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abcd are points of a parralelepiped
See I thought it was supposed to make a quad. Definitely feels like info is missing here.
Oh like corners?
yeah
Ok so abcd make some corners of a parraleliped and you need to find M such that abcm is one of its bases
Okay
You familiar with vectors?
yeah, but i have been stuck on this problem for hours
@nova swallow Has your question been resolved?
.
Go to one of the channels in Math Help (available)
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hi
• Show your work, and if possible, explain where you are stuck.```
@keen iron
@keen iron Has your question been resolved?
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when you're determining the equation of a logarithmic graph, is there no horizontal strethc only when the xintercept is 1 away from the vertical asymptote?
yes
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Thesr righr?
Yeah but the circle being empty or closed is flipped
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How do I turn factored form to vertex form?
VulcanOne
VulcanOne
how do I get rid of that -1 and -15??
@naive flare Has your question been resolved?
Move out where?
like i distribute the a value to the c value so that it becomes the k value
Show what you got
is it right?
Yeah
oh, then what the hay is the lesser coordinate?
i haven't learned about lesser coordinate i don't think 💀
💀💀💀
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How to prove that when f(x) = 2, as x approaches infinity, f does not have a slant asymptote
Show that the limit doesnt go to infinity
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,w Taylor series sin(x/3)/e^x
Do you know sin(x) = (e^(ix)-e^(-ix))/(2i)?
So no?
sin(x/3) =(a0 + a1x + a2x^2 +a3x^3+a4x^4) * (1+x+x^2 /2! +...)
Multiply and distribute and solve for the coefficients ai
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wait
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<@&268886789983436800> porno moment
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Calculate the velocity when I did your mom (please laugh I need emotional validation)
Man I'm so mature
I sadly clicked on the video to see what Shitpost it was
And uh
Well I've seen worse from raids and shit but like
¯_(ツ)_/¯
i didn't laugh
😵💫
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construct some isosceles triangles
like this?
well i don't see how ADC is an isosceles triangle but keep going
is M not the centre of the circle
yep
then what do i do now
ahhh so split the quadrilateral into triangles ABD and BDC
then you can find angle ABC in terms of x, and ADC in terms of x
since the quadrilateral is cyclic (all 4 vertices lie on the circumference)
ABD + BDC = 180º
how do i find angle ABC in terms of x?
yep, it worked
ABD is isosceles
and BDC is a right angle
can u guys help me, if i dont finish i have a F and i need to finish by 4 hours
this channel is occupied
oh so angle ABD is 34º?
nope
wait you're using the angle in the centre is 2x the angle at the circumference right
ok, if the triangle is isosceles, then its base angles are....
the same
yep
oh
oh wait it is
sorry, 180 - 68 = 112 (mental maths error)
yeah ok so it would help if you gave your reasoning for why
but I see now
then 180-112 = 68
shit I did this problem inefficiently, but that's okay
nhs i love 2turnt
nhs + 2t = winnipeg lrf
guys wrong channel
so abd is 34º?
112/4 = 28º no?
yeah
oh my bad
but it's also my bad because I totally missed the fact that it was a cyclic quad
and then mental maths error
so the answer i got is 56º
that answer doesn't make sense
because 4 * 56º > 180º
that's y not x..
and the maximum possible angle on the circumference is 180º when you have a straight line
yeah cuz i found x already
its right there
oh right, to find y
then yes you do need to break the quadrilateral apart into triangles ABD and BDC
y = 56º yes
oo ok tysm
you can also save a lot of effort by drawing either AM or DM
but it works 20 ways because geometry
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can someone help me figure out how you go from line 4 to 5?
