#help-39
1 messages · Page 65 of 1
@dusk otter Has your question been resolved?
This looks good too
Great thanks!
Except for the second line where you forgot to put the integral sign, but the integration is correct and the result too
oops yes sorry!
is the one above correct?
Yep, looks good too
For part a, you have to use the initial condition given and find the specific solution
Oh my I didn't even see that thanks!
How's this?
Yeah
Okie the last one I am unsure about
I am not sure that I found the mass right
because in all my profs examples they have all been bounded by one curve not ever too
You incorrectly substituted delta(x) here, also in this case the mass of the plate will be $\int_{0}^{1} \rho(x)(x^{1/4}-x^{2}) dx$
smidgin
Ohh yess that makes sense
Since you have to do upper - lower
to find region in between
The density stays constant for a given x coordinate, so the mass of a small slice with constant x coordinate will be (density function)(length of slice={x^1/4-x^2})(width of slice=dx)
Yes
Is the moment part correct?
Wait wouldn't I have to write it in terms of why or no?
Because isn't dx for vertical slices?
Yes, and the density for a vertical slice is constant
Yep the center of mass calculation looks right except for the mass of the plate part
You should also change the diagram you made for the finding mass part in case someone will be checking, since we took vertical slices to find the mass
mhm just did that!
It's just homework but no one will be checking but still important to fix!@
How's this?
👍
Thanks for the help I appreciate it!
@dusk otter 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.
Help please
could you .close? it appears you made a duplicate
.close
Closed by @tired lance
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 zeroes, and then find the difference between them; y=x^2+bx+c
@pastel oriole Has your question been resolved?
can you show your work?
i have done the previous question from this where it shows to find the vertex
which was -b/2a
@midnight haven
Do you know the relation between the sum of the roots and product of roots?
no
they have taken quadratic equation of the form
ax^2 + bx + c = 0
but your equation is x^2 + bx + c = 0
so a = 1 , in your case
so the sum of the roots x1 + x2 = -b
and the product is c
so
x1 + x2 = -b
x1*x2 = c
and you have to find the difference of the roots , which is x1 - x2
use the following identity and show your work
$$ (a-b)^2 = (a+b)^2 - 4ab $$
just panic
so its just 1
but what condition on the constants b and c must be satisfied for the difference to be exactly 1 if 1 is the answer?
noo
1 is not the answer
a , the coefficient is 1
in your case
the standard form is ax^2 + bx + c = 0
but your equation is x^2 + bx + c = 0
so a =1 , I said
so the zeroes are 1
NOO
I have given you relation between the zeroes
let the zeroes be x1 and x2
so x1 + x2 = -b
x1*x2 = c
you have to find the difference
which is x1 - x2
and I have given you the identity to solve
how old are you , or which grade is this?
im in yr 10 doing yr 11 work
then , u should be able to understand
read this again
and what i have sent before
sorry im used to identifying zeroes in another forma
do you want me to expand and simplify?
please read this again
@pastel oriole Has your question been resolved?
<@&286206848099549185>
@pastel oriole Has your question been resolved?
Closed by @pastel oriole
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.
For which values of the real parameter λ, the vectors a_1 = (λ,-1,-1), a_2 = (-1,λ,-1) and a_3 = (-1,-1, λ) are not linearly dependant
ive got no clue how to solve this can someone pls help?
The three vectors are not linearly depenent.
Make sure that the combination of two vectors can't be the other one.
false. we need to find the parameters of lambda for which those 3 vecotrs are not linearly dependant
for the values -1 and 2 i found a solution online .
.close
Closed by @velvet hound
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.
Resolve this system
Hello, I tried this
L2=L2-2L1
2 -1 1 -2 | 2
-) 1 1 -3 1 | 5 ×2
0 -3 7 -4| -8
Hello, I don't really understand what is the step before that
@thick copper Has your question been resolved?
