How to call a Bisect M file.

I was given a M-file with the algorithm for the bisection method and am having issues calling the file correctly.this is some of the code

function [root,fx,ea,iter]=bisect(func,xl,xu,es,maxit,varargin)

% bisect: root location zeroes

% [root,fx,ea,iter]=bisect(func,xl,xu,es,maxit,p1,p2,...):

% uses bisection method to find the root of func

% input:

% func = name of function

% xl, xu = lower and upper guesses

% es = desired relative error (default = 0.0001%)

% maxit = maximum allowable iterations (default = 50)

% p1,p2,... = additional parameters used by func

% output:

% root = real root

% fx = function value at root

% ea = approximate relative error (%)

% iter = number of iterations

I tried the following to call the function

bisect (log(x.^2)-0.7,0.5,2,0.0001,3)

my function is ln(x^2)=0.7,xl=0.5,xu=2....not sure what I'm entering wrong here.

[Geoff Hayes]

John - please describe the issues that you are experiencing. Is there a particular error message raised or are you just getting an incorrect result?

Your function input should be a handle to the function rather than

 log(x.^2)-0.7

Create an anonymous function as

 func = @(x)log(x.^2)-0.7;

and then call bisect as

 bisect(func,0.5,2,0.0001,3)

As well, you may want to include (i.e. attach) your bisect.m file to your question.