I don’t know how you end up with a 1/2 and 1/3 in the brackets?
can you factor 6x^2 + x - 1?
yeah
For which one
B
Oh wait nvm
That's what they were replying to
Let u = cos(x)
Make the replacement
6u^2 + u - 1
Mb I thought it was a random question lol
what do you get when you factor it
you get factors in two brackets
ohhhhh
(3x-1)(2x+1)
but like in this question
wait
Line 5 is wrong
if i factor it the way ur saying u don’t get the 1/2 and 1/3 values but instead a 1 and -1
oh
you get -cos x
not cos x
-2cosx?
wait
man I just have no idea how they got those fractions there 😭
cause the answer is correct
looks right to me 
but idk how you get the values 1/2 and 1/3
like u factor it
get two bracket
is it related to special triangles or the unit circle?
$$
\begin{align}
(3x-1)(2x+1) &= [3 \cdot (x-\frac{1}{3})][2 \cdot (x+\frac{1}{2})] = 0\
&\Rightarrow 6(x-\frac{1}{3})(x+\frac{1}{2}) = 0\
&\Rightarrow (x-\frac{1}{3})(x+\frac{1}{2}) = 0
\end{align}
$$
IV
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
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Milk contains 3% butter fat and cream contains 15% butterfat. How many liters of milk and cream must be mixed together in order to produce 20L of a mixture that contains 6% butterfat?
I have no idea how to do this, all i know is that you have to use a linear system method
start by identifying your variables
let m be milk and cream be c
you might want to be a bit more clear,
let m, c both be in liters, then:
- relate the amount of volume (in litres) of the target mixture with m,c
- relate the amount of butterfat in the target mixture with m,c
eh, everything seems like the hardest problem when it's new
can you do part 1?
nah
what the number of liters you want to get in the end
20L
so how can you express the amount of milk and cream in your final mixture in liters
the amount of milk and cream is equal to 20L
express this with an equation involving m and c
m + c = 20L
now you have one of the equations
now think about how you might do something similar with the amount of butterfat
m+c = 6% butterfat?
not quite, what's the amount of butterfat in m liters of milk
i mean you can work in percentages, but it ends up being the same thing
so thinking in amount should be a bit easier on you
3%=20L
Working in fractions would be easier
20/3
whats 20 divded by 3
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lol
.close
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I understand
up until a=(-2w^2+46w)
how does completeing the square give us the width?
why would solving this using completing the square give us the width
@mighty flower Has your question been resolved?
so basically you've written the area as a function of the width yeah?
yes
and you can see by inspection that it's quadratic
and you kinda also know that the quadratic is curved downward because otherwise you could get an unlimited area from your fencing (the problem wouldn't be so well posed)
and by solving for w by fineding the x intercepts of the parabola we fined the width
oh shoot
no
?
if you find the x-intercepts, you are finding where the area is 0
and I'm guessing that this problem is asking you to find the width such that the area is maximized
what does that mean
my teacher talked about maximizing area
but wont it be the same?
If you have Area = (-2 * width^2 + 46 width), then if you solve (-2 * width^2 + 46 width) = 0, then you're really solving for the widths where the area is 0
that's not what you want to do
the problem is asking for the biggest area that you can get with this fencing
does that make sense?
a bit yes
you are minimizing the negative term so you can maximize the positive term
wdym by a bit?
I tryed to do the same thing
do you understand that the goal of this problem is to maximize the size of the fenced area?
hi
yea
but if that was tru why wont it work on this
okay and you have written the area as a function of the width
wdym by "won't work"
you have to be more specific
this is not a problem
than solve for x
what are you supposed to do with that figure
and divide by 2
solve for x
okay so why do you think that problem has anything to do with the fencing one?
in the fencing one, you're asked to maximize an area
in the triangle, you're asked to find the side lengths basically
what does maximzing the area mean tho?
it means
look
if you have 46 feet of fencing and want to put it up
there are clearly many ways you can put the fence up, even if you're required to make it into a box shape
maximizing the area has basically the plain English meaning: how wide do I make the rectangle, so the space inside is as big as possible?
does that make sense?
the area will be the same regardless tho
no it won't
how come 1 and 46 and 6.8
Let's say I make the long side of the fence 45 feet long
that means that the two short sides are 0.5 feet long, since I only have 46 feet of fence
yea the area will be the sam
no it won't stop arguing and listen
ok sorry
what is the area of the space enclosed by my fence?
22.5
Area is equal to length times width
review the definition of area if you don't understand why
now let's say I make the long side of the fence 14 feet long
that means the short sides are each 16 feet long
what is the area of the part enclosed by the fence now?
