/sci/ - Science & Math

Hi /sci/,

Does anyone know any homological algebra here?

I was just wondering if anyone could explain intuitively what projective, injective, and flat modules are. Is there any type of geometric reasoning as to why they get those names? I find this subject to be really abstract and unmotivated, so I was hoping for some insight. Thanks.

>>5471922
>derivative of log(e^(sinx)) = sin(x)

I see this mistake all the time with calc 1 freshman and I don't know why this pisses me off so much.

IT'S A GODDAMN IDENTITY NOT THE DERIVATIVE DAMNIT

Same thing with the trig functions, but in the opposite direction.
>"So then what does tan(x) mean?"
>"Oh that's sec^2(x)."

OP, I know this is /Sci/ the smartest board on 4chan but you're a fucking moron for even going to 4chan at all for MEDICAL ADVICE. Think about that then see a doctor.

I love threads like this when all the bio fags come out and troll all the CS/Physics/Chem/Math fags all night long. Makes me glad to be in the Earth Sciences.

/Geofag

>physicians

>>3888021
ummmmmmmmm it's extraneous solution duuuuh that happens wen u hav sqare roots sometimez u no

>>3475598
Mfw my teacher was explaining relative perspective of light
>If you were a photon you would reach your destinations and then see yourself arrive later.

>>2877837

So now your buttravaged because I called your derp response so you come back with this pathetic troll attempt?

>>2432381
>mfw I was referring to grade school, i.e. when most people learn the basics of mathematics (and when it's most crucial to really understand the concepts not just memorizing).

ITT: Kids who don't actually know anything and are good at memorizing words from books suggest society should falsely label passing multiple choice tests are intelligence.

>>2292285
DAT CELLULITE

>>2268411
>Set the species back by hundreds of thousands of years.
>Implying that homo saipens are older than 200,000 years

>MFW I'm in Atlanta
>MFW there's no snow and I read this topic

j^2 = -1 j = ?

My face

>Do this experiment at work
>Have floating rulers, files, pencils, stupid shit everywhere just hanging off of stuff.
>Dumbass co-worker, "Dude! Where did you learn that trick! That shit is so fuckin crazy!"
>"It's just torque man, chill out"
>"Hurr I thought torque made cars go fast..."

My face

ITT: people dont believe in god

>>1599929
>wiki
and you expect me to believe you

>my face when all of your loans and scholarships get canceled because now you're not considered a full time student

http://www.youtube.com/watch?v=nl8lR69K7Zc&feature=related

/sci/

I start math & physics @ U of T in sept.

I know for my physics courses there will be corresponding labs per semester

My best friend didn't get accepted to U of T

so how do I go about picking a good lab partner, because I would like to do well.

>>1074945
>>1074964
>>1074945

>my face when that fucking guido