Worksheet for 3/26/2003


  1. Termination conditions: I will provide an example of a function,
     and will proceed to find its root in an iterative fashion.
     Your job: tell me when I should stop.  

     Criterion:  fractional change in estimate is less than 1% 

                 iteration       estimate         fractional change 
              -----------------------------------------------------
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
                             |              |                   
              -----------------------------------------------------



   2.  Practice using functions as arguments.  Write a function called
       "calculate", which should be placed in a source code file called
       "calculate.m".  This should take two input arguments:

                a) the name of a function, written as a "string";
                   that means surrounded by apostrophes, like this:

                          'sqrt'    or    'sin'

                b) a number


       Your program should evaluate the function on the given number,
       and return the result as its output argument.  Thus, if I type

                      calculate('sqrt', 25)

       I should get back 

                      ans =
                             5