#help-13
1 messages · Page 236 of 1
Closed by @livid swan
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Ye, not of human ilk, aid in the unraveling of this inquiry.
what have u tried
circle area
what does that mean
I have endeavored to calculate the area of the circle.
What dost thou signify, wherefore, brother?
We must ascertain the extent of the square, or do we not?
@gloomy bough Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Please help me with part b.
I am stuck in that part.
@little junco Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Find the sum 1+2i+3i^2+4i^3+...ni^(n-1)
how is this a geometric series
it's the derivative of the geometric series
$$f(x) = a + ax + ax^2 \cdots ax^n$$
$$f'(x) = a + 2ax + 3ax^2 + 4ax^3 \cdots anx^{n - 1}$$
jan Nejon
a = 1, x = i
yes thank you
you're welcome!
@indigo blaze do you know how to compute derivatives?
I do
yes
Another way is
S = 1 + 2i + 3i^2 + ... = (1 + i + i^2 + ...) + S i.
Well but yea, this is just discrete differentiation
you will also need the closed form
take the derivative of the finite sequence formula
wrt r
So i should take the formula of the geometric series and apply it on 1+i+...i^n
And then take the derivative
right?
Ig you can deform i as well
Closed by @indigo blaze
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.

,rotate
@vast pike U rude my writing is best!!
The third one
the book writing is better
Nope
megacosm for the win
Any idea how we would maximize it?
.
why is there a matrix ?
so you have to maximize this one?
Oh no it's modulus not matrix
yeah
are u using determinants?
ok diff determinants one row or column at a time and add them
yeah
Ok I think I know what to do lol
Nvm
No I don't
Yes
The angles add up to 0 symmetrically lol
Somehow
Lengthy
idk bruh but this stuff works
Also I don't have any intuition for this so I am not gonna do it lol
ok ur wish
If all angles become equal that would mean the area is 0
Which is basically minimum area
lol
But we need maximum
check the double derivative test
Is weed legal in your country
by the time you guys were suggesting ideas out of my league i solved the 4th one
you guys should try it
its a nice question
its a elllipse property
you can also theory of equation
which module is that btw?
istg this looks exactly like mine
but i dont think i have 3 excerises in ellipse
no?
my module is new
then your class people are scamming you
^
whats yours
ftj
intresting , is that ellipse module?
yes
lemme check i dont remember tbh
Closed by @spare turtle
Use .reopen if this was a mistake.
oh btw your question
i think you could not use sin (a-b) and maximise the product using am gm
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hey there can someone please take a look am i went something mistake?
The ans givem min x is 12
x is maxima
you need maximum
They asked area not the value of
x
substitute the value of x in A(x)
yea i understand but look at my working steps my x is 8 i cant figure it out where's the mistake...
huh
yes
how
answer isnt 192?
i see no mistake
then
yup youre right
there's no mistake
the value of x is also correct
But how the x is 12 ?
you switched the places of x and y
in your figure
.....
you said you did
but you didnt
@dry cargo Has your question been resolved?
Closed by @dry cargo
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
AB is a diameter AC = CD
AP = PC = CQ = DQ
how can i prove that triangle APO and BDQ are Congruence triangles
thats what i have dont so far
Do you see why angle CDB = angle CAB?
It seems like BQD and APQ are right angles, is that somehow given?
Yes, misread
yeah so it wasnt given
Maybe send the original question
tho ADB and ACB are 90
yes, by Thales
AB is a diamater in circle O.
AC and CD are equal
P is the middle of AC
Q is the middle of CD
we can draw out OD as a radius if that helps
as i think we need to prove that AO = BD
It might not be the quickest way, but you can prove that APO is 90, by proving APO and CPO are congruent
something similar can be done for Q as well
well i dont even need to prove that they are congurent
I mean, it's obvious, but that means that angle CPO is angle APO and they sum to 180, so both must be 90
yeah
because a line from the center that divides the chors into two is also forming that 90 degree
how can that be helpful tho
Same applies to angle BQD and BQC, right?
oh
yeah i see it
so that is why they are congurent
now i gotta prove that OQ = QB
is that the next exercise?
yeah its the second section
i mean
we already have 90 degrees
so maybe we can prove its an isosceles triangle
talking about ODB
QB = OP, by the previous exercise
ok
you meant equilateral probably
because of this, proving OP = OQ is enough
but i need to prove that OQ=BQ
yes, but BQ = OP, right?