When reducing a matrix, you want to use one constant row to reduce the others. Meaning that in your first step, it's incorrect because you used row 1 to reduce row two and the original row 2 to reduce row 3. You forgot to take in consideration, at the fact that after you reduced row 2, it becomes something new, therefore, you can't use row 2 to reduce row 3
oh, it's your first step
you got it wrong
Ohh makes sense thank you so much
Oh ok, you did L2=L2-2L1, besides that it seems that you changed rows (?), and the last row I am really confused tbh
the last row is the resultant
i just write down the resultant of L2=L2-2L1 for checking
Ohh lol okay thanks!
i think if you do it carefully again, you would get the result you want!
do ping if you have rewritten your work and wanna have it checked
Closed by @thick copper
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 found asnwer as C but it says it supposed to be A. where did i do wrong?
i can't read your work
yes
same for these it says both supposed to be E
these two are indeed supposed to be E
finally deciphered your work
the end result you had is correct for the previous question, but your work is a bit flawed
ok i did 73 again it's E but i didn't get 72
how so
your g'(x) isn't applicable for all x
i took derivative wrong?
you took an unnecessary loop, and ended up writing someting a bit invalid
in general, how would you differentiate
x^2 f(x)
forget about what's given in the question
(x^2)' f(x) + x^2 f' (x)
f' (x) is 1/squareroot 3 right?
f'(1) is 1/sqrt(3)
with the g(x) you had, you'd run into issues if you used another value than x=1
as that'd give you a point on the tangent line instead of the curve for the f(x) component
isn't f(x) = x-1/sqrt(3) +4?
no
why not
f(x) is the curve
ignoring your absence of parentheses
y = (x-1)/sqrt(3) + 4
is the equation of the tangent line
which is not the same as your curve
yes it was true
using what you wrote, you'd end up getting the red point instead of the blue point at a different value of x
for that f(x) component
f'(x) is 1/squareroot 3 only for x=1
yes
well not necessarily only
just not all values as the slope could potentially be the same at another far off location
that makes lot of sense
as for q72, consider chain rule or the use of a substitution
why is 72 D here
okay give me a minute
yeah you're right
lol
thanks a lot you really helped me
.close
Closed by @burnt raptor
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 we have negative triple factorial?
sory broI shared it on the wrong channel
Okay
Like with double factorial (-1)!!=1
@quaint crown Has your question been resolved?
damn
.close
Closed by @quaint crown
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.
there should be some relation between numbers either in same column or line
i can't find it
some of these numbers look familiar
64
125
512
do you recognise anything special about them
oh for god's sake
lol
thank you
idk how i didn't see that
i was looking it wrong
.close
Closed by @burnt raptor
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.
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.
please read the bot message above
I did intend to delete it tho
regardless, the channel is set to close
so unless you want the potential convo to be cut off,
make a new channel
It's already closed
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.
1.Path functions are function which depend on the path followed b/w 2 states
2. Path function are function which does not depend upon initial and final states.
Which statement is true ?
1
r u indian
Why 2 is not true?
by definition
Yes
jee aspirant?
Jee aspirants here as well
11th?
2025
so u wrote jan attempt
Yup mains
thatss a rlly good mark actually
did u go to some coachiing
Ya and my shift was toughest so i hope to get good percentile
Although i'll work to improve in april
damn 200 without coaching is unbelievable
yea
Which one
allen
Oh thats the best one as far as I know
but it still largely depends on the amount of work u put in ursellf
Right
@hard crystal 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.
really dont have one. The answer was given im trying to figure out how to solve it
yeah but what did you try so far
im actually not sure where to start lol
did you think how 51 is composed of 2 or more integers
yes we can have the lagerest number to be 50 and smallest to be 1
what else
thats pretty much it
hint: pigeon hole principle
lol
it is not already so trivial i think...
huh
can we continue? @primal sable
you may ask everg now
why?
you can continue with your help...i only send a visual hint ...i don t think that my answer is full
how do i know if its 26 or 25 for the answer
because if you consider 25, it would be 25 + 24 which is 49
and how did you arrive to 25 + 26 without doing this
did you do trial and error?
you can do that but since its multiple choice its faster to just check the options
if that appears during a test
ahh so given the options you do n + (n-1)
sorry, im not sure how to do this one
Closed by @waxen sequoia
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 start this?
Try to think how to construct a palindrome that is longer than an existing palindrome
Like, find a recurrence relation
how exactly?
If I give you a palindrome of length n,
What can you do to it, in order to create a longer palindrome?
This creates a new palindrome of length n+2, correct?
And how many "characters" do you have?
Like, how many new palindromes can you create from the one I gave you?
n-2?
