How do I avoid losing solutions from a non-linear system like this one? What should I do?
I already solved it, but I almost miss it, I'm afraid I'll get more problems like this one in the future
Would appreciate some book recommendations about this topic.
khan academy
you also get a free colour blindness test
>>8285986
Most of the time you just reason it out.
In this case, it's the line x=y.
>>8285986
You have to use non-linear algebra. Scmoodleberg and Bloch is the classic reference.
I want to learn economic theory from a mathematical perspective. I am reading "the wealth of nations" to get a basic understanding of modern economics, but I want to learn how to apply math to economics. Any books out there teach economics mainly from math? I am a math and physics double major so I probably already know all the math. I just want to learn how to apply it.
>>8285971
http://4chan-science.wikia.com/wiki//sci/_Wiki
Mems
>>8285971
Get daddy Varian. Micro econ is his specialty.
This guy walks up to you and color-codes your GF's ass, what do you do?
>>8285924
Run before I get allah akbared.
>>8285924
Jokes on you I have no gf.
>>8285924
Put him on 2x speed and then ask him to leave half-way through.
I have a crazy conspiracy theorist family member that is trying to convince people that the government blew off nuclear bombs on the moon. Is there any proof that I can cite anywhere that they didn't?
Fallacy flaw:
Shifting the burden of proof (see – onus probandi) – I need not prove my claim, you must prove it is false.
How can they nuke the moon if the moon isn't even real? The earth is flat and the moon is an illusion. He should know this. He's an ameture conspiracy theorist and will never reach true levels of crazy. He should quite now before he embarrasses himself with his weak levels of conspiracy theorizing.
How are you supposed to prove a secret shadow government secretly set off secret nuclear bombs on the moon in a secret opperation?
Just ask him all casually if the US landed on the moon. If he says no, ask why. Use that as evidence against the moon nuking.
How important is actual sunlight to the average person? I'm curious, /sci/. If you compared a NEET who never leaves his room to a person who goes out often, would the NEET be worse off than the other person?
What would the lack of sunlight do to the NEET?
>tfw you're a NEET but you you tan skin
>>8285762
lack of vitamin D
too tired to post more than that, going to bed
>>8285774
I understand that it leads to a lack of vitamin D, but what does that entail?
is it possible to use an induction field to heat up rocks that have rare earth metals in them so they slide out of the pores of the rock without having to be crushed and refined?
Huh?
>>8285716
>huh?
>>8285716
IS IT POSSIBLE TO USE AN INDUCTION FIELD TO HEAT UP ROCKS THAT HAVE RARE EARTH METALS IN THEM SO THEY SLIDE OUT OF THE PORES OF THE ROCK WITHOUT HAVING TO BE CRUSHED AND REFINED GRANDPA
So I'm reading all my textbooks exclusively on a computer screen through pirated PDFs.
How do I best prevent fucking up my eyes doing this?
>>8285667
Change screen color to reduce blues (which strain your eyes)
There's a program that does this, but I forget what it's called
>>8285667
You won't fuck up your eyes. If it is sunny out right now crawl out of your dark cave and go outside. It's fucking bright right? Now adjust to the light and go back inside and look at your screen you'll notice how dim it is. You will now realize the screen isn't bright enough to damage your eyes.
ITT: Post lecture courses available online for free
Abstract algebra:
https://www.youtube.com/playlist?list=PLelIK3uylPMGzHBuR3hLMHrYfMqWWsmx5
Covers:
>groups up to first isomorphism theorem and group actions
>examples of groups
>rings and ideals up to PIDs and UFDs
Recommended by anons: Pretty much anything by Schuller
A thorough introduction to the theory of general relativity - Frederic Schuller
https://www.youtube.com/playlist?list=PLFeEvEPtX_0S6vxxiiNPrJbLu9aK1UVC_
>a rigorous mathematical introduction to GR covering some topology and diff geo
Lectures on quantum theory - Schuller
https://www.youtube.com/playlist?list=PLPH7f_7ZlzxQVx5jRjbfRGEzWY_upS5K6
>rigorous mathematical "introduction" to quantum theory going through Banach spaces and measure theory
Lectures on Geometrical Anatomy of Theoretical Physics - Schuller
https://www.youtube.com/playlist?list=PLPH7f_7ZlzxTi6kS4vCmv4ZKm9u8g5yic
>rigorous mathematical footing of theoretical physics, from logic to set theory to topological manifolds, etc
Now, I'm looking for a decent lecture course on one of:
>differential geometry
>topology
>galois theory
>something interesting
I have background in real+complex analysis, linear algebra, abstract algebra, calculus up to multivariable.
galois theory:
https://www.coursera.org/learn/galois
https://www.coursera.org/learn/theorie-de-galois
https://www.wildberger.at
>>8285479
I tried some of his lectures but I get annoyed every time he starts criticising the reals, and I don't want to do a lecture course where the reals aren't taken into account. Any suggestions anyways?
