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Archived threads in /sci/ - Science & Math - 488. page


This is somewhat science related.
>biology

This was in a bottle of Ocean Spray Orange Juice.

Any idea what it is? I didn't think regular molds grow in acidic juices.
17 posts and 3 images submitted.
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Stop leaving your orange juice lying around nigga. Old food is bad for your health
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>>7768928
Shit was in a brand new bottle. I almost swallowed it too. It was hard.
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eewww duude

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why don't they make the subway trains run like this?
15 posts and 2 images submitted.
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>>7768854
What is this, a subway for ants?
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>>7768854
OP are you dumb, why are you posting here?

Why don't you take a 30cm ruler, go to the subway and measure the dimensions of a subway train and google its weight.

Then use that to calculate how much copper coil you'd need to transport that subway train from station to station at a velocity that matches the subway trains' current velocity.

Then calculate the cost of it, it will probably be like... 5 bucks. Really cheap to get copper coil, specially if you use slave labor. And then submit your design to the city council, ask to get 20% of everything the new subway makes and become a zilliobilliomilliofaggotnaire!

DELETE THIS THREAD NOW I BET THAT AHMED MOHAMMED ALREADY STARTED BUILDING IT! IT WILL PROBABLY EVEN HAVE A CLOCK IN IT!
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>>7768854
I actually remember reading a few years back about tests with electromagnets for trains. But idk whatever happened with it, they probably realised that it's a huge meme and would be inefficient.

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If anybody knew this program, then there is something wrong with this equation. Any suggestions to how I'm going to create this graph?
18 posts and 7 images submitted.
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>>7768788
I don't know the program, but should'nt you remove the "y=" ?
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>>7768903
It's MathGV if you look at the title.
I knew that I'll remove the y, but that didn't mattered because the same results are expected.
The only equation that is acceptable is 3cos(4)x but the result of it is a diagonal line. What I need is a wavelength patttern.
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>>7768903
Also that is the original equation, I just put there

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What is the point of trying, or being motivated, or putting in effort, when all life will eventually become extinct and the universe will become a cold, dark, empty abyss?
14 posts and 1 images submitted.
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>>7768784
We don't know that anon, it's all highly speculative. Astrophysics is basically popsci at this point.
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>>7768794
>astrophysics is basically popsci
Somebody sounds jealous that their science has no predictive power over the entire universe.
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>>7768784
Oh don't worry--your consciousness will expire long before that happens.

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how the fuck am i supposed to solve this without being able to use l'Hôpital's??

best i get to is

(lim of x*sqrt(x+1)-sqrt(x)/x^3/2 as x-> 0+)(lim 1/sqrt(x+1)) as x-> 0+)

but first function is indeterminate..
pls help
71 posts and 2 images submitted.
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>>7768583
>when a nigga's this stupid
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>>7768591
:(
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>>7768583
Maybe:

1/sqrt(x) - 1/sqrt(x^2+x)

1/sqrt(x) - 1/[sqrt(x)*sqrt(x+1)]

1/sqrt(x)*[1 - 1/sqrt(x+1)]

The limit of the term in brackets as x approaches 0 is 1

So now you only worry about the first term. And there's no debate about it. Since you can't approach it from 0-, the limit from 0+ is the limit at 0, and that would be infinity. Use logic, make a table of values, whatever you do will give you infinity.

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any medfags here got tips for the MCAT?
14 posts and 1 images submitted.
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Study.
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>>7768447
ya, but you can study like a tard or study high yield
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>>7768452
What do you want people to say? There's been literally mountains of studies on how to properly review. Listen, read, do practice work/tests, covers all your "types of learning". Teaching to others is also effective way to learn. Space your studying over a period of time. Nutrition, exercise, quietness. Flash cards apparently also work quite well.

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According to the general relativity, it's possible to exist the reverse of a black hole, called a white hole, a region of space-time where nothing comes in, just out.
A new theory, first studied by Stephen Hawking suggests that these holes are the cause of the emergence of other universes. As well as ours. The Big Bang is nothing more than that hole ejecting matter from another.
>What do you guys think about white holes? They can really exist?
I've been theorizing the existence of multiple universes before but never thought about a white hole can be the main reason.
23 posts and 7 images submitted.
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Where did the matter that made the first black hole come from.
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If whit holes exist then why do black holes evaporate?
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>>7768409
Wouldn't we have seen one by now?
They should be easier to see than black holes, there are plenty of black holes out there.

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I have a fewcstrange questions... can you smell things you've eaten through your body? Can you smell your blood through your skin?

Yesterday I drank a whole bottle of magnesium citrate(laxative) for fun, and I swear I could smell the diarrhea smell leaking out through by pores. It wasn't from farts, I didn't shit my pants, and when I wiped I used baby wipes to finish the cleaning and I got any splatter that hit my butt cheeks.

I promise I could smell it through my skin. The diarrhea smell.

And there are times when my balls smell like what I've eaten. I heard what you eat effects how your sperm tastes, but apparently it can leak through your skin? Balls have thin skin in particular.

And finally, I've smelled my skin and it smelled like blood. A coppery smell.

Now, I have sat on making this thread long enough. I've made sure my hands and skin were clean. I've done this enough times.


Is this normal? Being able to smell your own BLOOD though your skin?
14 posts and 3 images submitted.
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A more interesting question is why some things are odorless at all
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the only way to smell something is if it's vaporized in a gas medium. you can smell things youve eaten because its evaporating off your body through sweat into the air.

anything that has a taste will have a smell if its vaporized and small enough molecule.
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>>7768389

The theory is it's a survival mechanism.