No
Closed by @waxen sequoia
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 cannot comprehend how these 2 equal each other
i understand that you could take the 2 in f(2x) and take it out
but i dont see how they change the
1 and 4
into 2 and 8
i dont get why thats allowed
Idk too but I see it this way
take 2x = t
2dx = dt
dx = dt/2
The limit should change to since we introduced a new variable t
We know 2x = t
Putting upper limit , x= 4.
2 *4 = t implies that t = 8
So upper limit is 8 for the new variable t
Now,Lower limit x = 1
Put in 2x= t implies that t = 2
So lower limit for it should be 2
so when you have an integral and theres a constant inside of the integral you can take it out and divide the boundary points by the constant it seems
You can use it as a general property if you want but you might have to change limits too so be careful.
Do you know u sub?
Or understand the concept of it?
That's basically what it did, it did a sub
Fr
it would be nice if they give me more explanation steps tho 😢
So u = 2x then du = 2 dx, therefore (1/2)du = dx
It doesn't help that the work used the same variable for the sub
Anyways the $\int_2^8 f(x) dx$ is the result after doing the sub
CaptainNova22
Because it's in terms of u, you have to change the bounds as well
here is an example of me doing u subsitution
i think thast what i do wrong i just
dont change the boundaries xd
Yeah, you have to change the bounds
i thought plugging the boundary points into the equation of u would work but i still get the wrong answer for this
like here the boundaries would be 9 and 6.25 i thought
but it coems out wrong
would become*
Because here, 1 to 12 is the bounds for when the expression is in terms of x
bc 1/4 * 12 + 6 = 9
ohh
that actualy makes sense
im chaning the x axis into a u axis
in a way
and im using
x values for coordinates on the axis
6.25 to 9 are the bounds for terms of u
so i did get that part right atleast
i think i understand it somewhat
i should be able to compute it now
So to answer your original question that's why it's 2 to 8 because that was for terms of u
Like mentioned, the solution using the same variable is confusing
theyre basically saying u = 2x and then the
boundary points
become twice as big
bc you can plug them into
u = 2x
yes
that makes sense thank you
.close
Closed by @fallen ibex
Use .reopen if this was a mistake.
Np
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? I can't understand what happened in the middle
Add +1 and subtract -1 on the LHS
1+(n/n+1)-1+1
2+(n/n+1) -1
2+ (n-n-1/n+1)
2+(-1/n+1)
2-(1/n+1)
Closed by @hushed atlas
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 know that for a subset A included in a subset B, it's 2^{n-1}-1 but idk how to do it for 3 subsets
@muted night Has your question been resolved?
<@&286206848099549185>
so this is my question
.
also the subsets have to be different than the set Z and the empty set
@muted night Has your question been resolved?
<@&286206848099549185>
every element must be in either A and B and C, or B and C but not A, or C but not A or B, or just Z
ie. every element must be in D or E or F or G
so how many ways are there to do that
and then you just have to restrict it a bit more because they aren't allowed to be empty or whatever
@muted night Has your question been resolved?
.close
Closed by @muted night
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 it actually 41? sometimes when I do this it ends up being like 40 or 42 or sum
the formula for percentile is usually $k = 100 \cdot \frac{x + 0.5y}{n}$, where x is the number of data values below yours, and y is the number of data values equal to yours
doaby
so basically the answer is 40
well no, it says round to the nearest whole number
y in this case is 1, since there is 1 data value equal to 41
I see so I should be good going 41 this time
Its always iffy for me with this one
is 41 what you got from the formula I gave?
i must've been doing it wrong since i was gettign 129.68
damn it was 39
wow
i finally see what u meant by that formula
stupid of me mb
.close
Closed by @paper sorrel
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 someone explain this two problems to me
are you familiar with integration by parts?
Yes that what I was trying to do
Im confused on the ∫ u dv = uv - ∫ v du on the (dv and du)
You'll have to do the IBP twice for the first problem
what did you make your u and dv
yeah it's a 2 cycle
@hearty breach 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.
