The best geometry program!
v.3.1.0

This program started as a small area calculation program, but I kept adding to it. It is mostly about geometry, but is also has algebra and some other things.

It can do the following:
Calculate area
Calculate sides of a triangle
Solve quadratic equations in ax^2+bx+c=0 form, showing work
Partially factor quadratic equations in ax^2+bx+c=0 form, showing work
Find slopes, midpoints, and distance on graphs, including distance and midpoint of 3D graphs
Calculate volume
Calculate intercepts in 2D or 3D
Find parametric equations or display them in a table in 2D and 3D
Graph in 3D!!!, including lines, points, planes, parametric equations, and boxes.
Calculate surface area
FOIL two binomials
Fix problems/restore default settings
Display 228 (maybe less) digits of pi (more available, (I don't know why you would need more) my pi program has 1376. (api.zip))
Factor integers
Simplify/factor square roots (inaccurately)
Tell if a number is prime or a perfect square
Make a Sierpinski triangle (slowly)
Magic 8 ball game (not really a geme)
Arc length
Sector area
Sin(, cos(, and tan( solver

It has over 35 formulas! As far as I know, it is the only 3D graphing program for a TI-83+.

It has over 30 formulas! As far as I know, it is the only 3D graphing program for a TI-83+!

Version 2.3 has redesigned password protection

Please tell me if you find any bugs. [email address goes here (later)]

see the readme.txt file for information about the new password protection

I will make a program that will reset the password and settings lists if they get deleted or changed (they seem to malfunction often.  If you get an error when you run the program (usually at the beginning), you need to resend the lists.

Check for updates often.

Version 3.1 is availible!!! It is completely redesigned to be faster and easier to use (but has few new features - only arc length and 178 more digits of PI).
This is a cool movie.

Download it here (v.3.1.0).
Or download it from TI-Calc.org

Fix your calculator
v.1.0

This program fixes many common and/or mysterious problems your calculator might have. It also gives you the option of deleting all variables including strings and financial variables. Deleting variables alone will save more space than the program itself takes up.

Download it here (v.1.0)
Or download it from TI-Calc.org

1376 digits of pi
v.1.0.1376

This program displays the first 1376 digits of PI on six screens. I don't know if it is 100% accurate.

Download it here (v.1.0.686)
Or download it from TI-Calc.org

Learn to program TI-BASIC
v.1.0

This program teaches you some basics of BASIC programming on a ti-83+. It is not meant to be a complete tutorial. You should also read the programming section in the calculator manual. Don't email me with questions about programming. Three examples are included for output, if/then, and getkey. Email me if you find any bugs.

Download it here (v.1.0)
Or download it from TI-Calc.org

Sin(, Cos(, and Tan( solver
v.1.0

In this program, you select what you want to find and what you want to know, enter the nformation, and you will get the answer and how it was found. This sets the mode to Degrees.

Download it here (v.1.0)
Or download it from TI-Calc.org (not yet available)

Quadratic solving and factoring
v.2.0

This program can: Solve a quadratic equation with the quadratic formula, showing work, and (partially) Factor an equation with product / sum, showing work.

Download it here (v.2.0)
Or download it from TI-Calc.org (not yet available)

Other programs will be available later.