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https://sites.google.com/site/scienceandmathguide/
>>
Reminder: /sci/ is for discussing topics pertaining to science and mathematics, not for helping you with your homework or helping you figure out your career path.

If you want advice regarding college/university or your career path, go to /adv/ - Advice.

If you want help with your homework, go to /wsr/ - Worksafe Requests.

Please, please tell me no one on /sci/ actually fell for the "0.999999... = 1" meme.
51 replies omitted. Click here to view.
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>>8109627
Do you even realize the argument you have right there proves 0.999... = 1? Write 0.999... as a summation of fractions and literally plug it into that equation right there.

>>8109416
So you're going to tell me straight faced that decimal expansions are unique? Give me the proof for that and then you'll have a basis for dismantling very well established mathematics
>>
>>8109472
>>8109497
>>8109717
>0.000...1
>An infinite sequence with something after it.
Jesus. Are you even trying?

In any case, this seems like it's obvious shit being over-thought.
The sequence 0.9, 0.99, 0.999, 0.9999, ... obviously converges to 1 as the number of nines goes to infinity. 0.xxx... is notation that signifies the number of x's goes to infinity.
Problem solved: 0.999... = 1
>>
>>8109781
>Do you even realize the argument you have right there proves 0.999... = 1? Write 0.999... as a summation of fractions and literally plug it into that equation right there.
geomtric series doesn't work like that
>>
I honestly can't tell if people agreeing with OP are trolling.
>>
>>8109793
don't you think trolls would target more serious people and issues? and not brilliant /sci/entists who, since they're so quick-minded, would pick up on trolling very quickly?

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I don't believe the world is round. How can you prove the world is round to me?
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>>8108864
apparently there are 200 proofs that the earth is not a ball. Take it or leave it.
https://www.youtube.com/watch?v=h5i_iDyUTCg
>>
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>>8109010
thats assuming that the earth is round.

pic related.

you can scale this down.
Take a flashlight and two salt shakers and place each shaker a foot from each other on a flat surface, like a table.
turn on the flashlight and put the light source over one salt shaker and note the shadow.
then move the light source from one end to the other and note the shadows.
Boom! the table is round!!!!
>>
The earth is flat or a sphere. It's an irregular blob
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>>8109407
assuming thats the curvature, the mathmatics of circumfrence of the earth is wrong and the earth is alot smaller than it really is.

Eyesight curvature at ground level means that the earth is not 25,000 miles in circumference.

your pic can just be explained as vanishing point, horizon perspective.

pic related
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>>8109817
not according to NASA.

Protip
If the mathmatics works in 99% practical applications, then the earth is not round.

http://www.forbes.com/sites/jeffmcmahon/2016/05/29/harvard-scientist-engineers-a-superbug-that-inhales-co2-produces-energy/#4ff2faf05a9d

his month at the University of Chicago, he announced his bug converts sunlight ten times more efficiently than plants.

“Right now we’re making isopropanol, isobutanol, isopentanol,” he said in a lecture to the Energy Policy Institute at Chicago. “These are all alcohols you can burn directly. And it’s coming from hydrogen from split water, and it’s breathing in CO2. That’s what this bug’s doing.”
So over the last 18 months, Nocera worked with biologists from Harvard Medical School to engineer a bacteria called Ralston eutropha to consume hydrogen and CO2 and convert them into adenosine triphosphate (ATP), the energy molecule used by natural organisms. Building on discoveries made earlier by Anthony Sinskey, a professor of microbiology at MIT, they inserted more genes to convert the ATP into alcohol and cause the bacteria to excrete it.
“The proofs just came in yesterday. So you guys are getting it hot off the press,” he said on May 18. “And it’s going to be embargoed in Science, and two weeks from now you’re going to hear a lot.”
A one-liter reactor full of Nocera’s bacteria can capture 500 liters of atmospheric CO2 per day, he said. For every kilowatt hour of energy they produce, they’ll remove 237 liters of CO2 from the air.
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Is this a meme discovery?
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>>8109805
or better we could become space faring and liberate ourselves from these backwards terrestrial problems.
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>>8109809
yes
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>>8109805
>Which is why the hydrogen economy was always just a diversion.
Not really.
The efficiency of Oil -> petrol -> ICE -> Work is godawful. If you're in a situation where battery electric vehicles don't work (no charging, long trips, etc), it makes sense to use a fuel that can be produced from electricity. The issues with the hydrogen economy are transport and handling issues.

