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/sci/ - Science, Technology, Engineering, and Mathematics

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New Textbook/Book Request Thread deadbabies ## Mod ## 13/08/25(Sun)06:03 No. 15270 ID: f34135 [Reply] Stickied

File 137740339172.jpg - (401.45KB , 1680x1050 , titanfalsecolor.jpg )

First off, hello there, I'm deadbabies, and I will be taking over as /sci/ moderator. Rules will remain the same. Please use the report function if you see posts that violate the rules, but also do not abuse it.

I have officially expanded the scope of /sci/ a bit. You may discuss Science, Technology, Engineering, and Mathematics here now. No science is discriminated against as long as it's of the peer-reviewed variety. If someone wants to discuss Anthropology or Social Science, by all means, let them. If you do not like it, just don't post in the thread.

The IRC channel #/sci/ is now (finally) re-registered and I am running as operator on here. Feel free to stop by and say hi. I do leave my computer idling on IRC, so check back or leave me a message if you have any ideas, suggestions, or just want to tell me off. You can get onto #/sci/ by joining the server irc.7chan.org at port 6667. You can also use SSL at port 6697 but you will have to set your client to accept invalid certificates.

ADDITIONALLY and IMPORTANTLY I have had several requests on IRC regarding the old Ebook FTP that we used to have. Unfortunately, the mod who ran it entered the military and no longer runs or maintains it. I have no plans to make another one, but if one of you guys would like to, by all means advertise here.

That being said, I'm just going to leave this link here:


You may find what you seek here.

I will be unstickying the old ebook/source articles thread. Please post any new ebooks/source articles here, and feel free to post any working links from the old thread there; I will eventually be deleting it.
Message too long. Click here to view the full text.

14 posts and 2 images omitted. Click Reply to view.
Solutions Manual to E&M, 3rd Edition by Purcell Anonymous 16/11/19(Sat)00:05 No. 16384 ID: 1ae570

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Looking for the the solutions manual to Electricity and Magnetism, 3rd edition by Purcell and Morin. The problems are much more difficult and numerous than in the previous two editions, making it one of the best problem books on the subject. Was able to find the solutions to two analogous books in Classical Mechanics:



Sadly, all my searches for the solutions to the E&M book have been fruitless. It's the last manual that I need to complete my collection.

Homosexuality, could it be an anomaly in brain developement? Dr. Nick Riviera 15/02/05(Thu)04:59 No. 16039 ID: 8ec688 [Reply]

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Hi guys, to begin I just want to make a couple of things clear.

- This thread is NOT about discrimination of homosexuals.
- This thread is NOT about considering homosexuality as disease.
- This thread is for pure scientific discussion.

Well, let me begin by telling you that I'm a med student and a embriology assistant at my university and I'm not a native english speaker, so you may encounter some grammatical errors in the text, but you'll get the point.
This whole dilemma began two weeks ago, when my brother told my family that he is gay. It was quite a shock, not because of the fact of him being gay but because he doesn't fit the gay man stereotype. He's a big dude, loves sports, bearded, the true definition of what some call "manly man". We accepted him, of course, and I have to say I've never seen him happier.
But after a few days I began to think, was he always gay? Did he decided to be gay? Why now? These questions started lingering in my mind. So I went to talk with my him about it.
He told me that he always has been, for as long as he remembers. Nothing has changed about him, except for his sexuality (for us, not for him haha). So that got me even MORE questions. Why are some gay men that are like extremely feminine? Why are some gay women extremely masculine? Why are gay guys like my brother who don't appear to be gay? Why do some gay people feel like they are traped inside the other genders body and need to get medical treatment (sex change surgery, hormone therapy) and why others don't?And why are there women like that too? Why many species, whose main goal is to survive (actually this is every species main goal, it's literally in our DNA), has certain individuals who are the contrary to this?
So I decided to tackle all these matters from a scientific point of view? What if during the development of the lymbic system (the part of the brain which controles emotions, memory, sexual desire, etc.) something doesn't go as it should?
So after I thought of this I told myself I couldn't be the first one to ask myself these questions. And of course I wasn't in a world with 7 billion people so thanks to the magical power of the internet I managed to get a cool text about the subject. I took some paragraphs which I thought were the most interesting, still I'm leaving the link (please don't take the text as discriminatory, it's merely scientific, it refers to homosexuality as an anomaly in brain developement because seen from a medical point of view it is, still doesn't mean it's moraly wrong).

