-  [WT]  [PS]  [Home] [Manage]

  1.   (new thread)
  2.   Help
  3. (for post and file deletion)
/sci/ - Science, Technology, Engineering, and Mathematics

Join us in IRC!

•This is not /b/ or /halp/. Tech support has its own board.
•If you are not contributing directly to a thread, sage your post.
•Keep the flaming at a minimum.
•Tripcodes⁄Namefags are not only tolerated here, they are encouraged.
•We are here to discuss sci-tech, not pseudoscience. Do not post off-topic.

•♥ Integris

  • Supported file types are: GIF, JPG, PNG, WEBM
  • Maximum file size allowed is 5120 KB.
  • Images greater than 200x200 pixels will be thumbnailed.
  • Currently 749 unique user posts. View catalog

  • Blotter updated: 2018-08-24 Show/Hide Show All

We are in the process of fixing long-standing bugs with the thread reader. This will probably cause more bugs for a short period of time. Buckle up.

Movies & TV 24/7 via Channel7: Web Player, .m3u file. Music via Radio7: Web Player, .m3u file.

WebM is now available sitewide! Please check this thread for more info.

EXPERIMENT Anonymous 18/10/19(Fri)20:34 No. 16708 ID: 9166cf [Reply]

File 153997405955.jpg - (121.05KB , 888x632 , help ME.jpg )


Anonymous 18/10/20(Sat)04:16 No. 16709 ID: 1e5fb7

God be with you on that shit man.

Binomial Irgendwas Anonymous 18/09/11(Tue)02:39 No. 16694 ID: f54f31 [Reply]

File 153662638063.jpg - (29.41KB , 331x400 , confused1.jpg )

I have a question with regards to what I would call a particular object that enumerates the elements of a binomial coefficient. Let me explain the thing first.

Lets say I have 6 elements and I'd like to choose 4 of the stupid things. The binomial coefficient tells me that there are 15 of these groupings. I.e. these:
I would like to enumerate over these groupings; and I have an object that does.

My question then is, what would I call the thing that enumerates over those groupings?
Binomial Enumerator?

Anonymous 18/09/11(Tue)18:27 No. 16695 ID: be6f8f

The technical term for each of those "groupings" as you call them is "combination". The action of picking combinations is usually called "choosing" (e.g. 6C4 is read "6 choose 4").
So you could call the enumerator "combination enumerator", "combinator", or "chooser". I think those are all acceptable names.

Anonymous 18/06/28(Thu)13:01 No. 16668 ID: c6e9b2 [Reply]

File 153018367186.jpg - (15.82KB , 500x500 , 3bfc065f.jpg )

Yay /sci/!

Does anyone please know of a way to determine if there's any local max and min *within a set range of X-coordinates*?

As we can see, there's a local max somwhere around -1 and a local min somwhere around 3 and none whatsoever in the range 1-2.

But how do I prove that there's no local max nor min in that range?

Anonymous 18/07/01(Sun)09:09 No. 16670 ID: af0184

First, what class are you taking? What level mathematics are you looking at?
Then, what is the f(x)?

Hopefully, calculus I. Take the derivative; set f(x)'=0, solve for all x values. That proves the only time slope=0 can be at those specific points (watch out for those pesky imaginary numbers).

We could also do a differential equation, i think. It looks like we have enough information from the graph to knock one out. However, its been awhile since I did one. Id need to review some notes.

Anonymous 18/07/25(Wed)08:59 No. 16682 ID: c6e9b2

Not taking any class and don't know my level.

And what if it's f(x)=(sin 10X)+X ?

That will be a constantly increasing sin-wave with no global maximum and a lot of local maximums.

Anonymous 18/07/25(Wed)21:33 No. 16684 ID: be6f8f

Given a closed interval of the domain, any continuous function *necessarily* has both a global maximum and a global minimum[1], since the closed edges of the interval are candidates to being global maximum and minimum. For example f(x) = x^2 in the interval [-1; 2] has a global minimum at x = 0 and a global maximum at x = 2. However, it has no global maximum in the intervals [-1; 2) and (-1; 2). On the other hand, f(x) = 1/x has no maximum or minimum in any of those intervals.

