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/sci/ - Science & Math

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7415139 No.7415139 [Reply] [Original]

ITT: Post guaranteed replies.

https://en.wikipedia.org/wiki/Monty_Hall_problem

>> No.7415145
File: 4 KB, 645x132, easy.png [View same] [iqdb] [saucenao] [google]
7415145

>> No.7415256

>>7415145
2

>> No.7415259

>>7415145
-1/12

>> No.7415316

>>7415145
1.999...

>> No.7415424

>>7415139
You know, monty hall threads aren't that bad

>> No.7415431

>>7415424

Are you for real? The mysteries of conditional probability will forever troll imageboards into oblivion

>> No.7415560

>>7415316
here we go again.

GUYS, WHY IS 0.9999... = 1 ?!

>> No.7415565

http://www.telegraph.co.uk/news/science/6546462/The-10-weirdest-physics-facts-from-relativity-to-quantum-physics.html

>> No.7415577

>>7415259
so...infinity?

>> No.7415614

>>7415431
I'm not for real, I was just posting something which would get guaranteed replies.

>> No.7415652

>>7415139
Earth is flat. Prove me wrong.
CS is the GOD tier of sciences
We did not land on the moon. Ever. prove me wrong
Gender is a social construct. GTFO you cis privelige

>> No.7415655

dont reply to the post above this post, reply to this post instead

>> No.7415659

<div class="math">\lim_{n\rightarrow\infty} \frac{n(n+1)}{2} = -\frac{1}{12}</div>

>> No.7415712

>>7415139
the simple solutions are laughable and reinforce the intuitive 50% solution with their flaws. I believed in the 2/3 solution only when the table below showed that the person who opens a goat door randomly opens a goat door when the car is behind door 1, because I assumed he always had to open door 3 if a goat was there, and door 2 if not. I'm not sure if the correct solution is 50% if the 'opener' acts like I described now

>> No.7415911
File: 36 KB, 726x435, portals.jpg [View same] [iqdb] [saucenao] [google]
7415911

>> No.7416172

>>7415145
0.

PEMDAS
Parenthesis, Exponents, Multiplication, Division, ADDITION > SUBTRACTION.
2-(1+1) = 0

>> No.7416182
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7416182

>> No.7416185

>>7416172
>>7416172
PE M/D A/S

>> No.7416187
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7416187

>> No.7416190
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7416190

>>7416187

>> No.7416200
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7416200

>> No.7416205
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7416205

>> No.7416208
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7416208

>> No.7416209
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7416209

>>7416187
Impossible with an uneven number of edges

>> No.7416259

>>7416209
you can go through walls

>> No.7416272

>>7415659

CAN WE HAVE SOMEONE CONFIRM THAT THIS IS OKAY TO SAY? WHY NOT?

>> No.7416344
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7416344

>>7416187

>> No.7416620

>>7416172
Where does the parenthesis come from?

>> No.7416643

>>7415560
because its super infinitely close to one.

>> No.7416761

>>7415911
I never got this one. It's really obviously A. Go get a box and drop a hula hoop on it.

>> No.7417615

why is this problem hard to understand? you have a 2/3 chance of failure, so by changing, you have 2/3 chance of success.

>>7415560
n=.9999..
10n=9.999..
9n=9
n=1

>> No.7417633

>>7416172
Additions is subtraction and vice versa only with/without negative numbers. Not phasing out subtraction and division in favor of adding negatives and multiplying fractions is literally troll and retard enabling.

>>7416187
"trough" isn't a verb.

>>7416200
About zero fiddy percent.

>> No.7417659

>>7415911
>>7416761
It's b. An object must exit the portal at the same speed it enters, relative to the portal.

>> No.7417669
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7417669

>> No.7417671

>>7415139

>https://en.wikipedia.org/wiki/Monty_Hall_problem

First time I heard about this was Kevin Spacey explaining this shit in that dogshit movie "21"

>> No.7417675

>>7417669

Uhm... is this a joke?