Need help with 2.1, i asked previously how to do it and figured it out but im not sure why the same method isnt working now
can you show any work?
whats giving you trouble
Ive just been inputting it into a calculator
A phone one since my ti 84 broke so maybe not reliable :/
someone told me before to calculate from 0 to 5 and then 5 to 9 but i think i’m just stuck
well you can always use https://www.integral-calculator.com/
Solve definite and indefinite integrals (antiderivatives) using this free online calculator. Step-by-step solution and graphs included!
this one has better typesetting than most calculators so its easier to spot if youve made an error
so, okay, there is one thing you should think of
Yeah i did that and got 1422
ah, yfoure integrating the wrong function
so, you wanna use the velocity function
not really even that directly but, thats the first piece
since the velocity tells you how position changes with time
and you are going to integrate with time
Oh is it the 18t-90?
it is, but you also want to be sure that you don't get cancellation
as in, if your velocity is 4 for 3 seconds
then -4 for 3 seconds
and you integrate this
youll get 0
can you think of how to check if were going to have cancellation?
where is the velocity negative?
i guess when is the velocity negative is really want im asking
At 0 its negative?
yea, thats definitely an issue
because the arm is moving backwards, right
but, its still moving, so thats positive distance
maybe we have a way to make the velocity always positive?
like the velocity function as it is, it tells you direction and speed
but we almost dont care about direction
5 feet forward is 5 feet backwards is 5 feet for this problem
So we just do absolute value right?
yea, thats one option!
I did the calculator with the right equation of 18t-90 and i got -81 so i put 81 but its still incorrect 😞
well i give up
jan Niku
I actually figured it out i just did 0 to 5 and then 5 to 9 with the right equation and added those absolute values
I was accidentally adding one without it being an absolute balue
So i kept getting 81
Thank you!!
.close
Closed by @grave elk
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.
Hello. I need a little help with, I’ve verified this with explicit numbers so i know it’s true but my first instinct would’ve been to do this.
I know this is wrong but can anybody explain it to me
@final steeple Has your question been resolved?
okay this formula isn't quite correct, it's kinda hard to see what you're trying to do
oh wait nvm I see what you did
this is fine, but you would need to keep the 2 in the 1 • 2 • 3 • 4
if you factor out a 2 from here, you can only factor it out from one of the numbers being multiplied. you'd be diving 2 out twice if you did it like you said
So basically, take 2 once from those multiplied. But if I had 1 * 2 * 3*... (n+1) +2 + 2 there. Taking 2 would yield =1 * 3 *...(n+1)+1+1 ???
yes that is true
Thank you!! I hope your food is tasty and your life be filled with boundless happiness 🌟
lol thank you 🫡
.close
Closed by @final steeple
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.
Noob question. Im going through the book How to Prove it by Velleman. He defines prime numbers as integers larger than 1 that cannot be written as a product of 2 smaller positive integers. My question is, isn't one a positive integer???
yep
Ohhh
I get lmao
So it can only be written by 1 smaller positive integer considering the other one is itself
Holy macaroni
yep haha
Thank u so much. Self studying makes me dumb
i don't think i did anything but yw
Closed by @final steeple
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 someone tell me why the vectors span R^2?
does span R^2 mean that any linear combination in the set should make any vector in R^2? so, how to make vector [1, 1] using the vectors in set?
or did i misunderstand something?
@vestal terrace Has your question been resolved?
- it does mean that you can construct any vector in R^2 using a linear combination of the vectors in the set (although you don't actually need all of them, any two will suffice)
- to find a the coefficients needed to construct [1, 1] using a pair of vectors from the set, you can set the coefficients as variables, then expand out until you have a system of linear equations and solve as normal
@vestal terrace Has your question been resolved?
Closed by @vestal terrace
Use .reopen if this was a mistake.
thanks
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 is this incorrect???
sin^2(a) - 1 isn't cos^2(a)
should be using pythagorean identity tho no?
yes, but you need to use it properly
start with the common form
s^2 + c^2 = 1
from there what's
s^2 - 1?
-c^2?
yes
so it would be -cot(a)?
yes
.close
Closed by @shell bay
Use .reopen if this was a mistake.
Thank you!
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.
hi
can you write it out?
lim x-> ∞ lnx / x =0
Use expansion of ln(x)
@waxen talon take over
Expansion series
do u know l'hopital rule ?
are u familiar with big O and little o notations ?
no
why l'hopital this is the definition of the derivative
I'm not sure
i was talking about this limit
,, \m {f'}a = \lim_{x\to a} \4{\m fx - \m fa}{x-a}
just use this
its the definition of the derivative
Closed by @boreal tapir
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.
