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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
15270

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:

http://ebookee.org/index.php?tag=7

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.


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Solutions Manual to E&M, 3rd Edition by Purcell Anonymous 16/11/19(Sat)00:05 No. 16384 ID: 1ae570
16384

File 147951030462.jpg - (27.55KB , 406x500 , Purcell 3rd Edition.jpg )

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:

http://bookzz.org/book/2592413/e67f58

http://bookzz.org/book/2592412/fd6171

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.




Bitcoin donation of the 99% 17/12/16(Sat)04:25 No. 16598 ID: 26feca [Reply]
16598

File 151339473385.jpg - (73.41KB , 1024x600 , bitcoin-2643159_1920-34ga3r1e8yry21u4n6d5oq.jpg )

Thats what crypto is for. Helping one another and helping to bank those that are unbanked. Please, give me what you can. It has been a rough couple of months, and I... I don't know if im going to make it for next months rent.



13ebAGdM7TSbyWgbJWx4XZTbJLdkmbpv8X


>>
at wits end of+the+99% 17/12/16(Sat)04:36 No. 16599 ID: 26feca

>>16598

my next months rent, i just need $900 USD more. I don't know what to do, please donate what you can.

This is my hail mary. I promise i will pay you back at least half of the money as soon as i am able.

I'm so tired, and ready to give up.




PUMP DISCORD WOO! Anonymous 17/12/14(Thu)16:04 No. 16597 ID: e4c587 [Reply]
16597

File 15132638439.jpg - (71.49KB , 1080x771 , db71c93efeb74408b23b9bbacc1f0115.jpg )

Making shit go up, ez moneys baby!

https://discord.gg/KKZnkDa




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

File 150394348278.jpg - (28.69KB , 400x300 , bad-math-fotolia-29084487.jpg )

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?


1 post omitted. Click Reply to view.
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Anonymous 17/11/20(Mon)02:44 No. 16581 ID: b65d4e

So I know this is an older post but what the the heck.

Great math review site http://tutorial.math.lamar.edu/
awesome math videos this guy will explain that shit real clear and easy https://www.youtube.com/channel/UCoHhuummRZaIVX7bD4t2czg


>>
Anonymous 17/12/12(Tue)03:43 No. 16595 ID: 7332e9
16595

File 151304659797.gif - (0.97MB , 257x194 , 61821ef33dec6c32319b3fbd85b5869c083ed09fd13937ed22.gif )

My advice is to go through textbooks, and read them like you would an encyclopedia, just a rich conentrated resource full of info. As you read, compile a list of equaitons and concepts that serve as an outline of every major landmark of your learning. The goal of math learning is to wholely understand and to masterfully manipulate if you ask me; if you look at the textbook as a study guide while ytrying to understand each equation/concept it has to offer, you're done. With 80% of your development. Secondly is to drill in these equations and concepts until you feel yo have mastered them to what ever extend satsfies you. For me that means making my own tests and work sheets putting in random numbers and solving until i get some number correct in a row. Here I would say is the 100% mark of your journey in studying math. Then maybe mix and blend some concepts, play around with questions you have about whats posible, basically if you have time and drive, get creative with what youve learned. This is the last 10% of your 110% long journey.
As far as I can say, at that point you're done.

ethos: My passion for math and self taught math skills helped me skip almost two grades. I will major in math at Harvard this fall.

Knowing the source of info like this makes a big difference in how you take it. I once heard that to get better at maths you also need to practice the correct thinking methods and not drill in poor ones, or else you wont get any better. I was lead to belive that is not only futile but counterproductive to practice math unless you already know the correct/best methods for problem solving, orgaization, and avoiding simple mistakes. The unspoken context of this that I missed was that instead of trying desprately to start of your practicing with the correct methods, you should rather reach for perfection, fail, try and fail and try and try again until you find the right method for you (even if it means dirlling through wrong ones). What I shoul have done was tell myself that the advice I heard was directed at people who think that doing math without guiding your methods and mannerisms inorder to get better at it is indeed fruitful when in truth it is not.

I said all this because I want you to succeed in your campaign so I warn you of the dangers of taking advice without critical thinking and context of the advice.


>>
Anonymous 17/12/14(Thu)14:33 No. 16596 ID: f6bd79
16596

File 151325842013.jpg - (9.31KB , 300x225 , th492M0NPH.jpg )

>>16595
If OP has true aspiration for this second degree he'll follow your advice. What you've described is the consummate mathathlete. I like it, find it inspiring, and a hard truth people don't want. They most often want to be just good enough.

