#help-0
1 messages · Page 697 of 1
Basically you have 2 coins , one is head head (hh) , and one is head tails (ht). If one coin is picked ,and one of the sides showed it's a H , this is one of 3 possible scenarios , because the scenario in which the side showed is tails is eliminated
Yeah but this would be true if we didn't see that the shown side is heads
But, if the shown side is head, and we have 2 coins or the other side is heads or the other side is tails
If the side is not showns there are 4 scenarios:
Pick coin HH , flip and get h .
Same scenario as above but with the other side.
Pick coin HT and the side up is H so it gives T , or the other way around , so it gives H
But since we know that the shown side is Head the possibility in which tails was the side facing up is not there anymore
And from this we get to 2/3 probability of getting head again
in the text it says that one coin has head on both sides , and one has head on one and tail on the other
Here's what I'm thinking, if you care for my input (I am also a bit terrible at probability):
So, we grab one coin. We know there are only two coins, HH and HT.
We pick one coin with the coin on H. We know there is one more coin in the box, but the one you're holding is either HH or HT. We won't know unless it's flipped.
When flipped, it can either be heads or tails, since there are two coins with different outcomes on one side, and I conclude it's 1/2. (Take this response with a grain of salt)
What would the scenario be with three coins, two of which are HH, one HT?
The point that is missing is that you are shown one side , and that side is head
This changes things
Because you change the parameters
On of all the 4 possibile scenarios , the one in which tail is facing up , is not possible anymore
Hint: ||use the conditional probability formula||
So there are not 4 scenarios
Can anyone come Discord and help us by our problem? We think it is simple but too hard for us to solve xd
I dont remember 
@civic rivet please post in an unoccupied channel
I don't even know what it is , I didn't use mathematical formulas to solve it , that's why I'm asking it here
The way your explanation sounds with the three different scenarios is making it sound like you pick the HH coin twice as much than the HT coin.
We need a probability expert here lol
Basically $P(\text{HH coin | we see H}) = \frac{P(\text{HH coin AND we see H})}{P(\text{we see H})}$
@velvet pelican that's it?
yes
So, it must be 1/2 cause the numbers of intersection between A and B is 1 and the number of A is 2?
The possibile scenarios are: taking the hh coin on one side , and that side is h , doing it again with the other side and it's H again , taking the ht coin and doing the same process we get one scenario with a h outcome and one with t outcome. But now were given an other parameter in the question, it says that the side shown is H , and this is 100% true, if the shown side is H the scenario in which the shown side is T is impossible, so it's out of the data of the problem,
no, it's not
$P(\text{HH coin }| \text{ we see H}}) = \frac{P(\text{HH coin AND we see H})}{P(\text{we see H})}$
Frosty
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
ok this works
Does my logic work or is it flawed ?
what's your final answer?
the question asks for the probability that you have the HH coin given that you flipped a H
so I believe that is incorrect
So the numbers of intersection between coin 1 and coin 2 is 2, because we have 2 H left, and at total we have 3 Heads, is that correct?
there are two hh coins and one ht coin?
No
no 1 of each
yeah then what's wrong with 2/3
wait actually nvm
But the problem says that you get the coin on one specific side , so there is the probability of getting HH on both sides ,so 2 scenarios in which you get H , but if you got the HT coin you get T
it's (1/2)/(1/2 + 1/4) = 2/3
I still didn't get why is 2/3 and not 1/2
Because we change the parameters of the problem by saying that the shown side is H
because if you have no evidence it would be 1/2, the conditional probability changes based on the evidence
So 2/3 is correct?
Very similar to the monty hall problem
No , I'm the one who's sorry haha , I know very little about math , so I had to verify if my process was right
What problem?
