How to Write Differentiation Programs for a TI-83 Plus
- 1). Hit the "PGRM" button on your TI-83, move the cursor to "NEW," and hit "ENTER." You will be prompted to name your program. If you are planning to make more than one program (perhaps one for polynomial functions, one for trigonometric functions, and so on), perhaps name it "DERIVE1," otherwise "DERIVE" or any other title that clearly tells you the function of the program. Note that the program name has an eight-character limit. Hit "ENTER" when you're done.
- 2). Write the generalized form of the functions you will be differentiating out on paper. For a polynomial function, you may find that three terms is sufficient or you may want the ability to deal with five or more. A program capable of dealing with functions of 10 terms will work for any number less than this, but will take a long time to use, so only include the number of terms you will need regularly. For a generalized five-term polynomial, write it as, "Ax^F + Bx^G + Cx^H + Dx^I + Ex^J," where each of the coefficients and exponents are unknown.
- 3). Enter the general form of the function into the code as a display. Hit the "PGRM" button again, scroll over to "I/O," and down to "Disp" and hit "ENTER." Then enter, in quotation marks, the complete formula you wrote on paper. This is designed to make your program more user-friendly, by reminding the user the form of the equation whose variables they will prompted to input. Hit "ENTER" for the next line of code.
- 4). Code a prompt for all the necessary variable inputs. Hit "PGRM" and then scroll over to "I/O" again, then down to "Prompt" and hit "ENTER." Enter the first of your variables, A, without quotation marks. Hit "ENTER" for a new line. Repeat this step for each of your prompts, from A to J.
- 5). Enter the derivative of your generalized polynomial as a display. Hit "PGRM," scroll to "I/O" and down to "Disp" and hit "ENTER." Now, without quotation marks, write out the formula:
A*F*x^(F-1) + B*G*x^(G-1) + C*H*x^(H-1) + D*I*x^(I-1) + E*J*x^(J-1).
Hit "ENTER" for a new line and then hit "PGRM," stay on "CTL," scroll down to "Stop" and hit "ENTER." Use 2nd then "QUIT" to exit the program code. - 6). Test your program. Hit "PGRM," then select the name of your program under "EXEC," hit "ENTER," then hit "ENTER" again. Follow the prompts to ensure your program works. Please note that if you are taking the derivative of a polynomial with less than the number of terms in your program, you can enter the coefficient values of unneeded terms as zero at the prompt.