>We need clean CO2 neutral electricity first.
We need CO2 neutral electricity, but it doesn't have to come first; we shouldn't try to solve our problems one at a time.
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>>8109816
>We need CO2 neutral electricity, but it doesn't have to come first; we shouldn't try to solve our problems one at a time.
True.

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wtf is this shit?
Can anyone explain what this product log function is? Looked at the Wolfram documentation and don't understand. Can I get a closed form solution for y?
This is kind of fucking me over for an assignment due tomorrow and it's pissing me off.
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>>8109787

It's a special function that was rediscovered every ~10 years until the internet came around.

https://en.wikipedia.org/wiki/Lambert_W_function
https://cs.uwaterloo.ca/research/tr/1993/03/W.pdf
http://arxiv.org/abs/1003.1628

My ears turn towards loud noises automatically like a dog or cat. I can't control it.

Trips me out.

How is this possible? I thought humans lost this ability millions of years ago.
>>
>>8109808

It happens for everyone, though for most it's barely perceptible to the point that you can only pick up electrical signals from the muscles trying to do something.
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>>8109815
Ah I see, it happens mostly when something is behind me or to the side, my ears will go mental.

So lets say you build a flying colony on venus 55 km above the surface and you fall off, how do you die? Assume you are wearing a special acid resistant space suit and have been breathing heliox. Does the wind force kill you before the pressure kills you? Or do you survive the pressure long enough for the heat to cook you?

And just for fun, if you are wearing a magic 150 kg pressure suit, could you survive impact?
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>>8109700
Here is a temperature map of Venus' south pole, temperatures vary by 20 degrees, aka fuck all.

At best you get a chilly 422 C. Oh wait did I say chilly? What I meant to say was hot enough to melt zinc.

So you gonna calculate those cooling requirements or do I need to do that?
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>>8109738
Earth sees 250 deg F variations in temperature.
Mars has both cryogenic and almost room temperature at certain locations at certain times.
A planet's orbital orientation can create freezing north and south pole locations.
Without more study it seems we don't know for sure what the most favorable conditions to be found are at and around the surface of Venus.
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>>8109746
> Here is a temperature map of Venus' south pole, temperatures vary by 20 degrees

That data is produced using the basic thermal emission signature of the outer planet, and indicates primarily the temperature of Venus' dense thick atmosphere.
That temperature map will not accurately describe subsurface temperatures that will be found on the planet.
>>
>>8109760
Venus' atmosphere spins very fucking fast relative to venus's rate of rotation. Venus spins around every 243 days, where as the atmosphere spins around every 4 days. This mixes stuff up and helps keep the temperature nearly homogenous

>>8109777
Yeah, but there's no fucking way that venus' subsurface is gonna be colder than the surface. We are pretty damn sure that Venus has a molten core.
>>
>>8109789
> This mixes stuff up and helps keep the temperature nearly homogenous
Fine, in the atmosphere and outer surface.
200 to 1000 ft BGL at a specially chosen location ?
More difficult to estimate.

Earth has a molten core and it's < 150 deg F below at some locations.

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Is the second example not a set because it's not denoted by a capital letter? This seems silly; it would've been a set in complex analysis or linear algebra; why not in topology?
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>>8109571
>I read the prefaces and I feel like I got a personal student-teacher connection with the author
[math]\operatorname{Autism}~\operatorname{Detected}[/math]
>>
>>8109559
>CS discrete math book detected
>>
I don't even understand the author's argument. Can someone explain his reasoning?
>>
>>8109779
No idea. Let me know if you figure out it.
>>
>>8109779
I'm thinking the author meant to write (1,2,3), or [1,2,3], etc.

