Archived threads in /sci/ - Science & Math - 162. page
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What is the correct answer?
50%
-2/3 or 2/3 depending on how you solve the quadratic equation
Always change your choice.
Hello /sci/, I hope everyone's doing well. Let's get an interesting thread going, shall we?
There is a set $S$ of points in the plane with the property that any triangle with vertices in $S$ has area at most 1. Prove that there exists a triangle with area 4 containing all the points in $S$.
Let's see how /sci/ solves this.
(Problem is not original)
are you allowed to make the triangle as big as you want, because then it would be easy
>>8059520
OP here.
Let me ask you something, anon. Why are you still alive? Can you not fucking read?
'has area at most 1.'
'....there exists a triangle with area 4'
I'm not going to autistically write out a rigorous proof for this.
http://humansarefree.com/2016/02/big-pharma-is-injecting-us-with-cancer.html?utm_campaign=shareaholic&utm_medium=google_plus&utm_source=socialnetwork&m=0
scary shit
>>8059439
>Big pharma
Stopped reading there.
>>8059439
>conspiracy
>vaccines
yadda yada into trash
An object travelling at the speed of light would have infinite mass. So, why don't we say that photons have infinite mass? Is it because it functions as a wave instead of a particle? Or is it just because infinite mass would imply infinite volume?
It's duality phenomena
>>8059395
photons aren't objects like you're thinking of
>Infinite mass
Infinite momentum? How does it even work with the mechanics we know? Or is it guarded by something like: achieving c would also demand infinite amount of energy delivered.
Could a man be so smart that others percieve him as dumb?
Probably not. Besides, if people can only see that man as dumb, maybe he is just dumb.
no. please stop posting.
Yes.
Friends! Reminding you once more there will be a transit of Mercury across the sun TOMORROW, May 9th. This event lasts 7 1/2 hours beginning at 7:12 A.M. Eastern time. The last time this occurred was 2006 and it won't happen again until Nov. 2019.
A telescope with at least 60x magnification, and a solar filter over it is the ideal way to view the event, though there will be many observatories showing live streams. One of such can be found here: http://main.slooh.com/event/transit-of-mercury/
Western Europe, Eastern North America, and much of South America can see the entire transit. Most of the rest of the world may catch at least part of the event. Australia & east Asia is boned.
>> Just graduated college yesterday
>> Implying I'm going to wake up at 7 am to see a fucking transit
>> What kind of astrophysicist am I
>>8059279
I understand that's actually sadly common, for astrophysics or astronomy students to never once go out and actually look at the sky.
When do you think first contact will take place? What do you think about the great "roar" Which is blocking out signals or the object which follows earth? Post your thoughts! :)
>>8059117
Fuckoff and die.
Never
Never
Never
Heard of black knight satelite?
I can't think of a better board to ask on
>>8059107
u wot
I'm not certain, but I think emotion and sensation are other parts in the brain. They are linked but not in the same place, so I guess you can have sensation without emotion if you cut that connection.
>>8059107
hunger, pain, temperature, thirst and such are sensations aren't they?
I guess even a very emotionless person can still feel hunger, pain and etc.
We could devolve back into monkeys if we tried or evolution is an one way street?
>>8059073
technically that is an ape
>>8059078
Apes are a special case of monkeys.
>>8059073
>Devolve
Learn what evolution is before shit posting about it on /sci/
Short answer: technically, I guess.
Long answer is that we can technically a tempt to fuck up our genetics intentionally so we get a fucked up baby but that's illigal and stupid anyways.
Longer answer: http://www.nature.com/scitable/topicpage/genetic-inequality-human-genetic-engineering-768
How would you find out the angular velocity of a wind turbine only knowing the RPM and wind speed?
>>8059040
waaaaaait a second, is this homework?
>>8059046
Theres a wind turbine right over there see? I took a picture of it.
wind speed right now is 13 mph
so 5.811 m/s
and it's spinning at about 65 RPM
so angular velocity must be...
The function
[math] f: \{ 0,1,2,3 \} \to \{6,7\} [/math]
defined by
[math] f(0):=6 [/math]
[math] f(1):=6 [/math]
[math] f(2):=7 [/math]
[math] f(3):=6 [/math]
is surjective: Its range (the set of values, 6 and 7) indeed equals its codomain ([math] \{6,7\} [/math]).
The function has a right inverse
[math] r: \{6,7\} \to \{ 0,1,2,3 \} [/math]
For example,
[math] r(6):=3 [/math]
[math] r(7):=2 [/math]
makes it so that [math]f \circ r[/math] is the identity function on [math] \{6,7\} [/math]:
[math]f(r(6))=f(3)=6[/math]
[math]f(r(7))=f(2)=7[/math]
It's...
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>does every surjective function have a right inverse
Yes, this is the definition of surjectivity.
>>8059014
https://proofwiki.org/wiki/Surjection_iff_Right_Inverse
>>8059022
That proof uses the axiom of choice.
So I take it you say the axiom of choice is true?
Explain this, /sci/
I am dumb but I think simple logic proves airfoils are designed upside down.
The curved surface on the top would displace more air, creating a higher pressure than the flat surface on the bottom. This means that the lower pressure area on the bottom of the foil would suck the aircraft downwards, instead of upwards.
Am I just stupid? I don't get this at all. Please help. Assume the angle of attack is totally flat and the flat foil is totally flat also.
In this picture it's perfectly clear that the top surface has a greater surface area than the bottom, meaning it displaces more atoms and would have greater pressure on it....
Right?
>>8058957
>Assume the angle of attack is totally flat
That's not how wings work, senpai.
...and that's pretty much the answer to your question.
>>8058957
It's dynamic pressure, and since sum of dynamic and static pressure in.given area is constant, static pressure is pulling the wing from above and pushing from below.
I have my AP Physics C: Mechanics exam tomorrow.
Any tips? This is the second year they're allowing calculators on MC, so I'm not sure how the multiple choice is going to be compared to released exams.
>also, predictions for FRQ topics?
>allowing graphic calculators for past exams
>ban graphic calculators three years ago
>make exam questions harder
Fuck my life.
>>8058893
Oh, so will exams pre-2012 be like exam in 2016?
I'm an ap physics teacher, feel free to ask me specific questions. Yes I'm also on 4chan on a sunday morning; I'm good at physics not at life.
Always be sure to explicitly cite conservation laws when doing an FRQ. It's very often something that is specifically laid out in the point distribution. Same with units and an initial set up.
Remember the AP scoring guidelines are pretty forgiving (just setting up and attacking a problem is often the majority of the points) and additive (you can put wrong stuff and it's basically never penalized,...
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What does division mean in probability?
If I understand correctly, then when translated from math to English:
[math]P(A)*P(B)[/math]
becomes
>the probability that A and B are true
[math]P(A)+P(B)[/math]
becomes
>the probability that A or B is true
[math]P(A)/P(B)[/math]
becomes
>???
If it doesn't "mean" anything in particular, then is there at least a metaphor that would help me imagine it better?
>>8058839
>If I understand correctly
you don't
>>8058839
I always think of it as disregarding redundant cases.
>>8058839
>A 'if' B.
If you don't understand it just apply whatever variables you have to Bayes's theorem and it'll work.
How can a poor educated 20 year old get into MIT?
I have no money but access to a computer with internet.(i live in europe)
Lets assume i am not a brainlet.
Study
>>8058663
This. What did you expect OP? A person will just notice your non-brainletness and invite you to MIT?
