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Is tau really superior to pi or is it just a meme?
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Anon, do you really need someone to explain you the difference between π and 2π?
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>>8199475
No, rather the difference between 2π and τ.
I know they have the same value, but people still use one or the other. Why?
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i think pi is for non-physicists/brainlets with -0.999... IQ
Anonymous
Quadratic Formula Algebra Question 2016-07-12 16:48:14 Post No.8199403
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Quadratic Formula Algebra Question 2016-07-12 16:48:14 Post No.8199403
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Quadratic Formula Algebra Question
Anonymous
2016-07-12 16:48:14
Post No. 8199403
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So I was helping an algebra student with his homework, and this quadratic came up.
[eqn]\sqrt{2}x^2+(2\sqrt{2}-2)x-4=0[/eqn]
I can verify using the ABC method and just by plugging into the function that the roots are [math]\sqrt{2}[/math] and [math]-2[/math]. But for the life of me, I can't figure out how to show this with the quadratic formula.
[eqn]x=\frac{-(2\sqrt{2}-2) \pm \sqrt{(2\sqrt{2}-2)^2-4(\sqrt{2})(-4)}}{2\sqrt{2}}[/eqn]
Any ideas how to simplify this? I've tried every method I can think (factoring out of the square root, multiplying by conjugates, etc.).
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>>8199403
dont be lazy. open up the expression in the root, then divide the numerator by the denominator. that's it.
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foil on the first term under the square root
Anonymous
The problem with rearrange terms in infinite sum 2016-07-12 11:53:29 Post No.8198964
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The problem with rearrange terms in infinite sum 2016-07-12 11:53:29 Post No.8198964
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The problem with rearrange terms in infinite sum
Anonymous
2016-07-12 11:53:29
Post No. 8198964
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Why is it this a problem? My prof always shrug this off as something very delicate about the notion of infinity so unless we are careful we will be wrong. But this seems to be a philosophical answer more than a mathematical one.
Surely there's a well thought out reasoning using proper mathematics that explain what kind of rearrangement is acceptable.
Riemann only ever said you can add up converging alternating series to any value you want by rearranging right?
I am guessing this have to do with the fact that we have infinite amount of positive and negative term, so it is possible to do arrangement such that we can use it to approximate the summation to any value without "exhaustion" in a sense. Since our series is an convergent alternating series, our approximation will get better.
ie 1/100 - 1/1000 + 1/10000 ....... we can take the the positive term to some value up, then take the negative term to reduce it to some value down and our approximation will get better because the terms get smaller.
But this is done via choice, not algorithmic, so while I understand the idea, it feels incomplete and doesn't capture the full picture for me.
Is this also true for non-alternating series? Surely not, since we will only have either positive or negative terms.
>pic related
????
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>>8198964
>But this is done via choice
Not a problem. We're doing math here and not CS. An existence argument is sufficient.
>Is this also true for non-alternating series?
It is true only for conditionally convergent series, i.e. those which converge but don't converge absolutely. This implies that there are infinitely many negative and infinitely many positive terms.
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>>8198995
>Not a problem. We're doing math here and not CS. An existence argument is sufficient.
is this pretty much all I need to do show that every convergent alternating series can be manipulated to be equal to any value; QED?
>It is true only for conditionally convergent series
Then why can't I manipulate the sum of 1/(n^2) any way I can?
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>>8198964
>alternating series
please do not use that word.
riemann showed that any convergent series that DOES NOT CONVERGE ABSOLUTELY can be rearranged to converge against anything we want
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Every time someone talks to my son he traces their words into the couch he'd be sitting on, his pants, etc. What could this mean?
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>>8198952
How old is your son? What level of cognitive abilities does he possess?
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>>8198952
That is literally autism
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>>8198960
He's 7
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is consciousness ultimately separate from and independent of the brain or is just an inherent byproduct of the amalgamation of our most common thought patterns?
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>>8198894
Consciousness is a quantum mechanical phenomenon.