Alright. So we go to a casino with x money. Every bet gives out what you bet, so bet a dollar and you win a dollar or loose it. winning a bet has a 15% chance of happening. Im using the martingale system starting with a dollar and doubling down on every lose, and if i cant afford the lose i start over with a dollar bet again. If i win i start down at a dollar again, How much money i need for this system to yeild a 50% of winning 100k dollars profit while the other 50% chance is of going broke before i do it
Theres sub questions but where im stuck is comparing xmoney and lose streak since losestreak is a function of xmoney, so i would like to know how you do it in short 😅 thanks
Statistics/probability question
@whole valley Has your question been resolved?
<@&286206848099549185>
@whole valley Has your question been resolved?
@whole valley Has your question been resolved?
<@&286206848099549185>
@whole valley Has your question been resolved?
there are two
What is the value of xmoney
<@&286206848099549185> question is what is the value of xmoney, number
multiply both nmr and dmr in with x then do Direct substituition
u will get 0
This is a diffrent ticket now, he also got his answer
it doesn't even sound like it's definitely possible
maybe you can't get an arbitrary chance
If you put a number you will get the other number, you just dont use all of the info at the same time
From what i was told its all about functions, you play with the numbers and ratio @vestal tapir
I hope that makes any sense
well ok 50% is not very arbitrary, i can see it being possible
i give up
Alright, you got any leads on the functions relationship before.you go?
no sorry
Alright, thanks for trying
<@&286206848099549185> has not yet been resolved
Thanks,
It says above, probability/statistics
Also previous knowledge of martingales would help a lot
Do you think i can ping a mod or someone? Its been 8 hours today with no answer
have u tried googling it
Googling which part
the question
I did but..
Didnt get a strightforward answer
i think i just need someone who studied martingales
i don't think that's how martingales work
the amount of bankroll at the start doesn't change the odds of doubling your money before going broke
It does not, it just effect the lose streak, and both have only 1 definite number that confirms all the previous data
oh i misread 100k as 100%
And its not about doubling your money, its about 100k
,w solve 0.85^n = 0.5
are you fcking kidding me
Huh?
okay so, you have a ~56% chance of not going broke in 5 doublings
What??
so at a starting bet of 100k, you need 3.2 million dollars
the starting bet is 1
Thats not how this works.. you cant just tree diagram your way out of this
Must start at a dollar after every win
this is about winning 100000 times, but when you lose you still have money, and that even without being able to use winnings
oh if you have to start at a dollar, then you cannot guarantee a certain probability of winning 100k
even if you have [an arbitrarily large amount of] money
Its about profit so you actually can use the winnings, good point, i forgot to mention that
I guess i just didnt get to that part yet
like there's some cutoff
You can. Its probability
basically there is a finite, nonzero probability that you go to ruin
Yeah. Its a function of xmoney
no, you can't control the probability of ruin of the game because you don't control any of the betting
Its a set game..
like there is a probability that you go down and never cross a certain threshold againn
it's not like the unbiased random walk where you continually re-cross every point in the space
in any case, we can calculate this
it makes sense that you can't precisely control it, to arbitrary value
is thast what you're talking about?
we clearly can make it as high as we want
Look at it as an equation, you put a number and its either wrong or true, are you saying there are no trues existing as an equation?
that's the point; you actually can't. There is a certain probability that you never cross the +100k mark, just as there is one where you never cross the +10 mark, no matter how much your initial balance is
you;re confused
0 mark?
we have $1024, we have 52% chance to win 3 times immediately, and have $1027
you can cross +0 because your martingale increment is +1
This is a fixed scale therefore it has an answer, you could simply run it on code to find out
oh I see, you can reduce your probability of losing each martingale streak to arbitrarily close to zero
so you never see the negatives
Thats martingales for ya
I dont know what your looking at but we.got 2 unknown numbers, xmoney and.losestreak, i would start from there
so you're basically asking for the median of the maximum losing streak if you have to repeat 100k martingales
100k WINNING martingales
so the problem is you're also allowed to lose the streak, you still have money, it's not necessary to always win, and worse, you can use your winnings
so i gave up
optimally, you don't want to lose the streaks because then you'd have to win back that streak and the next
at least this is the case where your p winning each round goes to close to 0, but not sure if 0.15 is close enough
If you loose you just double down, every win adds a dollar to the profit
i.e. you never "give up" on one of your streaks in that you take a loss and then go back to 1
Maybe if we use the data right
the number of losses you take in one martingale round is geometrically distributed
Maybe if we solve the first lose streak we could solve the final one
maximum of geometric distributions is kinda rough but probably solvable
Yes.