224
so clearly, some ideas for fencing are better than others, right?
yes
the question is asking you to find the measurements that give you the biggest area
224 is not the biggest you can get
what would produce the biggest are tho
that's literally what the question is asking you to figure out
so with any sort of problem, mathematical or otherwise, you need to look at what your goals are and what you know
and then you can figure out what sorts of tools you can use to solve it
one neat insight about the problem is that if you pick the width of the fence, you don't have any choice of the length
if I say that the width is 4 feet, then I really can't choose any length except 38 feet
and since the area is the width times the length, if we know the width of the fence, we can find the area of the fence
that is what your teacher has written: A = -2w^2 + 46w
that is an equation that tells you how to calculate the area of the enclosed space, given the width of the fence
does that make sense?
yea
so then, naturally to solve our problem, we want to find the value of w that gives the biggest value of A
I still dont get how completing the square will give us the answer
I'm getting there
it's important to actually understand the problem before trying to solve it
yea
one thing that you can identify is that -2w^2 + 46w is quadratic in w
and it is a mathematical fact that's taught to you that it can be written in the form: a(w-c)^2 + b, for some numbers a, b, and c that are yet to determined
your teacher completes the square to write A = -2w^2 + 46w = -2(w-11.5)^2 + 264.6
do you know how to check that this is actually true?
not really
you can literally just expand (w-11.5)^2 and verify that everything matches up
alternatively, because both are quadratic polynomials, you can check that they're equal at minimum 5 points
can you at least follow along and understand why we can write A = -2(w-11.5)^2 + 264.6?
yes
now note that the first term -2(w-11.5)^2 is always less than or equal to 0
because (w-11.5)^2 is always 0 or bigger, and -2 makes it negative or 0
are you following along?
yes
so basically we know that A is at most 264.6, yeah?
yes
now, you can also observe that if we set the width = 11.5, the first term becomes 0, right?
yea
so that means that if we set our fence width to 11.5, the area enclosed by the fence is 264.6, right?
yea
and since we said before that you can't get any bigger than that
you have your answer to your question: if you set the width of the fence to 11.5, you get the biggest area, which is 264.6
thanks
I was working on this problem for a while cant couldnt get it
still kinda shaky but way better
completing the square allows us to write the area of the fence as <something that can't get bigger than 0> + <a constant>
and then you know that if you can make the first thing get to 0, you can solve the problem
now
that's actually a rather confusing way of going about it
the simpler way is to observe that A = -2w^2 + 46w is a quadratic function of w
and you actually know a formula for the location of the vertex, which is the tip of the parabola
and that is w = -b/2a = -46/4 = 11.5
and then there's a calculus-based way of doing it too
really?
yes
when will I be learning that?
in calculus
what grade I mean
depends on when you take calculus
some people it's first year of high school
some people it's second year of university lol
nope not with the way I am learning rn
kinda struggling with even simple crap like this
anyway gtg I have a test tmrw
o/
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did i do something wrong?
I don't think so, why?
because the answer i got was incorrect
in the book it says i should multiply each term by 3^x
oh, you said 3^-3 = 1/3^x which I don't think is true.....
a^-b = 1/a^b
i dont understand that
3^-3 = 1/3^3
then....
,w solve 3^x -3^(-x) = 3
i think i made a rounding error or something cause i was calculating it earlier and it gave me 1.7
,w log(3.303)/log(3)
alright i have one quick question
is this correct
sqrt(b) = b^1/2 and (n)sqrt(b) = b^1/n
logb(x^n) = (n)logbx
a^-b = 1/a^b
assuming (n)sqrt(b) is b under a sqrt with a little n in it, then yes.
my test is tomorrow and im scared of blanking when i get there 🥲
but thank you for the help
write out a note card 'cheat sheet'
then try to do it again from memory.
then do it again reading the rules,
then do it again
i can do it without the cheat sheet but i feel like when i look at new questions i blank
i already finished all of the revision
its just the laws about like log(n) + log(n) = log(n x n) and log(n) - log(n) = log(n/n)
that im worried about
for situations like that, I try to go through the problems and see when I used those rules and why. Write it down to help you remember it.
