Fucking Calculus...

Any of you guys know anything about calculus? I'm having a lot of trouble figuring out logistic growth models- among other things.

inb4NEEEEEEEEEEEEEEEEEEEEEEEEEEEEEERDS!

http://lmgtfy.com/?q=logistic+growth+models

angrywhiteguy wrote:

Any of you guys know anything about calculus? I'm having a lot of trouble figuring out logistic growth models- among other things.

inb4NEEEEEEEEEEEEEEEEEEEEEEEEEEEEEERDS!

Lrn2maffs.

Fucking fail you guys. Don't you think I wouldn't have already tried Google? It isn't explaining things for me any better than my text book. And I thought it was already pretty obvious that I'm trying to "lrn2maffs."

Uh, Calculus. I can totally do your calculus. Sort of. Kinda. Maybe. Not at all. But seriously, don't bother asking Catduck for help. He'll get the right answer for you, but he won't tell you how he arrived at that answer.

I think it was something to do with the form:

dP/dt=k/M*P(M-P)

AWG needs to STFU and gb2 work: dP/dt=k/M*P(M-P)
AWG needs to STFU and gb2 work: logistic growth
AWG needs to STFU and gb2 work: cant make heads or tails of the problems using it
The Beard: is that k divided by MP all times (M-P)
The Beard: or is the (M-P) on the bottom?
AWG needs to STFU and gb2 work: k/M times P(M-P)
The Beard: gotcha
The Beard: okay, what are the set variables in the problem?
AWG needs to STFU and gb2 work: natural log comes in somewhere usually
AWG needs to STFU and gb2 work: oh uh
AWG needs to STFU and gb2 work: p?
AWG needs to STFU and gb2 work: idk what set variable is, is that the one that isnt a constant?
The Beard: like which variables did they set values for
The Beard: like in the problem, p = whatever
AWG needs to STFU and gb2 work: heres an example they use
AWG needs to STFU and gb2 work: dP/dt= 0.001p(100-p)
AWG needs to STFU and gb2 work: p(0)=10
AWG needs to STFU and gb2 work: the answer is p= 100/ (1+9e^-0.1t)
AWG needs to STFU and gb2 work: they show some steps, but idk where they get them from
The Beard: hm
The Beard: since they've got dP/dt, i assume they integrate somewhere
AWG needs to STFU and gb2 work: i try to copy the steps directly, but cant figure what goes where
AWG needs to STFU and gb2 work: yeah
AWG needs to STFU and gb2 work: "with respect to t"
The Beard: gah, math books are always retarded
The Beard: they show you how do get from step A to step B
AWG needs to STFU and gb2 work: yes
The Beard: and the problems ask you to get to step E or F
AWG needs to STFU and gb2 work: ill show you the step where they integrate
AWG needs to STFU and gb2 work: ln |p| - ln |100-p| = 0.1t + C
The Beard: that's the result?
AWG needs to STFU and gb2 work: of integration? yes
The Beard: hm
AWG needs to STFU and gb2 work: theres 3 or 4 steps between
The Beard: ln | x | is the integral of 1/x
AWG needs to STFU and gb2 work: this is true
The Beard: so can assume that at some point they have 1/p and 1/100-p
AWG needs to STFU and gb2 work: damnit i should just scan the fuckin page
The Beard: hehe
AWG needs to STFU and gb2 work: this is b4 they integrate
AWG needs to STFU and gb2 work: (1/p + 1/(100-p))dp/dt = 0.1
AWG needs to STFU and gb2 work: do i need to tell all the steps?
The Beard: okay, let me think how they got that
The Beard: from .001p(100-p)
AWG needs to STFU and gb2 work: they had to use "partial fractions" to get there
The Beard: oy gevalt, those bastards
AWG needs to STFU and gb2 work: yes
AWG needs to STFU and gb2 work: idk how the fuck they do it
AWG needs to STFU and gb2 work: but i managed to get that far
The Beard: hrm
AWG needs to STFU and gb2 work: had test yesterday with this
AWG needs to STFU and gb2 work: half the kids just sat there the whole period
The Beard: well .001p(100-p) = .1(1/100)(p)(100-p
The Beard: )
AWG needs to STFU and gb2 work: he lets us finish the next days
AWG needs to STFU and gb2 work: but
The Beard: so (p)(100-p)
The Beard: -------
The Beard: 100
The Beard: that'd be (100p-p^2)/100
The Beard: which is (100p/100)-(p^2/100)
The Beard: which is p - (p^2/100)
AWG needs to STFU and gb2 work: hmm
AWG needs to STFU and gb2 work: i think this may be getting jumbled
The Beard: perhaps
AWG needs to STFU and gb2 work: lol
The Beard: but i think (p)(100-p)/100 is where to start
AWG needs to STFU and gb2 work: XD you may be taking it backwards
The Beard: probably lol
AWG needs to STFU and gb2 work: shouldve just typed more
The Beard: go back in time and kill isaac newton
The Beard: he invented calculus
The Beard: let some other schmuck find gravity again

More math fail, but at least we're trying...

Little more


The Beard: k, formula is Dp/dt = .001(p)(100-p), right?
AWG needs to STFU and gb2 work: ._. i think its amazing how anyone can hold these problems in their head, i cant focus unless i look right at it
AWG needs to STFU and gb2 work: uh
The Beard: heh
AWG needs to STFU and gb2 work: /checks
The Beard: well that's me
The Beard: i remember stuff that will never help me personally
AWG needs to STFU and gb2 work: you remember right
The Beard: cookie
The Beard: anyways
The Beard: if you divide (p)(p-100) over to the other side
The Beard: you get 1/((p)(p-100)) dP/dt = .001
AWG needs to STFU and gb2 work: thats the next step
The Beard: you can integrate the left by parts
AWG needs to STFU and gb2 work: you know what youre doing
The Beard: well that makes me feel better about having my calc final in a week
AWG needs to STFU and gb2 work: but
AWG needs to STFU and gb2 work: when i integrate by parts, it gets too messy to go further
AWG needs to STFU and gb2 work: is there some trick to this?
The Beard: umm
The Beard: cursing Newton to the depths of hell doesn't really move the problem along
The Beard: but it helps psychologically
AWG needs to STFU and gb2 work: NEWTON

Google: Automatic Calculus Solutions.
Lern 2 useh ur interwebz.