#help-0
1 messages · Page 708 of 1
rikusp2002
@alpine sable
I need help with a probability problem:
Pick 2 random numbers between 0 and 99 (no duplicate). Then we pick a random number between 0 and 99 27 times (there can be duplicate), what's the probability that we found 2 numbers (from the start) in those 27 numbers?
what have you tried?
27*(1/100)(1/99)((1/100)^2)
27* since we do it 27 times, (1/100)(1/99) for two random numbers (no duplicate), then (1/100)^2 because we pick 2 random numbers (can be duplitcate) from 0 to 99 two times. But I'm not sure if im correct
why would the probability of choosing the 2 numbers matter here?
multiplying by 27 is when you have 27 equivalent cases
this is binomial probability distribution
you will need to figure out the different cases and equivalent amounts using that
@sudden jacinth have you realized where you went wrong?
I'm still thinking, I don't understand how we can treat 27 cases differently and match with the 2 initial random number
ok I will do a rundown for you
think of it this way from the principle of counting you multiply the probability by the amount of equivalent cases you have for the same probability
you multiplying 27 here (and only 1 term) implies there are 27 different ways of getting those 2 numbers and the probability of all these ways is (1/100)^2
which is just false
alright I see my mistake, but then how can I tackle the problem differently, I might have to look up for binomial probability distribution since I'm unfamiliar with the method
thank you for the head start, I'll try to figure this out
Anyone free to explain 16 for me pls, don’t understand how to show that the line is normal to the curve
I’ve found the points
just don’t understand the second part
what don't you understand about the second part?
Idk how to show
like I know that the normal is perpendicular to the tangent
but I don’t understand how to show from the points
can you find the slope of tangent at those points?
if u know what I mean
What's the relationship between the slopes of 2 perpendicular lines?
Negative reciprocal
yes
So to show that they are perpendicular, just show that the slopes are negative reciprocals of each other
no I get that but I don’t understand the part when it says show that the line is the normal to the curve at One of these points
so do I have to find the tangent of these two points
and see which one is perpendicular to the curve?
Yep
wait um those two points that I find, which equation do I sub in to find tangent
the curve?
You don't need the equation for the tangent
You just need the slope of that tangent at that point
The slope of those two points?
Yep
how about 18? How do I show that it’s a tangent
A tangent touches the function at a point, and also has the same slope as the function at that point
wait but when i calculate the derivative of the curve and subbed in the gradient of the line it doesn’t equal
becoz u said it has the same slope as the function at that point
@topaz scaffold
The derivative tells you the slope of the function at the point you subbed in
And what's the gradient of y + x + 2 = 0?
I said -1
Oh sorry
it’s okay
Ig you need to find where y = x^3 - 4x has a derivative of -1
See if those two lines intersect at those points
The curve and the line? Intersecting at the two points
See where y + x + 2 = 0 and y = x^3 - 4x intersects
Yes
help
question 7
6 not 7 sorry
@silver shoal sorry for the ping but can you help
im just a middleschooler dont go too deep
Just use distance formula ig
Find one that has a distance of d from one point and 2d from another point
thanks
i was trying to do so
i probably messed up eqs
can i use section formula
nvm i was being dumb got it
im done with it so time to leave the server
Oof bye
When you put in a square root you need to remember to put the plus or minus
When you're solving equations like these, it usually includes the plus-minus sign
Nonexisty
But when you are asked to calculate the square root of 4, the answer is just +2
Nonexisty
oh so whenever i involve rooting in these equations then i have to add the plus minus symbol
Yes, usually
Don't forget to check
This is a quadratic equation, thus, x has 2 values
quick question it might be dumb but how to i get the x by itself in
13/sin(x) = 16/sin47
like find x basically
You'll need to use the inverse sin function
cross multiply sin(x) both sides and you have a trigonometric equation
principal solutions via the arcsin() function
wait why does the 16 mulitply with the sin47 now
n(pi)+(-1)^n*(primary solution) woud be the general solution
Look up "trigonometric equation"and their solution
Would it work if he multiplied lhs with sin(x), then divide rhs with 16sin(47) and just inverse sin(x) when its alone?
It's the same thing
Ok
That is how you get the primary solution
Are you Done?
yeh sorry guys i figured it out thanks for the help!