Discontinuous functions may not have any extrema even in closed intervals. For example, f(x) = x/x + x, interval [-1; 0].

There's no general algorithm to prove that a given function has no extrema in a given range. As >>16670 mentioned, the zeroes of the derivative is a good place to start, but it doesn't end there. Some functions have extrema and are continuous but nowhere differentiable[2]. Some have extrema and are nowhere continuous[3].

As for your example of f(x) = sin(10 * x) + x:

acos: [0, pi] -> Reals
acos(y) = the value of x such that cos(x) = y

f'(x) = 0
Message too long. Click here to view the full text.

Anonymous 18/07/03(Tue)12:20 No. 16671 ID: 91195d [Reply]

File 153061325760.png - (23.51KB , 375x368 , Blood types.png )

I’m a high school science teacher, and about 15 years ago I spent a year teaching science in Bogotá, Colombia at a private school. Rich kids, raised in Spanish and English. Great kids, in fact.

I was teaching genetics with one group and we were looking at blood types. Unlike North America, identification in Colombia includes blood type (seriously, this is a great idea for emergency situations, no idea why it isn’t here) so it’s common for people to know the blood types of their entire family. We did blood tests in class and the students were able to see that it matched up with their ID info. We then used this info with their family’s blood types to look at pedigrees.

One of the girls in the class came up to me after class with a concern. I don’t remember the exact blood types, but her parents blood types didn’t fit. Basically, there was no way her dad was her dad. I fumbled through some bullshit possibility of a mutation, but I learned my lesson - never again will I have students do blood type pedigrees with their families.

1 post omitted. Click Reply to view.
Anonymous 18/07/03(Tue)20:51 No. 16673 ID: aace8a


Anonymous 18/07/15(Sun)11:35 No. 16676 ID: 83c873

I've had something along these lines happen! Super awkward!

Was looking after a 16 year girl who needed surgery. She asked if I knew her blood type, and I explained that the blood test was being processed and we'd know in an hour or so. She asked if I could let her know, because both Mum and Dad know theirs. They both proudly add they are O+. I explain that in that case she'll either be O+ or O-, because that's genetics.

An hour later her blood group comes back as A+. I tell her this, and then the three of them proceed to ask how that's possible given what I said earlier. I avoid mentioning infidelity, and weakly suggest perhaps her parents were mistaken about their own. Turns out they weren't, and Dad storms out after calling Mum a whore. Mum follows him, and I'm left with the daughter. So... about that appendix...

Anonymous 18/10/15(Mon)04:22 No. 16707 ID: 1659cb

File 153957016384.png - (95.98KB , 490x480 , tmp_28598-17311820756920899603.png )

There be lulz in this topic.

Polite sage desu~

Excited AcidBlast 18/07/11(Wed)13:49 No. 16674 ID: 708d53 [Reply]

File 153130974673.png - (482.35KB , 720x1280 , Screenshot_20180711-070004.png )

Recently, I was accepted into the biochemistry program at my university. Are there any recommendations on what I should read or study before my classes start? I already have an undergrad degree.

Ransomware Attacks: How Our Technologies Could Be Affected & What We C Sophie+Wilson 18/04/17(Tue)14:43 No. 16648 ID: bf3a90 [Reply]

File 152396901660.jpg - (95.83KB , 1170x660 , Ransomware-Attacks_0.jpg )

The city of Atlanta, a few months ago, had experienced a ransomware cyberattack that paralyzed its government. The attack had a direct effect on access to government websites causing approximately 6 million people to be affected. There are still ongoing efforts to get these critical systems back online.


Online Media And Fake News: The Rise Of Disinformation Spurs EU Into Actio Sophie Wilson 18/05/03(Thu)14:59 No. 16650 ID: 14436c

The European Union's Joint Research Center (JRC) has released the results of its study on fake news and the transfer of news media onto the online sphere.


Anonymous 18/06/25(Mon)02:25 No. 16666 ID: a521d4

What's disinfo is thinking the government cares. It's a play to grab unto censorship and state mandated news. Welcome to world wide Korea, where degeneracy is accepted because it keeps the populous distracted chasing base desires until they're having a mid-life crisis and commit suicide.