If OP wants to be just good enough or just a little above average then I offer this advice that got me through my second degree, BS in Statistics. A degree I got at 36.

First, study everyday uninterrupted for at least 50 minutes. Next start with your foundation using this book amazon dot com/Forgotten-Algebra-third-Barbara-Bleau/dp/B006RIA67G/ . Read it front to back and do every problem. If you have trouble with a chapter plow through it and put it down for the day. If you can come back to it the next day and ace it, then move on. If not repeat until you've mastered the chapter. Once you've finished the book get an algebra text book and take each of the end of chapter tests. This will tell you where you need to go back and shore up your foundation.

Algebra is only part of the foundation. Next get your trig on. For me I had to take a JC course because I needed the hand holding and had never actually studied it. If you've the back ground an approach like I described for algebra may suffice. Regardless approach the material from the simplest chapter 1 concepts and move up as you master each.

With those out of the way it is time to take a calculus class; but not before you buy the book and pass all the diagnostic tests at the beginning to be sure your on solid footing. I am assuming the textbook will be the Calculus Early Transcendental, James Steward. Read it every page up to chapter 1 and master those diagnostic tests before day one of the class.

What I am talking about here is not some JC course or calculus for business majors. A real hard science course at a real university. Invest in a forgotten calculus book from the same series as above. It gives you more problems to work which tend to be simple enough to act as a soft introduction to something you may have had trouble with in class. This is in part because the problems tend to be worked fully enough that you are lost between step 4 and 5 of your proofs. I say this because I got very lucky at this point. I looked up the ISBN for the complete solutions manual and struck gold getting the manual for $1 versus the $1000 it sold for from the publisher. Even if you have to buy an old version and it solution manual as an extra study guide do it.

Finally don't be in a hurry. COMPLETELY understand each concept before trying to build on it. Take 7 pages to write out your proofs until your good enough to get that down to a page. And practice practice practice.

Message too long. Click here to view the full text.




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

File 151208524377.jpg - (54.24KB , 823x540 , 08902844.jpg )

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?


1 post and 1 image omitted. Click Reply to view.
>>
Anonymous 17/12/01(Fri)01:29 No. 16589 ID: 012486

So what you're saying is that instead of 800M jobs going away, 1.6B jobs are going to get much easier, while perhaps paying less?


>>
Anonymous 17/12/01(Fri)04:23 No. 16590 ID: 622297

In order for jobs to be replaced then the cost of hiring a
worker has to exceed the cost of buying and maintaining
an advanced piece of robotics, which isn't going to happen
by 2030 even if they continue to advance at this rate.
A T800 is not fucking cheap.


>>
Anonymous 17/12/01(Fri)13:49 No. 16594 ID: e4210a

>>16589
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.




Difference between instruments playing the same note Anonymous 17/11/30(Thu)16:21 No. 16585 ID: 864454 [Reply]
16585

File 15120552626.jpg - (85.73KB , 1180x613 , rd-2000_hero.jpg )

At the same pitch? I'm trying to create a piece of music from an advert since I cannot seem to pay anyone enough to recreate it as they fear copyright backlash as a piece of production music.

The original track uses several synthetic guitars

https://www.youtube.com/watch?v=_T3skSSt1xU

https://www.youtube.com/watch?v=5mqqj0yfiWM


This is my reasonable attempt :
https://vocaroo.com/i/s1epL4Ex3kBz


I'm an expert at the piano but unfortunately don't really know much about guitars and that's why despite me playing the same notes at the same pitch, it sounds almost entirely different.

Message too long. Click here to view the full text.


>>
Anonymous 17/11/30(Thu)17:03 No. 16586 ID: f9cb15

It's not possible to explain it in analogy to sine waves, because instruments are not sine wave generators. If instruments were capable of producing perfect sine waves at consistent phases, frequencies, and amplitudes then yes, they would all sound the same.

Comparing an electric guitar to a piano:
1. Plucking a string causes it to vibrate differently vs. striking it. For a given pitch, this generates differently shaped "main waves", which itself gives the sound different harmonics. Compare the sound of a piano to that of a harpsichord. The harpsichord has more harmonics.
2. The guitar doesn't have a resonance chamber, nor do its strings vibrate the air directly. Instead it uses electromagnets to measure the distance of a piece of metal several thousand times per second. Because the strings vibrate perpendicularly to the pickups, this adds a non-linear distortion to the wave, which adds harmonics.
3. Certain maneuvers are possible in a guitar but impossible in a piano. For example, a piano is not capable of doing a proper glissando, because it can only produce notes at discrete ranges. A guitar is also able to do tremolo, which I think it's impossible with a piano.
4. Finally, different mechanisms of producing sound cause the attack, decay, sustain, and release phases to have different lengths, which also affects the "feel" of the sound.