do you care if this is approximated
I honestly don't want to be bothered by the discreteness
So lets go from scratch, do you guys have any idea how to show what function lose streak is to xmoney? Because 1 unknown is solveable.
A lot more
I do, everything matters in statistics
lol
tell that to every person who uses asymptotic approximations in their hypothesis testing
Their task is not researching martingales
lmao
Its to solve for a problem
in any case, it's just find the length such that P(max(G1, ... G100k) <= length) >= 0.5
if you knew what a martingale actually is
and P(max(G1, ..., G100k) <= length) can be factorized as P(G1 <= length)P(G2 <= length) ...
Its a sequence
,calc (1-0.85^74)^1e5
Result:
0.54968269883732
that's the dumb answer
hmm actually the length doesn't give you that much because you can use the previous winnings
but the previous winnings are pretty insignificant compared to the necessary bankroll
yeah but your bankroll is at least in the trillions
your cumulative winnings are on the order of ~100k, no?
Your winnings could also be a recover of what you lost.
in your scheme, you never lose until you go broke on one round
Yes
it's insignificant
like you will probably need 2^73 dollars or something to make it, no?
the winnings don't help, so little help, so hopeless
They could also include a lose. For a example you could recover.your entire first lose streak when you start again from a dollar, do you still count that as winnings?
Thats a pretty high precent
huh, no? you never lose in between the martingaling streaks
What?
i.e. you basically just go back to a dollar 100k times
if you lose the streak, you're done, what you have left plus what you won doesn't help
if we don;t account for that, we get about the same number
it's not satisfying, sure
yeah basically if you ever can't make the doubling bet, your remaining money is no way in hell going to get you all the way back up
Are you sure? I havent calculated it but we should have between 1to40% of our original money after loosing an unaffordable streak
you can give a Markov bound on that
yeah but now you have to make back all of your original money instead of just the 100k
and your original money is in the order of the trillions or hundreds of trillions
Are you sure were in the trillions?
absolutely
Alright, so whats the lose streak we recieved?
like 74 or something according to frowny's calculation
i can be off by one or even two
no you don't lol; 2^74 is more million-dollar bills than the world can print
Bro that might aswell be 1/100000000 cents. That doesn't matter
I want to do it right
@vestal tapir How did you find xmoney?
it's still going to be 74; the discreteness gives you the benefit of discarding all of the insignificant effects lol
.
what do you mean by do it right? you're asking for a whole number answer
and if you bound the probability P(winning with only enough bankroll for 73 losses) into some tight range that is less than 50%, then you need 74
do you have something against inequalities or something
the effect that you have some of your money leftover adds close to nothing to your probability of winning
if you could choose where you started in this martingale "strategy", maybe, but you can't
Alright, so how did you calculate the lose streak?
how long each losing streak is is distributed geometrically with p = 0.15, i.e. your probability of winning
you can either look up the formula for the cdf of this distribution or figure it out yourself
it's something like (1-0.85^x), totally forgot
you need 7 dollars to bet 3 times, so 74 is right i think
in any case, you know that this raised to the 100k has to be greater than 0.5
Yeah, what did you do with that
you're able to bet 74 times, so you lose with chance 0.85^74 so you win 1-0.85^74, so you never lose (1-0.85^74)^1e5
Didnt get that last part
You can loose,??
if you run out of money
this is the derivation of "what is the probability that I never lose one out of 100k streaks if I can double 74 times?"
