[a / b / c / d / e / f / g / gif / h / hr / k / m / o / p / r / s / t / u / v / vg / vr / w / wg] [i / ic] [r9k / s4s / vip / qa] [cm / hm / lgbt / y] [3 / aco / adv / an / asp / bant / biz / cgl / ck / co / diy / fa / fit / gd / hc / his / int / jp / lit / mlp / mu / n / news / out / po / pol / qst / sci / soc / sp / tg / toy / trv / tv / vp / wsg / wsr / x] [Settings] [Search] [Mobile] [Home]
Settings Mobile Home
/sci/ - Science & Math

4chan Pass users can bypass this verification. [Learn More] [Login]
  • Please read the Rules and FAQ before posting.
  • Use with [math] tags for inline and [eqn] tags for block equations.
  • Right-click equations to view the source.

05/04/17New trial board added: /bant/ - International/Random
10/04/16New board for 4chan Pass users: /vip/ - Very Important Posts
06/20/16New 4chan Banner Contest with a chance to win a 4chan Pass! See the contest page for details.
[Hide] [Show All]

[Catalog] [Archive]

File: 5_Graph_types-750x456.png (179 KB, 750x456)
179 KB
179 KB PNG
Given a set of vertices, what's the fastest way to find what path they form on a graph?
What algorithm is the fastest for doing that?
>what path they form
What do you mean?
A set of vertices does not define a single path. When you tell someone the car journey you took to get somewhere, you don't tell them the cities you went through in an arbitrary order, do you?

It does however define a set of paths, which (in the case that there is a loop somewhere) is not necessarily finite

So what precisely are you after?
Your pic is pretty misleading.

Undirected means the adjacency matrix is symmetric (i.e. if you mirror around yellow diagonal it's the same matrix)

Directed means it's not necessarily symmetric.

Both types can have various information associated with nodes and/or edges such as labels and weights.

>There are 2 lightbulbs 2 light minutes apart from each other.
>The lightbulbs are set in the beginning to turn off and on every 120 seconds (2 light minutes visually).
>Their clocks are calibrated right next to each other.
>One lightbulb is then moved 2 lightminutes away from a from the other lighbulb.
Once the lightbulbs are 2 light minutes apart, do the lightbulbs stay synchronised?
Even if the lights aren't flashing on an off at the same time visually from your perspective, if you bring them back together, would they match up again?

I'm trying to wrap my head around time dilation and relativity. Any anon help would be great.



The answers from these questions might help illustrate what I'm talking about

If something is 1 light year away, if you model its movement forward in time 1 year relative to your own reference frame, isn't that where it is from a non relative perspective, or higher vantage point/dimension? As in the past is taken out of the way.
15 replies and 1 image omitted. Click here to view.
>observation time and occurrence time
In English we call them coordinate time and proper time.
Is that the correct term in Physics?
This is wrong. In my example, both observation time and occurrence time are coordinate times because they're times an observer records based on their own clock. Occurrence times are the meaningful coordinate times used in relativity, but it's important not to conflate observation times with occurrence times when performing calculations.
Proper time is time elapsed on a clock following the path of interest, and can be calculated by integrating the metric along the path.
Is this correct? This is with the seperate universes just being different reference frames very far apart within the same universe. You can't see the unobservable universe visually because the past is in the way.
Pretty much, yeah. But the reason you can't see the other observable universe isn't that the past is in the way: it's that the light from there hasn't had enough time to reach us yet. Check this out: https://www.youtube.com/watch?v=vIJTwYOZrGU

File: 1022191248.jpg (3.74 MB, 4656x2620)
3.74 MB
3.74 MB JPG
How did you guys do on your Bio 2 labs in college?
We are taking a lab practical on dissected worms, crayfish, fish, pig, heart, brain and livers and im not really sure how im supposed to study this.
We have 40 minutes for the lab practical in which we go around the lab with a paper and name what we see, 20 questions.

Do you think this is easy or hard? Pic related was one of the dissection guides and I'm not really sure whats truly important here


So there are already 21 Tabby Stars found. Using 20 years old data.