Monty hall problem, it was a gameshow some decades ago I think
you had 3 doors, 1 with a car and 2 with goats


It makes me think of those riddles in which an evil guy you tells you which door it's better to take to don't die lol
you pick one of the doors
then the host (who knows what's behind which door) opens a different door with a goat
oh HI
Ok , yes it has the same logic
is anybdoy free right now
now you get the choice to switch or keep your door
and the question asks whether you should switch or not
to maximise the chances to get the car
@alpine sable i can help you
001
oh lets move down yea
If you choose 0 it shows you the other 0 , if you switch you get 1 , of you choose one , he shows one of the 0s you switch and get the other 0
So if you accept to switch choosing the car would lead to goat and choosing the goat would lead to car
So yes ? @velvet pelican
yes
||you have to maintain?||
||no, the answer is you have to switch||
The coin one was easier, it think this one would have taken me a lot longer without knowing it worked similarly
Why??? I still didn't get this and the coin
I can draw a diagram
it's similar in the way that knowing that when the host shows a goat in the other door, the probabilities change
Yes
btw if you switch the door, you have a 2/3 chance of getting the car
and 1/3 chance of getting the goat
so it's much better switching
Sorry if it is a bit messy
I may have made some errors too , I'm tired and not a native speaker
It has the same process , try to make a diagram , keep in mind that the variable that changes is that you are shown one of the doors with a goat that is not the door you choosed
TheMane3
If I vertically stretch the above function by a factor of 2 and then reflect it across the x-axis, the function would become
TheMane3
right?
63>77
?
I think it does , but I'm not the right person to trust for an answer with this
hmm...the answer was $f\left(x\right)=-2\sqrt[3]{x+3}+14$
TheMane3
The 7 was out of the square root
You had to multiply it by 2
ah, what's the concept/reasoning behind that, if any? Or is it just a rule for transformations
It's a rule for transformations but as everything in math there's a concept behind it
16>33
...
44>33
Square root of 16 , then plus 4 it's 8 , square root of 16, times 2 then plus 4×2 it's 16
this channel is in use so do it elsewhere please
which?
@fluid kite well if you need help solving the riddle, than any of the question channels, if not, then go to #chill or #math-discussion
k
and yeah shanti makes sense because if I put $f\left(x\right)=-2\sqrt[3]{x+3}-7$ into desmos then its not reflected across the x axis
TheMane3
How can i demonstrates that ? $lim [sin(\theta)/\theta]; \theta \to 0$ I've seen the demonstration but didn't get it
Guilhotina
squeeze theorem
also
that goes to 1
not 0
if you want it to go to 0 you have to take the limit as $\theta$ approaches infinity
(バカ) baka
perms and combs is probably my weakest subject but it should be 1/2 right?
Yeah, but i was wondering why is my answer wrong
this is what I have right now $\frac{3C1\cdot 5C1 + 3C1\cdot 5P2+ 3C1\cdot 5P3 + 3C1\cdot 5P3 + 3C1\cdot 5P4 + 3C1\cdot 5P5}{
6P2 + 6P3 + 6P4 + 6P5 + 6P6}$
BorutoEyePower
$\frac{3C1\cdot 5C1 + 3C1\cdot 5P2+ 3C1\cdot 5P3 + 3C1\cdot 5P3 + 3C1\cdot 5P4 + 3C1\cdot 5P5}{
6P2 + 6P3 + 6P4 + 6P5 + 6P6}$
BorutoEyePower
I could explain how i managed to get this location if you want?
<@&286206848099549185>
I understand that it is 1/2 based on that either one having 50 percent of being chosen even or odd
Butt i just want clarification on why this won't work
is there a chat to talk about another thigs besides math ?
Why is the integral of 1/u = ln|u| and not ln(u) , like why is it || ? does this mean it is the ln of the absolute value of u?
@lilac lantern I thought this wasn't an integral question?
Please can anyone help me?
whats the question sir ?
the main reason for the absolute value sign is that x has to be > 0 if you want real values for ln(x)
this is what i have right now
$\frac{3C1\cdot 5C1 + 3C1\cdot 5P2+ 3C1\cdot 5P3 + 3C1\cdot 5P3 + 3C1\cdot 5P4 + 3C1\cdot 5P5}{
6P2 + 6P3 + 6P4 + 6P5 + 6P6}$
BorutoEyePower
do you have answers?