This is the perfect kind of problem to troll people. Its statement can be understood by high school students or anyone who has learned about functions (that's in Math 001). It should be easy. But is it?
Here is where the experts will start to shake their heads knowingly, but I'm conducting an experiment to see if people, including & especially math majors, can solve it without already knowing the main lemma used in the proof. Maybe they can give a new solution too? Try your best, /sci/.
>>8285394
Your question is making me wish I had taken set theory.
The formulation of the statement is odd. You could just say
>Then there is a set [math] A \subset X [/math] such that [math] g[ Y - f[A] ] = X - A [/math].
Anyway, I'll start.
If g is surjective, then A={} works:
[math] g[ Y - f[A] ] = g[ Y - \{\} ] = g[ Y ] = X = X - \{\} = X - A [/math]
If f is surjective so that f(X)=Y, then A=X works:
[math] g[ Y - f[A| ] = g[ Y - f[X| ] = g[ Y - Y ] = g[ \{\} ] = \{\} = X - X = X - A [/math]
...
Anyway, my next idea would be to try and factor the functions into surjective and non-surjective part.
inb4 this needs the axiom of choice or whateva.
...
What else can we construct?
A=X-g[Y]
Then
[math] X - A = g[Y] = g[ Y - \{\} ] [/math]
so this works if
[math] f[X-g[Y]] = \{\} [/math]
>>8285539
Yep. The surjective case is clear. You are probably on the right track, but here's where the problems start to appear...
Hello /sci/. I'm an amature chemist that's good with inorganic chemistry, but suck at organic chemistry. Could you please educate me in the field a bit more? Thanks. Also general chemistry thread.
>>8285271
no chemistry is boring lol
Just get an intro orgo text like clayden or something
>>8285289
bumps all around
Lol is Brian Cox a literal retard? He makes himself look like a child in this video and commits so many scientific fallacies
"L-l-look at my graph!!"
https://www.youtube.com/watch?v=LxEGHW6Lbu8
>>8285198
Yes.
anyone worried about global warming
https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering)
https://en.wikipedia.org/wiki/Carbon_sequestration
I bet he blows the cox
the permanent entropic state of the universe makes achievements rather pointless. everything we do will decay. so when you get down to it people achieve things ultimately for that dopamine reward, now drugs get straight to the point. these achievements are as relatively transient as being high but require so much more effort. now you can say there is value in achievement in itself but that is on a whim. the best one can do is say achievement makes them feel better than drugs but then most reasonably it's a matter of relative reward / relative effort. and a steady supply of drugs will almost always win out here (the only exception i can think of is adding significant amounts of time to your lifespan since that means more time to be dopamined). there is a physical limit to how happy we can be due to the availability of receptors, all or none principle, etc. drugs get right up there with no effort. meanwhile achievement can too but typically the most rewarding achievements are the most difficult.
tldr i'm not saying you might as well be high all day erry day but you might as well be high all day erry day
Congrats anon, you've figured it out.
Now go stick those needles in your arm and let happiness overflow.
>>8285166
You're going to feel dumb when something in the universe figures out how to stop the entropic state.
>>8285222
>something can break the laws of physics
good luck with that, especially in our lifetime.
What do you think of this? I find it deeply unsetlin. And its likely true.
Paanel discussion. World's leadin astrophicists.
https://m.youtube.com/watch?v=NsbZT9bJ1s4
Susskind.s lecture:
https://m.youtube.com/watch?v=2DIl3Hfh9tY
This could pay way for grand unfication. It could explain entaglement. Sppky action.
This finding also hints at a sub quantum reality. Like at planc scale.
Hawking resisted the idea, but eventually gave in.
REALITY IS AN ILLUSION THE UNIVERSE IS A HOLOGRAM BUY GOLD BYE
>>8285028
Its dumb and makes no difference anyway
>>8285028
Excuse the typos, new device.
What did they mean by this?
>>8284902
>When watering down the math curriculum is just not enough to make women's grades be as good as men's grades so you need to replace math entirely with a sociology class that studies the culture surrounding math instead of the math itself
Don't tell me don't tell me...
US?
Heh.... Women's Studies. I go there to fuck hot chicks.
>>8284924
> implying it isn't a free humanities credit for math majors
We had philosophy of qm
How do you calculate your age in kilometers?
I'll tell you how if you all fail to answer it.
Distance earth has moves around the sun in one year x myage
>>8284891
>How do you calculate your age in kilometers?
You cant you retard. You measure time in seconds while distance in meters.
>>8284900
What about all the kilometers you move around on the Earth?