Just input the solution in original to check
Ye definetly wrong
Although looks incorrect
What did i mess up
You forget the coefficient of cofactor
Where

You multiplied by 9 instead of divide
You actually have the correct signs in the next step so that's not it
Am i not supposed to multiply?
Nopp wait
I see the problem
Its not -9
Its supposed to be 1/-9
Damn
So just divide your answer by 81
Aha
You have another mistake in your matrix multiplication tho
And that is?
ohh ok but for this question how to determine the maximum points though
R-method or auxillary angle is the most appropriate
you can use information from the graph of cos(x) or sin(x) but plotting a graph is the same information so whatever works for you
okay
but if i use the r method i still cant get the answer though?
what is the problem?
you have the maximum value as amlitude of sinusoid
then i will be completely cluless how to do alr
now the question wants the smalles (positive I assume)
angle
as I said cos(x) has maxima at (2npi,1)
you would want to interpolate here somehow
ohhh
where did you get this from?
these don't seem like anything special. just two linear functions of a complex variable, nothing more.
the fuck is that photo lol
looks like a screenshot from a shitty popmath video if you ask me
from a puzzle, it was mentioned that it's used to find a curve but i have no clue
can you link the video this is from?
......okay can you link the puzzle
if you don't share anything else then nobody here has anything to go on
that pic is all i have tho 😐
Looks like some random funcs they threw in the bg of a video to look cool ngl
It could have a use, but we don't know what the use is because we don't know what it's trying to be used for
It could be anything.
$\frac{5}{2} - \frac{5}{2} = 0$ how
TheGameBot
By reflexivity.
by what?
so what does this do
Not fully sure if this is a legit question or a troll question
@gleaming warren anything subtracted from itself gives 0 lol
legit question
oh yeah i'm dumb
5/2 is a number just like any other
Guys, what's a natural number?
For some reason some people considered 0 as a natural number
a natural number starts from 1 to infinity
@teal epoch whether or not 0 is a natural number is a matter of convention and convenience
sometimes it is more convenient to include 0, other times it is more convenient to exclude 0
@nova sail thank you for this valuable contribution to the conversation at hand.
those are their only contributions
what is meaning of respectively
order
1+2 and 3*2 are respectively equal to 3 and 6
oh
you just say multiple things and your pair them up in order
depends on the definition >:(
you have 2 lists, each item in the list matching with the item in the same position
here we include 0
It depends on the definition, I said
In the US, 0 isn't included in the natural numbers
So, by the US definition, no
My point is to be aware that this is not an universal or obvious thing and that it depends on the agreed-upon definition
so if the question says find distance of OB and AB respectively then i should do OB first
??
No, it just means find both
that just reads "find both the distances of OB and AB"
oh
But when you give the answer, you might say "the distances are 3 and 6 respectively"
where 3 is OB and 6 is AB
ok thankyou
But you're not required to write it like that
what does "inserting n geometric means" mean? insert n numbers such that a GP is formed? if so, why so? how is the definition of geometric mean tied to a geometric progression?
What is the geometric mean, and why is it called such?
@pearl musk yes, insert n numbers to make a GP
you take the nth root of the product of n numbers. afaik qualitatively, a type of average so mean and geometric because it has to do with taking a product?
it's bad wording imo but yes that is what it means
No, it's called the geometric mean because it relates to the geometric series.
Namely, if you have the n + 1th and n - 1th element of a geometric series, the geometric mean gives you the nth element.
How to do this
hmm makes sense that way. thanks 🙂
@shrewd otter @vale wigeon
Use log properties.
Namely log(a / b) = log(a) - log(b).
Logarithm Rules.
Eh?
Ig works too
$log(a) + log(b) = log(a \cdot b)$
but addition makes it cleaner imo
No, it doesn't.
Nonexisty
How can something cancel out if you have a sum of positive values?
That's nonsense, I feel.
how is $(1.5 - 3)^2 = (1.5)^2$
,w calculate (1.5 - 3)^2
These are not questions for people.
Because x^2 is an even function.