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>tfw science cannot ever access or correspond to "reality"
>tfw science is all just stories we make up
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>>8109765
Exactly. Try telling your gf mid sex that she is just a figment of your imagination and see how much longer that lasts.
>>
Proof OP has a very limitted grasp of science and does not belong on this thread, posting his bullshit.
>>
Explain how scientific laws are fairytales
>>
Science can correspond to reality, but we can't know when it does.
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>>8109302
You again? Man, you keep getting lost, let me help you out.

>>>/x/

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Alright /sci/, hear me out.
19, currently sophomore in college
My major is neuroscience.
I'm extremely interested in the field and I'm fairly good at understanding the material currently being taught, but I don't aspire to be a neurologist or any kind of doctor whatsoever. I can settle for a masters or PhD. But I want to start a family and be able to have a family/social life, and I think medical school will make that virtually impossible.

What can I do with my neuroscience major that doesn't require a medical degree?
>>
>>8109546
Your 19, stop being a faggot. If you do well well, get BS when 21/22, MD/DO when 25/26, out of residency 28/29. By that time you'll actually be making a living enough to properly afford a family and be mature enough to care for one. Women will come with the territory, so don't worry about courtship time.
>>
>>8109546
Get a master's and work as a bench scientist in the private industry. Get a PhD and you can go into academia, biotech, pharma, etc.

I just finished my bachelor's and am applying to grad school in Neuroscience. I want to get my PhD and work in the private industry for a good paying job in a cool city.

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Can we get a /sci/ humor thread going again?
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>>8101785
Where can I find the proof for this
>>
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>>8102766
>>8102847
I obviously meant the link you, sorry for that mong pretending to be me.

This is why /sci/ should have IDs
>>
>>8098537

That isn't even calculus, you fuck.
>>
>>8109566
Take general form of polynomial:

sum(i 0 to N) a_i x^i = y

With points on the curve than you can make a system of four equations linear in the coefficients a_i from that form.

If you have 4 points then you can get 4 equations. Thus you can solve for a system with 4 unknowns. The polynomial that would correspond to 4 unknown coefficients here is the cubic.

Likewise if you have 5 points, then you have 5 equations so you can solve for 5 unknowns, i.e. quarctic.

Etc.
>>
>>8109309
>bane in the corner

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what are some degrees that would lead to really high-paying jobs and also allow me to create something innovative and inventive that could serve humanity for the better?
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>>8109502
>>8109238
>>8109068
So Progrmmes Engineering is useless?
>>
>>8109225
Yes, if you can't get into Medicine or Engineering then Accounting or CS is your next bet, thats if you dont want to die starving on the streets.
>>
I want to study biochemistry, but it seems to me that just going with either biology or chemistry will give me more viable options for employment and further education. Am I right or no? because if so I would just go with chemistry, I want to minor in physics too.
>>
>>8109256
What's up with the warning?

Im doing Chem research this summer and will decide if I should transfer for Chem e somewhere but I fail to see how chemistry is not practical and at least decent when it comes to getting gigs. My Chem grad friends are getting jobs. Location specific?
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>>8107856
>wtf is psychometrics
Basically means "g-guys psychology is useful and exact, look, we even deal with numbers".

The other one is at the bump limit

Why is slope-intercept form so popular, and why do we not use the x-intercept instead of the y-intercept?
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I'm currently gonna transfer to a state university in the fall for computer engineering. I was thinking of getting into a trade while going to school. What's a good trade that you guys recommend as I study at a university? Hopefully a trade that won't take too long to learn and isn't expensive. I live in southern california if that makes a difference on trades.
>>
I know that the order of an electric circuit equals the order of the DE that describes its behavior, and the natural response is the solution to the homogeneous DE, while the forced response is the solution to the inhomogeneous DE, but how can I identify which solution is which given only the total solution, and do I know the order of the circuits given the transfer function? I was only told that the forced response 'looks like' the excitation/forcing function, but how much does it have to look like?

Somewhere today I read that the natural response goes to zero as t->inf, is this always true? I've also read that solutions obtained from the transfer function poles are the natural response, what justifies this? And how is the order of a circuit related with the transfer function?
>>
So i'm particularily interested in physics and chemistry (that includes biochem) and maybe even math. I want to study something were new breakthroughs for the future should be made. I that feel that advanced physics like quantum physics is maybe a bit too early for us to focus on, and that maybe we should take care of human problems first instead. Like cures and enhancements.

