Newton’s Method TI-83

1. To enter the Newton’s method program in your calculator:
This is a new program.
NEWTON      Use the letters in white at the upper right of the keys to type the program name.

Formula is X - Y1/Y2; store the result in X

Display X.
Quit programming.
2. To run the program for f(x) = x2 - 4x with derivative f ´(x) = 2x - 4 and initial guess xo = 3:
  1. Enter the function x2 - 4x as Y1 in your grapher.
  2. Enter the derivative 2x - 4 as Y2; return to the home screen
  3. Store the initial guess of 3 in X:  
  4. Run the program: [press the # corresponding to NEWTON] ; the resulting value is the first approximation for the zero.
  5. For each successive iteration, press again. If two successive values are the same, that is the best approximation for the zero that the program will find.