Meaning f(x) = f(-x).
yes.
how
what is 2 - 4
2
no
-2
ok
and when you square it the minus sign disappears
oh
because (-1)^2 = 1
$(-a)^2=(-1)^2a^2=a^2$
Mosh
$$ - \cdot - = + $$
i know that
Hunnydrips
i also know this
ok then u should be done
yeah... sqrt and squaring are inverses
$\sqrt{(-1.5)^2}=\abs{-1.5}=1.5$
Mosh
f(x) = x^3 - 4x
What does f mean here?
And why is it written as f(x) specifically?
I always see equations written like this.
What fundamentally does it mean?
A function just takes input (in this case x) and then gives you an output, right?
yes
And the output is equal to F?
the output is f(x) which = x^3 - 4x here
yes
Also, functions can be used to do many different things, not just one thing, yes?
functions have a lot of uses
maybe try thinking about it this way: this f function takes some number, lets say 5, and applies a formula to that number and spits out the result
Like anytime you want to take input and put it into an equation you use a function?
Ah, i see.
Okay I think I get it.
Thanks guys!
So for example the easiest function which basically does nothing is f(x) = x - it takes x and spits out the same number x
Can you have a function that is not called f?
Ah alright, it's basically exactly how programming languages use functions then
the y and x axis?
Not really
Yeah so this is basically like giving x as 1 and then it gives output 1
this function f with formula f(x) = x take some x - lets say 0.5 and applies it to y
yeah
so as you can see in this case its a line
THanks 😄
y is basically the result f(x)
ure welcome
the one you sent has a weirder graph
,w graph f(x) = x^3 - 4x
Interesting
,w graph f(x) = tanx + x^3 -4x

,w graph weierstrass function
,w graph weirstrass
bruh
,w graph sinx/x
,w graph x>45x+102-x^15
,w graph sinx/x^2
,w graph x<1
,w graph f_a(x)=sum_(k=1)^infty(sin(pik^ax))/(pik^a)
,w graph loga*logb
,w graph (x-y)*(x+y)
,w log_10(-12)
Any tips on how to solve functional problems in general?
,w log_1(1)
,w log_2(1)
Kbyethx
$find x if 4^x - 4^x * 4^-^1 = 24$
Gladiator
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
can someone help me with this?
Nonexisty
Find $x$ if $4^x-4^x\cdot4^{-1}=24$.
Nonexisty
x = 5/2
take 4^x common
you get 4^x ( 1 - 1/4) = 24
4^x = 32
2^2x = 2^5
2x = 5
x = 5/2
Binomial Theorem?
Yes
welcome : )
how do i add 45 degrees in a point of a circunfere?
what's a "circunfere"?
any point in the circle limit
no idea what you're talking about...
so you want to rotate by 45 degrees around some center point?
circle. the word you're looking for is circle.
you keep saying "circumference" when you mean circle
if you mean the difference between the curve and what's inside the curve,
the inside is called a disk
anyway
What are functional problems?
is the center arbitrary or is it at the origin?
if it's at the origin the formula will be a little bit simpler
center is 0,0
okay so it's at the origin great
yeah
This isn't so weird. I know my language makes a distinction between the "circumference" and the circle.
so if you start at the point $\bmqty{x \ y}$ then rotating it by an angle of $\theta$ around the origin will take it to $\bmqty{x \cos(\theta) - y \sin(\theta) \ y \cos(\theta) + x \sin(\theta)}$
Ann
in your case θ = 45°
Namely:
kružnica := { (x, y) : x^2 + y^2 = 1 }
krug := { (x, y) : x^2 + y^2 <= 1 }
wtf
yeah, that's circle vs disk.
translate that to me
pls
i'm using $\bmqty{x \ y}$ to write $(x,y)$ purely for aesthetic value
Ann
the coordinates of your point
Is is actually great, because it taps into linear algebra.
You have a vector [x, y].
And you want to apply a linear operation to it.
Namely, rotation.
Can we talk to another channel?
yes
Yes.
?
you could also write it like this: $\begin{cases} x' = x \cos(\theta) - y \sin(\theta) \ y' = y \cos(\theta) + x \sin(\theta) \end{cases}$, where $(x,y)$ is the old point, $(x', y')$ is the new point and $\theta$ is your rotation angle
You simply need to find the matrix which describes a rotation operator.