>> No.7417682

>>7415577
no, thats negative one twelfth
>or is this bait

>> No.7417683

>>7415911
define the portal's "opening" material and its momentum carrying capabilities

>> No.7417924

>>7417675
careful, anon...

>> No.7417929

>>7417669
Ever lift a heavy stone under water? It is easier, because even if an object sinks, it has bouyancy. The weight of the steel ball on the suspending cord is reduced by the weight of the volume of water displaced. This weight is instead taken by the supporting water.

On the other side, the only weight that can be taken by the water is the full mass of the pingpong ball, which isnt equal to the volume of the water displaced (hence the positive bouyancy). Therefore, the right side of the scale is heavier, by an amount equal to the weight of the water displaced minus the weight of the pingpong ball.

>> No.7417931
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7417931

IQ

>> No.7417934

>>7415614
I love it. 10/10

>> No.7417972
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7417972

>>7416187
wtf this was easy?

>> No.7417997

>>7417972
well played

>> No.7418136
File: 678 KB, 1143x1133, 1437673784923.jpg [View same] [iqdb] [saucenao] [google]
7418136

:(

>> No.7418869

>>7415139
The world is flat

>> No.7419667

>>7415139
the chance is always 33 percent because of the way the pint-observable phenomenon is modeled

idg how people can't into common sense

>> No.7419709

>>7415139
Any simple arithmetic that requires you to know the order of operations. Also, checkmate atheists threads are good, but too easily get you banned.

>> No.7419718

>>7415911
A obviously since the cube doesn't get kinetic energy from anywhere

Even me the CS major gets this

>> No.7419730

>>7419667

such bait

>> No.7419840

>>7415911
Why is the portal moving?

>> No.7419903

>>7419718
why did you major in cs

>> No.7419907

>>7419903
because maybe he likes it?
also fuck physic majors

>> No.7419920

>>7419907
i love cs my boyfriend majored in cs and he is cool he wears a scarf and a turtle neck sweater and he also smokes
he says when we have a family he's going to be a billionaire

>> No.7421001

>>7415911
in the game they don't let you put portals on moving objects for a reason. 0/0

>> No.7421702

>>7415145
2-1+1=
2(-1)+1=
-2+1=
-1

>> No.7421708

>>7416208
I don't get it, so I'll just give a counter-example to filename.

>> No.7421709

>>7419920
>btw im a grill
GET OUT GET OUT

>> No.7421729

Is Who wants to be a millionaire just a game of luck?

I mean, there's 33.34% chance of being right unless the person happen to know the answer, and lifelines can only get you so far into the game.

Let's say there are 15 questions with 4 choices each. Let's also say there are 3 lifelines: call-a-friend, 50-50, and ask-the-audience.

For each of the 15 questions, there is only 1 correct answer, and 3 incorrect answers, so immediately your chances are 1/3 = 33.34%. You can use each lifeline once. Using phone-a-friend, let's say gives you a 95% chance the person you call is correct. So 1 question is 95%. Similarly, we can say ask-the-audience gives you a 95% chance. Finally, 50-50 will remove 2 wrong answers, so you have 1 right answer and 1 wrong answer, so you basically know the answer. To recap:

Question 1: 33.34%
Question 2: 33.34%
Question 3: 33.34%
Question 4: 95% <--- ask-the-audience
Question 5: 33.34%
Question 6: 33.34%
Question 7: 33.34%
Question 8: 33.34%
Question 9: 95% <--- phone-a-friend
Question 10: 33.34%
Question 11: 33.34%
Question 12: 33.34%
Question 13: 33.34%
Question 14: 33.34%
Question 15: 100% <--- 50-50
Total: 690.08%

Divided by 15 questions = 46.00%

So basically, it's more a less a game of chance, but more than half the people on the show will lose, so it's not very fair. That show is making tons of money off of people.

>> No.7421730

What would happen if a sun made of lava collides with sun made of ice?