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>>8198894
>Consciousness
It's just a manifestation of your physical neurology, there's nothing to else to it.
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>>8198896
>there's nothing to else to it.
Denialist pls go.
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Philosophy of mind thread.
Eliminative materialism is the only thing that makes sense and psychology in general must adapt this principle. Your thoughts?
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>>8198868
>>/his/
Philosophy board.
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>>8198868
p-zombie pls go
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>>8198870
Philosophy of mind = philosophy of science with focus on psychology. I dont think /his/ is the appropriate place to go when discussing science.
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I saw a report on mangroves on about how over 10,000 hectares of mangroves have died in Australia, and no one is paying attention to it since they are visually appealing. They seem to fairly important to the environment however, and I just wanted to know exactly why?
Also, there has been no set reason as to why they have all died apart from lack of water however I'd like to know about some other factors. So, my questions are; What are mangroves and what are their adaptations to deal with factors such as salinity, substrate, oxygen availability and wind?
Thanks!
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Pneumatophore's are an adaptation to low oxygen.
IIRC magrove habitats store more carbon per hectare than regular forests, and provide a nursery for the juveniles of many species of commercially important fish species.
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>>8198838
Mangroves seem pretty neat.
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>>8198840
Also, Grey mangrove (Avicennia marina) excrete salt on the underside of their leaves.
Lick the leaf and you can taste it.
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Is this map legit? I mean IQ lower than 70 would mean you have some form of developmental disability in the first world, but there are actually countries where half of population has even lower scores than that? How would they be able to run a functioning country if this was for real?
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low IQ = slower development
pretty simple concept
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Its probably from Lynn
Look into him at wiki and his "IQ and wealth of nations".
He does shitty approximations.
In one country in Africa for example his only basis for the IQ is a shitty cultural IQ test on 14 year olds.
Although there are real differences in IQ between nations, but the most effect has malnutrition.
For example a deficit in iodine and a change of the iodine diet after that let to an increase of 15 IQ points from 85 up to 100
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>>8198727
This is purely conjecture, opinion and anecdote, but you can train yourself for IQ tests.
Schooling system may actually develop your thinking in a way that increases your IQ. That would pretty much also explain why many East-Asian countries seem to perform better than western countries.
I see it as a case of chicken and egg. Does a non-functioning country create people with lower intelligence, and do smart people want to stick around anon-functioning country, when they can leave and make use of their skills.
Also would stand to reason that dumb people will not help create a functioning country. But then again, lowering your IQ is as easy as sniffing glue or getting hit on the head, both of which might be easier to do in a non-functioning country. Nutrition also hugely influences intelligence, and many non-functioning states suffer from famine.
To actually answer: Many of those countries can be barely described as functioning. Intelligence seems to possibly correlate. Too many variables to make meaningful analysis. So many arguments flow around since you can come to so many conclusions based on stats like this.
Anonymous
Why are /sci/ jobs/internships pay so fucking shite? 2016-07-12 07:54:39 Post No.8198704
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Why are /sci/ jobs/internships pay so fucking shite? 2016-07-12 07:54:39 Post No.8198704
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Why are /sci/ jobs/internships pay so fucking shite?
Anonymous
2016-07-12 07:54:39
Post No. 8198704
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>Working on ground-breaking robotic medical device at SV startup
>Doing significant work using ROS, machining with my hands, PCB design
>Often have to work 65-70 hour weeks
>I'm getting paid $9 a fucking hour
Why is this allowed? Jimmy the fucking shift manager at mcdonalds makes twice what I do. Why is this allowed? I'm a mechanical engineering intern from Caltech. Can someone tell me why this is allowed?
I understand I am getting valuable experience, but what the fuck, why is my work worth $9 a fucking hour?
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>>8198704
>Jimmy the fucking shift manager at mcdonalds makes twice what I do.
You are doing something meaningful and you have a future. Fuck off with your whining.
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>>8198707
I understand, it's great, it's great - but there's a lot of shit I want to buy for myself (Vive compatible PC + Vive so I can do my own development w. unity) and I physically cannot buy SHIT because I get paid rent+food essentially.
