Introduction: How to Factor Polynomials on a Graphing Calculator (TI-83 and TI-84)
These instructions will explain step-by-step on how to factor polynomials on a TI-83/TI-84 graphing calculator
Begin by selecting the PRGM button and scroll over to NEW, click ENTER and name the program and then click ENTER. Having the name relate to the formula is always a good idea. (Example: Factors)
Press the PRGM button, scroll once to the right to I/O, scroll down and select ClrHome. Press PRGM again, scroll once to the right to I/O and select Input, then hit 2ND ALPHA and type in “ENTER A:” (use the + to make quotations). After “ENTER A” put a comma followed by the variable A.
Follow the above instructions to create the same input but with “ENTER B” and “ENTER C” You should have 3 sets of inputs at the end of this step. ex - Input “ENTER B:” , B Press ENTER
Press MATH, scroll once to the right and select “gcd(“. Press MATH again, scroll right and select “abs(“. In the of the “abs(“ put your variable A and then close the parenthesis. Repeat these steps for the variable B. For variable C all that is needed is “abs” followed by three sets of parenthesis. After the parenthesis press STO,located above the ON button, which is the store button followed by the variable G. Press ENTER
Select PRGM and select the If statement. Skip a few lines and select a left parenthesis and put the variable G into it. Select 2nd MATH and then select the not equal sign followed by zero and the end of the parenthesis. Press ENTER
Press PRGM and select the Then statement. Press ENTER
Begin with a parenthesis on a new line followed by the variable A divided by variable G and end parenthesis. Then STO the answer with variable A. Press ENTER. Repeat these same steps but with variables B and C. ex - (C/G)->C (To store an answer press STO, it will be followed by an arrow then enter the variable as instructed)
Select PRGM and put End statement after the three above lines in step 7.
Begin with a parenthesis and put variable A multiplied by C followed by a parenthesis. After the parenthesis STO with variable D. Press ENTER.
Select 0 and STO it with variable L. Press ENTER.
Select 1 and STO it with variable J. Press ENTER.
Select PRGM and select the While statement. Begin a parenthesis followed by variable L does not equal(≠) variable B, end with a parenthesis. Press ENTER. ex - While (L x=B)
Begin with a parenthesis followed by variable D divided by variable J. End the parenthesis and STO to variable K. Press ENTER.
Select PRGM and select the If statement. Press the MATH button and scroll once to the right and select fPart( (#4 on the list) followed by a parenthesis then variable K followed by another parenthesis and set that equal to 0 followed by once more parenthesis. ex - If (fPart(K)=0) Press ENTER
Select PRGM and select Then. Press ENTER.
Select variable J and add K to STO variable L. Press ENTER. Select variable J and add 1 to STO variable J. Press ENTER.
Select PRGM and select statement Else. Press ENTER.
Select variable J and add 1 to it followed by STO variable J. Press ENTER.
Select PRGM and select statement END. Repeat this once on a new line. Press ENTER.
Select variable J and subtract by 1 and STO variable J. Press ENTER. Select variable A and STO it to O. Press ENTER.
Press MATH and scroll once to the right to select gcd( (located at the bottom of NUM) followed by abs( which is located at the same spot. After the parenthesis on abs( follow it with variable K. then put a comma followed by abs( with a 0 in the parenthesis. Add two more parenthesis to finish the statement followed by STO variable H. Press ENTER
Begin with a parenthesis followed by variable K divided by variable H followed by a parenthesis and STO with variable K. Press ENTER. Begin with a parenthesis followed by variable O divided by H and STO it to O. Press ENTER
Select gcd( and abs( followed by variable J and end parenthesis. Begin with a comma followed by abs( with variable A followed by two parenthesis and STO it to variable M. Press ENTER.
Begin with a parenthesis followed by variable J divided by M, end parenthesis and STO it to variable J. Press ENTER. Begin with a parenthesis followed by variable A divided by M, end parenthesis and STO it to variable A.
Select 2nd 0 which will bring up the CATALOG and select PlotsOff. Press ENTER. Select CATALOG again and select AxesOff. Press ENTER. CATALOG once again and select ClrDraw. Press ENTER.
This step is for the display of the formula. Select 2nd PRGM and then select Text followed by a parenthesis with the numbers -1,15,0,G,”(,O,”X+”,K,”)(“,A,”X+”,K,”)(“,A,”X+”,J,”)” (You can skip to a new line for each parenthesis to make it cleaner)
To test program press PRGM (make sure EXEC is highlighted) and scroll to your program name and press ENTER.