For example, if the taste of water was stronger than it's contaminants, it would be harder for you to detect contaminated water.

If the smell of air overpowered the smell of animals, it would make it harder for predators to hunt and harder for prey to smell predators.

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Any of you have experience grading undergraduate courses before? I just got offered a position to grade an undergrad CS course and I was wondering if you guys had any experiences doing this kind of stuff.

Teaching experiences/thoughts/horror stories thread?
14 posts and 1 images submitted.
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>>7768351
Sounds fucking awful.
Grading is the worst part of being a teacher.
Hence why them niggas is outsourcing it to poor students.
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>>7768351
Uh... you just grade homework and tests for minimum wage... Do you really need advice on this?
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>>7768356
>>7768359
Well it's not entirely grading. I have to hold office hours too. But I get to charge the department for the office hours every week and report my own hours grading so it's 2-18hr/week at $10.25/hr. That's pretty good for a part time job student job IMO, especially since it will help me not forget the material.

Is it really that bad of a job? I was hoping it would be easy. I'm most worried about students arguing with me about grades since most of them will be around my age or older

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I'm in talks with two professors regarding my PhD studies. I have noone to ask so I'll post here

1. Detection of drones using passive antennae -- the basic idea is to observe disturbances in the EM fields of routers and such, and to try to guess what kind of object causes the disturbance. Basically all computational physics
Pros :

Super helpful guy and has good connections
I think this topic would be useful when looking for a job later

2. Trying to find and detect new terms in heat conduction effects.
So this one is tricky, because I feel like if people havent come by these effects, they might not be really important from a practical point of view, but

1. guy is also enthusiastic, if somewhat less so than the first one
2. really interesting topic
3. Has experimental, theoretical and computational elements.

Any opinions to share?
15 posts and 3 images submitted.
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Learn proper communication skills and then come back and try your post again.
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>>7768243
The second one seems less risky. You don't want to still be in grad-school in your 30s and there's so much that could go wrong with 1.
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>>7768243
1 is legitimately interesting and I'm a layman

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>"the proof of this important theorem is left as an exercise for the reader"
11 posts and 3 images submitted.
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>f'(x) instead of df/dx
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>>7768204
f' is just the "name" of the function obtained by taking the derivative. The real travesty is that you don't seem to understand the difference between a function evaluated at x and a function.
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>>7768204
>df/dx
>Not [math] D _ x ^ 1 f(x)[/math]

Plebius Maximus

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Is there a specific way to find out if a matrix's rank depends on a variable inside said matrix?
In this example I've just been trying to replace beta (alpha being any value) with random values until I get the rank down to 2.
15 posts and 1 images submitted.
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Use GauB
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>>7767966
Even after Gauss it's hard to get to a conclusion, unless I'm doing it wrong.
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>>7767964
The rank of a matrix is equal to the size of the biggest non zero determinant you can calculate from it.

That matrix already has got at least two as rank, since it has a non zero 2x2 size determinant. To test if its rank is three, simply calculate the bigger determinant possible, which is the unique of size 3x3.

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the only possible way to travel to another planet or extraterrestrial planet is to invent a transport that can travel at lightning speed
when will human be able to do that ?
11 posts and 1 images submitted.
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Actually, we are NOT part of the virgo supercluster but the Laniakea Supercluster.

https://www.youtube.com/watch?v=rENyyRwxpHo
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>>7767918
why did God created another solar system where it is beyond human reach ?
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>>7767918
even travelling at the speed of light would be slow as fuck. and imagine how long it would take to accelerate to that speed and what kind of long term effects the g's would have. we'd have to be suspended.

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Is this a thing already?

I call it pipe theory, or fat-graph theory. Its 1 dimension up from normal, 'thin' graph theory. As seen in 1a, the vertices become 2D smooth, non intersecting curves, and the edges become surfaces with boundaries only on the curves in 1b. All the fat graphs drew here are 'volumetric' graphs, the equivalent of planar thin graphs. meaning the surfaces do not intersect each other. The process of 'fattening up' a planar graph to a volumetric is however not just redrawing all the lines as surfaces, as seen in 3, fattening up a thin graph requires a different configuration than the thin graph to make the graph representation volumetric.

I have shown in 4 that any planar thin graph can be fattened up by rotating the graph around a vector not intersecting the graph.

I have a conjecture that i have not been able to prove. First lets define some termsWhen you thin down a fat graph, you get the corresponding thin graph A volumetric fat graph is 'genetically fat' if they can not be thinned down. My conjecture is that no genetically fat graphs exists.

Another conjecture is that the number of volumes separated by surfaces in a fat graph is equal to the number of areas separated by edges in the thinned down graph (given by Eulers formula)

The stronger form of the conjectures is that all of fat-graph theory is equivalent to graph theory on the thinned down graphs, in other words, this new fields yields nothing new to mathematics.

Anyone wiling to help me prove this?
14 posts and 1 images submitted.
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>amerimath
>>
Neato. I'll look at this later.
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Formalize it and come back.
You didn't even bother drawing the pics in a way that shows what's in the fore-and background.

The chance that the questions are not questions of homotopy and homology theory is practically zero.

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we're all turing machines.

prove me wrong.
30 posts and 5 images submitted.
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>>7767881
stop using words you don't understand, idiot
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>>7767885
Protip: You can't.
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>>7767881
almost.
Turing is basically related to infinite sets and we're not.
Yet, in practical engineering, yeah, we are, so what.

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