Quadratic Formula on the TI-82/83/83plus (and maybe other TI's)

This program solves equations of the form Ax^2 + Bx + C = 0 using the quadratic formula.   What is typed in the start column is what should be on each line of your calculator program.   This is a detailed program that gives a very understandable response.   Shorter versions are available on the internet.   Information between { } is not put in the calculator.   Note that you press PRGM, even though you are in PRGM all along, to find certain key words.

To begin, press PRGM, arrow over to NEW, Press ENTER.   I recommend naming this AQUAD so it is always first in your list.   Press 2nd Green (alpha) to keep alpha on until done spelling things out.   Press 2nd Quit to save and exit your programming.   Use normal symbols for divide (/) and multiply ( *) and subtract ( - ).   Be sure to use the negative in front of B rather than subtract.

Start                                           Help

Prompt A,B,C

{Prompt is found in PRGM in the I/O Menu}{comma is a white key right of x^ 2}

(B^2-4*A *C) -->D

{The arrow is STO which is in the left column}

If D<0

{If is found with PRGM in the CTL Menu}{< is found at the bottom of catalog which is 2 nd 0}

Then

{Then is found with PRGM in the CTL Menu }

Disp “NO REAL SOLNS”

{Disp is found in PRGM in the I/O Menu }{space is a weird green bracket over 0}{Quotes are needed, they are above +}

Goto 1

{Goto is found with PRGM in the CTL Menu}

Else

{Else is found with PRGM in the CTL Menu }

((-B+ sq rt D))/(2 *A)) -->E

{Use the square root symbol for "sq rt"}

((-B- sq rt D))/(2 *A)) -->F

{Use the square root symbol for "sq rt" }

Disp “SOLNS ARE”,E,F

{Disp, quotes, and space are all described above}

Lbl 1

{Lbl is found with PRGM in the CTL Menu}{Don't forget 1}

To test your program press PRGM, arrow to your program and press ENTER twice.   The program will prompt you for A, B, C.   Press ENTER   after each one.

Good test values:   A = 2, B = 3, C = 4.   Your answer should be NO REAL SOLNS

And A = 5, B = 4, C = - 2.   Your answer should be 0.3483314 and – 1.1483314.

Note:   If you accidentally create a program you want to delete press 2 nd Mem {the + key}, then 2 {delete}, 7 (prgm), then arrow to its name and press ENTER.