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>>8198708
>Vive compatible PC + Vive so I can do my own development w. unity
You're doing robotics in SV and you want to jump on the meme development wave with a $2000 pc and $600 meme-o-vision with memewands? Don't be an early adopter, anon. VR will be MUCH better in two years, when you have income.
Anonymous
Earth from space NO FISHEYE 2016-07-12 06:13:36 Post No.8198595
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Earth from space NO FISHEYE 2016-07-12 06:13:36 Post No.8198595
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Earth from space NO FISHEYE
Anonymous
2016-07-12 06:13:36
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Can anyone link a video of anything that has gone high enough to film the curvature of the earth that does NOT use a fisheye lens??
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>>8198595
If you do not trust the images by any of the numerous space and aeronautics agencies, I don't know what to say to you.
You seem to assume it's all false rather than actually approaching this with an open and curious mind, in which case, what's the point in responding?
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here ya go
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Ok, I agree flat earth is some bunk.
But Hollow Earth? Was Admiral Byrd a kook?
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They would have figured out the earth was hollow a long time ago through the behavior of seismic waves from earthquakes. The Earth does not behave like a hollow object.
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>>8198591
How would you explain the earth's magnetic field? Also, we know the mass and average radius of the Earth and thus the average density. This density is much higher than the density of the crust (which we can measure directly), thus there's more dense stuff underneath. Also volcanic activity.
It would take quite a lot of patchwork to explain a hollow earth. The fun part is that Gauss's law tells us that a hollow earth will behave exactly as a solid earth in terms of gravity and orbit (if they have the same total mass).
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Milk in the US is laden with hormones and whatever else garbage. How can anybody do proper studies when it's almost impossible to purchase milk in the US that hasn't been tempered with?
I grew up on the outskirts of a city and drank mostly fresh, raw goat milk since we owned a goat. I never had any diseases or parasites growing up. Moving to US I was shocked to find out what people actually called milk.
I can't say much about milk's effect on bones but I can say that drinking milk in the US is a bad idea.
There's several studies on the ever decreasing girls' age when they hit puberty and I'm confident that it is linked to the processed foods , milk, and growth hormone treated meats.
Pre pubescent girls 30 years ago looked nothing like they do now.
Sorry for going off tangent.
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Goddamn it, this was meant to be a reply, not a new thread.
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>Hirasawa
Good taste.
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>>8198751
enlighten me
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Hey /sci/, I am extremely interested in learning electronics. Are there any really good and insightful books, YouTube videos, ect. for beginners?
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google.com
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>>8198424
Google led me here
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What kind of electronics do you want to learn? If you are interested in pic related, you should read the relevant chapter in Griffiths' book: Electrodynamics. That'll give a fundamental understanding. If you are interested in practical electronics, don't bother. Hall has a good book, but you may not have the will to read through that thing (it's the best book you'll find, but that doesn't mean I think it is any good). I would advise getting some equipment for tinkering. Learning the theory behind circuits is great, but actually building them afterward is far more rewarding (IMO). Once you know what you don't know, youtube will be super easy to use.
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https://en.wikipedia.org/wiki/Chinese_room
Do i know chinese or not?
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Useless word games. There are no insights to be gained in thought experiments like this, save about the limitations of our language(s). And most do not even make it that far.
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Well its not completely useless. It gives us an insight of how especially the field of psychology and how the avarge man looks at a why humans do why they do. The dualistic split between a) he is speaking chinese, and b) but he does not understand it.
The understanding part part is so broad and nearly not measurble at all.
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>>8198100
what's wrong with this thought experiment?
What is the evolutionary advantage of listening to music?
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>>8196812
what is the evolutionary advantage of not listening to music
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>>8196816
/thread
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>>8196812
There isn't an inherent advantage.
Our enjoyment of music is, however, a consequence of our brains ability to detect patterns, which is evolutionarily advantageous.