why is OP = OQ?
oh
i see
because the chords are equal
so that means the distance from the center is equal
yes, to be more exact maybe, you can prove that APO and DQO are congruent
unless that's a theorem you are allowed to use
yes there is
oh, then it's fine
Closed by @dire turtle
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
cricles N and M are equal while their radiuses are 8 cm, they are tangent to each other at point A. BC is a tangent to both circles at point B and C. and there is another small circle which is tangent to BC and the other circlces.
i need to calculate the radius of the small circle
what i did was this
the radiuses are all parallel and BCMN is Parallelogram
i cant see what to do next
use pythagoras
in what triangle
half the equilateral triangle
what equilateral triangle
how many equilateral triangles are there in the image?
zero?
yes
O is the middle of the small circle
lets say the raidus is r
so what would that make AO?
8 - r?
you can find all sides of those right angle triangles by using some clever ideas
yes
yeah now i see
now you can find the size of O
my guess its two
that's what i got
why is DA 8 again
D being the point where
the small cricle
is tangent to BC
oh ok
its a square
i see
thanks
.close
Closed by @dire turtle
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
What I did just added 200 for upcoming number 500+700+900+1100+1300+1500. Is there any other ways to solve this?
if you know how to find the sum of an arithmetic progression in general, you can view this one as a progression with 6 terms, first term 500 and common difference 200
I have heard of that but not sure
ok lets analys it
500 + 200 + 200 + 200 + .....
6th birthday?
500 + (200 * 5) = 1500?
Wait what
oh sh it says 200 more
yeah
im bad in english sorry let me reanalyse it
Sn is the answer
n is the parameter used to define this relationship meaningfully
1st,2nd,3rd,....6th
but for 1st birthday its not in AP , AP starts from 2nd birthday
oh that makes sense
n is number of iterations, and d is the difference
ok
oh okay
wait wat but theres no answer like that
its K
wait how come its 6/2 and not 5/2??
you said its the nth term
oh yeah sorry
and its asking for 6th term
Closed by @gloomy bough
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
How would I compare $\frac{dx}{log(x)}_e^{e^2}$$ and $\int$\frac{e^x dx}{x}_1^2$ without Li(x)?
.close
Closed by @mighty shuttle
Use .reopen if this was a mistake.
.close
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
does this apply to closed subsets as well?
It does, and you shouldn't have too much trouble.proving it using this proposition
(Hope the fireworks were fun)
I think i got the idea for that other one down
its pretty simple I think. A closure is literly a closed set. it has all its limit points
that was a result from a lemma right
its a mixture of lemmas i think
because its taking into account what an interior point is
what a boundry point is
and that a closed set is defined as its limit points, which are related to an arbitary sequence
yes
A bar is closed so all limit points are inside it and so you have one half of the set inclusion
${x \mid \exists (a_n) \subset A s.t. a_n \to x} \subseteq \bar{A}$
ΣΑC
so that proposition gives you that set inclusion
you just need the other direction
Let F be closed, and x_n a convergent sequence of elements of F. Since F is closed, it is equal to its own closure, e.g. it has its interior points and its boundary points. The limit point is either an interior point or a boundary point, and F contains both.
sure thats true just seems a bit redundant when you could just cite this proposition^^
or are you just restating the prop
bc i see ur using F and not Abar
i just used the prop to make this as my proof for answering the question
since i thought this prop was the solution essentially
i mean its one half of the "if and only if" yes
you are trying to show that these two sets are equal
${x \mid \exists (a_n)_n\ \subset A\ s.t.\ a_n \to x} = \bar{A}$
ΣΑC
that proposition tells you that the left hand side set is contained within the right hand side set
the LHS represents the limit points from the set, and the right hand side is saying that the closure is all points plus the boundry right?
sure yeah
your definition of closure is interior union boundary
youre trying to show its equivalently all limit points
man i gotta say, this stuff here makes me question my hobbies
in a good way or a bad way lol
haha, its fine. its like a crossword puzzle
tbh i dont undestand. I get what the closure is and I understand the idea of limit points being sequences
i understand their eqivilent statements
if you have a closure then it has all its limit points
just for context (chartbit lurking :p )
okay but this is only one half of the "if and only if"
your proposition has allowed you to show "all limit points lie inside the closure", you now need to show that "the closure is contained inside the set of all limit points"
then those two sets will necessarily be equal
@cerulean sail do you wanna jump in? i gotta start getting ready
okay maybe go and think about proving this second quotation
you've spoke about the ideas before, open balls and stuff. try splitting it into two cases, interior and boundary
okay happy new year!!
