so x-4
hrm?
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thé 4th term in what ordering
you can
do it with a and b
yes
did you expand the whole thing
like this
that's what it means to expand
ok what exactly is your original question
gotta expand the whole thing ig
doesn't matter
isn't it symmetrical
yes it is
you have n
so you can write it as an equation
right?
now you subtitue in a and b
you have a=(w+x) right
and b=(y+z)
you did your substitution up there
so what were you trying to do
that looks exactly like brute force
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@royal sphinx Has your question been resolved?
try u = sqrt(1-x)
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in general this entire part
WhereWolf(ping if needed)
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how to do this
make denominator the same
add them up
oh right
u need to find the denominator
wait
this is the answer . I dont know about the third line
why and how does this work
You can check yourself that $\frac{1}{n(n+1)} = \frac1n - \frac{1}{n+1}$
ΣΑCu
by means of partial fractions decomposition
this is a formula for this kind of question?
what level of math are you at?
Its just something you can sometimes do to fractions with a product in the denominator
you can write it as
3 - [1+
(- 1/2 + 1/2)+
(-1/3+1/3)+
...
(-1/7+1/7)
-1/8]
by regrouping, and all those middle terms =0 so they disappear.
why?
think they were asking about the step before that
oh, oops.
[
\f1{n(n+1)} = \f A {n} + \f B {n+1}
]
and solve for $A$ and $B$
i think
then what is the a and b
year 7 is perhaps early for partial fraction decomposition
because I was taught it as part of calc 2
yeah but let's not jump the gun here
$\frac{1}{n(n+1)} = \frac{1+0}{n(n+1)} = \frac{1 + (n - n)}{n(n+1)} = \frac{1 + n}{n(n+1)} + \frac{-n}{n(n+1)} = \frac{1}{n} - \frac{1}{n+1}$
accialto
why does this thing equal to 1/n - 1/ n+1
$\frac{1 + n}{n(n+1)} = \frac{1(n+1)}{n(n+1)} = \frac{1}{n}$
accialto
$\frac{\cancel{1 + n}}{n\cancel{(n+1)}} + \frac{-\cancel{n}}{\cancel{n}(n+1)} = \frac{1}{n} - \frac{1}{n+1}$
tushar
but in this case isnt there is still a negetive up there
$\frac{1}{n} + \frac{-1}{n+1} = \frac{1}{n} - \frac{1}{n+1}$
accialto
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Can someone help me with a?
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Can someone help me with question 1a?
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<@&286206848099549185>
.close
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so my teacher said that Fcostheeta won't produce any torque but i want to know why it does it not don't mind my drawing btw i was just trying to draw a wrench thingy not math related i know but i would appreciate if someone would help