Yeah
it isn't 1/2?
I would say 1/2 since only the last digit matters
It is 1/2
But i'm confused how come my working out does not give out 1/2
Like i've taken all taken all the cases when it is even, and numbers are even when their first digits are divisible by 2
last digit*
Yeah last digit
So basically in my numerator, I take cases of various amount digits i want to make
Like forexample $3C1\cdot 5C1$
BorutoEyePower
I choose 1 one of the 3 even numbers and then times it with the rest of the numbers left
It doesn't matter which is picked, as long as the last digit is even. It will still work
I finally figured why i got it wrong
@crisp iron
right now i have $\frac{3^{13} \cdot 48^2}{52^5}$
BorutoEyePower
I’m pretty sure you’re supposed to find each part separately
Isn't this with replacements
It doesn’t specify
Which leads me to believe that each part is an independent event from the previous part
Asking as if nothing had happened before the draw for each part
I am confused
Basically treat each part as it’s own separate entity
Don’t even consider the other parts when solving for any particular part
I am confused with what you mean by treating what as a separate entity
this is part (a) we are talking about
This is all parts
Pretend that you’re given a full deck in part a, you draw the cards and calculate the probability, then you reset the deck and put in all needed cards then you do the same procedure for part b and c
How can we solve part (a) then in your view when separating each of the entity
Just calculate the probability of drawing 3 hearts from a deck of cards given non replacement each time
Because once you draw those 3 hearts, it won’t matter what the next 2 cards are
You’ve already satisfied the requirements
But then once you draw 3 cards, there are many other options you can draw it with
But that doesn’t matter
Like forexample 3 hearts and 2 spades is one option and 3 hearts and 2 aces are another
You’re asked for 3 hearts
That’s it
You could draw any other 2 cards you wanted, you still got 3 hearts
Part a simply asks for 3 hearts
But then there are many ways you can get the 3 hearts though
When dealing with a situation such as this, you’re gonna multiply every single time, and multiplication is commutative, so order does not matter
What equation do you think it will be
Basically, solve as if you draw 3 hearts in the first 3 cards, and then you draw anything but a heart for the last 2
Based on what you have interpretated and just doing it non replacement it would be 13C3 over 52^5
(13/52)(12/51)(11/50)(39/49)(38/48)
The first 3 are hearts, and the last 2 are anything but hearts
I’ll have exactly 3 hearts at the end
I’m sorry I couldn’t explain it in more detail
@hazy dome That is the right answer, but I am still confused
Like isn't it supposed to be with replacement
The problem is that the question doesn’t specify
Like you can have HHHAA
It’s kind of assumed that if you draw 5 successive cards that you’re not gonna replace them
Doesn't it say with replacement
so then it’s (13/52)^3 times (39/52)^2
Ok now I’m confused XD
,w solve (13/52)(12/51)(11/50)(39/49)(38/48)
Wait this is still wrong
The only difference with the answer is with the denominator being an extra 0
That is the answr i had before i'm pretty sure
Why are you decrementing the values?
You're replacing the cards back into the deck
@wary stream Well we now have a different answer
right now we have $\frac{3^{13} \cdot 39^2}{52^5}$
BorutoEyePower
@hazy dome I think there is another issue i think
Idk what it is then
I think it is because we have duplicatse
Like we can have AABPP
And we can have ABAPP
which would be the same when we select 5 cards
Do you know what the exact answer is?
,w solve (13/52)^3 times (39/52)^2
,w 2717/33320
the channel is already used, @warped phoenix
This channel is busy
,w solve (3^13 * 39^2) divide (52^5)
,w solve (13^2 * 2^39) divide (52^5)
,w solve (13^3 * 39^2 * 2) divide (52^5)
,w solve ( (13^3 times 39^2) divide 4!) divide (52^5 divide 5!
expand it, then find coefficients of p^2, p and the constant term, the values of coefficients will be a, b and c, respectively.
yes
ok
<@&286206848099549185>
ok so lets take food A first
Sure
so you need 500 units of calcium
and food A gives 32 units of calcium every ounce
so how many ounces are needed?