okay an interior point is less than r, and an boundry point is r with the balls and such then
so its gonna be the union of points that are less than r and points that are less than or equal to r
haha something like that maybe
.close
Closed by @meager pike
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Find a basis of P2 in which the vector x+3 has all coordinates equal to 1
so you want to find a basis (b1,b2,b3) such that x+3=1*b1+1*b2+1*b3
Derivative
is b1 b2 b3 in the form (1,x,x^2) ...
since it says p2
i just looked at your problem and i guessed it at once, look:
$\left{ \overrightarrow{b_{1}},\overrightarrow{b_{2}},\overrightarrow{b_{3}} \right}=\left{ 3,x-x^{2},x^{2} \right}\\rank\begin{pmatrix}
3 &0 &0 \
0& 1 &0 \
0& -1&1
\end{pmatrix}=3$
Joanna Angel
yes but how do i get that
you can try such method:
$\begin{pmatrix}
1 \
1\1
\end{pmatrix}=P^{-1}\begin{pmatrix}
3 \
1\0$
Joanna Angel
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
$\begin{pmatrix}
1 \
1\1
\end{pmatrix}=P^{-1}\begin{pmatrix}
3 \
1\0
\end{pmatrix}$
Joanna Angel
P is the transition matrix from the old basis to the new basis, note that your problem has many solutions, so you just need to guess the system and then show that it is a basis, as I show the rank of the matrix
i didnt learn rank
i just learnt coordinates, dimensionm basis, span and linear combination
In every linear space, all bases are equinumerous, this is a very well-known theorem and from this, I can conclude that every system of independent vectors in a given space, which is equinumerous to any basis of this space, is itself a basis of this space.,
The basis of the space of polynomials of at most degree 2 has three vectors, so every system of three independent vectors in this space is also a basis
So all you really need to do is guess three vectors that are independent, and this will be your solution.
@crimson sedge Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Lucas
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Hello,
I'm doing an exercise on the analaytical way of solving the quantum harmonic oscillator.
I first start with schrodinger's equation
$-\frac{\hbar^2}{2m} \frac{d^2\phi(x)}{dx^2} + \frac{1}{2}m\omega^2x^2\phi(x) = E\phi(x)$
Then I do a substitution to nondimensionalize x $x =\tilde x / \beta$ with $\beta = \sqrt{\frac{m\omega}{\hbar}}$
By doing so I find :
$\frac{d^2\psi(\tilde{x})}{d\tilde{x}^2} - (\tilde{x}^2 - 2\epsilon)\psi(\tilde{x}) = 0$ with $\epsilon=\frac{2E}{\hbar\omega}$
Then it is suggested to use a solution of the form :
$\psi(\tilde{x}) = e^{-\frac{\tilde{x}^2}{2}}h(\tilde{x})$
So I plug it in and derive the following differential equation for $h(\tilde{x})$:
(From now on i'll use Lagrange's prime notation for derivative with respect to $\tilde{x}$)
$h''(\tilde{x}) - 2\tilde{x}h'(\tilde{x}) + h(\tilde{x})(2\epsilon - 1) = 0$
It is then said to use a solution of the form :
$h(\tilde{x}) = \sum_{m=0}^{\infty} a_{2m}\tilde{x}^{2m + p}, \quad a_0 \neq 0$
And now I have to show that there exist two independent solutions that corresponds to p=0 and p=1.
So first I derived h two times:
$h'(\tilde{x}) = \sum_{m=0}^{\infty} (2m + p) a_{2m}\tilde{x}^{2m + p - 1} $
$h''(\tilde{x}) = \sum_{m=0}^{\infty} (2m + p)(2m + p - 1) a_{2m}\tilde{x}^{2m + p - 2}$
and plugged it into the equation and I get :
$\sum_{m=0}^{\infty} a_{2m} \tilde{x}^{2m + p} [(2m + p)(2m + p - 1)\tilde{x}^{-2}-(4m+2p-2\epsilon+1)]=0$
So my guess is that the sum cannot equal zero since It would mean the wave function is always zero.
So now I think I should try to solve the following but I have no ideas.
$[(2m + p)(2m + p - 1)\tilde{x}^{-2}-(4m+2p-2\epsilon+1)]=0$
Thanks in advance !