>>
Anonymous 17/12/01(Fri)09:22 No. 16593 ID: 0c2267

i think some of your later notes are off
also it will sound slightly different if it's in the context of a chord or if there are other parts playing
i think i phrased that wrong
a phrase will sound different in terms of "mood" or "tone" (not tone as in timbre, etc) if it has accompanying notes
i think i phrased that wrong again
whatever
Also yes the timbre of an instrument and the harmonics/partials will effect how it is perceived
but
it probably shouldn't be so different that it sounds so wrong
try a different register, play higher
check your notes again




creating fake money Anonymous 17/07/25(Tue)16:01 No. 16529 ID: d4675d [Reply]
16529

File 150099130911.jpg - (211.41KB , 1000x588 , day 4 passport.jpg )

Hey guys, want to create counterfit Euros. No, I'm not dumb enough to use them, I want to give them to an unsuspecting victim in exchange for genuine bills.

I have a inkjet printer and scanner. What to do?


>>
Anonymous 17/08/05(Sat)12:16 No. 16533 ID: ff4656

>>16529
kind of go and fuck yourselves... sincerely: everyone.


>>
Anonymous 17/08/05(Sat)12:48 No. 16534 ID: 40ad14

Go ask Interpol.


>>
Anonymous 17/12/01(Fri)08:59 No. 16592 ID: 86f262

You google an image of an euro bill, then print it, repeat the other side. If police stopped you with a bunch of those, i bet you'd get in trouble.




Request: Post HD images of technology Anonymous 17/10/08(Sun)00:10 No. 16561 ID: 864454 [Reply]
16561

File 150741422126.jpg - (105.64KB , 640x966 , OracleExadataExalogic.jpg )

Hey guys, I recently started a computer science class in college and my networking teacher who is the head of the IT department wants us to impress him with the best personalization of our desktops.

> inb4 impress him with your computer programming skills as opposed to flashy images

No anons, No. The motto that he always repeats is that it's important to be "all rounded". He's seen lots of autist computer geeks who are geniuses at what they do but are pretty much mediocre/shit at nearly everything else in their life (social skills, organisation of themselves, writing CV's).

I would like to show off images that highlight an interest in tech along with high quality photography; so if I may ask you kindly to post your favorite images

> I would to the other chan but those fags banned me since June of this year and my shitty ISP hasn't renewed my "dynamic" I.P. address for 4 months.


4 posts and 2 images omitted. Click Reply to view.
>>
Anonymous 17/10/27(Fri)02:12 No. 16569 ID: 43ed39

>>16568
A modern computer is an adult's toy. It is a gateway to entertainment. If the computer is not pleasing to the eye of the user, then its entertaining value will be diminished. Smear a computer with feces, and most people won't even want to use it because it stinks so badly; in this case, the computer's usefulness has dropped to zero.


>>
Anonymous 17/10/27(Fri)16:15 No. 16570 ID: 012486

>>16569
Your entire argument hinges on the premise that a computer must be within eyesight of the user in order for them to use it, which is an undemonstrated assertion. You can always hide an unpleasant computer under a table, inside a cupboard, or even in a different room.

Additionally, this is a non sequitur:
>If the computer is not pleasing to the eye of the user, then its entertaining value will be diminished.
This is like saying that the quality of a movie is affected by the appearance of the theater's entrance.


>>
Anonymous 17/12/01(Fri)08:53 No. 16591 ID: 86f262

personalization of the desktop doesn't sound like a assignment....

if you want to make it personal, you need to take the picture yourself. There is nothing special about a good quality pic from the web.

For offtopic, i second this guy -> >>16570
Offcourse i would choose the ugly powermachine instead of nice looking computer that barely even computes.




Card shuffling problem Anonymous 17/11/26(Sun)11:40 No. 16584 ID: e4210a [Reply]
16584

File 151169285858.jpg - (527.09KB , 1200x1200 , PromotionalDeckOfCardsAndCase572.jpg )

I've got a deck of C cards. I shuffle it and deal D cards.

I shuffle it again and pick two cards at random.

The first card is not to be reshuffled in the second iteration.

The second will be exempt from the reshuffling and be part of the second iteration.

How many iterations will it be before it's a 100% probability of identical results?




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

File 150661734419.jpg - (3.64MB , 4608x3456 , 20170928_124631.jpg )

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


>>
Anonymous 17/09/28(Thu)19:08 No. 16554 ID: ebea66

Oh god the math


>>
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!




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