15.625?
yes
Oh so its division
So i add them up?
yes
Like (500/32) + (470/24)
yes
Thanks
np
@ember lava is there any discord group for chemistry too
yes there is. im in it.
if you want, i can send the link in dm
ok
Does anyone know about the card game Hand and Foot?
Because I have an idea about the game, but I need help with it.
So how am I supposed to do the working for this
I know the answer but in general how do I show steps
with words
perhaps a good intermediate step is to find the common difference of this AP
How would I start this one?
1+1=
Huh?
"i didn't read #❓how-to-get-help and i think it's funny if i post a 1st grade math question hoping for someone to give out the answer, in violation of this server's purpose"
$2005=2183\cdot(1-r)^15$
Vex
Ok fuck latex lol
but i think you now just need to reverse to find the rate
Assuming in 1990 the population was 2,005
Which i think the reverse is
It will look like this
@tired hamlet
but that fifteen will be above the square root thingy
I'm probably way off
Is this right or is the way you did it right?
Oh I think I need to switch the 2183 and 2005
,w 2183 = 2005e^(15k)
0.0056 about
Oh 15 instead of 0?
there is a question being asked here already. Please refrain from asking until this question is answered. or ask elsewhere
Oh I didn't know that im sorry!
it's all good; just thought I should bring it to your attention
is there actually any combination?
you can't use digision, besides between the 4 and the 2 i don't think
and that's not useful
i don't see a way and i don't really want to try all 256
Exactly what I'm thinking
Its $(\sqrt{9} 7) - (42)$
Quinnt
Which is (3 * 7)-(4 * 2)= 21-8=13
but can we use sqrt though
Does it come under a sign? Because I've never heard of it
but your answer is correct, so maybe yea
someone help pls 🙏🏿
i though square roots (and parenthesis although yours don't matter are illegal)
but fair solution then, id still call it a trick question
this is a 3rd (odd) degree function and in odd degree functions, it rises at one side and falls to the other which means that we can eliminate options B and D. Now since the leading coefficient is negative (-4) it will rise to the left and fall to the right, and thus it will be option C.
thank u sm bro fr
no problem, hope you understood it.
also
why does it have to rise from the left and decrease from the right? how does that correlate w the coefficient
why cant the end behaviour go both up or down
like they’re both positive or negative infinity
because it is -4x^3 which is an odd degree and if there is an odd degree then both ends will not go to the same end behavior
i don't feel like explaining but you should probably tl;dr limits and how to approximate infinite limits with big numbers
don't make him memorize all the cases
yeah I guess.

ohh that makes sense ok
that is a nice emoji 
thank u
no problem
if p and q are the roots of ax^2 + bx + c then what equation yields the roots 1/p and 1/q
(x-1/p)(x-1/q)
in terms of a, b, and c
are you trying to solve abc in terms of pq or the other way around?
if you want a,b,c in terms of pq just multiply out how i sent it
if you want it the other way do the quadratic eqn
oh I'm illiterate sorry
a good hint could be vieta's formulas
29 thru 43
you could yes
that would be an annoying expression though
Find integers of n if possible 🙂
not if you're smart
so the better way is just doing 550/15 then using the answer as your middle term and it'll probably work
,w (1+2^n+3^n)/5 = n!
that's not even an integer
thanks man!!
exactly
looks like no integer solutions
😠
,w (1+2^n+3^n)/5 = n! over the integers
yeah just round it's close enough, you use it as your "guess" then change as needed
bruh
(╯°□°)╯︵ ┻━┻
wherw is this problem from
ME
the sum of the integers from 1 to n is n(n+1)/2
it's not a diophantine common form, so idk how you expected to do it
I thought it had integers
ye thats why im asking
so you have 15x+14*(15)/2 = 550
was asking
it works, but it's easier to just approximate then edit as needed
ye
yeah
thanks guys!