Even reworking the problem you've already solved can help
you cn also try to remember those ones are like the exponent rules
maybe it would be best to sleep now since i have to wake up for this in about 6 hours
i feel like i know all the laws but i dont want to get there and use the wrong ones
yea maybe it would be best to sleep then 🙂
my test criteria things are
I agree that the logarithmic function is the reciprocal of the exponential function.
I compare the main characteristics of graphs of exponential and logarithmic functions (domain, range, coordinates at the origin, intervals of growth/decline, asymptote).
I relate the logarithm of a number to the corresponding exponential expression.
I evaluate simple logarithm expressions using reciprocal expressions.
I demonstrate and describe transformations applied to graphs of logarithmic functions.
I recognize equivalent expressions involving logarithms and simplify them.
I solve exponential equations using a common base to write powers.
I establish the links between the laws of exponents and the laws of logarithms.
I simplify and evaluate logarithmic expressions using the laws of logarithms.
I solve logarithmic equations by expressing it in its equivalent exponential form.
I formulate and solve algebraically problems drawn from various applications that can be modeled by an exponential or logarithmic function.
i hope it works out alright thats all 😅
sounds kinda poetic
oh haha
😅 my bad
i think i should be alright for the test im just worried about solving complex equations
it’s okkk just sleep so you feel your best for tomorrow if you think you’re ready enough c:
Yes i will sleep now thank you guys 🥹
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how do I complete the diagram?
it's just a bit of algebra really
A + B + (A U B)' - (A n B) = 20
three of those unknowns are given
just solve for the intersection of A and B
Why is it A + B + (A U B)' - (A n B) = 20
I mean like, where does A + B + (A U B)' - (A n B) come from
The whole is the sum of the parts.
and why are there a subtract in this, when everything add together should be 20
inclusion exclusion principle
I dont really understand whats the concept of finding this
A n B is counted twice
let's say there are 10 red and blue marbles in a box. 5 of them are red. how many are blue?
5
how did you know that?
because 10 subtract 5
Red + Blue = Total
red + blue = overall
yes
Yes
but like, how are the - in the + B + (A U B)' - (A n B)
part
The whole is the sum of the parts. Are you with me on that?
so the entire rectangle must be the sum of what's inside the rectangle
not really, the "of the parts"
yes make sense
alright we can proceed from here
?
depend on the size of the rectangle?
the size doesn't matter
?
lots of little square?
Rectangle
Some solid object that made up this rectangle
ohhhh
ok
i got it
yes
2 circles
intersecting each other
sorry my bad
how many distinct regions are in the rectangle
4
name them
are those distinct?
No
- theres a Intersect region between B and A
- Area in the A circle
- Area in the B circle
- The outside of the circle
ok sure that's a starting point
how about this
does this match what you're saying
so you just label each part?
yes
10
nope
why?
A is W that doesnt intersect with B
but W is just the part of A that doesn't intersect with B
yes
wait im trying to catch up
so A is the entire circle
and to find the W I need to subtract A by the intersect
right?
yes
how is knowing that going to help me answer the question
trust me
ok
x = (A+B)/2
oh
X is the region where the two circles overlap, isn't it?
I just know that the intersect is the numbers that exist in A and B
yes
so X is the intersection of A and B
yes
so X = (A n B)
OH yes
so you're just teaching me to understand stand of the W, X, Y, Z concept?
Y = B-X
Y=B-(A n B)
Region Z is every numbers but are not in the A, B or intersect
that are already given but not are any of those
ok yeah
criteria
Z is everything not in A or B
so how we write that is:
Z = (A u B)'
Z is the complement of the union of A and B
i'm just giving you the definition
complement of the union
yes it is
it sounds correct but doesnt at the same time for some reason
it logically correct
but like
the union of A and B is just A and B together
the complement of that is everything not in A or B
yes
the whole B and A and the intersect too
but the )' make its not any of those
yes
no?
yes
doesnt A+B have an extra intersect?
nope
?