Ann
don't overload kusterzin with info they don't need.
i am lost guys
you asked for the formula, you got the formula
i even did you one better
instead of giving you just the formula for rotation by 45 degrees, i gave you one that can let you rotate by ANY angle
what is that 0 in the parenthres
that's not a zero
that's the greek letter theta
and here i am using it to denote the angle by which you want to rotate (even though i already wrote that, but apparently it needs to be said again)
which in your case is 45°
wait so you don't know any trigonometry??
you can't calculate cos(45°) and sin(45°)?
the 0 is where i put 45?
what is that above x
?
is just to get the new x
or is a mathf term that i dont know
?
in this case x' just denotes "new x", as i say explicitly
in general, this symbol ' is called a prime and has several different uses
in calculus, the prime symbol can be used to denote derivatives
ik im supposed to avoid this question, but if i proved that steve can carry 156 million banana's, where do i post it?
is there any mathematical functions if output is known the inputs (must be two or more ) can be predicted ?
hmm, idk im only 13 so im not 100% sure
I have a question where I'm supposed to find if a person did better on one test compared to the other.
Should I use a coefficient of variation or a z-score?
and what is this
?
is another mathematics term that i need to use in the equation
?
a)
1 0 1 1 ----> constant
1 0 0 0 xor operation
0 0 1 1
b)
1 0 1 1 ---> constant
1 1 1 0 xor operation
0 1 0 1
so basically if i know only these 0011 and 0101 and is it possible to extract 1011 from that. Is this possible ?
no it's just grouping the equations together @lime rain you can ignore it if you want
is this eligible? i never know where to put the arrows
help me with this please someone
If you get whole number then?
For part f you get 7. Something then there you want lb and ub
Are you familiar with lb and ub?
too bad you should have
ye ik
Then first read the definition of lb and ub
This feels like an X Y problem.
Just ask your actual question.
Or state your actual problem.
Then ask.
If the number is whole number then what’s lower bound and upper bound?
?
Suppose x=5 then lower bound of x and upper bound x ?
not sure 😦
is it 10?
Nope
57.7
57.7 has been rounded to
1
1 decimal place. Work out the upper and lower bounds (or error interval) of this value.
To calculate the upper and lower bound we need to use the size of the interval which is
1
1 decimal place (
0.1
0.1).
Next we need to divide the size of the interval by
2
2 to get half the interval:
0.1
2
0.05
2
0.1
=0.05
Step 1: Calculate the lower bound.
For the lower bound, we subtract half the interval.
Lower bound
57.7
−
0.05
57.65
=57.7−0.05=57.65
Step 2: Calculate the upper bound.
For the upper bound, we add half the interval.
Upper bound
57.7
+
0.05
57.75
=57.7+0.05=57.75
So, we express our error interval for
x
x like
57.65
≤
x
<
57.75
57.65≤x<57.75
Now try to understand how it’s work
damn
125/15 is around 8. Something right
8.333333 I think
the question is saying each number given is rounded to nearest integer, so 14 could be 13.8 for example
so calculate lower and upper bound of 14 * 20
do you know when you round up and when you round down?
if I were to round 2.4 to nearest integer what would I get? If I were to round 2.6 what would I get? If I were to round 2.5 what would I get?
oh damn you are so cool
4 6 5
no
me right now
No
,w number line for 2.4
what is the nearest integer to 2.4?
2.2
integers are whole numbers like 1,2,3,7,8
so not another decimal number
Whole numbers are {0,1,2,…}
can anyone help me with this please
2
also negative
indeed
Whole number
what if I were to round 2.6 then?
7?
dumbness level increases
You can do it
it can only ever be 2 or 3 if you have 2.(something)
o ok
,w number line for 2 and 2.4 and 2.6 and 3
2.6
so it can always only be 2 or 3
k
so if it is 2.0,2.1,2.2,2.3,2.4 we round it down, if it is 2.5,2.6,2.7,2.8,2.9 we round it up
so if the digit just after decimal point is either 0,1,2,3,4 you round it down
otherwise round it up
ok
so what would 18.3 be?
hmmmm
Guys can i text here for any math questions i have with some exercises?
18
POG
you sure?
ye
you are wrong then
e oof
told you the rule right here
why not use it?
if you don't understand how rounding works you can't do it
19?
what is the digit after the decimal point?