because the first term is x+0 so it's actually the sum from 1 to n-1
nah doesn't look like it, and in general finding integer solutions to non-polynonial equations is not going to go well for you
yes
wait
how did the computer calculate the non-integer value of factorials
it showed a graph
confusion
it certainly cant have positive integer solutions
since the numerator of that fraction is even
haha gamma function go whoosh
this is a fun one @tidal grotto
😆
,w plot gamma function
except it's off by 1
if cos(0) = 1 then how can cos(pi) be lower than 1
laugh
yes, it has an integral definition iirc
,w gamma function
um
oh
😎
im supposed to prove the above identities
but im not sure how to continue from here lol
@ivory otter I can help you if you want? unless you help me?
Combinatronics
xD
I will help you with trig, however yuou must help me with combinatronics
lmfao i cant help
just use cos^2y=1-sin^2y
Only the doctors on mathematics can help me cure this nightmare
This is the only question left until I'm up to the easy part of the combinatronics section, dealing with binomial expansion
This morning my equation that I had is
dont see how that would solve it
ah but it will
it will
$\frac{13^{3} \cdot 39^2}{52^5}$
you will see when you try it
BorutoEyePower
also remember that cos^2x + sin^2x =1
ye
@ivory otter Try subbing it in
i did
@ivory otter To solve proof question in trig, you want to try to make the functions the same as the equation that you are trying prove
you dont say
@ivory otter Havee you got it yet?
ye
i mean
i dont like this
i wouldnt have thought about this
unless you told me
how the fk am i gonna solve it like this during exams
i cant use discord in exams
@ivory otter Don't worry, I was like you before 2 years ago. It is going to get extremely easy once you practice more
i have been practicing for days..........
@ivory otter Just make sure to make the functions the same as the equation that you are trying to prove as well as the degrees
Degrees priority first and then the functions
also sometimes it helps to look at the question backwards
as in starting from the answer and thinking 'how could i make this look like the thing they gave me?'
@ivory otter When is your exam?
This question implicitly assumes that the order of selection doesn’t matter
in september
So 52^5 shouldn’t be the denominator
@dark granite I thought that might be the case, how can we remove the duplicates?
That is the only issue I have so
far
I was thinking of dividing 52^5 by 5!
What is with minusing 1?
You may have learned that as 52 multichoose 5.
It has to do with boxes and balls with dividers
don't know what you mean by boxes and balls?
So you have 52 distinguishable boxes
5 identical balls
So you only need 51 dividers to tell boxes apart
So 51+5 choose 5 places the dividers down and the balls fill the remaining slots
Also known as stars and bars
What do you men by dividers?
Literally just bars that divide the distribution of the 5 balls amongst the 52 boxes.
If all the balls are to the left of the 51 dividers, that means we picked all 5 of say aces
So line up the 5 identical balls in a row. Where these balls land, represents which cards you’re selecting
i have never seen this in perms and combs before and now i am scared
Yeah it’s fun yo
I am still rather confused how can just 51 bars can divide the distributin of the 5 balls amongst the 52 boxes
You’ve learned selection with repetition where order matters right?
Can you please give me a smaller example?
Sure
So I'm right now imaging like 6 boxes and there are at least 3 bars minimal to divide them
From a store that sells only three varieties of coke, I wish to order exactly two cans of coke. How many ways can I order two cans of coke if I’m allowed to have cokes of the same variety?
No, look at my example
okay
So I need three distinct boxes
yes
Using this method, if I have n distinct boxes, I need n-1 dividers to distinguish between the distribution of balls into the boxes
Remember only two balls for this example
how do i calculate probability
You’d need 5 dividers
Why is that the case for 6 ?