A U B U (A n B) = A U B
so there's no reason to write A U B U (A n B)
the intersection is already a part of A and B
now
now
we have formulas for W,X,Y,Z in terms of A and B
W = A - (A n B)
X = (A n B)
Y = B - (A n B)
Z = (A u B)'
i can either remember that, or just work it out right? if it pop up on an exam
how could i do that, are there like some website link that have copies of those question? cuz when i tried, i only sees the probability one
;-;
let's just try solving this problem first
would you agree that W+X+Y+Z makes up the entire rectangle?
ok
(A - (A n B)) + (A n B) + (B - (A n B)) + (A u B)' = R
let's simplify the left side
what do we get
R = (A - (A n B)) + (A n B) + (B - (A n B)) + (A u B)'
wait
let me rephase it
i need some logical thinking
its hard
think about what happens to the (A n B)
you subtract it twice
and add it once
-2 + 1 = ?
-1
yes
so that's the same thing as just subtracting it once
so we finally get
A + B + (A u B)' - (A n B) = R
R = (A - (A n B)) + (A n B) + (B - (A n B)) + (A u B)'
wait
let me try to understand
how do you get these equation again?
R = (A - (A n B)) + (A n B) + (B - (A n B)) + (A u B)'
W+X+Y+Z=R
and when i look carefully i see there's 4 intersect, 2 of those have + infront of another 2 have subtract
oh yes
then we just plug in the formulas we derived here
ok
there's only 3 intersections
oh sorry, im mistaken with the union
A + B + (A u B)' - (A n B) = R
R = (A - (A n B)) + (A n B) + (B - (A n B)) + (A u B)'
R = A + (B - (A n B)) + (A u B)'
?
i got that
yes according to the formula
now let's look back at what we had
we know that the entire rectangle is 20, so R = 20
R = 20, A = 10, B = 13, (A u B)' = 3
yes
oh ok i think i kinda got it
how about the B, theres an (A' n B)
doesnt that means that they just told us to get the number in Y?
Y = B - (AUB)
not quite
13 - 3?
Y = B - (A n B)
am I right?
6
yes
thank you alot
you really help me
ill spend rest of today revising for the theory you just teach me, thank you
ok ill do it
when we got the help and understand, what do we do?
oh ok, so theres no like command to tell the server that I already got help and this chat is free for the next person
ok
this is what you need practice on
gg
ok thank you
do you mind if im asking why are you helping me for? cuz Ik that you also probably have something else busy to do in life
i'm on break
i'm usually very busy with my job and school and everything
but i'm home right now and it's getting kind of boring already haha
oh ok, thanks alot Mr. Gamer
gl
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I wanna show that N and M have the same cardinality
So I need to define a function f(x) which maps each element x in N to the element x in M
And vice versa ofc
$M = [3,5] \cup [7,10]$ and $N = [0,5]$?
Ann
Yes
does the problem say "construct a bijection between M and N" or does it say "prove M and N have the same cardinality"
I guess they want me to construct a bijection yes
the former is going to be nasty
wdym "guess"???
Wait, I have to translate it
from what language
so it's "prove M and N have the same cardinality".
and you are not asked for a bijection. not explicitly.
so the question becomes "are you a masochist"
lmao
yes
you know how to show that any two closed intervals have the same cardinality right
idt it would be that bad to construct one explicitly?
Okay how to proof this? I mean I have to deal with real numbers so.. dont I need a bijective function for that??
do you know schröder bernstein?
Yes
a bijective function wouldn't be that bad but you would have to worry about a few details. injective functions are much easier
also btw the first set is [3, 5) and not [3,5] so glueing them together isnt annoying with having to account for a double 5
So I need two injective functions from M->N and N->M right?
that's one way to show it, yes
surely just gluing the two intervals together is fine
the problem statement even made the first interval half open for that to be easy
How to "glue" them together?
shift the second interval down by 2
(that's clearly a bijection)
then your union is now just [3,8]
or well, same cardinality and all that
Am I allowed to do that?
