Author Topic: Equation to graph this  (Read 3063 times)

0 Members and 1 Guest are viewing this topic.

Offline Michael_Lee

  • LV9 Veteran (Next: 1337)
  • *********
  • Posts: 1019
  • Rating: +124/-9
    • View Profile
Equation to graph this
« on: December 08, 2011, 08:27:38 pm »
Ok, I feel really stupid for asking this, but what is the name and general form of an equation that would be like one graphed below?  The red line is the graph and the blue lines are two horizontal asymptotes. 

It almost sort of like an inverse tan, but I was wondering if there was another equation that would graph to something similar.
My website: Currently boring.

Projects:
Axe Interpreter
   > Core: Done
   > Memory: Need write code to add constants.
   > Graphics: Rewritten.  Needs to integrate sprites with constants.
   > IO: GetKey done.  Need to add mostly homescreen IO stuff.
Croquette:
   > Stomping bugs
   > Internet version: On hold until I can make my website less boring/broken.

Offline parserp

  • Hero Extraordinaire
  • LV10 31337 u53r (Next: 2000)
  • **********
  • Posts: 1455
  • Rating: +88/-7
  • The King Has Returned
    • View Profile
Re: Equation to graph this
« Reply #1 on: December 08, 2011, 08:30:54 pm »
looks like a logistic function to me.
(1/(1+e^X))
where e is [2nd] [divide]


(but don't graph with zstandard, use zoomfit) :)
« Last Edit: December 08, 2011, 08:34:15 pm by parser padwan »
ticalc.org | Cemetech | TI-Freakware | casiocalc.org

Spoiler For inactive:
Serving an LDS (Mormon) mission from Dec 2014 - Dec 2016

Offline epic7

  • Chopin!
  • LV11 Super Veteran (Next: 3000)
  • ***********
  • Posts: 2200
  • Rating: +135/-8
  • I like robots
    • View Profile
Re: Equation to graph this
« Reply #2 on: December 08, 2011, 08:34:16 pm »
I dont know much about graphs. My attempt failed :P

And using parser's I think instead of
(1/(1+e^X))

-(1/(1+e^X)) makes it go in the right direction even though I have no clue what it really does XD
« Last Edit: December 08, 2011, 08:38:38 pm by epic7 »

Offline parserp

  • Hero Extraordinaire
  • LV10 31337 u53r (Next: 2000)
  • **********
  • Posts: 1455
  • Rating: +88/-7
  • The King Has Returned
    • View Profile
Re: Equation to graph this
« Reply #3 on: December 08, 2011, 08:38:39 pm »
I dont know much about graphs. My attempt failed :P
is it -4+2[sqroot](X+4)  ?
* parser padwan runs
ticalc.org | Cemetech | TI-Freakware | casiocalc.org

Spoiler For inactive:
Serving an LDS (Mormon) mission from Dec 2014 - Dec 2016

Offline epic7

  • Chopin!
  • LV11 Super Veteran (Next: 3000)
  • ***********
  • Posts: 2200
  • Rating: +135/-8
  • I like robots
    • View Profile
Re: Equation to graph this
« Reply #4 on: December 08, 2011, 08:39:47 pm »
No it was
(something)log(x-(something))+(something)
I just randomly guessed since when you said "logistic", I interpreted "use log" for it :P

Offline parserp

  • Hero Extraordinaire
  • LV10 31337 u53r (Next: 2000)
  • **********
  • Posts: 1455
  • Rating: +88/-7
  • The King Has Returned
    • View Profile
Re: Equation to graph this
« Reply #5 on: December 08, 2011, 08:40:32 pm »
No it was
(something)log(x-(something))+(something)
I just randomly guessed since when you said "logistic", I interpreted "use log" for it :P
D:
I was close :P
(compare the 2 graphs)
ticalc.org | Cemetech | TI-Freakware | casiocalc.org

Spoiler For inactive:
Serving an LDS (Mormon) mission from Dec 2014 - Dec 2016

Offline jacobly

  • LV5 Advanced (Next: 300)
  • *****
  • Posts: 205
  • Rating: +161/-1
    • View Profile
Re: Equation to graph this
« Reply #6 on: December 08, 2011, 08:44:54 pm »
I dont know much about graphs. My attempt failed :P

And using parser's I think instead of
(1/(1+e^X))

-(1/(1+e^X)) makes it go in the right direction even though I have no clue what it really does XD

Or 1/(1+e^(-X)), the usual form of the logistic function.
[wikipedia]Logistic function[/wikipedia]

Offline parserp

  • Hero Extraordinaire
  • LV10 31337 u53r (Next: 2000)
  • **********
  • Posts: 1455
  • Rating: +88/-7
  • The King Has Returned
    • View Profile
Re: Equation to graph this
« Reply #7 on: December 08, 2011, 08:46:18 pm »
Yay! I was right!
Can i have a cookie?
...or a post rating?
* parser padwan runs

EDIT: 900th post!
« Last Edit: December 08, 2011, 08:46:37 pm by parser padwan »
ticalc.org | Cemetech | TI-Freakware | casiocalc.org

Spoiler For inactive:
Serving an LDS (Mormon) mission from Dec 2014 - Dec 2016

Offline Michael_Lee

  • LV9 Veteran (Next: 1337)
  • *********
  • Posts: 1019
  • Rating: +124/-9
    • View Profile
Re: Equation to graph this
« Reply #8 on: December 08, 2011, 09:11:55 pm »
looks like a logistic function to me.
(1/(1+e^X))
where e is [2nd] [divide]


(but don't graph with zstandard, use zoomfit) :)

Sweet, a logistic function fits the graph (and makes sense within the context of the problem I'm working with).  Thanks!
My website: Currently boring.

Projects:
Axe Interpreter
   > Core: Done
   > Memory: Need write code to add constants.
   > Graphics: Rewritten.  Needs to integrate sprites with constants.
   > IO: GetKey done.  Need to add mostly homescreen IO stuff.
Croquette:
   > Stomping bugs
   > Internet version: On hold until I can make my website less boring/broken.