A question is being answered rn. Please wait until this question is finished or ask elsewhere
Because 6-1=5
Unless they are lined up linearly
Read my comment bout n boxes
yeah
So you’d be essentially arranging a ‘word’ with bars and balls where everything to the left of the left most bar represents one box, everything in between two consecutive bars represents another box, and everything to the right of the rightmost bar represents another box
okay
Make sense?
yes
0|0| is a different ordering of the cans of coke than |0|0 for instance
Not quite make sense
I’d say it’s (52+5-1) Choose 5
Well the first distribution there says I bought cherry coke and Diet Coke, but not sprite. The second distribution says I bought Diet Coke and sprite but not cherry coke
Okay that now makes sense
Nice
Where the 0 is represents that I ordered that item
If there’s more than one 0 in a box, that means I ordered more than one item of that variety
Make sense?
yes
Dope
So back to your card question
Essentially we’re choosing 5 cans of coke from a store that sells 52 varieties and were allowed to select cans of the same kind
Right?
yes
Hence the whole (52+5-1) choose 5 denominator
So what’d the numerator be for part c?
is the 5 for the extra replacements that is necessary to keep up with the amount of choice the user is making?
Essentially yeah, but it makes more sense to think in terms of the identical balls into distinguishable boxes idea
so i think it will be like (13+3 -1 ) choose 3 times (39+2 -1 ) choose 2
That ain’t the answer for part c man
If we can’t allow hearts in the selection, just throw em away in the first place. So the numerator for part c should be (52-13+5-1) choose 5
do you guys know the answer for part a?
yeah
Were working on it
i was thinking about maybe using binomial probability?
since the chance of pulling a heart is 1/4
I am still rather confused how the idea of 52 + 5 is related to the identical balls idea
This is the numerator for part a yes
Rewrite 52+5-1 as 5+(52-1)
Now see it?
wouldnt that be 56 chose 5
how to skip count by 6 and 7
Yes
Help
A question is being answered here at the moment
Well answer my question first mf
Still confused with how you put it like that
Like what?
so you getting the divider and then you adding 5 more bars
Those 5 more things aren’t bars, those are the balls
Rested we've eggs seen wii eh ez u yum tea to tea to gx t yum tea yum tea
To ez 60 tea tea td up tea to dm tea cm f4
🖕
can you please represent it in like a diagram out of text, maybe for a smaller example?
Answer my question first mf
If you’re not going to wait your turn or help answer he current question previously asked, please leave and go to another chat room and ask your question if one isn’t already being answered.
what language is this
idk
Bruh the can example is about as small as I’d go. Any smaller and the big picture becomes lost
mfs really tryna cast a spell on me
lmfao
@dark granite like something like this 0|0|0
No I’m talking about @plucky sun
anything can happen 😉
@plucky sun knock it off
oh ye sowwy @dark granite
So in the can example where you want two cans of the same type. It will be (3+2-1) choose 2 1||
@dry thunder dude I literally have no prob with you. Im just talking about that other dude who flipped us off
mathematical beef
yeye im sowwy
didnt see shit
didnt mean too :))
It’s all good just get that other dude outta here
Yes!
(3+2-1) choose 2 is right
what about the 1||
Oh I thought that was a typo you made
the | is the bars
Would you be able to please represent that scenarioo in terms of | |
Sure
0|0| is one distribution
Notice there is no zero to the right of the rightmost bar
yes
yes
Kk well there you go! You should be gold now
But i'm confused with how the + 2 relates to that?
You’re talking about 3+2-1?
yeah
Okay if I give you the word aabb and ask you to arrange the letters in that word in a row, how many distinct arrangements are there?
there will be 4! divide by 2! and 2!
aa represents the 2 balls (cans of coke we’re selecting) and bb represents the 3-1 dividers
Also known as 4 choose 2
why does bb represent 3-1 dividers?