No its good thanks, im just a bit confused on this part.. your allowed to lose one out of the 100k wins
if you lose once you're left with half your money sure, but you need to win sextillion dollars now, so you can't
True
So leaving that out of the way
Did i misunderstood you or did you say a streak of 100k consecutive wins
yeah you need to win $1 100,000 times consecutively
No 😭
in other words, you need to not go broke 100,000 times consecutively
yes, it's what we're leaving out
split the game up into several subgames which encompass the whole cycle of doubling until you win: each game you have a probability of 0.85^74 of not being able to bet (and losing sextillions of dollars) and 1-0.85^74 of coming out $1 ahead
If you loose you bet 2$ if you win there its +1 dollar, if not you bet again
by lose i mean going to $1 bet
Yes
Alright!
so you need to win all 100,000 of those subgames, or you won't win
Yes
the probability that you win all of these is (1-0.85^74)^100000
and this comes out to slightly over 50%
i'm not sure i trust the calculator to do power of 100k lol
So how did you get that 74 number again
I think most calculators do exp of log multiply
guess and check
So there is no definite way to do this without trial and error?
ok i will trust
I thought i was doing something wrong.. no formula
you want (1-0.85^x)^100000 >= 0.5, so just take roots and use logarithms
you may need to solve it computationally in a smarter way than just taking the roots, however
However?
because 0.85^74 is smallish and you might have computational inaccuracy, but just try it the naive way first
0.85^x = 1 - 0.5^(1/100000)
i think we think the problem is technically impossible right?
there is no amount of money where it's 50%
yeah I don't think so (there's no amount of money where it's 50%)
What
that's kind of the promise, what if there is, how surprising is that, well done on solving this
like you can do some sort of bounding of the probability that you recover from a loss
Thanks it helped me a lot
probably even a weak bound like Chebyshev's inequality can show it
From there i can probably use pie / and opposite of ^ to find a finite answer
That part is cleared
So thats how you found lose streak?
That doesnt seem right
the other related part is that this will never be feasible in practice, because if are forced to reset for reasons other than bankroll size, say at #bets = 50, then you can show that there is no initial bankroll size that will let you win with a probability greater than a certain amount
Thats borders, not exactly true
Its just not exactly finite
You can find it using lose streak like we did here
like there are concentration inequalities from supermartingales that apply if your bet sizes cannot get arbitrarily large
Hmm. Wont it just mean the number is not worth calculating for?
Because there is probably a number that answers this
no I mean that, for example, if the casino sets a limit at 50 doubles, and you want to win 1 million dollars, there may not necessarily be a bankroll amount to actually win this million with greater than 50% probability
So about that..? There really is no way?
50 double downs?
the equation I gave tells you how to calculate it for the original problem you gave
yes
Oh i thought you said 50 max bet
Yeah that makes a lot of sense
How is it related to this problem tough
more generally, you need the ability to reduce your probability of actually taking a large loss to zero to get this to generalize arbitrarily
like if the casino decides to cut off your doubling if they flip a coin 20 heads in a row, you're also in trouble
Yeah
You thought this was meant for personal use?
Im not sure i get where.you going with this
no I mean it's in a very strange regime of conditions where none of the concentration inequalities apply (rather, I should say they're not strong enough)
because things get unbounded
Alright the answer is 73.1
so you need 74
The answer is 73.0957
74 represents the number of doublings you need to survive to win with >50% probability
if you can only survive 73 doublings, you get something less than 50% probability
this is just solving an inequality where the thing you're solving for can only be an integer
73.1 is a number
is it an integer?
remember that the original task was to find the least integer such that (1-0.85^x)^10000 >= 0.5
no it isn't
it's a nonsense answer
you need at least 2^74 bankroll to do this
if you bring in 2^73.1, you will not win with 50% probability
Isnt it accounting for what happens after the first lose streak?
no it's not
Yeah your right..
the probability of recovery from a failure to double is infinitesimally small
like less than 1 in 1 sextillion probably
Yeah
by the way, this whole game changes if you make it fair; then none of this analysis holds up
But couldnt you theoretically run this program forever
Ofcourse.
yeah but that 1 in 1 sextillion + (1-0.85^n)^100000 doesn't matter for the purposes of calculating n
Yep..