"49" is 2 digits is it not?
it is
so what is the digit right after the decimal point?
2 digits?
clearly there are like 20 digits after the decimal point
brain is dying right now
9?
okay that wasn't so hard was it
2?
yes it is 4
18.6319831938198319381831414913931'
the first digit after decimal point is 6
not very hard is it?
nope
okay so if first digit after decimal point is 4 do we round up or down?
down
indeed so this rounded is 18
ok
so when would we round a number to 14?
can you give an example of something that would be rounded to 14?
This is sad
He legit just t0ld u 😭
showed what
.
oh right
Btw, you have to be at least 13 to use discord.
i am 13+
solve over naturals 3^x+2^y=2^z+1
i am just too dumb in maths
Oh fair enough
so the answer to your question is 15?
What was my q again
whats 14.7 rounded
Oh noice
to how many sf?
Yh u got the hang of it :)
2
nice
then 15

you used a tiny photo
So find the upper bounds for all the multiplication ones to find the upper bound results
Then the lower bounds of each
For division, find the upper bounds of the top and the lower bounds of the bottom to find upper bound results
For lower bounds
Find the lower bound of the top
And the upper bound of the bottom
:)
pog
helpful i think
IQ increases 1.00000000000000000000000000000000000000000000000000000000000000000000001
xd
a company has 30 members. how many ways are there to select a president, vice president and secretary. Assume that nobody can occupy more than one position
pick the people one at a time
bro help me./
this one
so to find upper bounds i have round it up?
if you start w/ the president, how many people can you choose from?
eh ok
im assuming that there 30! possible ways of selecting anyone to be the president but assuming i have to subtract out the 3 occupied spots would I do 30!/(30-3)! ?
dont give answers
cause im kind of confused if I should be using nCr or nPr
use logic
30
yes
we know that 1 person has occupied the first slot
so how many people can choose the second one?
so 29?
28
ahh i get it thanks
i confused myself again welp
<@&286206848099549185> :/
<@&286206848099549185>
what have you tried?
i just need to know if i should round the 1st number up or down
Hi, I'm new, amm in this group, they help with the homework.
you'd consider both cases
i confused myself so i should round the number up then upper bound it?
i confused myself so i should round the number up then upper bound it?
no, you the values given are already rounded.
oh
you should consider the potential values of the original numbers
and using those consider the smallest and largest values that could've been possible
btw this
but i dont see how i can do in this
lets look at a)
14*20
for the lower bound,
since you're dealing with the product of two numbers,
you'd want to consider the smallest number that would round to 14
and the smallest number that would round to 20
(when rounding to the nearest integer)
HMMMMMMMMMMM
wait but i gotta multiply upper bound into upperbound
wdym
its 9th grade stuff
honestly i dont wanna
The lower bound is the smallest value that would round up to the estimated value.
The upper bound is the smallest value that would round up to the next estimated value.
i gotta find the closest numbers to 14 so i can multiply with 20 @gray isle ?
no
so you've never seen an inequality..?
so then you know what bounding something is
what's the smallest number that would round to 14 (when rounding to the nearest integer)?
how do i see the line thing from the bor
I have seen an inequality and have no idea what bounding is lol
bot
what line thing?
,w
the bot that shows you stuff
$5+5$
Ladan
like that
dollar signs at the start and end if you know what you're doing
look up how to tex in your spare time
ye
otherwise communicate with plain text instead of exprimenting blindly
how can i use it for bounding
i need to see the closest integer from the bot
the bot doesnt solve stuff for you i think
14 is the closest integer of some unspecified number
can someone explain fractional exponents pls
it's easy
20 is the closest integer of a different unspecified number
you'd want to consider the upper and lower bounds of those (given that they were rounded to the nearest integer)
and hence determine the upper and lower bounds of their product
ok but i want to know how to solve for it without knowing the root
wdym
The lower bound is the smallest value that would round up to the estimated value.
The upper bound is the smallest value that would round up to the next estimated value.
the channel is in use, dont help someone else as it can be annoying
since you're dealing with the product of two numbers,
you'd want to consider the smallest number that would round to 14
and the smallest number that would round to 20
(when rounding to the nearest integer)
like how do i solve 3^1/3 without knowing its root
do you know how to normally round to the nearest integer?