Lucas
@flat forge Has your question been resolved?
A series is zero if all the coefficients are zero
Oh you say that
It's unclear what your question is
Show the original question
Sure, wait 5 min while I'll translate it
Lucas
(There are still some questions after in case you were wondering)
Yea I think you just apply this and make observations about what p has to be
You just need to group the coefficients for each power of x by either shifting the index for one of the sums, or shift the power of x
I'm not sure to understand, isn't what i've done (at the end of my initial post) what you've just said?
Because I get $(2m+p)(2m+p-1)\tilde{x}^{-2}=4m+2p-2\epsilon+1$
Lucas
and it seems strange
I havent tried this problem because this amount of notation exceeds my own laziness, but I suggest starting by simplifying the problem by setting p = 0 and trying to find the coefficient corresponding to x^0 in your power series representation. What system of equations do you get when you do this?
This isn't shifted
Your coefficients in a power series shouldn't depend on x
If you are having trouble finding this by just observing the equation and being careful about your choice of m. Note that you can extract the nth coefficient of any power series by taking the nth derivative, dividing by n! and evaluating at x = 0.
But you probably shouldn't do it that way because this should be easy enough by solving it via "inspection"
e.g., find the coefficients of the polynomial
(1+2x+3x^2) +(4x+5x^2+6x^3)
Yeah I got it i think
So since I have the following equation
$h''(\tilde{x}) - 2\tilde{x}h'(\tilde{x}) + h(\tilde{x})(2\epsilon - 1) = 0$
Lucas
I see that the h' and the h will get factorized nicelly
But I'll have trouble with h''
So I should do something so that the sum depends on x^(2m+p) and not x^(2m+p-2)
To factorize it
I can't decipher what you are saying, but I get the impression you didn't try either of the approaches because I think your response would be less vague if you did.
I'm sorry I'm not really familiar with power series, I'm trying to "verify" if I understood what you were saying
But from this message I had the impression i was on the right track with what i've said
Just tell me, in the case that p = 0, what value you need to set m to for you to get information about the coefficient of x^0
Well, I would say m=0 ?
Is that the only m?
for x^2m=x^0 I think so
What happens when m = 1?
I get x^2?
Take your whole equation here
sure
and plug in p = 0 and m = 0, then plug in p = 0 and m = 1
The point is that when m = 1, you will have an x^(2(1) + 0) coefficient multiplied by a x^-2 which gives you x^0
So to extract the coefficient of x^0, you need to look at multiple values of m because of that x^-2 term. This is what Riemann meant by needing to shift the indices
Because you need multiple m's, this is going to give you multiple equations for your unknowns and you can reduce it to a linear algebra problem with a nontrivial solution.
Ok, but then how should I shift the indices ?
Do example 7.2.3
And the one after
Or review your own calculus book
Oh I think I did something wrong right from the start then
Because I did not shifted the indices when deriving the sums
Wait no
The term a_0 =/ 0 in my case
So it's still correct
But then for h'' I can rewrite it as :
$h''(\tilde{x}) = \sum_{m=-1}^{\infty} (2m + p + 2)(2m + p + 1) a_{2m+2} \tilde{x}^{2m + p}$
Lucas
Oh
I have two solutions
for h''=0 at m=-1
p=0 and p=1
Ok
It' still somewhat strange but It looks better
$\sum_{m=0}^{\infty} \tilde{x}^{2m + p} \left[ a_{2m+2} (2m+p+2)(2m+p+1) + a_{2m} (2\epsilon-1-4m-2p) \right] \+ a_0 p(p-1)\tilde{x}^{p-2}=0$
Lucas
I find this equation
@flat forge Has your question been resolved?
@flat forge Has your question been resolved?
Ok I got it
from this equation I can deduce two things
For the term in x^2m+p i can find the following recurrence relation
$\frac{a^{2m+p}}{a^{2m}}= \frac{4m+2p-1-2\epsilon}{(2m+p+2)(2m+p+1)}$
Lucas
This is the condition for the first term to equal 0. Now for the second one it is oviously p=0 and p=1
therefore I have two "couples" of conditions:
p = 0 and the recurrence relation, and the same for p=1
And if somehow a_0 wasn't non-zero, I would only have the recurrence relation
thanks for your help and happy new year !