and now you have to find a bijection between [3,8] and [0,5] and that's hopefully easy
why not
kinda looks like uh
this lmfao
technically the function would look like that
$f(x) = \begin{cases} x & x \in [3,5) \ x-2 & x\in [7,10] \end{cases}$
Denascite
and then you compose it with your bijection of [3,8] -> [0,5]
The cardinality is the same for both okay
yes but that so far does not count as a proof
a key idea of these "show sets have the same cardinality" questions is to do it step by step and then in the end compose all the bijections you used along the way
the bijection [3,8] -> [0,5]? yes
And vice versa f(x) = x + 3
yes
Ahh yes thank u
although you should not use the same letter for both directions
So f(x) = x -3 and its Reverse function g(x) = x + 3 are bijective
as functions on those sets, yes
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can anybody explain how the centripetal force changes along the simple pendulum? can we know the centripetal force even if there are not given the highest point of the motion?
I already asked before, but I'm still confused I don't know what I'm missing for now

yes if I have to get the centripetal force in the lowest point
I can utilize the cons of energy right
Ug = KE
depends
mgh = 0.5mv^2
well yes but
It really does depend on what you are given, haha
but we don't know the h
there are only given the mass of the ball and the length of the string
at the very bottom of the circle
yes
Nothing else at all? Then we don't have enough info.
For all we know, it isn't even moving
then we are unable to determine the centripetal force in this case?
Actually, maybe I'm speaking too soon haha
what is si
lol
also to answer your question
you probably want to think about theta and how the components are split
as the ball moves at different stages
like this
No I'm back to my original thought. We have no info on the speed at all. The pendulum may not even be moving for all we know. Not enough info here.
you can create expressions for it but not obtain a numerical value
using the diagram posted
dude I have completely forgot since I have last looked at this and have been up for like 36 hours, so I would give the worst possible explanation even if I could
head to the physics server and make a post there
theres a rlly good guy in there who will help you out
what is this?
centripetal force = tension - weight
but centripetal force is the tension
yes
wdym
the tension in the string is due to mv^2/r
I searched a lot and still confused
what are you still confused about @atomic coral ?
do you agree with the equation: centripetal force = tension - weight?
I would agree 👀
ill leave this to Clarkie, i was never given Centripetal force while learning pendulum

if so, the centripetal force should change as well
yes, and its balanced by the differing components in theta I believe
at y_max you have max acceleration and minimum velocity
max potential energy
yes.
that is mgh, right
potential energy is
have you done simple harmonic motion?
it describes the acceleration and velocity , also displacement through the motion
that is why I'm wandering
then can you answer the only question
if there are given the mass and the length of the string, and the simple pendulum is moving
ok
at the very lowest point?
because the tension is the same as the weight?
and you can get it from deriving a wave equation for a simple pendulum modelled as a sin/cos wave
oh i see now, centripetal force is F_net in pendulum
I haven't learn about it
then you agree with the equation that I mentioned?
yah i agree, i thought centripetal force is tension force
thanks
for your clarification
do you think the tension is the same as the weight at the lowest point
it is
f=ma=mg=mv^2/r
and then as soon as you want an individual point on a higher value you have to think about components
i see
still, I dont trust what im saying with 100% accuracy , I would still go physics server and the absolute god that is in there will answer your question with ease
so
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I was going to use the multiplication rule, but I dont know how to work out the intersection
I need to find out the probability of it being R B R B R and also B R B R B
<@&268886789983436800>
Do you think you could help me?
no I dont have a clue in the world about anything to do with probability
ok
ha what does the giant size of the playing cards have to do with anything...
no clue
hint: the probability of RBRBR is the same as the probability of RRRBB
Ive been stuck on this for 15 mins
How
They r both ordered differently
either way you're drawing three reds and two blacks without replacement from a shuffled deck
but if you don't like that you can just work out RBRBR directly
probability that the first card is red is 26/52
Ok so i got
Yh i jsut worked that out
so the final black is 25/49
probBILITY
probability*
Red 1: 26/52, Red 2:25/51, Red3: 24/50, Black1:26/49, Black 2 25/48
Do I multiply them together?
yep that looks better
notice that by rearranging the numerators you can change RRRBB to RBRBR
without changing the value of the product
in any case yeah multiply them together
then do i do it for B R B R B