14.7 would round to 15 yes
for now I chose to focus on the lower bounds first
you'd want to consider the smallest number that would round to 14
can it be like 14.15 or something?
14.15 would round to 14, but it isn't the smallest value that wound round to 14
can someone look at the question I send at #help-7|zen1thxyz
||shouldnt that be $14.0000000..01$ or something?|| for @gray isle
Ladan
pog
i looked
no
similar to 14.15, 14.000000...1 would round to 14, but it isn't the smallest number that would round to 14
,w numberline 14 to 20
do you think that numbers below 14 don't exist or something?
im dumb
lol
LMAO
got it
I GOT IT
nvm
i tried to do 14.199
do you think that numbers below 14 don't exist or something?
15 16 17 18 19 20
numbers below 14
why are you listing integers between 14 and 20
what types of numbers round to 14?
ok good, you've found the
The lower bound is the smallest value that would round up to the estimated value.
the lower bound for 14 is 13.5
similarly, what will the lower bound be for 20?
19.5
and hence according to your info sheet,
the lower bound for 14 * 20 (given that values were rounded to the nearest integer)
will be 13.5 * 19.5
The upper bound is the smallest value that would round up to the next estimated value.
example
15
and similarly what's the smallest number that would round to that?
14.7
no
wait
are you saying that anything smaller than 14.7 won't round to 15?
14.5 14.6 14.7 can round to 15
what's the "smallest" possible value?
14.5
yes
that will be your upper bound for 14
similarly what will be the upper bound for 20?
19.5
oh
19.9
No
oof
at this point I should probably ask you to explain the basic rules of rounding
lower bounding i can do i forgot how to do upper bound
same process outlined for upper bound of 14
what did I ask you to do there?
apply the same process for 20
find the lowest number
read the logs
that can bound to 14
no, that's not exactly what I said
that's not what I said
Let's walk through the process again
What's the next integer after 20
21
and what's the smallest number that will round to that?
19.5
No
by "that", seeing it was immediately following the response of 21 is in reference to 21
what is the smallest number that will round to 21
(this is the lower bound of 21 which will also be the upper bound of 20)
20.5 maybe?
50 50
20.5 is indeed the smallest number that rounds to 21
20.5 will be you upper bound for 20
ok
the next one is super hard
how so?
exact same idea
number of digits changes nothing
If you know your round rules
are you implying you don't know how to round to the nearest integer for numbers greater or equal to 100?
yes
25 is 24.5
yes
for simplicity, since the numbers have been rounded to the nearest integer,
-0.5 for the lower bound, +0.5 for the upper bound
ok
And that's all I have time for
ok
does someone here speak german and can help me with economy math ?
❓
Parentheses first then go from left to right
dont comment if you're not going to actually help
i think the question is broken, it doesnt work out
Oh yea
3² + 2⁴ – (6 . 5 + 3 . 4 – 5 . 8) + √49 – 4² + 25⁰ - √225
oh
,w 3 + (52) - (48 + 32) + 47
Hehhh
its 3. this aint on bedmas
15?
Oh I typed it in wrong
work it out with the decimals being multiplication, and put brackets around them
Can't help with tests
In these type of questions use BODMAS
You can check by simple integrating
Okay
,w \int_{1}^{3}(x^2+3)
Hey y'all! I am a college student taking Calc for business rn and was wondering if someone could help me find the correct answer to this problem with the given conditions.
take the derivative of it while thing
4xy requires the product rule
the rest is power rule (or constant rule if you call it that(
then sub in the values given
ah, I see it wasn't the worst to do, just with all the conditions was making it seem harder than I thought. Thank you!
ok is 135.5 and 25.5 the upper bound
Trying to figure out all the 4:3 aspect ratios on a graph as I am trying to print a canvas with an abnormal aspect ratio and want to find the closest one I can use and then crop. Basically need a graph showing x/y=1.3333 and all combinations up until 2000. so like, 4x,3y; 8x,6y; 12x,9y;... etc Not sure how to write an equation for this to plot into WolframAlpha
4/3 = (x + 4)/(y + 3), something like that
I think I answered my own question...