.close
Closed by @flat forge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
The base of a solid is a circular region of radius 3. For each cross-section perpendicular to the x-axis is an equilateral triangle. What is the volume of this solid?
what do you think the solid looks like
i can picture it but idk how to describe it
if you draw a circle and then draw small triangles from the edge to big triangles in the middle
it kinda looks like a cone
which it should be
then using equilateral triangle ratios, you can find the height of the cone
solve for the volume
how do you get the function
i found a solution online to a similar problem, since i think im wrong i can send you the link instead
yeah
so top function minus bottom function
√(9-x²)-(-√(9-x²))
2√(9-x²)
ohhh
f(x)=2√(9-x²)
and the volume is $\frac{\sqrt{3}}{4}\int_{-3}^3 (f(x))^2 \dd{x}$
mXd
i mean you dont need to use integrals for this
i’m in ap calc so that’s what we have to do xd
😭
ngl idk how to do this with regular integrals
im thinking of using polar integratoin but like idt that's what ur going for
oh wait i got it
yeah this makes sense
@gloomy crater Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
is this correct
What’s the question
just let last part
i want to express the solution of the matrix [3,-1,0,0]
Solution to what
@summer lintel Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
so I am analyzing the probabilities of 5 card hands where the player is dealt 2 cards, then 3 more cards are dealt onto the table.
if the player recieves say 2 jacks, what's the probability that when the dealer deals the house cards, the five card hand will contain 3 of a kind?
i'm not quite sure how i should approach the 2 cards + 3 cards, but I do know how to calculate the total probability of the hand even occurring
the conditions under which the five card hand will contain 3 of a kind are: the house contains exactly 1 jack, or the house has 3 of a kind
so you just want the probability of drawing exactly 1 jack or 3 of a kind in 3 draws from the remaining 50 cards
@viscid scaffold Has your question been resolved?
ok so the probability of making it a triple should be something like
$P(\text{make triple w/ jack})+P(\text{draw 3 of a kind (not jack)})$
notnick
Try composing the event into being dealt 3 cards one-by-one (you will need to decompose it further, but this is a start)
well can't i calculate the probabilities with n(E)/n(S)?
so i should just be able to find the total selections of just jack and 3 of a kind dealt out in those 3 cards
and divide by 50c3
ah yeah you can
i think
yeah you can
how would you decompose your (3 of a kind) event?
i would say ${12\choose1}{4\choose3}/{50\choose3}$
notnick
choose a card out of the remaining 12 * 3 out of 4 suits
I think this is right
so if i just add the two events (since its OR) i should be at my answer then
so like
yeah
cos the events where you draw jack and where you form a triple are already exclusive
$\frac{{2\choose1}{12\choose2}{4\choose1}^2}{{50\choose3}}+\frac{{12\choose1}{4\choose3}}{{50\choose3}}$
notnick
I'm still kind of uncomfortable with the 4C3 / 50C3
what about say (48/50) * 3/49 * 2/48 ?
@viscid scaffold Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
why so? shouldn't that be the way to choose 3 suits
it's all the ways to select 3 suits for 4 cards
multiplied by the 12 different cards no?
since we know none of those 12 have been dealt
@viscid scaffold Has your question been resolved?
Closed by @viscid scaffold
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
@sonic robin Has your question been resolved?
Closed by @sonic robin
Use .reopen if this was a mistake.
.reopen
✅
<@&286206848099549185>
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 was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
1
bymistake
i tried
i tried using properties
i might be doing it wrong
i mean
wrong approach
What have you tried?
i used properties
can you be more specific?
he meant odd even function right?
to me it seems like you just have to do u-sub 2 times
the limit half
5x^4 in numerator gives easy u-sub for 1+x^5
tried
1 + x^5 = u?
write x^5 as u-1
yeah
separate the terms
for the new one there is a new u-sub
try p=1/u
or any other variable name you prefer
okay i'll try
u goes from 1 to 2
yeah keep changing the limits and signs according to your substitution/whatever other properties you might use
ahhh its getting complicated
what did you get?
numerator was 1+(u-1)^2022 and denominator u^2024 right?
kasper should we try binomial splitting?
thats the issue
what is thta
u can seperate out 1 and u-1^2022
with 2022 power that would be very impractical
yeah for the right side one
you have (u-1)^2022/u^2024
write it as (1-1/u)^2022*1/u^2
and then do the substitution for 1/u
um
im confused
why the 1/u
okay
okkk
new integral limits are from 1 to 1/2
now?
its so looooong
use it reverse the limits
or whatever
it doesnt matter
final result after integration i got is
k^2023/2023
from 1/2 to 0
but whoever made this integral is just insane
.close?
ahh integrals are like sea
u can use whatever that clicks
theres is nothing wrong or right
Closed by @sonic robin
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Happy new year!