>> No.7421767

>>7421730
They would cancel each other out, creating steam which would form into a gas giant. Like Neptune.

>> No.7421776

>>7421729
>3 incorrect and 1 correct
>4 total
>chance for guessing correct is 1/3
What am I reading

>> No.7421806

>>7415911
B, because the blue portal isn't moving, and the cube exits the blue portal with the same speed it entered the orange one.
When it goes through the orange portal, the cube is not moving, but to understand this, you must think focusing in the blue portal.
If we see what is happening through the blue portal, we only see a wall pushing a cube against the portal with high speed, so the cube will have this speed when it goes through the blue portal.

>> No.7421808

>>7421729
Your statistics are wrong

>> No.7421816

>>7417669
Right side goes up.
Left side has water+ball
Right side only has water, the iron ball is held by a string, and it isn't on the scale.

>> No.7421821

>>7421730
If they are made of lava or ice, they are not "suns".
Also, it depends on mass and temperatures of each one.

>> No.7421950

>>7421001
they do

>> No.7421953

>>7416205
But that is actually correct

Assuming you do it an infinite times

>> No.7421957

>>7421953
No it's not. It would be 2pi because you have 2 lines for each one, if it were a perfect circle.

>> No.7422121

>>7421953
noice trole

>> No.7422268

If for some matrix A and vector v <div class="math">Av =\lambda v</div> so <div class="math">Av - \lambda v = 0</div> then trivially <div class="math">Det(A - \lambda I)=0</div>

>> No.7422749

>>7416187
To any one who is trying to do this, don't listen to this retard >>7416205 who didn't learn his graph theory properly. If you want to solve this, you cannot start wherever you want.

Don't give up anon >>7418136

To solve this, you have to start in the middle room on the bottom and end on the outside of the rectangle or vice versa. Look up semi hamiltonian paths if interested in the theory.

>> No.7422762

>>7422749
Meant this retard >>7416209

>> No.7423051

>>7421808
> Op says this is bait sharing thread
> People on this board are so asspie they argue with bait which is stated to be bait.

How do u people even exist?

>> No.7423056

>>7415139
Um, "moot is a cuck?"?

>> No.7423124

>>7421729
>so immediately your chances are 1/3 = 33.34%
No your probability of getting it right is 1/4 = 25%

>Total: 690.08%
You do not add up probabilities in successive independent events , you multiply.
Probability of success = (0.25)^12*(0.95)^3 = 5.110^(-8) = 0.000000511%.

It is not a game of chance because you may know the answer, in which case you have 100% chance of answering correctly. Also, the contestant can bank their earning and walk away at any time. The only thing you show is that is very unlikely to rely on random chance and win the top prize is unlikely.

>> No.7423708

>>7417659

No, an object retains it's momentum through a portal. The cube has no momentum.

>> No.7423715

>>7422268
i take the bait. how do you get the third equation

>> No.7423956

>>7423708
>an object retains it's momentum through a portal.
Not necessarily.
If you can't figure out that an object must enter and exit as portal at the same speed, then you are retarded.

>> No.7424452 [DELETED] 

>>7423715
It's a false proof of the Cayley-Hamilton Theorem. The bait is that the last step is actually nontrivial and takes work to prove.

>> No.7424465

>>7423715
Aw shit I screwed up.
Sorry what I intended to write was a certain false proof of the Cayley-Hamilton theorem but I actually wrote some simple correct thing by mistake. Probably a simptom of not having thought about the cayley hamilton theorem in four years or so.
Here is the bait properly:
Define a polynomial by: <div class="math">p(x)= Det(x I-A)=0</div> You can actually apply polynomials to matrices to get other matrices. So in particular <div class="math">p(A)= Det(A I-A)=Det(0)=0</div>

>> No.7424469

>>7415139

Sometimes mathematicians are breathtakingly stupid

The reason it's in your best interest to switch is simple. The host does not want to you to get the car. You know this. You expect him to attempt to trick you out of it, so when he offers you another choice, you suppose it's only because you've picked the right door. So in trying to outwit the host, you're led to keep the original choice, and lose the car.

