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TI-82 & TI-83 Quadratic Equations

This program will solve quadratics with real or imaginary roots.  Answers are given in factored radical form when appropriate and imaginary roots are followed by "i."   Because of the formatting limitations for fractions with the TI-82/83, the -b/2a and the fraction, if any, before the radical are listed separately.  While I don't like this, but I know of no way to prevent it at this time.  The only input required for this program are a, b, and c when prompted. 

DISCLAIMER:  This program is free, and, therefore, I make no claims about it's efficacy, efficiency, or proper operation.  If you find a problem with this program, or can suggest an improvement, please e-mail me at knosummath@aol.com  .

Use of this Program:  You may use this program freely for your own personal use and for the use of other students, but use for publication or any means of profit requires my permission.

Memory Usage:  This version of the program uses 312 bytes of memory. I estimate it will take an inexperienced programmer about 20 minutes to enter by hand.

Revisions:  Version V1.0  Date: 10/13/03.  Version 1.1  Date: 10/2/04




Program Name

Disp "V1.1 FKIZER 050207"

PRGM; I/O; 3
2nd ALPHA (Enter Text)

a +bi


"X="→Str1 Alpha, 2nd, TEST, 1; STO,VARS 7
"AND X="→Str2  

Prompt A, B, C

PRGM;I/O; 2;

B2 -4AC→I  

√(abs (I))→J


round(J,0)® K

MATH; NUM; 2 (for round)

-B/(2A)® X


If K ≠ J




Goto 1



PRGM,  3


PRGM, I/O, 8

√(B2 -4AC)/(2A)→Y


Disp Str1 PRGM;I/O;3;VARS;7;1

Disp (X+Y)►Frac


Disp Str2


Disp (X-Y)►Frac




Goto 3  
Lbl 1  
For (L, K,1,-1)  
If I/L2 =round(I/L2 ,0)  
Goto 2  
End: End  
Lbl 2  
If L<1  
Disp "IF R=",X►Frac  
Disp "AND S=",T►Frac  
Output (5,1, Str1  
Output (5,4, "R+-"  
Output (5,7, "S√("  
Output (5, 10, abs(M)  
Output(5,15, ")"  
If M<0  
Output(5,16, √(-1)  
End: Stop  

The answer to quadratics such as 2x -6x +10 may look a little strange because of the formatting limitations of the TI Calculators.  It will appear like this:

If R =               
AND  S=         
X=  R+- S√(11   )i
In this case, just replace "R" in the last line with 3/2 and S with 1/2 or, better yet, just write the radical over 2.  The extra space in the parentheses is in case the number under the radical has more digits. 


Revised 10/2/04