No
Closed by @hollow minnow
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Me again
I came back
I cannot find any relation between the fn
To have a closed form
I think you have to prove that f_n(1) = e^n
It's not always the case
yeah, nvm
Im trying the derivatives
And each time i get a polynomial multiplied by exp x
Helloooo? 🥺
what did you get for the first few? n up to 3 or 4 for example?
f_0(x) = e^x
f_1(x) = xe^x
f_2(x) = xe^x + x^2e^x
f_3(x) = xe^x +3 x^2e^x + x^3e^x
hello @sleek condor
oh no
f4 is wrong
no nvm
sorry i gotta go
Closed by @olive sluice
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
. A uniform rod 𝐴𝐵 of mass 10𝑘𝑔 and length 6𝑚 rests in equilibrium with 𝐴 on rough
horizontal ground. The rod is resting on a smooth peg at 𝐶, where 𝐴𝐶 = 4𝑚. The angle
between 𝐴𝐵 and the ground is 𝜃,
Where tan 𝜃 = 0.4
Given that the rod is on the point of slipping,
Find the coefficient of friction between the rod and the ground giving your answer to 2
significant figures.
Not sure how to get to the correct answer
@mighty tree Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
this question doesnt make sense to me
these were the only options
but shouldnt it be 0,0 and then 5,8??
SOMEONE HELP
IM GOING CRAZY
wait like yeah what
calm down
lol chill out i have like 4 phrases
YES
yeah the ones you've shown are all wrong
is it possible at all to skip this question
It sounds very urgent for some reason
Being calm and focused will help to think better
💕🐾
🐾💕
or is this an "if i don't do this i will literally get expelled from school and my life will be ruined" situation
ok.
i was actually helping a friend but then i came here because i thought i was going crazy
Since 5,8 is not in option take 8,5
and are the stakes high at all for the friend?
that isnt there either
option third has 8,5
they are sure there are no more options.
ok wait
oh wait oh my god yeah
wait
smart boy i am not sure it's a good idea to try to look for the least wrong answer of 3 obviously wrong ones
WHAT
it is ??
oh wait
STOP CONFUSIN
see first one is marked (b) there will be an (a)
what da hel
are u saying
hes saying maybe your friend missed a 4th answer option
which is actually the first
but who knows
maybe the question itself is fucked
👍
@toxic coral Has your question been resolved?
Closed by @toxic coral
Use .reopen if this was a mistake.
@tropic oxide @low plover @limber marsh there was a 4th option that my friend missed...
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
. A uniform rod 𝐴𝐵 of mass 10𝑘𝑔 and length 6𝑚 rests in equilibrium with 𝐴 on rough
horizontal ground. The rod is resting on a smooth peg at 𝐶, where 𝐴𝐶 = 4𝑚. The angle
between 𝐴𝐵 and the ground is 𝜃,
Where tan 𝜃 = 0.4
Given that the rod is on the point of slipping,
Find the coefficient of friction between the rod and the ground giving your answer to 2
significant figures.
Not sure how to solve
you assumtion that Rc is horizontal is wrong
rc will be applied perpendicular to the rod
@mighty tree Has your question been resolved?
Closed by @mighty tree
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
can somebody please help?
THEOREM The set N is infinite.
Proof. By contradiction: suppose that there exists an application f: N --> In bijective; f|In is injective and has, as immediately occurs, an image that is a proper subset of In. Thus In is placed in one-to-one correspondence with one of its proper subsets, which is absurd.
What part do you want help on
The proof, I don't get it
Visually I don't understand
What is ln or In or wtv
In = {0,1,2,...,n-1} if the set has cardinality n
Alright, so obviously those are finite
You can try proving any injection In -> In is actually a bijection
Then that might make things more obvious
What is f|In ?
the function f but only taking elements of In as inputs?
its a new function called f| ln : ln --> ln and f| ln( x )=f(x)
called f restricted in ln
the arguments says we have found a way to put ln (finite set) into something smaller (still finite) than it self by a bijective map
which is absurd
and thus such application f can not exist, leading the conclusion that f must be not finite (infinite)
@hollow storm Has your question been resolved?