More quickly, 4 choose 2. Since we could select two of the 4 spots for the a’s and the remaining spots will be where the b’s will go
please just ask in one channel
yeah
Sorry, I am sitll confused with the bb being two bars
Like i get how you do 4C2 being you choose 2 aa and the rest being the bb
Okay we must place bars and balls in a row
Don't quite link this to the bar idea
Aabb makes up four total spots
Of those 4 spots place the a’s (the balls) and then the b’s (the bars) go in the remaining spots
The distribution of balls around the bars represents the distribution of balls into boxes
Because the dividers help us distinguish between what balls are in what boxes
How would the aa and the bb in the idea of | |
Aa is two identical letters the bars are two identical symbols
Okay explain this whole boxes into balls business back to me the best you can and hopefully we can figure out where your confusion is
Or dm me if you don’t wanna do this publicly
So basically the boxes have n total boxes - 1 divisors, and we know what the distribution balls are because of the divisors
Should say n-1 instead of just -1 there
Yeah, and forexample something liek 1 | | , there are 2 balls in that specific type
whereas those who are null, would not be selected
What does 1 represent there?
The 1 represents that there are 2 balls in that specific type forexample, blue red and green. There would be 2 blue balls
Uh okay, so how would you represent that there is only one ball in that type?
Okay, why not just put two zeros where that 1 is originally?
I thought you meant before that 0 is suppose to mean 1 item
Because the way you have the 1 there doesn’t allow us to choose one item of one kind and another of another kind
Yes
To two items being selected would be two zeros
3 items, three zeros
And so on
The number of balls is the number of things you’re selecting
The number of bars is one less than the number of distinct varieties you have to choose from
A question is being answered rn. Please wait or ask elsewhere
Does that make sense @rich basin
Yeah i get that
but don't quite see the distinction of adding the amount of balls ontop of forexample 3 +2 -1 choose 2
5 identical balls and 52-1 dividers
That is the only confusion I have
Well remember it’s (3+2-1) choose 2
That whole quantity In parenthesis choose 2
3+2-1 represents how many spots we can choose 2 from to place the 2 dividers
is it written as (3+2) -1 or is it (3-1) + 2?
Lile how is it seen?
Addition is associative
Because i see the fifrst one as +2 being that it will firstly add the 2 replacement balls and then getting the dividers
$\binom{3+2-1}{2}$
logician_pdx
Like that
and then the second being finding the dividers first
Okay yeah the way you just described doesn’t quite encapsulate what’s going on here
Do you mind if I chat with you bout this later today? It’s 2:24am where I live and I’m doing this from my phone so I’ll be able to provide better explanation once I’m on my laptop
Could ya dm me the card question?
Yeath that is fine, but what would the equation be before you go?
Would it look something likw
,w solve ((13+3 -1 ) choose 3 times (39+2 -1 ) choose 2) divide ( 56 choose 5)
Yeah that’s for part a
But then the answer is different
it is different frm the wolfrma
That first fraction that I saw you post. Did that fraction equal this one here that you say is the answer?
unfortunately not
Can this answer not be reduced?
,w solve 2717/33320
It has a different decimal approximation
Hmm any explanations that came with that answer?
They didn't say anything, this is one of the even type question
I’d email your prof of the answer we worked out
Wait really?
Why are you using that textbook then?
This is the textbook we have to use
Damn but you’ve noticed it’s had wrong answers before?
I got a wrong answer question before,
Like there was a question with a wrong answer in the previous chapters
Oh gotcha
So there is a chance this one could be wrong
Okay thanks. I will try to DM you tomorrow
Okay cool sounds good
When you email your teacher, I’d show em exactly what we worked out and provide explanation for our answer
Good night
Thanks
My teacher barely reply to emails
Wow
Maybe also Throw your Question in the competition math chat and see if other people get what I’ve got
Just In case your prof doesn’t answer
This chat is open for questions now
Okay I sure will, thanks
You’re welcome
This question is from a book and that book usually contains pretty less solutions (solutions to selected problems) and I am stuck on this since quite a while; I will be glad if somebody helps me prove this.