>> No.7424476

>>7415560
the sum of the series
9/10 + 90/100 + 900/1000...
converges to 1 as the limit of the index goes to infinity

>> No.7424480

>>7424476
That is just 0.9*infinity. The numerator has to be 9 in all of them

>> No.7424481

>>7415911
I think the portal would transfer it's momentum (or energy, I don't know, I was bad at physics) not to the box but onto the table which holds the box

>> No.7424485

>>7424481
>>7415911
That being said, the faster the portal moves, the faster the box would appear out of the other portal, but once it's fully out of the portal it will have 0 momentum, meaning it wouldn't even "plop", it would just fall back again (unless the other portal is, of course, blocked, then the box would just sit on top of blue portal)

>> No.7424489

>>7417669
veratasium answered this

>> No.7424495

>>7424489
https://www.youtube.com/watch?v=stRPiifxQnM&feature=youtu.be

>> No.7424504

>>7421729
still one of my favourite /sci/ copypastas

>> No.7424517

>>7417671
was the movie dogshit because you couldn't understand the protagonist because he's smarter than you?

>> No.7424892

>>7415145
0

>> No.7424921

>>7424892

No, 2
bcs
2 - 1 + 1
= 1 + 1
= 2

>> No.7424957
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7424957

Hey guys, what's going on in... Whoa! A thread full of trapped autists!

>> No.7425616

>>7415655
guaranteed reply!

>> No.7425638

>>7415139
I think Ray kurzweil is:

> A intellectual mastermind
> A sham

>> No.7425928

>>7423956
It doesn't need to shoot out to exit at the same speed it enters. You're the one who looks retarded right now.

>> No.7425933
File: 24 KB, 1002x648, Untitled2.png [View same] [iqdb] [saucenao] [google]
7425933

>> No.7425943

Why is it men's fault that women aren't interested in science?

>> No.7425958

>>7415659
(inf) times (inf) equals number

wtf

>> No.7425975

>>7417615
but in the third step you should have substracted "n" from both sides.

>> No.7426006

>>7415911
It's obviously A.

To say the object would gain momentum is to say that the portal either resists an objects entry in proportion to it's mass, or can impart infinite energy on a mass entering it with no apparent source.

>> No.7426032

>>7426006
Both answers break relativity.

If it's A the reference frame of the portal is broken. From the perspective of an observer sitting on the edge of the orange portal, you would see a cube speeding towards you, go through the portal at some speed, then instantly lose all momentum for no reason and fall down on the other side.

If it's B, you have the opposite problem: The reference frame of the cube has you instantly gain kinetic energy the moment the portal slams down on you, even though all you touch is empty space (as you note: energy with no source).

Either way, the result depend on your observed frame of reference, which is not exactly conductive to puzzles involving classical mechanics.

Someone actually tried making it in the level maker. The game physics fuck up.

>> No.7426034

>>7416172
addition and subtraction have the same priority

>> No.7426050

>>7426032
No, that is not correct and you are a moron from /v/ who was peddling the same dumbshit there and kept getting BTFO by everyone.

>> No.7426058

>>7426050
>That is not correct
>No counterarguments

>> No.7426076

>>7426032
I believe it would essentially be a physical circumstance as though the blue portal were itself moving to reveal the object without actually moving.

A circumstance which can only exist as a result of the special properties of the portal.

>> No.7426103

>>7426032
>>7426058
Fine, I'll argue with you.
The cube never has momentum. Consider the portal as a hole in the wall that leads to another room: A from the reference frame of the cube sees a wall with a hole falling on top of you, after which you fall down. A from the reference frame of the portal sees the cube going through a hole, then falling down.

>> No.7426282

>>7416187
Is impossible and
>>7422749
is wrong.
Easy proof.