File: 32fe.jpg (54 KB, 735x400)
54 KB
I'm taking physical chemistry and want to hang myself, would like to know what my /sci/bros had trouble with so I can distract myself even if just for a little bit.
95 replies and 4 images omitted. Click here to view.
I literally can’t build muscle
Combinatorial Design (Design Theory)
The real analysis series at my school was tough, but I think hardest was numerical analysis for me.
File: 1488587320296.png (257 KB, 832x680)
257 KB
257 KB PNG
Electromechanical Systems

Honestly the subject matter isn't too hard, just the professor was a fucking asshole that made his tests hard as shit with averages in the 40s/50s. Honestly if I wasn't a brainlet and actually put in more effort I could've done well, but I'm a brainlet so I got a B. Some chink got a 100 on each test so honestly no excuse

besides that though, not really. I got a B+ in calc III because I was sleep deprived for the final and forgot to solve an integral that I set up for one of the free response problems, but besides that all As a few A-'s. Engineering isn't hard it's just a lot of work
I think I may be retarded, but Organic Chemistry has thoroughly kicked my ass for a while. Retaking it currently for the fifth time. On the bright side, I am perfectly happy with not pursuing medical school.

File: photo_2019-10-19_11-49-53.jpg (192 KB, 1280x1246)
192 KB
192 KB JPG
Any good book to re-learn math/physics from highschool onwards? my goal is to get to the level of a college graduated on math or something but i need to start from basics
21 replies and 5 images omitted. Click here to view.
good enough
>Calculus: Spivak, Courant, Apostol (he has a more geometric book of a very different flavor as well).

What about Larson, Stewart, etc?
Lang is a meme.
File: z1o5bkxd00q31.jpg (420 KB, 716x659)
420 KB
420 KB JPG
yeah ok mr. passive agressive.
anything Lang
great goy.
engineer tier shit.
I haven't read either of those books, but from what I can see, they aren't as rigorous as the three I mentioned. Granted, calculus books don't need to be that rigorous, but they should help you build mathematical maturity, the ability to understand and integrate increasingly abstract mathematical theorems or proofs. Not to mention, those books are really expensive and go through different editions almost every year with little substantial change. Keep in mind that this is from the perspective of doing mathematics.

File: aputi.png (227 KB, 657x657)
227 KB
227 KB PNG
Guys can you actually burn out your dopamine receptors with masturbation?

And if yes, at how much of a risk do I stand? I usually jack off once every 2 days.
2 replies omitted. Click here to view.
Yeah but can it cause my dopamine receptors to burn out?
Those are rookie numbers
So I'm not a coomer?
Youre a fucking retard
yes, permanently, with no possible way of getting them back

Is this the biggest hoax in all of the sciences?
69 replies and 7 images omitted. Click here to view.
File: deny-everything.png (189 KB, 1280x666)
189 KB
189 KB PNG
grats on being a dumb frog with no argument
No need for argument against someone who denies basic facts.
typing whatever you want without citation is not a fact, friend. so did you get here in 2016 or 2015?
>>11085050 (You)
Happy ?

File: 1528525110486.png (707 KB, 752x620)
707 KB
707 KB PNG
How much debt is a CS degree worth?
37 replies and 5 images omitted. Click here to view.
Possibly true but there is a reason why they change partners often.
And frankly indulging them or not should be careful consideration.
Shut the fuck up, faggot.

from MIT, Harvard, Standford, or CMU?

anywhere else?


the upper end is only if you are disciplined enough to dedicate a significant part of your salary to paying it off
Yeah, it depends on the genetics of the town you're in. Among white Nordic girls she's about a 1 in 20, but her rating goes up if you start comparing her against slavs and italians and shit.
She's not even that good looking. Wtf dude.

File: 1570740960704.jpg (199 KB, 1600x1304)
199 KB
199 KB JPG
I've three days to submit the GRFP applications and I haven't even completed a draft. My fucking school's grad student assistant hasn't given me any revisions or guidance and i reached out to her over a week ago. I'm desperate as shit. Can /sci/ help me with it?
She wants the D op. Sidle on over there and give her a whiff of your Ph.

File: 1571761601790.gif (2.86 MB, 636x357)
2.86 MB
2.86 MB GIF
Assuming this is historical footage, I ask you gentlemen and perhaps one (1) lady of /sci/, how is this possible?

How did the camera move?
And how was the film retrieved from the camera?
23 replies and 2 images omitted. Click here to view.
>how is this possible?
>How did the camera move?
>And how was the film retrieved from the camera?