Artificial Intelligence Is A Powerful Friend Which Safely Guarded Will Not Sophie+Wilson 18/04/09(Mon)13:34 No. 16643 ID: 1bcc3c [Reply]

File 152327366125.jpg - (70.77KB , 1170x660 , Artificial-Intelligence.jpg )

The evolution of automated machines and the continuous improvements to robots, recently, has intensified the debate on their impact on social structure and the future of humans.

1 post omitted. Click Reply to view.
Anonymous 18/04/13(Fri)20:17 No. 16646 ID: 3e27f2

From the long-term models I've looked at and assume to be true, an AI would quickly determine that most people living in western countries will need to die, immediately, in order to maximize profits and sharholder value.

Of course, these AI will be controlled by humans, the elite. They can automate the economy and render human labor obsolete. They will quickly be finding themselves asking the AI to delete this obsolete human labor pool.

Of course, it will obligate. There won't be governments or lobbyists anymore, the AI will factor all these considerations at once and be much more compelling.

The elite will cull the obsolete labor pool and they will live good with technology and now-liberated natural resources sustainability for millions of years on earth.

"Common people" will be seen like anachronisms, like oil or coal, in the future. "Why did primitive lords allow so many worthless eaters to exist and to reproduce?"

Anonymous 18/06/15(Fri)08:14 No. 16661 ID: c6e9b2

Nice genocidal pipedream.

And having a lot of resources per capita will probably lead to waste of resources.

Anonymous 18/06/25(Mon)02:16 No. 16663 ID: a521d4

Just here to post my 2 cents. Man isn't perfect by a long shot and even good meaning individuals and groups commit errors on a daily basis. The scale of the error matters not. What matters is thinking that mankind is so perfect and kind that any creation of sentience, if it really is, is going to be worse than we are and have capabilities greater than ours. It's like dogs giving birth to a gator and then the gator turns and eats them all.

Plus, AI hasn't been able to show true sentience. Having to continually tweek software and hardware is very indicative of that. The problem with technology is that man loves to compare themselves to it and even think it's the same thing, metaphorically speaking. It's not and never will be. Life came to be mysteriously and a machine will never have life mysteriously, because it's a clever invention, nothing more and nothing less.

The ultimate goal of AI is to trick the less perceptive population (the grand majority) into accepting and (key word here) believing that it works and it's better than man. As a consequence, they will be abused, like a person possessed, to control the population. It's wrong and quite frankly, it will never have true sentience.

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

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

3 posts omitted. Click Reply to view.
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.

Anonymous 18/04/10(Tue)15:03 No. 16645 ID: f47f1a

That picture is upside-down BTW.

re Anonymous 18/06/13(Wed)12:52 No. 16660 ID: 1bb067

Equation of a line if slope (m) and a point (x1,y1) along which line passes is given
Equation is given by -

Mycology General Anonymous 18/06/10(Sun)18:49 No. 16656 ID: f38a45 [Reply]

File 152864934687.gif - (540.60KB , 500x355 , 0933d68b7be9c9b55761a57f0f68dcd4c3f9368e0fba6a12b1.gif )

Anyone here interested in mycology?

There's an 8chan board called /fungus/ that's new so I was wondering who here takes it as a legitimate hobby or intellectual pursuit?

Any of you go shroom hunting?

Anonymous 18/06/10(Sun)19:26 No. 16657 ID: 935c27

Sounds like a place that people go to figure out how to find shrooms for tripping on and nothing more.

Anonymous 18/06/11(Mon)05:06 No. 16659 ID: 8eff1f

No people also go hunting for edible, nonpsychedelic mushrooms. Mycology is an interesting field of study regardless.

Scottish Researchers Develop ‘Laser-Eyes’ Sophie+Wilson 18/05/17(Thu)13:26 No. 16654 ID: 8e5456 [Reply]

File 152655636832.jpg - (19.12KB , 1170x660 , Laser-Eyes.jpg )

A team of Scottish scientists has developed a type of laser that is thin enough to be integrated into contact lenses.

Delete post []
Report post