Okay I get it now thank you!!
.close
Closed by @hollow storm
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Guys explain this to me i cant understand orthonormal only orthogonal
orthogonal == perpendicular
orto+normal == perpendicular(ortho) + length 1 (normal)
so orthogonal only asks delta(i,j) = 0 when i is not j
that is just the dirac delta
Ohhh i see
inner product with others in the set is 0
innerproduct with itself is 1
Yes
Whats the point of number 3
Have you learned what a basis is
Yeah
Apply the definition of basis to S and T for the given v
@bronze pivot Has your question been resolved?
Closed by @bronze pivot
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
so basically i have to find the positive and negative coterminal angles
normally i would resort to add 360 and subtract 360
but i saw somewhere that -920+360(2)
and -920+360(3) also work
how does that work ?
@sinful field Has your question been resolved?
.close
Closed by @sinful field
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
can i get some help on what to do?
i mean if ur allowed to compute u can pretty much just use cas ig
This is what I drew
I don’t think I’m allowed to use a computer

i guess they dont mean computer when they say "compute"?
also yeah this looks right
u know where to go from here?
Not really
i would try finding the side length of the small square
How would I do that?
Do I have to use a theorem
umm not really
i figured it out u just need to see that this is equal to the radius of the circle
The black line is the radius right
yes
How does that help?
use pythagoras on this triangle lol
in terms of side length of small square and radius
and the big square ofc
Well
The bottom leg of the triangle is half the side length of the small square
And the hypotenuse is the radius
Not sure about the other leg
@native vale I have to introduce variables?
yes
call the side length of small square s or something like that
the other leg would be half the side length of big square plus side length of small square
u can find half the side length of big square pretty easily
no u can find that out pretty easily by using pythagoras on this
@kindred hornet Has your question been resolved?
@kindred hornet Has your question been resolved?
If my little sister is 10 years old and im 5 years older than her. How much older am i?
Huh
.close
Closed by @kindred hornet
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
im a bit confused as to how E(X0 + X1 ...) = the answer
isnt part b asking for the expected number of stickers the collector must buy to fill his album
wouldnt summing those individual geometrically distirbuted events just tell me the expected amount of stickers i would need to collect to obtain a new unique sticker ?
@crimson sedge Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I am trying to prove the fact that $x + x = x$ and $x \cd x = x$ in a Boolean algebra using the postulates. I will just prove the former and conclude the latter by the duality of a Boolean Algebra.
\vs{5 mm}
\env{alignat*}{{2}
x + x & = (x+x) \cd 1 \q &\c b{x \cd 1 &= x} \\
&= (x+x)\cd (x+x') &\c b{x +x' &= 1} \\
&= \bs{x\cd(x+x')} + \bs{x' \cd(x+x')} &\c b{x \cd (y + z) &= (x\cd y) + (x \cd z)} \\
&= \bs{(x\cd x) + (x\cd x')} + \bs{(x'x) + (x'x')} &\\
&=\bs[\big]{(x\cd x) + \underbrace{(x\cd x')}_{=0}} + \bs[\big]{\underbrace{(x'\cd x)}_{=0} + (x'\cd x')} &\c b{x \cd x' &= 0} \\
&=(x\cd x) + (x'\cd x')
}
either something went wrong or im going no where with this
like what do i do now 
okay fuck something definitely went wrong lol
the last line is saying [
(x\cd x) + (x' \cd x') = x + (x'\cd x') = (x+x') \cd (x+x') = 1 \cd 1 = 1
]
it feels so weird
what postulates are you working with? I never worked with boolean algebras but I always thought idempotence was part of the axioms
in your third line what substitutions are you using?
i like
foiled it basically by the distribution of the multiplication operator over addition
ok interesting. the 4b and the fifth one must be quite powerful. cause the other ones are just standard ring stuff
like whys the second one a x' multiplied by stuff
shouldnt it be x multiplied by stuff
do you have 0x=0?
no thats a theorem i will also be proving
but like
the issue is now
im still going in circles i think

i mean is it fine if i take some of the other theorems as fact and then use them to prove the implication
wait is there not even associativity?
no
i dont have associativity
i mean associativity is valid
but its not a postulate
the proof for that is very convoluted i believe
it follows from the other ones? very interesting
yes
hmm ok. sry but I cant help you. but interesting stuff