The state of /sci/
>How did it pop off like that from a few strips of magnesium being lit up underneath it for the special effects.
>16% of Earths gravitational force, 0.1% of thrust provided for a real lift off.
>its le juice guys gud goi xD
File: jewsownmedia.jpg (201 KB, 1024x1011)
201 KB
201 KB JPG

pure coincidence


Read this thread

File: pend.jpg (25 KB, 720x691)
25 KB
Hi /sci/,
Can you please recommend software (preferably free) to make this type of diagram for the purpose of a report?
18 replies and 4 images omitted. Click here to view.
i have used TikZ successfully in e.g. my PhD thesis among other things. it's not TOO hard as long as you know a little bit about TeX and a little general programming too
Is it really that much work though? You work with tikz by using angles and coordinates. I feel like that is pretty efficient/easy for stuff like this. Nodes may be a bit tricky but otherwise I feel like tikz would be a pretty good option.

Then again I'm an autistic fuck who used latex for 2-3 pages long reports for highschool and undergraduate stuff. But seriously, even during my first few reports I never really felt that LaTeX slowed me down much if at all. When doing force diagrams and circuits it was pretty hard to do them with ms word and inkscape, the graphs were almost impossible to get equations in them looking nice, and messing with the fonts and stuff for consistency was very time consuming. For LaTeX, all I had to do was use a plain data file and gnuplot or pgfplot, and do the drawings in tikz. I honestly believe it saved me time more than anything. Text and math is fast, graphing with gnuplot is actually fairly fast, or using a pgfplot saved preset. Only thing that was extremely annoying at first was tables, and not knowing the mini pages and tabularx, or redfining stuff (could just copy paste from stackoverflow at first).
File: 33-Figure8-1.png (31 KB, 632x566)
31 KB
Obliterates your physics diagram

Ya, actually I change my mind. Just googling "tikz free body diagram pendulum" pretty much gives you the code on stack overflow. All he would have to do is figure out setting it up

File: 1518194078581.jpg (202 KB, 1339x597)
202 KB
202 KB JPG
So, I'm doing some game mechanics calculations for my game to make hp more tied to the size of your body and how much dmg weapons do based on motherfucking kinetic energy in joules, and I'm wondering if you guys could give me a hand figuring out how to do these calculations right. The second won’t get used too much except people who want to custom make weapons, but it’s good to get a base I can work with, for example using those calculations I got the numbers I would have guessed to put for a 9mm dinky pistol: 15 dmg

The calculation for the damage output is something along the lines of the kinetic energy in joules divided by 30 (I based this on how the game has been developed so far, on this site: https://www.hearth.com/talk/threads/physics-calculating-the-impact-of-different-size-axes-mauls-used-for-splitting.1761/
a 4 lb wood axe swung at around 70 mph has about 900 J of kinetic energy, this really isn't accounting for the penetration able to be done by the axe head, but this is a WIP, and the amount of dmg in my game I've given to my character's tomahawks is 30 dmg swung, 25 dmg thrown. Thus with around 900 J of energy in the swung axe I just divided by 30 to get a rough estimate of 30 dmg from 900 J. Like I said, Im not sure the calcs on that website take in account the penetration by the axe head, and my character also is in the future with assumingly futuristic tomahawks that might be more efficient.

Working with that, a 9 mm pistol: from http://wredlich.com/ny/2013/01/projectiles-muzzle-energy-stopping-power/ has about 500 J, divide by 30 is about 15 (rough estimates and rounding are fine for the mechanics of this game btw, easier to keep simple numbers to work with when playing for a decent amount of "simulation").

1 reply and 1 image omitted. Click here to view.
In my experience simple physics, biology, and fantasy games don't go well together.
File: 1549276047415.gif (2.88 MB, 500x500)
2.88 MB
2.88 MB GIF
before bed bump in case someone has some insight
Then I break your game by shooting lots of spit balls with low kinetic energy.
How? With a "normal, baseline human" Speed stat, you could only spit one spitball per turn, and a spitball would do zero damage. If you had a ridiculous, godlike speed stat a spitball barrage would actually be a bit formidable.
nigga im not reading all that shit. what is your question?

File: Snapchat-2128613637.jpg (35 KB, 555x977)
35 KB
Ignore Jjeke

File: .png (3.31 MB, 1256x1624)
3.31 MB
3.31 MB PNG
What do you need to know before Linear Algebra
6 replies omitted. Click here to view.
Nothing. Maybe the field axioms and basic arithmetic / elementary algebra from high school. That’s it.

you can start from basic af algebra knowledge
How to eat a finger is not needed here
addition, subtraction, multiplication, division

Delete Post: [File Only] Style:
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
[Disable Mobile View / Use Desktop Site]

[Enable Mobile View / Use Mobile Site]

All trademarks and copyrights on this page are owned by their respective parties. Images uploaded are the responsibility of the Poster. Comments are owned by the Poster.