The Ultimate Quadratic Equation Program

 -- By Philip Shirey (Phil Software)
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=================
Table of Contents
=================
1. Introduction
2. What it does _EXACTLY_
3. How to read the ASCII simplified equation
4. About me (and contact information)
5. To other programmers
6. Boring stuff


[INTRODUCTION]

This program solves for a quadratic equation.  It finds just about
everything about the equation.  It can easily find the vertex, it can
find the roots (where the graph crosses the x-axis), it can tell you if
the parabola opens up or down, it can display the graph (centered on
the screen and everything), and it can display the simplified equation
(as if you would write it using the quadratic formula).

The program is also dummy-proof.  I spent an extra day (and that's a
lot of time to work on a BASIC program) just making sure there was no
way you could crash the program and that all the answers it spits out
are correct.

You may be thinking right now as you're reading this that this is just
another moron writing stupid BASIC math programs to get to the top of
the "Busiest Author" list at ticalc.org.  However, this is not the case
(on the title screen, it states directly that the program was written
for my Honors Algebra teacher during our unit on quadratic equations).
I really think that anybody could benefit from this program.  It is
incredibly easy to use, and it has some [cool] easter eggs as well.

[WHAT IT DOES EXACTLY]

Here is a step-by-step pseudo-code program, showing exactly what this
program does.

[1] Title Screen, waits a few seconds, goes to instructions

[2] Instructions.  Hit Enter.

[3] You'll see A=? on your screen.  Type the value for A and hit enter.
    Do the same for the values of B and C.  If A doesn't equal zero,
    it goes onto the first information screen (4).

[4] Displays the X and Y values of the vertex and which direction the
    parabola opens.  Hit Enter.

[5] Displays the Y-intercept and X-intercepts.
    Hit 2nd to directly jump to the graph (7) or hit Enter to go to
    the equation (6)

[6] Displays the equation in ASCII mode (see far below for explanation)
    If the equation doesn't fit on the screen, then it says
    "EQUATION DOESN'T FIT ON SCREEN".  Either way, hit Enter.

[7] Displays the graph of the equation.
    Hit Y= for a very odd surprise ;-) (Hit any key to stop it and go
    back to the graph.--Good for teachers)
    Hit 2nd to directly end the program
    Hit Enter to go back to (3), the input of A, B, and C
    Hit any other key to see a logo animation (8)

[8] Displays a cute little logo animation and ends the program.


[HOW TO READ THE ASCII SIMPLIFIED EQUATION]

When reading the X-intercepts, more often than not, they're some
irrational number.  You also have the option of viewing a simplified
equation for these numbers (using the quadratic formula).  This is much
better for students who don't want to do the work and need to see a
simplified equation (I still suggest you do the work yourself... this
is better for... checking your answers, hehe).  As with many of my
programs, it may not make immedieate sense.  That's what this is here
for.
Let's start off with an example.  If I say A=2, B=8, and C=7, I'll see
something like this:

-8+-2#2   (NOTE: the # (pound) symbol is the square root symbol on the
-------    calculator.  There is no square root symbol in windows, so I
   4       had to subsitute.)

This is a more obvious one... it's supposed to be read as
Negative eight plus or minus two times the square root of two, all over
four.

If there are imaginary numbers involved, you'll see an I.  Here's an
example of that:
A=1 B=2 C=2

-2+-2I
------
  2

This is read as: negative two plus or minus imaginary two all over two.

If the numbers have too many decimal places, or if they're just too
big, then you'll get a safe error message, the calculator will skip
this section, and you'll go directly to the graph.  An example of that
is: A=2.338 B=-.175 C=9876.1

THE EQUATION
CAN'T FIT ON THE
SCREEN.

(NOTE: Equations with lots of decimal places, or overall large numbers
will take a very long time to load.  It's best, in these cases, to
skip the simplified equation if you don't need to see it.

(NOTE: If the X-intercepts on the previous screen are not irrational,
then that means that the ASCII equation isn't 100% simplified, but it
should be obvious in these situations.  The correct simplified form at
these times is X=<first X-intercept> OR X=<other X-intercept>.)

I hope all of this information is helpful to you.

[ABOUT ME]
I am 14 years old and I love math and programming.  My e-mail address
is no_one_20000@yahoo.com.  You can find some of my other programs
at http://www.ticalc.org/archives/files/authors/52/5283.html
This program was written on March 03, 2003.
If you found any errors in my program (I doubt you will), or if you
have any suggestions, then just e-mail me :)

[TO OTHER PROGRAMMERS]
Feel free to edit my program in any way.  Sorry, but the source is
slightly hard to read.  If you have any questions, just e-mail me.
You may use some of my code in any of your own programs, but if you're
going to distrubute it on the internet, then please, give me a little
credit for the code in the documentation or program.  Thanks!

[BORING STUFF]
I attempted to write a program very similar to this about three months
ago.  It really stunk, except its detailed on-calc explanation of what
a the quadratic formula represented and all that of that information.

History for this program:
v1.1 - Classroom release, all it did was display the vertex
v1.2 - Added wheter the parabola opened up or down
v1.3 - Added Y-intercepts and X-intercepts
v1.4 - Classroom release, Added graph, title screen, and "easter eggs"
v1.5 - Classroom release, Added simplified quadratic formula; buggy
v1.6 - Fixed some errors
v1.7 - Added better control over program and fixed more errors
v1.8 - Internet Release, fixed bug-proof leaks (Current Version)
     - Starting TI-83/+/se versions (2150 bytes)

Special thanks to:

Me          - For writing the program
Mr. Feldman - For teaching me all the stuff I didn't know about
              quadratic equations
My Friends  - For testing the program and sending to everybody in my
              Alg class (I get popularity quickly)
ticalc.org  - For adding this program to their archives (hopefully) :)
              AND for being the best internet resource on TI programs

NO thanks to:

The bullies at my school
The people who tried to steal my calculators
Anybody who got on the computer when I wanted on
Anybody who said that I was unintelligent



That's it!






P.S If any information in this documentation is wrong... TELL ME!