What's your opinion? Do you know of any studies that are currently undergoing rapid growth?
>>
Where (in which book) can I read about (Riemannian..?) metrics induced by kinetic energy and what do I need to know to actually understand what that means?
>>
How can I memorize the name/term/appearance of +150 structures on +150 preparations before Thursday?

>pic related
is vagina parts

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So we all know the high school textbook explanation of lift is incorrect. It explains that air molecules traveling over a cambered airfoil must travel faster over the top, a larger distance, in order to "meet up" with the molecules traveling along the bottom. This is wrong, as there is no physical principle or rule that necessitates that the molecules must "meet up." Amazing how often this myth is still perpetuated.

Anyway, I know that lift is predominately the result of angle of attack, in accordance with Newton's 3rd law. This is the reason why most aircraft are designed with an angle of incidence (a slight upward angle on the wing relative to the aircraft's longitudinal axis), so that they can fly level while producing enough lift.

However, I also know that a cambered airfoil, such as the one pictured, also produces a slight amount of lift at zero angle of attack as a result of its shape, via Bernouli's principle. My question is why? What causes the air to move faster over the top than bottom at zero AoA, thereby inducing lower pressure on the top than bottom? I haven't really found a straightforward explanation for this online. All resources simply state that air moves faster over the top but not why this particular shape creates this condition. This is what I'm interested in. Anyone have a concise explanation?
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ok mech eng here

the way I like to think about is is there are more atoms / molecules with relative momentum hitting the underside of the wing than are the the top of the wing. A result the forward velocity of the plane. and angle of attack. So the resultant upwards force is due to the m(v1.-v2) cos 0 (OR sine 0 or tan) I can't be bothered thing about if it is cos or sin. This way of thinking means I don't have to worry about Bernoulli etc etc, laminar flow, turbulent flow or why a plane can fly upside down. Stick your hand out side the car window some day , angle it a bit and see it get pushed up.

It's that simple.
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>>8109369
>That depends entirely on the shape of the wing.
Orientation (AoA) is just as important - moreso, really. But yes.
My point was that on most airfoils, including moderately-cambered ones, flow over the bottom surface is still accelerated and suction occurs on both the top and bottom surface at zero (or negative) AoA. For example, the cambered example I posted has overunity v/V and negative Cp from about 5% to 70% of the lower surface. But as you pointed out, it's the imbalance of these pressures that results in net lift, and with a cambered airfoil such imbalance still exists at zero AoA. That's not to say you can't cancel out the lift of a cambered airfoil by pushing it to negative AoA - that you most certainly can do.
>>8109476
Sad but true. Not saying anything about that Anon - his explanation was perfectly passible - but I've been flying since I was 15, and just from being part of the community, it's clear that the prevalence of stupid misconceptions amongst pilots - even professional ones - is outrageous. "Aerodynamics for Naval Aviators" should be mandatory reading for all licensed pilots IMO.
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>>8104626
>there is no physical principle or rule that necessitates that the molecules must "meet up."
horror vacui
>>
>>8108664
>>8108664
>a flat, rigid surface held at an angle to the direction of motion.
That works under a completely different principle

The flat plane you described sort of "pushes" the air downwards

Whereas a wing is being "pulled" by the air

Sails work exactly like wings, so maybe looking at those will help you.
>>
>>8109774
False dichotomy. The principles at work are exactly the same. Both deflect air downwards.

What's the best university in Ontario if I want to get into ChemE?
Also, should I minor in Math or Business?
1 reply omitted. Click here to view.
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>>8109690
/thread
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>>8109668
What are your opinions on Mining Eng?
>>
>>8109718

It's generally a legitimate degree, probably should be done at the University of Alberta (If you're OP and still in Canada). They have the best Mining co-op placements / industry contacts, by far, in Canada.
>>
>>8109690
I know, I'm just gonna take a 5th year because my grades weren't good this year. Do you think i would have a chance at admission if I'm in the 90% range for first semseter the next school year?
>>
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