Author Topic: Normal lines and a slider  (Read 2258 times)

0 Members and 1 Guest are viewing this topic.

Offline calcdude84se

  • Needs Motivation
  • LV11 Super Veteran (Next: 3000)
  • ***********
  • Posts: 2272
  • Rating: +78/-13
  • Wondering where their free time went...
    • View Profile
Normal lines and a slider
« on: April 14, 2012, 10:04:42 pm »
I'm posting on behalf of HavokDelt on IRC, who doesn't currently have access to a GUI to be able to post. I'm going to pretend it's my problem for easier reading.
So, I want to create a slider that will draw the normal line to a parametric curve at a given time.
My current setup is this: a and b are y and x for the parametric curve, and are defined in terms of t. The variable y and x themselves represent the line. byx represents the slope of the tangent line, calculated as "da/dt*(db/dt)^-1". So, the line is "y=a+byx^-1*(x-b)".
The problem is this: while byx gives the expression for the derivative just fine when t is not defined, when the slider is in use t is given a numeric value. Because of that, a and b are no longer expressions, but values, so da/dt and db/dt are both 0, and byx is undefined.
Now, another calculator I have has an Exchange function that replaces one variable with another, say t with k, and I can use it to make a similar thing work there.
But how can I do this on the Nspire?
"People think computers will keep them from making mistakes. They're wrong. With computers you make mistakes faster."
-Adam Osborne
Spoiler For "PartesOS links":
I'll put it online when it does something.

Offline alberthrocks

  • Moderator
  • LV8 Addict (Next: 1000)
  • ********
  • Posts: 876
  • Rating: +103/-10
    • View Profile
Re: Normal lines and a slider
« Reply #1 on: April 15, 2012, 12:49:51 pm »
Just a quick bump for the Nspire guys to see it, since it has fallen out of the recent posts list. ;)

EDIT: Just to clarify the question above, it's asking about the TI-Nspire CX CAS.
« Last Edit: April 15, 2012, 12:52:36 pm by alberthrocks »
Withgusto Networks Founder and Administrator
Main Server Status:
Backup Server Status: Not available
Backup 2/MC Server Status:

Proud member of ClrHome!

Miss my old signature? Here it is!
Spoiler For Signature:
Alternate "New" IRC post notification bot (Newy) down? Go here to reset it!

Withgusto Networks Founder and Administrator
Main Server Status:
Backup Server Status: Not available
Backup 2/MC Server Status:

Activity remains limited due to busyness from school et al. Sorry! :( Feel free to PM, email, or if you know me well enough, FB me if you have a question/concern. :)

Don't expect me to be online 24/7 until summer. Contact me via FB if you feel it's urgent.

Proud member of ClrHome!

Spoiler For "My Projects! :D":

Computer/Web/IRC Projects:
C______c: 0% done (Doing planning and trying to not forget it :P)
A_____m: 40% done (Need to develop a sophisticated process queue, and a pretty web GUI)
AtomBot v3.0: 0% done (Planning stage, may do a litmus test of developer wants in the future)
IdeaFrenzy: 0% done (Planning and trying to not forget it :P)
wxWabbitemu: 40% done (NEED MOAR FEATURES :P)

Calculator Projects:
M__ C_____ (an A____ _____ clone): 0% done (Need to figure out physics and Axe)
C2I: 0% done (planning, checking the demand for it, and dreaming :P)