"..the body and the brain first become sexually differentiated at about the third fetal month. Prior to this age, although genetically male or female, the fetus is physically/sexually-neutral. With the formation of the testes, and the secretion of testicular androgen, target ti Message too long. Click here to view the full text.

22 posts and 1 image omitted. Click Reply to view.
Anonymous 17/11/18(Sat)10:06 No. 16577 ID: c33d6a

>gets banned from 4chan for making a homophobic shitpost
>comes here and sees user banned for giving his opinion on a subject

7chan mods confirmed faggots, fuck you


Anonymous 18/01/21(Sun)09:42 No. 16615 ID: 674f65

Totally in accord with you, genetics has a role smaller than op thinks.

Anonymous 18/03/20(Tue)03:00 No. 16636 ID: 5a2853

There is evidence in rodents that there is more male homosexuality when the colony is stressed by crowding. I don't know if it was followed up to see if a similar correlation existed with other stressors (isn't that how u spell it? Stupid program). Anyway this is consistent with the idea that genes that lead to some adults practicing non reproductive sex, especially if they are more manifest in difficult circumstances lead to a higher adult/child ratio which leads to greater reproductive fitness through kinship selection. In essence an ESS like philandering or staying-at-home-and-helping-wifey-take-care-of-the-kids. The more common it is the less advantage in it. So you get an equilibrium. Queer uncles can be valuable. A lot of speculation in there but it is a serious speculation that's been out there for a while and taken seriously by some evolutionary biologists.

Hypothetical Question Anonymous 18/03/08(Thu)15:46 No. 16633 ID: 9469d5 [Reply]

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If I were to throw a paper air plane from northern Texas would the global winds more likely carry it towards Canada or the east coast?

Anonymous 18/03/20(Tue)02:39 No. 16635 ID: 5a2853

If you throw it from a standing position on the ground they will carry it to . . . /me mumbles . . . just a moment while I do some calculation . . . /me mutters . . . Ah, yes, I thought so. To Texas.

Magnetic Particle Inspection Anonymous 18/03/17(Sat)16:37 No. 16634 ID: bf1cc6 [Reply]

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Anybody on this board done any MPI and has experience with different methods. Im newish and want to learn some new ways that are better suited to my work

Is cold air denser than hot air? Anonymous 18/02/27(Tue)19:46 No. 16630 ID: dfa669 [Reply]

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Plz help

Anonymous 18/02/28(Wed)01:07 No. 16631 ID: a5c275

Yes. You would have known that by now: hot air balloons rise due to the warm air being less dense. The molecules in warm air spread out, becoming less dense, conversely, cold air molecules remain close, making it dense.


Anonymous 18/03/02(Fri)04:56 No. 16632 ID: 6914e6

volume = mass / pressure * temperature * constant

If you hold all the variables on the right side but increase the temperature, the volume also increases, and since density = mass / volume, when the volume increases, the density decreases. So an ideal gas under constant pressure becomes less dense as the temperature increases.

Anonymous 17/08/28(Mon)20:04 No. 16539 ID: 269c1e [Reply]

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I'm hoping to return to college and do a second degree in math/a math related subject (ideally Computer Science). Unfortunately, I haven't done math in well over a decade, and when I did math previously it wasn't exactly the highest level math.

Can anyone recommend how I can best learn/re-learn/catch up to college level math and be ready and prepared?

11 posts and 3 images omitted. Click Reply to view.
Anonymous 18/01/22(Mon)00:19 No. 16617 ID: 7332e9

If he’s catching up to college level stuff he has to do highschool math first, best starting with analytic geometry ending somewhere in calculus I or II.
Arithmatic mastery will make the difference between doing well on a timed test, and the discipline from mastering arithmatic when used to master secondary school math concepts will make the difference between getting 80s n 90s vs getting 100s.

Anonymous 18/01/22(Mon)10:08 No. 16618 ID: 2a858b

>the discipline from mastering arithmatic when used to master secondary school math concepts
So please explain how arithmetic helps you solve quadratic equations, or systems of linear equations.
Like, if I need to find the exact roots of f(x) = -sqrt(pi) * x^2 + e*x + 10, how does it help me to know how run a multiplication algorithm by hand?

Anonymous 18/02/09(Fri)23:58 No. 16622 ID: bee93c

which one

start learning about computers Bigattao 16/03/10(Thu)06:19 No. 16297 ID: 00af9a [Reply]

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Hi sci,
I'm a noob about computers and going to do college of Computer Engineering. I don't know even how to start learning. Can somebody give a tip?