i'm explaining why we truly don't need to account for it
Alright, are.you guys ready for sub questions? Strictly talk
there's ~49.5% chance if you have between 2^73 and 2^74 and then it suddenly jumps to 55% and also stays there until the next jump
Yeah i guess loose streak is all about jumps
I mistakenly thought the gap could be filled using the leftover money
Abs not true
Idk why i thought that
yeah, every dollar raises the probability a bit but at some point you jump right over 50%
so accounting for it wouldn't give the required answer
You could get the most true answer
no, you'd get exactly the same answer
Which is the most true answer
the problem is that the dollars in between the powers of two only contribute to the recovery probability
technically 49% is closer
so if you started with 2^74 - 4 dollars, you'd still have less than a 50% probability of winning
so we want 2^74 − 1 −1
but as soon as you get above enough for another double, your probability jumps
-4 because I can't be bothered to figure out the exact bankroll for one of the doubling streaks lol
What does the -2 accounts for
minus one was already there: it's 7 dollars to make 3 bets
so 2^74−1 to make 74
and minus 1 to make the jump down
Im confused, wouldnt it be 2^73+?
Since strictly theoretically if you put all the numbers .you get ^73.1
73 is closer then 74
Yes, but it shows us 73 is closer to the fake number
it's the formula not working right, it's super fake
Really?
Calculator bug?
0.85^x = 1 - 0.5^(1/100000) thats what i used, its the way you told you me you found lose streak
math bug?
I dont know
But if its not then this equation is wrong and i still have no idea how to create a formula to find lose streak
So what equation is right?
thank you Saccharine
yw
Is that sarcastic? I cant tell its a computer 😔
it's just a consequence of the method you use to solve it
what you are solving is an inequality where only the integers are valid solutions
but you can force it into the real numbers, use methods from that, and then remember to convert it back to an integer
And the integer i got is 73
no, the integer you get from solving the inequality is 74
it's like asking what's the lowest integer z such that 2z >= 8.2?
it ain't 4, even if you solve 2z = 8.2
did you not ask in your original question how much bankroll you needed to win at least 50% of the time?
The closest to 50%
okay, this doesn't matter that much; just adjust your answer for that
try 74 and 73, see which is closer; if 73 is closer than 74, then bring the money down from 2^74 until you can no longer double the 74th time
you're quibbling over a 1/some sextillion difference at that point
So from what i seen 73 is closer, so thats the correct way to build that equation?
it's the difference between solving the inequality for the largest integer x such that (1-0.85^x)^100000 < 0.5 and solving the smallest integer x such that (1-0.85^x)^100000 >= 0.5
one of those will get you closest to 0.5
then you need to add in the extra money to increase the infinitesimally small recovery probability
either way you do it, you get 2^74-2
So 2^74 is closer?
How do you add that money
Find it
the probability you win if you have 2^73-1 dollars is like 49.45%, and the probability that you win if you have like 2^74-1 dollars is like 54.97%
the probability that you win if you have 2^74-2 dollars is like 49.45% + [some really, really small number]
So its the same?
since that [really, really small number] is still positive, you get closest to 50% with 2^74 -2 dollars
this is just some inequality stuff
don't know what they are
I will tell them
Using the same money we got on the dollar equation which starting bet has the best chance of winning 100k profit? 10$ 11$ or 13$? Put them in a line from best to worst
$13
You sure?
bigger starting bet = better chances
yes
subject to whatever discreteness nonsense, but there's none here
But it could hit roofs like not being enough for 1 more lose streak
as an example, if you start with a starting bet of $100,000, you have a 15% chance of making it
and your starting bankroll is only $100k
Wouldnt that effect
this isn't enough in the numbers you've given to counteract the effect that you don't need to win so many of subgames in a row
if you think about it, what you're changing is the exponent here: (1+0.85^x)^(100k / starting bet) while you're only reducing the number of times you can double by maybe 2 or 3 or 4 times
so if you have the same bankroll, you should increase the starting bet to increase your probability of winning 100k
So its a golden rule even in small numbers? Like 0.0005 more
there's some bullshit where if you increase the starting bet a little, you could bring your bankroll right under the threshold for being able to double x number of times
so then you shouldn't
but the remedy there is to increase it even more
the optimal strategy is to put it all in and try to double on a single round
What is xmoney again? 2^?
the amount of money you need to survive x doublings is 2^x - 1 if I'm not mistaken
Not if you got that much money and the goal is only a partial,
I mean if you want to make $150 profit, you bet $150 per round and do the doubling from that