there's also a hint on the book and the hint says: ||use the argument used in IMO 1988 #6 or in other words use vieta jumping/ infinite descent||
I have made some progress as well
let a^2+b^2+1 != 3ab or a^2+b^2+1 = kab where k != 3
and there exists (a,b) belongs to positive integers such that a^2+b^2+1=kab
then rearranging it we get x^2-(kb)x+b^2+1=0
Let (a,b) be the smallest solution possible (a+b= minimal)
wlog assume a>=b
then let ab=l
then, a^2+b^2+1=kl
and I don't see how I can proceed
I tried to prove it using contradiction
<@&286206848099549185>
MEOWBRO 父
MEOWBRO 父
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Wait, its 5x^2/2
Oh yes then it would be x^5
ok
$\int 5x^4$ = x^5 + c
ye
Phantom々Rakshit
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Hi guys, I'm trying to solve a task using gauss' method but I'm struggling a bit. Could you help me please?
maybe share more information?
A horizontal tangent line simply means that the derivative equals 0 at that point
Use the method of proof known as constant descent root flipping
that's what the hint says
Really? Okay I’m on point
Hmph well I tried it with small values like (1,1) and it worked but how will I prove it
I mean that's the thing right
I have to prove it
Bro look at what I just said
how to get the alternate form of this n/(n+1) ?
right
A question is being answered here. Please wait or ask elsewhere
@dire pilot that is a
ok so I can basically assume that a=b instead
At first yes
and do the grunt work
okay
we can change the equation and make that a^2|2a^2+1=3
No
Still no
Look at the left hand side of the divides symbol
There we go
But why did you set that equal to 3?
We can’t do that
so are we trying to contradict the statement ab|a^2+b^2+1=3
No
We are directly proving the equality case holds
Then we will use contradiction later for a>b
Dude change everything back to what you had with the equality case, but delete =3
Yeah
which is only possible for a=1
prove it? 😳
You can’t just jump from that and say it only works for a=1 without showing any work
I don't really see how I can prove my claim
Right but why
Yeah it is a proof right?
because a^2 divides 2a^2 and it must divide 1 to make the expression true
We have a^2 divides two things, so it must divide their positive difference
And that positive difference is 1
right
yes
we need to show that this whole thing =3 right
yes
but did we really need to show that it works lol
ofcourse it did
it is because even if we change the places of a and b it'll be the same
Perfect
basically we don't lose generality
So let’s assume without loss of generality that a>b
yes
Suppose the statement is false now
Then what happens
Think about what it means for the statement to be false
Which was
a^2+b^2+1 != 3ab
Right
or just a^2+b^2+1=kab with k != 3
Exactly
Okay now let’s make that equation look like a quadratic in terms of a
So move kab to the left hand side
lol so my solution was not completely wrong
Quickly jumping in to say that there is one case of inequality that can be very easily eliminated
attempt to sol*
Yeah sounds like you weren’t too far off
nevermind
umm
Look up em formulas yo
something like b^2+1/a?
right
Don’t forget order of operations. We’re dividing the sum by a, not just 1
(b^2+1)/a
because a>b and b^2<a unless b is a natural number b<=1
Um all you need to show c is positive is the fact that a,b>0
ah
So the numerator and denominator of that fraction must both be positive
yes and we proved that it should be an integer from the other part
yes
yea
Notice that we can also assume that there is a smallest pair of natural numbers a and b for which it’s false. We can define them to be the smallest pair by saying the product ab is smallest
We’re allowed to do this by the well ordering principle
We need to show know that cb <ab
This will contradict the minimality of ab and finish the proof
right
So using the fact that a>b and all we know about c, how can we show cb <ab?
Hint:
Show a^2>b^2+1
ca=b^2+1
Right
and a^2>b^2
Yes
But that won’t help with showing a^2>b^2+1
Since a>b, how can we relate a and b?
Write a in terms of b
hmph