10 posts and 2 images omitted. Click Reply to view.
Arduino is a great place to start! Anonymous 16/12/30(Fri)09:26 No. 16404 ID: 01d2f8

Code academy and cybrary are pretty helpful sites but I really learned a lot building and programming little projects with the arduino mega2560. Jeremy Blum has some great tutorials on you tube to get you started. Also building raspberry pi projects is a great way to get your feet wet. Best of luck to you.

Nooby Anon 17/01/07(Sat)07:51 No. 16408 ID: 122f98

Also use Udemy if you have a little bit of money their courses are very informative and useful. Also very good for Python beginner courses.

Good luck bro

Anonymous 18/02/01(Thu)04:53 No. 16621 ID: fcbe0a

how good is cybrary? been told it's a meme and not too good

Overrated robot threat Anonymous 17/12/01(Fri)00:40 No. 16587 ID: e4210a [Reply]

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So I've read the n:th alarmist article about how robots will replace some 800 M people before 2030 and so fucking on. It will be an endless summer citizen's wage afternoon until the AI exterminates us and so fucking on.

Tell you why this is not going to happen?

3 posts and 1 image omitted. Click Reply to view.
Anonymous 17/12/01(Fri)13:49 No. 16594 ID: e4210a

Easier, maybe. The wage is a strict union question. Maybe we have to re-assume a lot of things. The post-WW2 economy was founded on the assumption that there would be an constant growth. Then the financial markets got de-regulated and the financial sector grew too large. That was some 40 years ago and the unions haven't still caught up.

And another thing the unions have to catch up is the introduction of computers. I don't recall the name, but there was a french sociologist who in the 70-s warned that computerization would change the work. Back then computers was magic boxes that no one cared about.

Anonymous 18/01/20(Sat)22:51 No. 16614 ID: 7332e9

that would be relevant if he was doing college level math
but hes not
hes catching up to college level math
hes doing highschool analytic geometry and precalculus and basic calculus.

Anonymous 18/01/30(Tue)01:35 No. 16620 ID: a2a9aa

The idea of people losing jobs to machines is nothing new, it's when the machines appreciate the concept of currency that you will have a problem.

Calculus help? Anonymous 17/09/28(Thu)18:49 No. 16553 ID: ebea66 [Reply]

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Hey guys, quick noob math question if I may.. in the picture i posted you see the equation y-1=(-1/2)(x-(-4))

Its then simplified to 2y -2 = -x-4
And then again to 2y+x+2=0

..my question is could someone breakdown the simplifying into steps? Im not sure the process they used to arrive at their final answer

1 post omitted. Click Reply to view.
Anonymous 17/09/30(Sat)03:24 No. 16555 ID: 012486

y - 1 = (-1/2)(x - (-4))
(y - 1)2 = 2(-1/2)(x - (-4))
2y - 2 = (-2/2)(x - (-4))
2y - 2 = (-1)(x - (-4))
2y - 2 = -x + (-4)
2y - 2 = -x - 4
2y - 2 - (-x - 4) = -x - 4 - (-x - 4)
2y - 2 + x + 4 = 0
2y + x + 2 = 0

Anonymous 17/11/25(Sat)02:28 No. 16583 ID: 4b785f

This ain't no gawt daing calcuebutts!

Anonymous 18/01/21(Sun)17:25 No. 16616 ID: 10df8c

This isn't even calculus. This is very basic week 1 algebra, and I recommend revisiting it before you attempt "calculus".
The first step was that they distributed the -(1/2) term across the right hand side of the equation and then multiplied the entire equation by 2. Then they simply brought all terms to one side to set the equation equal to zero.

Earth Hole Anonymous 17/01/05(Thu)16:26 No. 16406 ID: 4318e8 [Reply]

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Hello /sci/. If there was a giant hole in the earth leading from one end to the other and- if you jumped in- would you just be pulled to the other side, or just be trapped in the middle by gravity?
>Pic unrelated

4 posts omitted. Click Reply to view.
Anonymous 17/07/18(Tue)15:21 No. 16528 ID: 9eed6d

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You would bounce a view times around the center just like in that star wars spoof scene- like a jojo or what that crap is called...

Anonymous 17/11/10(Fri)21:43 No. 16576 ID: ea535a

you would be trapped like a spring

Anonymous 18/01/12(Fri)09:30 No. 16612 ID: 42dc73

>people still doesn't know how gravity doesn't work

If there was a hole like that then the planet would just merge back into a ball because o gravity. Let's say it doesn't then it means the whole planet somehow lost a lot of mass which means that the planet is going to fall to you because your gravity pulls it to you.

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