If room X has odd number of doors, then :
- if you start outside room X you must finish inside room X
- if you start inside room X, you must finish outside room X

There are 3 odd rooms, X Y and Z. Since you start from a single position, you have to start outside at least 2 odd rooms, say X and Y. Following previous reasoning, you must finish inside both X and Y at the same time, which is obviously imnpossible.

>> No.7426285

>>7426282
Forgot to mention that the outside can be considered a 4th odd room, too.
it doesn't change the only possible conclusion that if there are strictly more than 2 odd rooms, you cannot solve this.

>> No.7426381

>>7425928
Yes it does, unless there is some buffer zone inside the portals where it slows down before exiting.

>> No.7426408

>>7426103
he's right about it breaking the universe btw

in pic related if you use the same logic as a hoola hoop the stationary cube would enter with velocity v and exit with velocity 2v therefore gaining momentum from nothing

>> No.7426410
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7426410

>>7426408
>pic related

>> No.7426498
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7426498

>>7416187
was that supposed to be hard?

>> No.7426501

>>7426498
You forgot one door :)

>> No.7426505

>>7426498
get wrecked you smug motherfucker

>> No.7426513
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7426513

>>7426501
>>7426505
Of course not

>> No.7426519
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7426519

>>7426513
That's cheating, also your solution is way too complicated
Just do this, the question didn't specify the thickness of the line :^)

>> No.7426727

>>7415911
>all these A answers
Speed is defined relatively to the frame of reference. The two portals have the same frame of reference by nature of being portals. The object is moving in the reference frame of the left portal so it should have the same speed relative to the right portal. Conservation laws do not apply here because we're talking about portals which go against such laws by their very nature. It should be impossible for the same frame of reference to be defined in relation to two different points, but we suppose just that when we assume those points to be connected through a portal.

>> No.7426737

https://youtu.be/D-v_K1k8Se0

>> No.7428482
File: 2.40 MB, 540x360, quantumcatloli.webm [View same] [iqdb] [saucenao] [google]
7428482

I have a theory: Why don't we use Schrödinger's cat to prove whether animals are conscious? Because only the species with consciousness will collapse the wave function.

>> No.7428495
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7428495

>>7428482
I'm not sure how I feel about this

>> No.7428878

>>7426727
Portals are paradoxical in nature, so we will always reach a logical paradox at some point when applying logic/physics to portal behavior. You chose to "put" the paradox in the fact that the same frame of reference is defined in relation to two points. It's not the only way to see things.
Basically you have to chose what physical or logical laws you have to discard in order to allow the assumption of the existence of portals.

By the way. GLADos explicitly says in the game that momentum is conserved when crossing a portal. And the game is where this whole meme comes from. Of course, it wasn't developed by physicists, but if we have to arbitrarily choose some rule or behavior (which we have to do, cf above), then it would make sense to go with the developer's choice.

Going with your point of view and the situation in >>7415911, consider the following :
The yellow portal suddenly stops dropping when half the cube has already crossed it. Half the cube is at rest in the room's frame of reference, and the other half (the one that exited the blue portal) has a large momentum. The cube is torn in half with the same force that would be required to put the cube in movement with the parameters set by the experiment (falling velocity etc).

Other scenario now. You are standing in a room and on the wall in front of you is a portal. The other portal is right behind the same wall, is such a way that if you stand in front of the wall, you can see right through it (light seems to cross the portal without any disturbance etc).
The wall starts moving toward you at a great speed by some mechanism, you stand still.
According to your view, when you exist the portal, you will experience (in your own frame of reference) a great force that will push you in front of you will stumble.
But for an observer above the room, the room did not move (only part of a wall did, or a vertical platform or whatever), ad neither did you until the portal crossed you.

>> No.7428881

>>7428878
>cont
The wall "supporting" the portals did not experience any force either. The force experienced by yourself seems to come from literally nothing.

tl;dr : non-conservation of momentum is not the most natural choice when explaining portal behavior

>> No.7428921
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7428921

>>7428482
I would a Komoe